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58<p class="text-center"><a href="command-line-options.html#adaptive-blur">‑adaptive‑blur</a> <span class="bull"> • </span> <a href="command-line-options.html#adaptive-resize">‑adaptive‑resize</a> <span class="bull"> • </span> <a href="command-line-options.html#adaptive-sharpen">‑adaptive‑sharpen</a> <span class="bull"> • </span> <a href="command-line-options.html#adjoin">‑adjoin</a> <span class="bull"> • </span> <a href="command-line-options.html#affine">‑affine</a> <span class="bull"> • </span> <a href="command-line-options.html#alpha">‑alpha</a> <span class="bull"> • </span> <a href="command-line-options.html#annotate">‑annotate</a> <span class="bull"> • </span> <a href="command-line-options.html#antialias">‑antialias</a> <span class="bull"> • </span> <a href="command-line-options.html#append">‑append</a> <span class="bull"> • </span> <a href="command-line-options.html#attenuate">‑attenuate</a> <span class="bull"> • </span> <a href="command-line-options.html#authenticate">‑authenticate</a> <span class="bull"> • </span> <a href="command-line-options.html#auto-gamma">‑auto‑gamma</a> <span class="bull"> • </span> <a href="command-line-options.html#auto-level">‑auto‑level</a> <span class="bull"> • </span> <a href="command-line-options.html#auto-orient">‑auto‑orient</a> <span class="bull"> • </span> <a href="command-line-options.html#backdrop">‑backdrop</a> <span class="bull"> • </span> <a href="command-line-options.html#background">‑background</a> <span class="bull"> • </span> <a href="command-line-options.html#bench">‑bench</a> <span class="bull"> • </span> <a href="command-line-options.html#bias">‑bias</a> <span class="bull"> • </span> <a href="command-line-options.html#black-point-compensation">‑black‑point‑compensation</a> <span class="bull"> • </span> <a href="command-line-options.html#black-threshold">‑black‑threshold</a> <span class="bull"> • </span> <a href="command-line-options.html#blend">‑blend</a> <span class="bull"> • </span> <a href="command-line-options.html#blue-primary">‑blue‑primary</a> <span class="bull"> • </span> <a href="command-line-options.html#blue-shift">‑blue‑shift</a> <span class="bull"> • </span> <a href="command-line-options.html#blur">‑blur</a> <span class="bull"> • </span> <a href="command-line-options.html#border">‑border</a> <span class="bull"> • </span> <a href="command-line-options.html#bordercolor">‑bordercolor</a> <span class="bull"> • </span> <a href="command-line-options.html#borderwidth">‑borderwidth</a> <span class="bull"> • </span> <a href="command-line-options.html#brightness-contrast">‑brightness‑contrast</a> <span class="bull"> • </span> <a href="command-line-options.html#cache">‑cache</a> <span class="bull"> • </span> <a href="command-line-options.html#canny">‑canny</a> <span class="bull"> • </span> <a href="command-line-options.html#caption">‑caption</a> <span class="bull"> • </span> <a href="command-line-options.html#cdl">‑cdl</a> <span class="bull"> • </span> <a href="command-line-options.html#channel">‑channel</a> <span class="bull"> • </span> <a href="command-line-options.html#charcoal">‑charcoal</a> <span class="bull"> • </span> <a href="command-line-options.html#chop">‑chop</a> <span class="bull"> • </span> <a href="command-line-options.html#clamp">‑clamp</a> <span class="bull"> • </span> <a href="command-line-options.html#clip">‑clip</a> <span class="bull"> • </span> <a href="command-line-options.html#clip-mask">‑clip‑mask</a> <span class="bull"> • </span> <a href="command-line-options.html#clip-path">‑clip‑path</a> <span class="bull"> • </span> <a href="command-line-options.html#clone">‑clone</a> <span class="bull"> • </span> <a href="command-line-options.html#clut">‑clut</a> <span class="bull"> • </span> <a href="command-line-options.html#coalesce">‑coalesce</a> <span class="bull"> • </span> <a href="command-line-options.html#colorize">‑colorize</a> <span class="bull"> • </span> <a href="command-line-options.html#colormap">‑colormap</a> <span class="bull"> • </span> <a href="command-line-options.html#color-matrix">‑color‑matrix</a> <span class="bull"> • </span> <a href="command-line-options.html#colors">‑colors</a> <span class="bull"> • </span> <a href="command-line-options.html#colorspace">‑colorspace</a> <span class="bull"> • </span> <a href="command-line-options.html#combine">‑combine</a> <span class="bull"> • </span> <a href="command-line-options.html#comment">‑comment</a> <span class="bull"> • </span> <a href="command-line-options.html#compare">‑compare</a> <span class="bull"> • </span> <a href="command-line-options.html#complex">‑complex</a> <span class="bull"> • </span> <a href="command-line-options.html#compose">‑compose</a> <span class="bull"> • </span> <a href="command-line-options.html#composite">‑composite</a> <span class="bull"> • </span> <a href="command-line-options.html#compress">‑compress</a> <span class="bull"> • </span> <a href="command-line-options.html#connected-components">‑connected‑components</a> <span class="bull"> • </span> <a href="command-line-options.html#contrast">‑contrast</a> <span class="bull"> • </span> <a href="command-line-options.html#contrast-stretch">‑contrast‑stretch</a> <span class="bull"> • </span> <a href="command-line-options.html#convolve">‑convolve</a> <span class="bull"> • </span> <a href="command-line-options.html#crop">‑crop</a> <span class="bull"> • </span> <a href="command-line-options.html#cycle">‑cycle</a> <span class="bull"> • </span> <a href="command-line-options.html#debug">‑debug</a> <span class="bull"> • </span> <a href="command-line-options.html#decipher">‑decipher</a> <span class="bull"> • </span> <a href="command-line-options.html#deconstruct">‑deconstruct</a> <span class="bull"> • </span> <a href="command-line-options.html#define">‑define</a> <span class="bull"> • </span> <a href="command-line-options.html#delay">‑delay</a> <span class="bull"> • </span> <a href="command-line-options.html#delete">‑delete</a> <span class="bull"> • </span> <a href="command-line-options.html#density">‑density</a> <span class="bull"> • </span> <a href="command-line-options.html#depth">‑depth</a> <span class="bull"> • </span> <a href="command-line-options.html#descend">‑descend</a> <span class="bull"> • </span> <a href="command-line-options.html#deskew">‑deskew</a> <span class="bull"> • </span> <a href="command-line-options.html#despeckle">‑despeckle</a> <span class="bull"> • </span> <a href="command-line-options.html#direction">‑direction</a> <span class="bull"> • </span> <a href="command-line-options.html#displace">‑displace</a> <span class="bull"> • </span> <a href="command-line-options.html#display">‑display</a> <span class="bull"> • </span> <a href="command-line-options.html#dispose">‑dispose</a> <span class="bull"> • </span> <a href="command-line-options.html#dissimilarity-threshold">‑dissimilarity‑threshold</a> <span class="bull"> • </span> <a href="command-line-options.html#dissolve">‑dissolve</a> <span class="bull"> • </span> <a href="command-line-options.html#distort">‑distort</a> <span class="bull"> • </span> <a href="command-line-options.html#distribute-cache">‑distribute‑cache</a> <span class="bull"> • </span> <a href="command-line-options.html#dither">‑dither</a> <span class="bull"> • </span> <a href="command-line-options.html#draw">‑draw</a> <span class="bull"> • </span> <a href="command-line-options.html#duplicate">‑duplicate</a> <span class="bull"> • </span> <a href="command-line-options.html#edge">‑edge</a> <span class="bull"> • </span> <a href="command-line-options.html#emboss">‑emboss</a> <span class="bull"> • </span> <a href="command-line-options.html#encipher">‑encipher</a> <span class="bull"> • </span> <a href="command-line-options.html#encoding">‑encoding</a> <span class="bull"> • </span> <a href="command-line-options.html#endian">‑endian</a> <span class="bull"> • </span> <a href="command-line-options.html#enhance">‑enhance</a> <span class="bull"> • </span> <a href="command-line-options.html#equalize">‑equalize</a> <span class="bull"> • </span> <a href="command-line-options.html#evaluate">‑evaluate</a> <span class="bull"> • </span> <a href="command-line-options.html#evaluate-sequence">‑evaluate‑sequence</a> <span class="bull"> • </span> <a href="command-line-options.html#extent">‑extent</a> <span class="bull"> • </span> <a href="command-line-options.html#extract">‑extract</a> <span class="bull"> • </span> <a href="command-line-options.html#family">‑family</a> <span class="bull"> • </span> <a href="command-line-options.html#features">‑features</a> <span class="bull"> • </span> <a href="command-line-options.html#fft">‑fft</a> <span class="bull"> • </span> <a href="command-line-options.html#fill">‑fill</a> <span class="bull"> • </span> <a href="command-line-options.html#filter">‑filter</a> <span class="bull"> • </span> <a href="command-line-options.html#flatten">‑flatten</a> <span class="bull"> • </span> <a href="command-line-options.html#flip">‑flip</a> <span class="bull"> • </span> <a href="command-line-options.html#floodfill">‑floodfill</a> <span class="bull"> • </span> <a href="command-line-options.html#flop">‑flop</a> <span class="bull"> • </span> <a href="command-line-options.html#font">‑font</a> <span class="bull"> • </span> <a href="command-line-options.html#foreground">‑foreground</a> <span class="bull"> • </span> <a href="command-line-options.html#format">‑format</a> <span class="bull"> • </span> <a href="command-line-options.html#format_identify_">‑format[identify]</a> <span class="bull"> • </span> <a href="command-line-options.html#frame">‑frame</a> <span class="bull"> • </span> <a href="command-line-options.html#frame_import_">‑frame[import]</a> <span class="bull"> • </span> <a href="command-line-options.html#function">‑function</a> <span class="bull"> • </span> <a href="command-line-options.html#fuzz">‑fuzz</a> <span class="bull"> • </span> <a href="command-line-options.html#fx">‑fx</a> <span class="bull"> • </span> <a href="command-line-options.html#gamma">‑gamma</a> <span class="bull"> • </span> <a href="command-line-options.html#gaussian-blur">‑gaussian‑blur</a> <span class="bull"> • </span> <a href="command-line-options.html#geometry">‑geometry</a> <span class="bull"> • </span> <a href="command-line-options.html#gravity">‑gravity</a> <span class="bull"> • </span> <a href="command-line-options.html#grayscale">‑grayscale</a> <span class="bull"> • </span> <a href="command-line-options.html#green-primary">‑green‑primary</a> <span class="bull"> • </span> <a href="command-line-options.html#hald-clut">‑hald‑clut</a> <span class="bull"> • </span> <a href="command-line-options.html#help">‑help</a> <span class="bull"> • </span> <a href="command-line-options.html#highlight-color">‑highlight‑color</a> <span class="bull"> • </span> <a href="command-line-options.html#hough-lines">‑hough‑lines</a> <span class="bull"> • </span> <a href="command-line-options.html#iconGeometry">‑iconGeometry</a> <span class="bull"> • </span> <a href="command-line-options.html#iconic">‑iconic</a> <span class="bull"> • </span> <a href="command-line-options.html#identify">‑identify</a> <span class="bull"> • </span> <a href="command-line-options.html#ift">‑ift</a> <span class="bull"> • </span> <a href="command-line-options.html#immutable">‑immutable</a> <span class="bull"> • </span> <a href="command-line-options.html#implode">‑implode</a> <span class="bull"> • </span> <a href="command-line-options.html#insert">‑insert</a> <span class="bull"> • </span> <a href="command-line-options.html#intensity">‑intensity</a> <span class="bull"> • </span> <a href="command-line-options.html#intent">‑intent</a> <span class="bull"> • </span> <a href="command-line-options.html#interlace">‑interlace</a> <span class="bull"> • </span> <a href="command-line-options.html#interpolate">‑interpolate</a> <span class="bull"> • </span> <a href="command-line-options.html#interline-spacing">‑interline‑spacing</a> <span class="bull"> • </span> <a href="command-line-options.html#interword-spacing">‑interword‑spacing</a> <span class="bull"> • </span> <a href="command-line-options.html#kerning">‑kerning</a> <span class="bull"> • </span> <a href="command-line-options.html#kuwahara">‑kuwahara</a> <span class="bull"> • </span> <a href="command-line-options.html#label">‑label</a> <span class="bull"> • </span> <a href="command-line-options.html#lat">‑lat</a> <span class="bull"> • </span> <a href="command-line-options.html#layers">‑layers</a> <span class="bull"> • </span> <a href="command-line-options.html#level">‑level</a> <span class="bull"> • </span> <a href="command-line-options.html#level-colors">‑level‑colors</a> <span class="bull"> • </span> <a href="command-line-options.html#limit">‑limit</a> <span class="bull"> • </span> <a href="command-line-options.html#linear-stretch">‑linear‑stretch</a> <span class="bull"> • </span> <a href="command-line-options.html#linewidth">‑linewidth</a> <span class="bull"> • </span> <a href="command-line-options.html#liquid-rescale">‑liquid‑rescale</a> <span class="bull"> • </span> <a href="command-line-options.html#list">‑list</a> <span class="bull"> • </span> <a href="command-line-options.html#log">‑log</a> <span class="bull"> • </span> <a href="command-line-options.html#loop">‑loop</a> <span class="bull"> • </span> <a href="command-line-options.html#lowlight-color">‑lowlight‑color</a> <span class="bull"> • </span> <a href="command-line-options.html#magnify">‑magnify</a> <span class="bull"> • </span> <a href="command-line-options.html#map">‑map</a> <span class="bull"> • </span> <a href="command-line-options.html#map_stream_">‑map[stream]</a> <span class="bull"> • </span> <a href="command-line-options.html#mask">‑mask</a> <span class="bull"> • </span> <a href="command-line-options.html#mattecolor">‑mattecolor</a> <span class="bull"> • </span> <a href="command-line-options.html#median">‑median</a> <span class="bull"> • </span> <a href="command-line-options.html#mean-shift">‑mean‑shift</a> <span class="bull"> • </span> <a href="command-line-options.html#metric">‑metric</a> <span class="bull"> • </span> <a href="command-line-options.html#mode">‑mode</a> <span class="bull"> • </span> <a href="command-line-options.html#modulate">‑modulate</a> <span class="bull"> • </span> <a href="command-line-options.html#moments">‑moments</a> <span class="bull"> • </span> <a href="command-line-options.html#monitor">‑monitor</a> <span class="bull"> • </span> <a href="command-line-options.html#monochrome">‑monochrome</a> <span class="bull"> • </span> <a href="command-line-options.html#morph">‑morph</a> <span class="bull"> • </span> <a href="command-line-options.html#morphology">‑morphology</a> <span class="bull"> • </span> <a href="command-line-options.html#mosaic">‑mosaic</a> <span class="bull"> • </span> <a href="command-line-options.html#motion-blur">‑motion‑blur</a> <span class="bull"> • </span> <a href="command-line-options.html#name">‑name</a> <span class="bull"> • </span> <a href="command-line-options.html#negate">‑negate</a> <span class="bull"> • </span> <a href="command-line-options.html#noise">‑noise</a> <span class="bull"> • </span> <a href="command-line-options.html#normalize">‑normalize</a> <span class="bull"> • </span> <a href="command-line-options.html#opaque">‑opaque</a> <span class="bull"> • </span> <a href="command-line-options.html#ordered-dither">‑ordered‑dither</a> <span class="bull"> • </span> <a href="command-line-options.html#orient">‑orient</a> <span class="bull"> • </span> <a href="command-line-options.html#page">‑page</a> <span class="bull"> • </span> <a href="command-line-options.html#paint">‑paint</a> <span class="bull"> • </span> <a href="command-line-options.html#path">‑path</a> <span class="bull"> • </span> <a href="command-line-options.html#pause_animate_">‑pause[animate]</a> <span class="bull"> • </span> <a href="command-line-options.html#pause_import_">‑pause[import]</a> <span class="bull"> • </span> <a href="command-line-options.html#perceptible">‑perceptible</a> <span class="bull"> • </span> <a href="command-line-options.html#ping">‑ping</a> <span class="bull"> • </span> <a href="command-line-options.html#pointsize">‑pointsize</a> <span class="bull"> • </span> <a href="command-line-options.html#polaroid">‑polaroid</a> <span class="bull"> • </span> <a href="command-line-options.html#poly">‑poly</a> <span class="bull"> • </span> <a href="command-line-options.html#posterize">‑posterize</a> <span class="bull"> • </span> <a href="command-line-options.html#precision">‑precision</a> <span class="bull"> • </span> <a href="command-line-options.html#preview">‑preview</a> <span class="bull"> • </span> <a href="command-line-options.html#print">‑print</a> <span class="bull"> • </span> <a href="command-line-options.html#process">‑process</a> <span class="bull"> • </span> <a href="command-line-options.html#profile">‑profile</a> <span class="bull"> • </span> <a href="command-line-options.html#quality">‑quality</a> <span class="bull"> • </span> <a href="command-line-options.html#quantize">‑quantize</a> <span class="bull"> • </span> <a href="command-line-options.html#quiet">‑quiet</a> <span class="bull"> • </span> <a href="command-line-options.html#radial-blur">‑radial‑blur</a> <span class="bull"> • </span> <a href="command-line-options.html#raise">‑raise</a> <span class="bull"> • </span> <a href="command-line-options.html#random-threshold">‑random‑threshold</a> <span class="bull"> • </span> <a href="command-line-options.html#red-primary">‑red‑primary</a> <span class="bull"> • </span> <a href="command-line-options.html#regard-warnings">‑regard‑warnings</a> <span class="bull"> • </span> <a href="command-line-options.html#region">‑region</a> <span class="bull"> • </span> <a href="command-line-options.html#remap">‑remap</a> <span class="bull"> • </span> <a href="command-line-options.html#remote">‑remote</a> <span class="bull"> • </span> <a href="command-line-options.html#render">‑render</a> <span class="bull"> • </span> <a href="command-line-options.html#repage">‑repage</a> <span class="bull"> • </span> <a href="command-line-options.html#resample">‑resample</a> <span class="bull"> • </span> <a href="command-line-options.html#resize">‑resize</a> <span class="bull"> • </span> <a href="command-line-options.html#respect-parentheses">‑respect‑parentheses</a> <span class="bull"> • </span> <a href="command-line-options.html#reverse">‑reverse</a> <span class="bull"> • </span> <a href="command-line-options.html#roll">‑roll</a> <span class="bull"> • </span> <a href="command-line-options.html#rotate">‑rotate</a> <span class="bull"> • </span> <a href="command-line-options.html#sample">‑sample</a> <span class="bull"> • </span> <a href="command-line-options.html#sampling-factor">‑sampling‑factor</a> <span class="bull"> • </span> <a href="command-line-options.html#scale">‑scale</a> <span class="bull"> • </span> <a href="command-line-options.html#scene">‑scene</a> <span class="bull"> • </span> <a href="command-line-options.html#screen">‑screen</a> <span class="bull"> • </span> <a href="command-line-options.html#seed">‑seed</a> <span class="bull"> • </span> <a href="command-line-options.html#segment">‑segment</a> <span class="bull"> • </span> <a href="command-line-options.html#selective-blur">‑selective‑blur</a> <span class="bull"> • </span> <a href="command-line-options.html#separate">‑separate</a> <span class="bull"> • </span> <a href="command-line-options.html#sepia-tone">‑sepia‑tone</a> <span class="bull"> • </span> <a href="command-line-options.html#set">‑set</a> <span class="bull"> • </span> <a href="command-line-options.html#shade">‑shade</a> <span class="bull"> • </span> <a href="command-line-options.html#shadow">‑shadow</a> <span class="bull"> • </span> <a href="command-line-options.html#shared-memory">‑shared‑memory</a> <span class="bull"> • </span> <a href="command-line-options.html#sharpen">‑sharpen</a> <span class="bull"> • </span> <a href="command-line-options.html#shave">‑shave</a> <span class="bull"> • </span> <a href="command-line-options.html#shear">‑shear</a> <span class="bull"> • </span> <a href="command-line-options.html#sigmoidal-contrast">‑sigmoidal‑contrast</a> <span class="bull"> • </span> <a href="command-line-options.html#silent">‑silent</a> <span class="bull"> • </span> <a href="command-line-options.html#similarity-threshold">‑similarity‑threshold</a> <span class="bull"> • </span> <a href="command-line-options.html#size">‑size</a> <span class="bull"> • </span> <a href="command-line-options.html#sketch">‑sketch</a> <span class="bull"> • </span> <a href="command-line-options.html#smush">‑smush</a> <span class="bull"> • </span> <a href="command-line-options.html#snaps">‑snaps</a> <span class="bull"> • </span> <a href="command-line-options.html#solarize">‑solarize</a> <span class="bull"> • </span> <a href="command-line-options.html#sparse-color">‑sparse‑color</a> <span class="bull"> • </span> <a href="command-line-options.html#splice">‑splice</a> <span class="bull"> • </span> <a href="command-line-options.html#spread">‑spread</a> <span class="bull"> • </span> <a href="command-line-options.html#statistic">‑statistic</a> <span class="bull"> • </span> <a href="command-line-options.html#stegano">‑stegano</a> <span class="bull"> • </span> <a href="command-line-options.html#stereo">‑stereo</a> <span class="bull"> • </span> <a href="command-line-options.html#stretch">‑stretch</a> <span class="bull"> • </span> <a href="command-line-options.html#strip">‑strip</a> <span class="bull"> • </span> <a href="command-line-options.html#stroke">‑stroke</a> <span class="bull"> • </span> <a href="command-line-options.html#strokewidth">‑strokewidth</a> <span class="bull"> • </span> <a href="command-line-options.html#style">‑style</a> <span class="bull"> • </span> <a href="command-line-options.html#subimage-search">‑subimage‑search</a> <span class="bull"> • </span> <a href="command-line-options.html#swap">‑swap</a> <span class="bull"> • </span> <a href="command-line-options.html#swirl">‑swirl</a> <span class="bull"> • </span> <a href="command-line-options.html#synchronize">‑synchronize</a> <span class="bull"> • </span> <a href="command-line-options.html#taint">‑taint</a> <span class="bull"> • </span> <a href="command-line-options.html#text-font">‑text‑font</a> <span class="bull"> • </span> <a href="command-line-options.html#texture">‑texture</a> <span class="bull"> • </span> <a href="command-line-options.html#threshold">‑threshold</a> <span class="bull"> • </span> <a href="command-line-options.html#thumbnail">‑thumbnail</a> <span class="bull"> • </span> <a href="command-line-options.html#tile">‑tile</a> <span class="bull"> • </span> <a href="command-line-options.html#tile-offset">‑tile‑offset</a> <span class="bull"> • </span> <a href="command-line-options.html#tint">‑tint</a> <span class="bull"> • </span> <a href="command-line-options.html#title">‑title</a> <span class="bull"> • </span> <a href="command-line-options.html#transform">‑transform</a> <span class="bull"> • </span> <a href="command-line-options.html#transparent">‑transparent</a> <span class="bull"> • </span> <a href="command-line-options.html#transparent-color">‑transparent‑color</a> <span class="bull"> • </span> <a href="command-line-options.html#transpose">‑transpose</a> <span class="bull"> • </span> <a href="command-line-options.html#transverse">‑transverse</a> <span class="bull"> • </span> <a href="command-line-options.html#treedepth">‑treedepth</a> <span class="bull"> • </span> <a href="command-line-options.html#trim">‑trim</a> <span class="bull"> • </span> <a href="command-line-options.html#type">‑type</a> <span class="bull"> • </span> <a href="command-line-options.html#undercolor">‑undercolor</a> <span class="bull"> • </span> <a href="command-line-options.html#unique-colors">‑unique‑colors</a> <span class="bull"> • </span> <a href="command-line-options.html#units">‑units</a> <span class="bull"> • </span> <a href="command-line-options.html#unsharp">‑unsharp</a> <span class="bull"> • </span> <a href="command-line-options.html#update">‑update</a> <span class="bull"> • </span> <a href="command-line-options.html#verbose">‑verbose</a> <span class="bull"> • </span> <a href="command-line-options.html#version">‑version</a> <span class="bull"> • </span> <a href="command-line-options.html#view">‑view</a> <span class="bull"> • </span> <a href="command-line-options.html#vignette">‑vignette</a> <span class="bull"> • </span> <a href="command-line-options.html#virtual-pixel">‑virtual‑pixel</a> <span class="bull"> • </span> <a href="command-line-options.html#visual">‑visual</a> <span class="bull"> • </span> <a href="command-line-options.html#watermark">‑watermark</a> <span class="bull"> • </span> <a href="command-line-options.html#wave">‑wave</a> <span class="bull"> • </span> <a href="command-line-options.html#weight">‑weight</a> <span class="bull"> • </span> <a href="command-line-options.html#white-point">‑white‑point</a> <span class="bull"> • </span> <a href="command-line-options.html#white-threshold">‑white‑threshold</a> <span class="bull"> • </span> <a href="command-line-options.html#window">‑window</a> <span class="bull"> • </span> <a href="command-line-options.html#window-group">‑window‑group</a> <span class="bull"> • </span> <a href="command-line-options.html#write">‑write</a> </p>
cristyad41c0c2012-10-31 00:49:28 +0000[diff] [blame]59
cristyd2432012015-05-04 23:15:15 +0000[diff] [blame]60<p class="lead magick-description">Below is list of command-line options recognized by the ImageMagick <a href="command-line-tools.html">command-line tools</a>. If you want a description of a particular option, click on the option name in the navigation bar above and you will go right to it. Unless otherwise noted, each option is recognized by the commands: <a href="convert.html">convert</a> and <a href="mogrify.html">mogrify</a>.</p>
61
62<div style="margin: auto;">
63 <h4><a id="adaptive-blur"></a>-adaptive-blur <var>radius</var>[x<var>sigma</var>]</h4>
cristyad41c0c2012-10-31 00:49:28 +0000[diff] [blame]64</div>
65
cristyd2432012015-05-04 23:15:15 +0000[diff] [blame]66<p class="magick-description">Adaptively blur pixels, with decreasing effect near edges.</p>
cristy8ee7f242013-06-20 16:08:44 +0000[diff] [blame]67
cristyd2432012015-05-04 23:15:15 +0000[diff] [blame]68<p>A Gaussian operator of the given radius and standard deviation (<var>sigma</var>) is used. If <var>sigma</var> is not given it
69defaults to 1.</p>
70
71<div style="margin: auto;">
72 <h4><a id="adaptive-resize"></a>-adaptive-resize <var>geometry</var></h4>
cristy149d58c2013-08-07 19:44:54 +0000[diff] [blame]73</div>
cristyd2432012015-05-04 23:15:15 +0000[diff] [blame]74
75<p class="magick-description">Resize the image using data-dependent triangulation.</p>
76
77<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <a href="command-line-options.html#adaptive-resize">-adaptive-resize</a>
78option defaults to data-dependent triangulation. Use the <a href="command-line-options.html#filter">-filter</a> to choose a different resampling algorithm.
79Offsets, if present in the geometry string, are ignored, and the <a href="command-line-options.html#gravity">-gravity</a> option has no effect.</p>
80
81<div style="margin: auto;">
82 <h4><a id="adaptive-sharpen"></a>-adaptive-sharpen <var>radius</var>[x<var>sigma</var>]</h4>
cristy149d58c2013-08-07 19:44:54 +0000[diff] [blame]83</div>
cristyd2432012015-05-04 23:15:15 +0000[diff] [blame]84
85<p class="magick-description">Adaptively sharpen pixels, with increasing effect near edges.</p>
86
87<p>A Gaussian operator of the given radius and standard deviation
88(<var>sigma</var>) is used. If <var>sigma</var> is not given it
89defaults to 1.</p>
90
91<div style="margin: auto;">
92 <h4><a id="adjoin"></a>-adjoin</h4>
93</div>
94
95<p class="magick-description">Join images into a single multi-image file.</p>
96
97<p>This option is enabled by default. An attempt is made to save all images of
98an image sequence into the given output file. However, some formats, such as
99JPEG and PNG, do not support more than one image per file, and in that case
100ImageMagick is forced to write each image as a separate file. As such, if
101more than one image needs to be written, the filename given is modified by
102adding a <a href="command-line-options.html#scene">-scene</a> number before the suffix, in order to
103make distinct names for each image. </p>
104
105<p>Use <a href="command-line-options.html#adjoin">+adjoin</a> to force each image to be written to
106separate files, whether or not the file format allows multiple images per file
107(for example, GIF, MIFF, and TIFF). </p>
108
109<p>Including a C-style integer format string in the output filename will
110automagically enable <a href="command-line-options.html#adjoin">+adjoin</a> and are used to specify
111where the <a href="command-line-options.html#scene">-scene</a> number is placed in the filenames. These
112strings, such as '<code>%d</code>' or '<code>%03d</code>', are familiar to those
113who have used the standard <code>printf()</code>' C-library function. As an
114example, the command</p>
115
116<pre>
117convert logo: rose: -morph 15 my%02dmorph.jpg
118</pre>
119
120<p>will create a sequence of 17 images (the two given plus 15 more created by
121<a href="command-line-options.html#morph">-morph</a>), named: my00morph.jpg, my01morph.jpg,
122my02morph.jpg, ..., my16morph.jpg. </p>
123
124<p>In summary, ImageMagick tries to write all images to one file, but will
125save to multiple files, if any of the following conditions exist...</p>
126<ol>
127<li>the output image's file format does not allow multi-image files,</li>
128<li>the <a href="command-line-options.html#adjoin">+adjoin</a> option is given, or</li>
129<li>a printf() integer format string (eg: "%d") is present in the output
130 filename.</li>
131</ol>
132
133
134<div style="margin: auto;">
135 <h4><a id="affine"></a>-affine
136 <var>s<sub>x</sub></var>,<var>r<sub>x</sub></var>,<var>r<sub>y</sub></var>,<var>s<sub>y</sub></var>[,<var>t<sub>x</sub></var>,<var>t<sub>y</sub></var>]</h4>
137</div>
138
139<p class="magick-description">Set the drawing transformation matrix for combined rotating and scaling.</p>
140
141<p>This option sets a transformation matrix, for use by subsequent <a href="command-line-options.html#draw">-draw</a> or <a href="command-line-options.html#transform">-transform</a> options. </p>
142
143<p>The matrix entries are entered as comma-separated numeric values either in
144quotes or without spaces. </p>
145
146<p>Internally, the transformation matrix has 3x3 elements, but three of them
147are omitted from the input because they are constant. The new (transformed)
148coordinates (<var>x'</var>, <var>y'</var>) of a pixel at
149position (<var>x</var>, <var>y</var>) in the original
150image are calculated using the following matrix equation.</p>
151
152<div class="eqn">
153<img alt="affine transformation" src="../images/affine.png">
154</div>
155
156<p> The size of the resulting image is that of the smallest rectangle that
157contains the transformed source image. The parameters
158<var>t<sub>x</sub></var> and <var>t<sub>y</sub></var>
159subsequently shift the image pixels so that those that are moved out of the
160image area are cut off.</p>
161
162<p>The transformation matrix complies with the left-handed pixel coordinate
163system: positive <var>x</var> and <var>y</var> directions
164are rightward and downward, resp.; positive rotation is clockwise.</p>
165
166<p> If the translation coefficients <var>t<sub>x</sub></var> and
167<var>t<sub>y</sub></var> are omitted they default to 0,0. Therefore,
168four parameters suffice for rotation and scaling without translation.</p>
169
170<p>Scaling by the factors <var>s<sub>x</sub></var> and
171<var>s<sub>y</sub></var> in the <var>x</var> and <var>y</var> directions,
172respectively, is accomplished with the following.</p>
173
174<p>See <a href="command-line-options.html#transform">-transform</a>, and the <a href="command-line-options.html#distort">-distort</a> method '<code>Affineprojection</code> for more
175information </p>
176
177
178<pre>
179-affine <var>s<sub>x</sub></var>,0,0,<var>s<sub>y</sub></var>
180</pre>
181
182<p>Translation by a displacement (<var>t<sub>x</sub></var>, <var>t<sub>y</sub></var>) is accomplished like so:</p>
183
184<pre>
185-affine 1,0,0,1,<var>t<sub>x</sub></var>,<var>t<sub>y</sub></var>
186</pre>
187
188<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle
189<var>a</var> by letting <var>c</var> = cos(<var>a</var>), <var>s</var>
190= sin(<var>a</var>), and using the following.</p>
191
192<pre>
193-affine <var>c</var>,<var>s</var>,-<var>s</var>,<var>c</var>
194</pre>
195
196<p>The cumulative effect of a sequence of <a href="command-line-options.html#affine">-affine</a>
197transformations can be accomplished by instead by a single <a href="command-line-options.html#affine">-affine</a> operation using the matrix equal to the product of the matrices
198of the individual transformations.</p>
199
200<p>An attempt is made to detect near-singular transformation matrices. If the
201matrix determinant has a sufficiently small absolute value it is rejected.</p>
202
203<div style="margin: auto;">
204 <h4><a id="alpha"></a>-alpha <var>type</var></h4>
205</div>
206
207<p class="magick-description">Gives control of the alpha/matte channel of an image.</p>
208
209<p>Used to set a flag on an image indicating whether or not to use existing alpha
210channel data, to create an alpha channel, or to perform other operations on the alpha channel. Choose the argument <var>type</var> from the list below.</p>
211
212
213<div class="table-responsive">
214<table class="table table-condensed table-striped">
215 <tbody>
216 <tr>
217 <th>Type</th>
218 <th>Description</th>
219 </tr>
220
221 <tr>
222 <td><code>Activate</code> or <code>On</code></td>
223 <td>
224 Enable the image's transparency channel. Note normally <code>Set</code>
225 should be used instead of this, unless you specifically need to
226 preserve existing (but specifically turned <code>Off</code>) transparency
227 channel. </td></tr>
228
229 <tr>
230 <td><code>Associate</code></td>
231 <td>
232 associate the alpha channel with the image.</td></tr>
233
234 <tr>
235 <td><code>Deactivate</code> or <code>Off</code></td>
236 <td>
237 Disables the image's transparency channel. Does not delete or change the
238 existing data, just turns off the use of that data.</td></tr>
239
240 <tr>
241 <td><code>Disassociate</code></td>
242 <td>
243 disassociate the alpha channel from the image.</td></tr>
244
245 <tr>
246 <td><code>Set</code></td>
247 <td>
248 Activates the alpha/matte channel. If it was previously turned off
249 then it also resets the channel to opaque. If the image already had
250 the alpha channel turned on, it will have no effect.</td></tr>
251
252 <tr>
253 <td><code>Opaque</code></td>
254 <td>
255 Enables the alpha/matte channel and forces it to be fully opaque.
256 </td></tr>
257
258 <tr>
259 <td><code>Transparent</code></td>
260 <td>
261 Activates the alpha/matte channel and forces it to be fully
262 transparent. This effectively creates a fully transparent image the
263 same size as the original and with all its original RGB data still
264 intact, but fully transparent. </td></tr>
265
266 <tr>
267 <td><code>Extract</code></td>
268 <td>
269 Copies the alpha channel values into all the color channels and turns
270 '<code>Off</code>' the the image's transparency, so as to generate
271 a gray-scale mask of the image's shape. The alpha channel data is left
272 intact just deactivated. This is the inverse of '<code>Copy</code>'.
273 </td></tr>
274
275 <tr>
276 <td><code>Copy</code></td>
277 <td>
278 Turns '<code>On</code>' the alpha/matte channel, then copies the
279 gray-scale intensity of the image, into the alpha channel, converting
280 a gray-scale mask into a transparent shaped mask ready to be colored
281 appropriately. The color channels are not modified. </td></tr>
282
283 <tr>
284 <td><code>Shape</code></td>
285 <td>
286 As per '<code>Copy</code>' but also colors the resulting shape mask with
287 the current background color. That is the RGB color channels is
288 replaced, with appropriate alpha shape.
289 </td></tr>
290
291 <tr>
292 <td><code>Remove</code></td>
293 <td>
294 Composite the image over the background color.
295 </td></tr>
296
297 <tr>
298 <td><code>Background</code></td>
299 <td>
300 Set any fully-transparent pixel to the background color, while leaving
301 it fully-transparent. This can make some image file formats, such as
302 PNG, smaller as the RGB values of transparent pixels are more uniform,
303 and thus can compress better.
304 </td></tr>
305 </tbody>
306</table>
307</div>
308
309<p>Note that while the obsolete <code>+matte</code> operation was the
310same as "<code><a href="command-line-options.html#alpha">-alpha</a> Off</code>", the <code>
311&gt;-matte</code> operation was the same as "<code><a href="command-line-options.html#alpha">-alpha</a>
312Set</code>" and not "<code><a href="command-line-options.html#alpha">-alpha</a> On</code>". </p>
313
314
315<div style="margin: auto;">
316 <h4><a id="annotate"></a>
317 -annotate <var>degrees</var> <var>text</var><br>
318 -annotate <var>Xdegrees</var>x<var>Ydegrees</var> <var>text</var><br> -annotate <var>Xdegrees</var>x<var>Ydegrees</var> {+-}<var>t<sub>x</sub></var>{+-}<var>t<sub>y</sub></var> <var>text</var><br> -annotate {+-}<var>t<sub>x</sub></var>{+-}<var>t<sub>y</sub></var> <var>text</var></h4>
319</div>
320
321<p class="magick-description">Annotate an image with text</p>
322
323<p>This is a convenience for annotating an image with text. For more precise
324control over text annotations, use <a href="command-line-options.html#draw">-draw</a>.</p>
325
326
327<p>The values <var>Xdegrees</var> and <var>Ydegrees</var>
328control the shears applied to the text, while <var>t<sub>x</sub></var> and <var>t<sub>y</sub></var> are offsets that give the location of the text relative any <a href="command-line-options.html#gravity">-gravity</a> setting and defaults to the upper left corner of the image.</p>
329
330<p>Using <a href="command-line-options.html#annotate">-annotate</a> <var>degrees</var>
331or <a href="command-line-options.html#annotate">-annotate</a> <var>degrees</var>x<var>degrees</var> produces an unsheared rotation of the text. The
332direction of the rotation is positive, which means a clockwise rotation if <var>degrees</var> is positive. (This conforms to the usual mathematical
333convention once it is realized that the positive <var>y</var>–direction is
334conventionally considered to be <var>downward</var> for images.)</p>
335
336<p>The new (transformed) coordinates (<var>x'</var>, <var>y'</var>) of a pixel at position (<var>x</var>, <var>y</var>) in the image are calculated using the following matrix
337equation.</p> <div class="eqn"><img alt="annotate transformation" src="../images/annotate.png"></div>
338
339<p>If <var>t<sub>x</sub></var> and <var>t<sub>y</sub></var> are omitted, they default to 0. This makes the
340bottom-left of the text becomes the upper-left corner of the image, which is
341probably undesirable. Adding a <a href="command-line-options.html#gravity">-gravity</a> option in this
342case leads to nice results.</p>
343
344<p>Text is any UTF-8 encoded character sequence. If <var>text</var>
345is of the form '@mytext.txt', the text is read from the file
346<code>mytext.txt</code>. Text in a file is taken literally; no embedded
347formatting characters are recognized.</p>
348
349<div style="margin: auto;">
350 <h4><a id="antialias"></a>-antialias</h4>
351</div>
352
353<p class="magick-description">Enable/Disable of the rendering of anti-aliasing pixels when drawing fonts and lines.</p>
354
355<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when
356drawn. Use <a href="command-line-options.html#antialias">+antialias</a> to disable the addition of
357antialiasing edge pixels. This will then reduce the number of colors added to
358an image to just the colors being directly drawn. That is, no mixed colors
359are added when drawing such objects. </p>
360
361<div style="margin: auto;">
362 <h4><a id="append"></a>-append</h4>
363</div>
364
365<p class="magick-description">Join current images vertically or horizontally.</p>
366
367<p>This option creates a single longer image, by joining all the current
368images in sequence top-to-bottom. Use <a href="command-line-options.html#append">+append</a> to
369stack images left-to-right. </p>
370
371<p>If they are not of the same width, narrower images are padded with the
372current <a href="command-line-options.html#background">-background</a> color setting, and their
373position relative to each other can be controlled by the current <a href="command-line-options.html#gravity">-gravity</a> setting. </p>
374
375
376<div style="margin: auto;">
377 <h4><a id="attenuate"></a>-attenuate <var>value</var></h4>
378</div>
379
380<p class="magick-description">Lessen (or intensify) when adding noise to an image.</p>
381
382<p>If unset the value is equivalent to 1.0, or a maximum noise addition</p>
383
384<div style="margin: auto;">
385 <h4><a id="authenticate"></a>-authenticate <var>password</var></h4>
386</div>
387
388<p class="magick-description">Decrypt a PDF with a password.</p>
389
390<p>Use this option to supply a <var>password</var> for decrypting
391a PDF that has been encrypted using Microsoft Crypto API (MSC API). The
392encrypting using the MSC API is not supported.</p>
393
394<p>For a different encryption method, see <a href="command-line-options.html#encipher">-encipher</a>
395and <a href="command-line-options.html#decipher">-decipher</a>. </p>
396
397
398<div style="margin: auto;">
399 <h4><a id="auto-gamma"></a>-auto-gamma</h4>
400</div>
401
402<p class="magick-description">Automagically adjust gamma level of image.</p>
403
404<p>This calculates the mean values of an image, then applies a calculated <a href="command-line-options.html#gamma">-gamma</a> adjustment so that is the mean color exists in the
405image it will get a have a value of 50%. </p>
406
407<p>This means that any solid 'gray' image becomes 50% gray. </p>
408
409<p>This works well for real-life images with little or no extreme dark and
410light areas, but tend to fail for images with large amounts of bright sky or
411dark shadows. It also does not work well for diagrams or cartoon like images.
412</p>
413
414<p>It uses the <a href="command-line-options.html#channel">-channel</a> setting, (including the
415'<var>sync</var>' flag for channel synchronization), to determine which color
416values is used and modified. As the default <a href="command-line-options.html#channel">-channel</a> setting is '<var>RGB,sync</var>', channels are modified
417together by the same gamma value, preserving colors. </p>
418
419
420
421<div style="margin: auto;">
422 <h4><a id="auto-level"></a>-auto-level</h4>
423</div>
424
425<p class="magick-description">Automagically adjust color levels of image.</p>
426
427<p>This is a 'perfect' image normalization operator. It finds the exact
428minimum and maximum color values in the image and then applies a <a href="command-line-options.html#level">-level</a> operator to stretch the values to the full range of
429values. </p>
430
431<p>The operator is not typically used for real-life images, image scans, or
432JPEG format images, as a single 'out-rider' pixel can set a bad min/max values
433for the <a href="command-line-options.html#level">-level</a> operation. On the other hand it is the
434right operator to use for color stretching gradient images being used to
435generate Color lookup tables, distortion maps, or other 'mathematically'
436defined images. </p>
437
438<p>The operator is very similar to the <a href="command-line-options.html#normalize">-normalize</a>, <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a>, and <a href="command-line-options.html#linear-stretch">-linear-stretch</a> operators, but without 'histogram binning' or 'clipping'
439problems that these operators may have. That is <a href="command-line-options.html#auto-level">-auto-level</a> is the perfect or ideal version these operators. </p>
440
441<p>It uses the <a href="command-line-options.html#channel">-channel</a> setting, (including the
442special '<var>sync</var>' flag for channel synchronization), to determine
443which color values are used and modified. As the default <a href="command-line-options.html#channel">+channel</a> setting is '<var>RGB,sync</var>', the
444'<var>sync</var>' ensures that the color channels will are modified
445together by the same gamma value, preserving colors, and ignoring
446transparency. </p>
447
448
449<div style="margin: auto;">
450 <h4><a id="auto-orient"></a>-auto-orient</h4>
451</div>
452
453<p class="magick-description">adjusts an image so that its orientation is suitable for viewing (i.e. top-left orientation).</p>
454
455<p>This operator reads and resets the EXIF image profile setting 'Orientation'
456and then performs the appropriate 90 degree rotation on the image to orient
457the image, for correct viewing. </p>
458
459<p>This EXIF profile setting is usually set using a gravity sensor in digital
460camera, however photos taken directly downward or upward may not have an
461appropriate value. Also images that have been orientation 'corrected' without
462reseting this setting, may be 'corrected' again resulting in a incorrect
463result. If the EXIF profile was previously stripped, the <a href="command-line-options.html#auto-orient">-auto-orient</a> operator will do nothing. </p>
464
465
466<div style="margin: auto;">
467 <h4><a id="average"></a>-average</h4>
468</div>
469
470<p class="magick-description">Average a set of images.</p>
471
472<p>An error results if the images are not identically sized.</p>
473
474
475<div style="margin: auto;">
476 <h4><a id="backdrop"></a>-backdrop</h4>
477</div>
478
479<p class="magick-description">Display the image centered on a backdrop.</p>
480
481<p>This backdrop covers the entire workstation screen and is useful for hiding
482other X window activity while viewing the image. The color of the backdrop is
483specified as the background color. The color is specified using the format
484described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
485
486<div style="margin: auto;">
487 <h4><a id="background"></a>-background <var>color</var></h4>
488</div>
489
490<p class="magick-description">Set the background color.</p>
491
492<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option. The default background color (if none is
493specified or found in the image) is white.</p>
494
495<div style="margin: auto;">
496 <h4><a id="bench"></a>-bench <var>iterations</var></h4>
497</div>
498
499<p class="magick-description">Measure performance.</p>
500
501<p>Repeat the entire command for the given number of <var>iterations</var> and report the user-time and elapsed time. For instance,
502consider the following command and its output. Modify the benchmark with the
503-duration to run the benchmark for a fixed number of seconds and -concurrent
504to run the benchmark in parallel (requires the OpenMP feature).</p>
505
506<pre>
507convert logo: -resize 1000% -bench 5 logo.png
508Performance[4]: 5i 0.875657ips 6.880u 0:05.710
509</pre>
510
511<p>In this example, 5 iterations were completed at 0.875657 iterations per
512second, using 4 threads and 6.88 seconds of the user's allotted time, for
513a total elapsed time of 5.71 seconds.</p>
514
515<div style="margin: auto;">
516 <h4><a id="bias"></a>-bias <var>value</var>{<var>%</var>}</h4>
517</div>
518
519<p class="magick-description">Add bias when convolving an image.</p>
520
521<p>This option shifts the output of <a href="command-line-options.html#convolve">‑convolve</a> so that
522positive and negative results are relative to the specified bias value. </p>
523
524<p>This is important for non-HDRI compilations of ImageMagick when dealing
525with convolutions that contain negative as well as positive values. This is
526especially the case with convolutions involving high pass filters or edge
527detection. Without an output bias, the negative values are clipped at
528zero.</p>
529
530<p>When using an ImageMagick with the HDRI compile-time setting, <a href="command-line-options.html#bias">‑bias</a> is not needed, as ImageMagick is able to store/handle any
531negative results without clipping to the color value range
532(0..QuantumRange).</p>
533
534<p>See the discussion on HDRI implementations of ImageMagick on the page <a href="high-dynamic-range.html">High Dynamic-Range Images</a>. For more
535about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this
536<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
537entry. </p>
538
539<div style="margin: auto;">
540 <h4><a id="black-point-compensation"></a>-black-point-compensation</h4>
541</div>
542
543<p class="magick-description">Use black point compensation.</p>
544
545<div style="margin: auto;">
546 <h4><a id="black-threshold"></a>-black-threshold <var>value</var>{<var>%</var>}</h4>
547</div>
548
549<p class="magick-description">Force to black all pixels below the threshold while leaving all pixels at or above the threshold unchanged.</p>
550
551<p> The threshold value can be given as a percentage or as an absolute integer
552value within [0, <var>QuantumRange</var>] corresponding to the
553desired <a href="command-line-options.html#channel">‑channel</a> value. See <a href="command-line-options.html#threshold">‑threshold</a>for more details on thresholds and resulting values. </p>
554
555
556<div style="margin: auto;">
557 <h4><a id="blend"></a>-blend <var>geometry</var></h4>
558</div>
559
560<p class="magick-description">blend an image into another by the given absolute value or percent.</p>
561
562<p>Blend will average the images together ('plus') according to the
563percentages given and each pixels transparency. If only a single percentage
564value is given it sets the weight of the composite or 'source' image, while
565the background image is weighted by the exact opposite amount. That is a
566<code>-blend 30%</code> merges 30% of the 'source' image with 70% of the
567'destination' image. Thus it is equivalent to <code>-blend 30x70%</code>.</p>
568
569
570<div style="margin: auto;">
571 <h4><a id="blue-primary"></a>-blue-primary <var>x</var>,<var>y</var></h4>
572</div>
573
574<p class="magick-description">Set the blue chromaticity primary point.</p>
575
576<div style="margin: auto;">
577 <h4><a id="blue-shift"></a>-blue-shift <var>factor</var></h4>
578</div>
579
580<p class="magick-description">simulate a scene at nighttime in the moonlight. Start with a factor of 1.5</p>
581
582<div style="margin: auto;">
583
584<div style="margin: auto;">
585 <h4><a id="blur"></a>-blur <var>radius</var><br>-blur <var>radius</var>x<var>sigma</var></h4>
586</div>
587
588<p class="magick-description">Reduce image noise and reduce detail levels.</p>
589
590<p>Convolve the image with a Gaussian or normal distribution using the given
591<var>Sigma</var> value. The formula is:</p>
592
593<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png">
594</div>
595
596<p>The <var>Sigma</var> value is the important argument, and
597determines the actual amount of blurring that will take place. </p>
598
599<p>The <var>Radius</var> is only used to determine the size of the
600array which will hold the calculated Gaussian distribution. It should be an
601integer. If not given, or set to zero, IM will calculate the largest possible
602radius that will provide meaningful results for the Gaussian distribution.
603</p>
604
605<p>The larger the <var>Radius</var> the slower the
606operation is. However too small a <var>Radius</var>, and sever
607aliasing effects may result. As a guideline, <var>Radius</var>
608should be at least twice the <var>Sigma</var> value, though three
609times will produce a more accurate result. </p>
610
611<p>This option differs from <a href="command-line-options.html#gaussian-blur">-gaussian-blur</a> simply
612by taking advantage of the separability properties of the distribution. Here
613we apply a single-dimensional Gaussian matrix in the horizontal direction,
614then repeat the process in the vertical direction.</p>
615
616<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
617pixels which are outside the image proper are blurred into the final result.
618</p>
619
620
621<div style="margin: auto;">
622 <h4>-blur <var>Width</var>[x<var>Height</var>[+<var>Angle</var>]]</h4>
623</div>
624
625<p class="magick-description">Variably blur an image according to the overlay mapping.</p>
626
627<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted
628Average (EWA) of the source image, scaled according to the grayscale
629mapping. </p>
630
631<p>The ellipse is weighted with sigma set to the given <var>Width</var> and <var>Height</var>. The <var>Height</var>
632defaults to the <var>Width</var> for a normal circular Gaussian
633weighting. The <var>Angle</var> will rotate the ellipse from
634horizontal clock-wise. </p>
635
636<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
637pixels which are outside the image proper are blurred into the final result.
638</p>
639
640
641<div style="margin: auto;">
642 <h4><a id="border"></a>-border <var>geometry</var></h4>
643</div>
644
645<p class="magick-description">Surround the image with a border of color. </p>
646
647<p>Set the width and height using the <var>size</var> portion of the
648<var>geometry</var> argument. See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets are
649ignored. </p>
650
651<p>As of IM 6.7.8-8, the <var>geometry</var> arguments behave as follows:</p>
652
653<table id="borderTable">
654 <col width="20%"> <col width="80%">
655 <thead>
656 <tr>
657 <th style="text-align:center"><var>size</var></th>
658 <th>General description</th>
659 </tr>
660 </thead>
661 <tbody>
662 <tr>
663 <td><var>value</var></td>
664 <td>value is added to both left/right and top/bottom</td>
665 </tr>
666 <tr>
667 <td><var>value-x</var>x</td>
668 <td>value-x is added only to left/right and top/bottom are unchanged</td>
669 </tr>
670 <tr>
671 <td>x<var>value-y</var></td>
672 <td>value-y is added only to top/bottom and left/right are unchanged</td>
673 </tr>
674 <tr>
675 <td><var>value-x</var>x<var>value-y</var></td>
676 <td>value-x is added to left/right and value-y added to top/bottom</td>
677 </tr>
678 <tr>
679 <td><var>value-x</var>x<code>0</code></td>
680 <td>value-x is added only to left/right and top/bottom are unchanged</td>
681 </tr>
682 <tr>
683 <td><code>0</code>x<var>value-y</var></td>
684 <td>value-y is added only to top/bottom and left/right are unchanged</td>
685 </tr>
686 <tr>
687 <td> </td>
688 <td> </td>
689 </tr>
690 <tr>
691 <td><var>value</var>%</td>
692 <td>value % of width is added to left/right and value % of height is added to top/bottom</td>
693 </tr>
694 <tr>
695 <td><var>value-x</var>x%</td>
696 <td>value-x % of width is added to left/right and to top/bottom</td>
697 </tr>
698 <tr>
699 <td>x<var>value-y</var>%</td>
700 <td>value-y % of height is added to top/bottom and to left/right</td>
701 </tr>
702 <tr>
703 <td><var>value-x</var>%x<var>value-y</var>%</td>
704 <td>value-x % of width is added to left/right and value-y % of height is added to top/bottom</td>
705 </tr>
706 <tr>
707 <td><var>value-x</var>%x<code>0</code>%</td>
708 <td>value-x % of width is added to left/right and top/bottom are unchanged</td>
709 </tr>
710 <tr>
711 <td><code>0</code>%x<var>value-y</var>%</td>
712 <td>value-y % of height is added to top/bottom and left/right are unchanged</td>
713 </tr>
714 </tbody>
715 </table>
716
717
718<p>Set the border color by preceding with the <a href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
719
720<p>The <a href="command-line-options.html#border">-border</a> operation is affected by the current <a href="command-line-options.html#compose">-compose</a> setting and assumes that this is using the default
721'<code>Over</code>' composition method. It generates an image of the appropriate
722size colors by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> before
723overlaying the original image in the center of this net image. This means that
724with the default compose method of '<code>Over</code>' any transparent parts may
725be replaced by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
726<p>See also the <a href="command-line-options.html#frame">-frame</a> option, which has more
727functionality.</p>
728
729<div style="margin: auto;">
730 <h4><a id="bordercolor"></a>-bordercolor <var>color</var></h4>
731</div>
732
733<p class="magick-description">Set the border color.</p>
734
735<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
736
737<p>The default border color is <code>#DFDFDF</code>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p>
738
739<div style="margin: auto;">
740 <h4><a id="borderwidth"></a>-borderwidth <var>geometry</var> </h4>
741</div>
742
743<p class="magick-description">Set the border width.</p>
744
745<div style="margin: auto;">
746 <h4><a id="brightness-contrast"></a>-brightness-contrast <var>brightness</var><br>-brightness-contrast <var>brightness</var>{x<var>contrast</var>}{<var>%</var>}}</h4>
747</div>
748
749<p class="magick-description">Adjust the brightness and/or contrast of the image.</p>
750
751<p>Brightness and Contrast values apply changes to the input image. They are
752not absolute settings. A brightness or contrast value of zero means no change.
753The range of values is -100 to +100 on each. Positive values increase the
754brightness or contrast and negative values decrease the brightness or contrast.
755To control only contrast, set the brightness=0. To control only brightness,
756set contrast=0 or just leave it off.</p>
757
758<p>You may also use <a href="command-line-options.html#fill">-channel</a> to control which channels to
759apply the brightness and/or contrast change. The default is to apply the same
760transformation to all channels.</p>
761
762<p>Brightness and Contrast arguments are converted to offset and slope of a
763linear transform and applied
764using <a href="command-line-options.html#fill">-function polynomial "slope,offset"</a>.</p>
765
766<p>The slope varies from 0 at contrast=-100 to almost vertical at
767contrast=+100. For brightness=0 and contrast=-100, the result are totally
768midgray. For brightness=0 and contrast=+100, the result will approach but
769not quite reach a threshold at midgray; that is the linear transformation
770is a very steep vertical line at mid gray.</p>
771
772<p>Negative slopes, i.e. negating the image, are not possible with this
773function. All achievable slopes are zero or positive.</p>
774
775<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5
776at brightness=+100. Thus, when contrast=0 and brightness=100, the result is
777totally white. Similarly, when contrast=0 and brightness=-100, the result is
778totally black.</p>
779
780<p>As the range of values for the arguments are -100 to +100, adding the '%'
781symbol is no different than leaving it off.</p>
782
783<div style="margin: auto;">
784 <h4><a id="cache"></a>-cache <var>threshold</var></h4>
785</div>
786
787<p class="magick-description">(This option has been replaced by the <a href="command-line-options.html#limit">-limit</a> option).</p>
788
789<div style="margin: auto;">
790 <h4><a id="canny"></a>-canny <var>radius</var><br>-canny <var>radius</var>x<var>sigma</var>{<var>+lower-percent</var>}{<var>+upper-percent</var>}</h4>
791</div>
792
793<p class="magick-description">Canny edge detector uses a multi-stage algorithm to detect a wide range of edges in the image.</p>
794
795<p>The thresholds range from 0 to 100% (e.g. -canny 0x1+10%+30%) with {<var>+lower-percent</var>} &lt; {<var>+upper-percent</var>}. If {<var>+upper-percent</var>} is increased but {<var>+lower-percent</var>} remains the same, lesser edge components will be detected, but their lengths will be the same. If {<var>+lower-percent</var>} is increased but {<var>+upper-percent</var>} is the same, the same number of edge components will be detected but their lengths will be shorter. The default thresholds are shown. The <var>radius</var>x<var>sigma</var> controls a gaussian blur applied to the input image to reduce noise and smooth the edges.</p>
796
797<div style="margin: auto;">
798 <h4><a id="caption"></a>-caption <var>string</var></h4>
799</div>
800
801<p class="magick-description">Assign a caption to an image.</p>
802
803<p>This option sets the caption meta-data of an image read in after this
804option has been given. To modify a caption of images already in memory use
805"<code><a href="command-line-options.html#set">-set</a> caption</code>". </p>
806
807<p>The caption can contain special format characters listed in the <a href="escape.html">Format and
808Print Image Properties</a>. These attributes are expanded when the caption
809is finally assigned to the individual images. </p>
810
811<p>If the first character of <var>string</var> is <var>@</var>, the image caption is read from a file titled by the
812remaining characters in the string. Comments read in from a file are literal;
813no embedded formatting characters are recognized.</p>
814
815<p>Caption meta-data is not visible on the image itself. To do that use the
816<a href="command-line-options.html#annotate">-annotate</a> or <a href="command-line-options.html#draw">-draw</a> options
817instead.</p>
818
819<p>For example,</p>
820
821<p class="crtsnip">
822 -caption "%m:%f %wx%h" bird.miff
823</p>
824
825<p>produces an image caption of <code>MIFF:bird.miff 512x480</code> (assuming
826that the image <code>bird.miff</code> has a width of 512 and a height of
827480.</p>
828
829
830<div style="margin: auto;">
831 <h4><a id="cdl"></a>-cdl <var>filename</var></h4>
832</div>
833
834<p class="magick-description">color correct with a color decision list.</p>
835
836<p>Here is an example color correction collection:</p>
837
838<pre>
839&lt;?xml version="1.0" encoding="UTF-8"?&gt;
840&lt;ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"&gt;
841 &lt;ColorCorrection id="cc06668"&gt;
842 &lt;SOPNode&gt;
843 &lt;Slope&gt; 0.9 1.2 0.5 &lt;/Slope&gt;
844 &lt;Offset&gt; 0.4 -0.5 0.6 &lt;/Offset&gt;
845 &lt;Power&gt; 1.0 0.8 1.5 &lt;/Power&gt;
846 &lt;/SOPNode&gt;
847 &lt;SATNode&gt;
848 &lt;Saturation&gt; 0.85 &lt;/Saturation&gt;
849 &lt;/SATNode&gt;
850 &lt;/ColorCorrection&gt;
851&lt;/ColorCorrectionCollection&gt;
852</pre>
853
854<div style="margin: auto;">
855 <h4><a id="channel"></a>-channel <var>type</var></h4>
856</div>
857
858<p class="magick-description">Specify those image color channels to which subsequent operators are limited.</p>
859
860<p>Choose from: <code>Red</code>, <code>Green</code>, <code>Blue</code>,
861<code>Alpha</code>, <code>Gray</code>, <code>Cyan</code>, <code>Magenta</code>,
862<code>Yellow</code>, <code>Black</code>, <code>Opacity</code>,
863<code>Index</code>, <code>RGB</code>, <code>RGBA</code>, <code>CMYK</code>, or
864<code>CMYKA</code>.</p>
865
866<p>The channels above can also be specified as a comma-separated list or can be
867abbreviated as a concatenation of the letters '<code>R</code>', '<code>G</code>',
868'<code>B</code>', '<code>A</code>', '<code>O</code>', '<code>C</code>',
869'<code>M</code>', '<code>Y</code>', '<code>K</code>'.
870
871For example, to only select the <code>Red</code> and <code>Blue</code> channels
872you can either use </p>
873<p class="crtsnip">
874 -channel Red,Blue
875</p>
876<p>or you can use the short hand form</p>
877<p class="crtsnip">
878 -channel RB
879</p>
880
881<p>All the channels that are present in an image can be specified using the
882special channel type <code>All</code>. Not all operators are 'channel capable',
883but generally any operators that are generally 'grey-scale' image operators,
884will understand this setting. See individual operator documentation. </p>
885
886<br>
887
888<p>On top of the normal channel selection an extra flag can be specified,
889'<code>Sync</code>'. This is turned on by default and if set means that
890operators that understand this flag should perform: cross-channel
891synchronization of the channels. If not specified, then most grey-scale
892operators will apply their image processing operations to each individual
893channel (as specified by the rest of the <a href="command-line-options.html#channel">-channel</a>
894setting) completely independently from each other. </p>
895
896<p>For example for operators such as <a href="command-line-options.html#auto-level">-auto-level</a> and
897<a href="command-line-options.html#auto-gamma">-auto-gamma</a> the color channels are modified
898together in exactly the same way so that colors will remain in-sync. Without
899it being set, then each channel is modified separately and
900independently, which may produce color distortion. </p>
901
902<p>The <a href="command-line-options.html#morphology">-morphology</a> '<code>Convolve</code>' method
903and the <a href="command-line-options.html#compose">-compose</a> mathematical methods, also understands
904the '<code>Sync</code>' flag to modify the behaviour of pixel colors according
905to the alpha channel (if present). That is to say it will modify the image
906processing with the understanding that fully-transparent colors should not
907contribute to the final result. </p>
908
909<p>Basically, by default, operators work with color channels in synchronous, and
910treats transparency as special, unless the <a href="command-line-options.html#channel">-channel</a>
911setting is modified so as to remove the effect of the '<code>Sync</code>' flag.
912How each operator does this depends on that operators current implementation.
913Not all operators understands this flag at this time, but that is changing.
914</p>
915
916<p>To print a complete list of channel types, use <a href="command-line-options.html#list">-list
917channel</a>.</p>
918
919<br>
920
921<p>By default, ImageMagick sets <a href="command-line-options.html#channel">-channel</a> to the value
922'<code>RGBK,sync</code>', which specifies that operators act on all color
923channels except the transparency channel, and that all the color channels are
924to be modified in exactly the same way, with an understanding of transparency
925(depending on the operation being applied). The 'plus' form <a href="command-line-options.html#channel">+channel</a> will reset the value back to this default. </p>
926
927<p>Options that are affected by the <a href="command-line-options.html#channel">-channel</a> setting
928include the following.
929
930<a href="command-line-options.html#auto-gamma">-auto-gamma</a>,
931<a href="command-line-options.html#auto-level">-auto-level</a>,
932<a href="command-line-options.html#black-threshold">-black-threshold</a>,
933<a href="command-line-options.html#blur">-blur</a>,
934<a href="command-line-options.html#clamp">-clamp</a>,
935<a href="command-line-options.html#clut">-clut</a>,
936<a href="command-line-options.html#combine">-combine</a>,
937<a href="command-line-options.html#composite">-composite</a> (Mathematical compose methods only),
938<a href="command-line-options.html#convolve">-convolve</a>,
939<a href="command-line-options.html#contrast-stretch">-contrast-stretch</a>,
940<a href="command-line-options.html#evaluate">-evaluate</a>,
941<a href="command-line-options.html#function">-function</a>,
942<a href="command-line-options.html#fx">-fx</a>,
943<a href="command-line-options.html#gaussian-blur">-gaussian-blur</a>,
944<a href="command-line-options.html#hald-clut">-hald-clut</a>,
945<a href="command-line-options.html#motion-blur">-motion-blur</a>,
946<a href="command-line-options.html#morphology">-morphology</a>,
947<a href="command-line-options.html#negate">-negate</a>,
948<a href="command-line-options.html#normalize">-normalize</a>,
949<a href="command-line-options.html#ordered-dither">-ordered-dither</a>,
950<a href="command-line-options.html#radial-blur">-radial-blur</a>,
951<a href="command-line-options.html#random-threshold">-random-threshold</a>,
952<a href="command-line-options.html#separate">-separate</a>,
953<a href="command-line-options.html#threshold">-threshold</a>, and
954<a href="command-line-options.html#white-threshold">-white-threshold</a>.
955</p>
956
957<p>Warning, some operators behave differently when the <a href="command-line-options.html#channel">+channel</a> default setting is in effect, verses ANY user defined <a href="command-line-options.html#channel">-channel</a> setting (including the equivalent of the
958default). These operators have yet to be made to understand the newer 'Sync'
959flag. </p>
960
961<p>For example <a href="command-line-options.html#threshold">-threshold</a> will by default gray-scale
962the image before thresholding, if no <a href="command-line-options.html#channel">-channel</a> setting
963has been defined. This is not 'Sync flag controlled, yet. </p>
964
965<p>Also some operators such as <a href="command-line-options.html#blur">-blur</a>, <a href="command-line-options.html#gaussian-blur">-gaussian-blur</a>, will modify their handling of the
966color channels if the '<code>alpha</code>' channel is also enabled by <a href="command-line-options.html#channel">-channel</a>. Generally this done to ensure that
967fully-transparent colors are treated as being fully-transparent, and thus any
968underlying 'hidden' color has no effect on the final results. Typically
969resulting in 'halo' effects. The newer <a href="command-line-options.html#morphology">-morphology</a>
970convolution equivalents however does have a understanding of the 'Sync' flag
971and will thus handle transparency correctly by default. </p>
972
973<p>As a alpha channel is optional within images, some operators will read the
974color channels of an image as a greyscale alpha mask, when the image has no
975alpha channel present, and the <a href="command-line-options.html#channel">-channel</a> setting tells
976the operator to apply the operation using alpha channels. The <a href="command-line-options.html#clut">-clut</a> operator is a good example of this. </p>
977
978
979
980<div style="margin: auto;">
981 <h4><a id="charcoal"></a>-charcoal <var>factor</var></h4>
982</div>
983
984<p class="magick-description">Simulate a charcoal drawing.</p>
985
986<div style="margin: auto;">
987 <h4><a id="chop"></a>-chop <var>geometry</var></h4>
988</div>
989
990<p class="magick-description">Remove pixels from the interior of an image.</p>
991
992<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <var>width</var>
993and <var>height</var> given in the of the <var>size</var>
994portion of the <var>geometry</var> argument give the number of
995columns and rows to remove. The <var>offset</var> portion of
996the <var>geometry</var> argument is influenced by
997a <a href="command-line-options.html#gravity">-gravity</a> setting, if present.</p>
998
999<p>The <a href="command-line-options.html#chop">-chop</a> option removes entire rows and columns,
1000and moves the remaining corner blocks leftward and upward to close the gaps.</p>
1001
1002<p>While it can remove internal rows and columns of pixels, it is more
1003typically used with as <a href="command-line-options.html#gravity">-gravity</a> setting and zero
1004offsets so as to remove a single edge from an image. Compare this to <a href="command-line-options.html#shave">-shave</a> which removes equal numbers of pixels from oppisite
1005sides of the image. </p>
1006
1007<p>Using <a href="command-line-options.html#chop">-chop</a> effectively undoes the results of a <a href="command-line-options.html#splice">-splice</a> that was given the same <var>geometry</var> and <a href="command-line-options.html#gravity">-gravity</a> settings. </p>
1008
1009<div style="margin: auto;">
1010 <h4><a id="clamp"></a>-clamp</h4>
1011</div>
1012
1013<p class="magick-description">set each pixel whose value is below zero to zero and any the pixel whose value is above the quantum range to the quantum range (e.g. 65535) otherwise the pixel value remains unchanged.</p>
1014
1015<div style="margin: auto;">
1016 <h4><a id="clip"></a>-clip</h4>
1017</div>
1018
1019<p class="magick-description">Apply the clipping path if one is present.</p>
1020
1021<p>If a clipping path is present, it is applied to subsequent operations.</p>
1022
1023<p>For example, in the command</p>
1024
1025<pre>
1026convert cockatoo.tif -clip -negate negated.tif
1027</pre>
1028
1029<p>only the pixels within the clipping path are negated.</p>
1030
1031<p>The <a href="command-line-options.html#clip">-clip</a> feature requires SVG support. If the SVG
1032delegate library is not present, the option is ignored.</p>
1033
1034<p>Use <a href="command-line-options.html#clip">+clip</a> to disable clipping for subsequent operations.</p>
1035
1036<div style="margin: auto;">
1037 <h4><a id="clip-mask"></a>-clip-mask</h4>
1038</div>
1039
1040<p class="magick-description">Clip the image as defined by this mask.</p>
1041
1042<p>Use the alpha channel of the current image as a mask. Any areas that is
1043white is not modified by any of the 'image processing operators' that follow,
1044until the mask is removed. Pixels in the black areas of the clip mask are
1045modified per the requirements of the operator. </p>
1046
1047<p>In some ways this is similar to (though not the same) as defining
1048a rectangular <a href="command-line-options.html#region">-region</a>, or using the negative of the
1049mask (third) image in a three image <a href="command-line-options.html#composite">-composite</a>,
1050operation. </p>
1051
1052<p>Use <a href="command-line-options.html#clip-mask">+clip-mask</a> to disable clipping for subsequent operations.</p>
1053
1054<div style="margin: auto;">
1055 <h4><a id="clip-path"></a>-clip-path <var>id</var></h4>
1056</div>
1057
1058<p class="magick-description">Clip along a named path from the 8BIM profile.</p>
1059
1060<p>This is identical to <a href="command-line-options.html#clip">-clip</a> except choose a specific clip path in the event the image has more than one path available. </p>
1061
1062<p>Use <a href="command-line-options.html#clip-path">+clip-path</a> to disable clipping for subsequent operations.</p>
1063
1064<div style="margin: auto;">
1065 <h4><a id="clone"></a>-clone <var>index(s)</var></h4>
1066</div>
1067
1068<p class="magick-description">make a clone of an image (or images).</p>
1069
1070<p>Inside parenthesis (where the operator is normally used) it will make a
1071clone of the images from the last 'pushed' image sequence, and adds them to
1072the end of the current image sequence. Outside parenthesis
1073(not recommended) it clones the images from the current image sequence. </p>
1074
1075<p>Specify the image by its index in the sequence. The first image is index
10760. Negative indexes are relative to the end of the sequence; for
1077example, <code>−1</code>
1078represents the last image of the sequence. Specify a range of images with a
1079dash (e.g. <code>0−4</code>). Separate multiple indexes with commas but no
1080spaces (e.g. <code>0,2,5</code>). A value of '<code>0−−1</code> will
1081effectively clone all the images. </p>
1082
1083<p>The <a href="command-line-options.html#clone">+clone</a> will simply make a copy of the last image
1084in the image sequence, and is thus equivalent to using a argument of
1085'<code>−1</code>'. </p>
1086
1087<div style="margin: auto;">
1088 <h4><a id="clut"></a>-clut</h4>
1089</div>
1090
1091<p class="magick-description">Replace the channel values in the first image using each corresponding channel in the second image as a <b>c</b>olor <b>l</b>ook<b>u</b>p <b>t</b>able.</p>
1092
1093<p>The second (LUT) image is ordinarily a gradient image containing the
1094histogram mapping of how each channel should be modified. Typically it is a
1095either a single row or column image of replacement color values. If larger
1096than a single row or column, values are taken from a diagonal line from
1097top-left to bottom-right corners.</p>
1098
1099<p>The lookup is further controlled by the <a href="command-line-options.html#interpolate">-interpolate</a> setting, which is especially handy for an
1100LUT which is not the full length needed by the ImageMagick installed Quality
1101(Q) level. Good settings for this are the '<code>bilinear</code>' and
1102'<code>bicubic</code>' interpolation settings, which give smooth color
1103gradients, and the '<code>integer</code>' setting for a direct, unsmoothed
1104lookup of color values. </p>
1105
1106<p>This operator is especially suited to replacing a grayscale image with a
1107specific color gradient from the CLUT image. </p>
1108
1109<p>Only the channel values defined by the <a href="command-line-options.html#channel">-channel</a>
1110setting will have their values replaced. In particular, since the default <a href="command-line-options.html#channel">-channel</a> setting is <code>RGB</code>, this means that
1111transparency (alpha/matte channel) is not affected, unless the <a href="command-line-options.html#channel">-channel</a> setting is modified. When the alpha channel is
1112set, it is treated by the <a href="command-line-options.html#clut">-clut</a> operator in the same way
1113as the other channels, implying that alpha/matte values are replaced using the
1114alpha/matte values of the original image. </p>
1115
1116<p>If either the image being modified, or the lookup image, contains no
1117transparency (i.e. <a href="command-line-options.html#alpha">-alpha</a> is turned 'off') but the <a href="command-line-options.html#channel">-channel</a> setting includes alpha replacement, then it is
1118assumed that image represents a gray-scale gradient which is used for the
1119replacement alpha values. That is you can use a gray-scale CLUT image to
1120adjust a existing images alpha channel, or you can color a gray-scale image
1121using colors form CLUT containing the desired colors, including transparency.
1122</p>
1123
1124<p>See also <a href="command-line-options.html#hald-clut">-hald-clut</a> which replaces colors
1125according to the lookup of the full color RGB value from a 2D representation
1126of a 3D color cube. </p>
1127
1128
1129<div style="margin: auto;">
1130 <h4><a id="coalesce"></a>-coalesce</h4>
1131</div>
1132
1133<p class="magick-description">Fully define the look of each frame of an GIF animation sequence, to form a 'film strip' animation.</p>
1134
1135<p>Overlay each image in an image sequence according to
1136its <a href="command-line-options.html#dispose">-dispose</a> meta-data, to reproduce the look of
1137an animation at each point in the animation sequence. All images should be
1138the same size, and are assigned appropriate GIF disposal settings for the
1139animation to continue working as expected as a GIF animation. Such frames
1140are more easily viewed and processed than the highly optimized GIF overlay
1141images. </p>
1142
1143<p>The animation can be re-optimized after processing using
1144the <a href="command-line-options.html#layers">-layers</a> method '<code>optimize</code>', although
1145there is no guarantee that the restored GIF animation optimization is
1146better than the original. </p>
1147
1148
1149<div style="margin: auto;">
1150 <h4><a id="colorize"></a>-colorize <var>value</var></h4>
1151</div>
1152
1153<p class="magick-description">Colorize the image by an amount specified by <var>value</var> using the color specified by the most recent <a href="command-line-options.html#fill">-fill</a> setting.</p>
1154
1155<p>Specify the amount of colorization as a percentage. Separate colorization
1156values can be applied to the red, green, and blue channels of the image with
1157a comma-delimited list of colorization
1158values (e.g., <code>-colorize 0,0,50</code>).</p>
1159
1160<div style="margin: auto;">
1161 <h4><a id="colormap"></a>-colormap <var>type</var></h4>
1162</div>
1163
1164<p class="magick-description">Define the colormap type.</p>
1165
1166<p>The <var>type</var> can be <code>shared</code> or <code>private</code>.</p>
1167
1168<p>This option only applies when the default X server visual
1169is <code>PseudoColor</code> or <code>GrayScale</code>. Refer
1170to <a href="command-line-options.html#visual">-visual</a> for more details. By default,
1171a shared colormap is allocated. The image shares colors with
1172other X clients. Some image colors could be approximated,
1173therefore your image may look very different than intended.
1174If <code>private</code> is chosen, the image colors appear exactly
1175as they are defined. However, other clients may go <var>technicolor</var>
1176when the image colormap is installed.</p>
1177
1178<div style="margin: auto;">
1179 <h4><a id="colors"></a>-colors <var>value</var></h4>
1180</div>
1181
1182<p class="magick-description">Set the preferred number of colors in the image.</p>
1183
1184<p>The actual number of colors in the image may be less than your request,
1185but never more. Note that this a color reduction option. Images with fewer
1186unique colors than specified by <var>value</var> will have any
1187duplicate or unused colors removed. The ordering of an existing color
1188palette may be altered. When converting an image from color to grayscale,
1189it is more efficient to convert the image to the gray colorspace before
1190reducing the number of colors. Refer to
1191the <a href="quantize.html">
1192color reduction algorithm</a> for more details.</p>
1193
1194<div style="margin: auto;">
1195 <h4><a id="color-matrix"></a>-color-matrix <var>matrix</var></h4>
1196</div>
1197
1198<p class="magick-description">apply color correction to the image.</p>
1199
1200<p>This option permits saturation changes, hue rotation, luminance to alpha,
1201and various other effects. Although variable-sized transformation matrices
1202can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6
1203for CMYKA (or RGBA with offsets). The matrix is similar to those used by
1204Adobe Flash except offsets are in column 6 rather than 5 (in support of
1205CMYKA images) and offsets are normalized (divide Flash offset by 255).</p>
1206
1207<p>As an example, to add contrast to an image with offsets, try this command:</p>
1208
1209<pre>
1210 convert kittens.jpg -color-matrix \
1211 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \
1212 0.0 1.5 0.0 0.0, 0.0, -0.157 \
1213 0.0 0.0 1.5 0.0, 0.0, -0.157 \
1214 0.0 0.0 0.0 1.0, 0.0, 0.0 \
1215 0.0 0.0 0.0 0.0, 1.0, 0.0 \
1216 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png
1217</pre>
1218<div style="margin: auto;">
1219 <h4><a id="colorspace"></a>-colorspace <var>value</var></h4>
1220</div>
1221
1222<p class="magick-description">Set the image colorspace.</p>
1223
1224<p>Choices are:</p>
1225
1226<pre>
1227 CMY CMYK Gray HCL
1228 HCLp HSB HSI HSL
1229 HSV HWB Lab LCHab
1230 LCHuv LMS Log Luv
1231 OHTA Rec601YCbCr Rec709YCbCr RGB
1232 scRGB sRGB Transparent xyY
1233 XYZ YCbCr YCC YDbDr
1234 YIQ YPbPr YUV
1235</pre>
1236
1237<p>To print a complete list of colorspaces, use <a href="command-line-options.html#list">-list colorspace</a>.</p>
1238
1239<p>For a more accurate color conversion to or from the linear RGB, CMYK, or grayscale colorspaces, use the <a href="command-line-options.html#profile">-profile</a> option. Note, ImageMagick assumes the sRGB colorspace if the image format does not indicate otherwise. For colorspace conversion, the gamma function is first removed to produce linear RGB.</p>
1240
1241<table class="table table-condensed table-striped">
1242 <caption>Conversion of RGB to Other Color Spaces</caption>
1243 <tr><th valign="middle">CMY</th></tr>
1244 <tr><td valign="middle">C=<var>QuantumRange</var>−R</td></tr>
1245 <tr><td valign="middle">M=<var>QuantumRange</var>−G</td></tr>
1246 <tr><td valign="middle">Y=<var>QuantumRange</var>−B</td></tr>
1247 <tr><th valign="middle">CMYK — starts with CMY from above</th></tr>
1248 <tr><td valign="middle">K=min(C,Y,M)</td></tr>
1249 <tr><td valign="middle">C=<var>QuantumRange</var>*(C−K)/(<var>QuantumRange</var>−K)</td></tr>
1250 <tr><td valign="middle">M=<var>QuantumRange</var>*(M−K)/(<var>QuantumRange</var>−K)</td></tr>
1251 <tr><td valign="middle">Y=<var>QuantumRange</var>*(Y−K)/(<var>QuantumRange</var>−K)</td></tr>
1252
1253 <tr><th valign="middle">Gray</th></tr>
1254 <tr><td valign="middle">Gray = 0.298839*R+0.586811*G+0.114350*B</td></tr>
1255
1256 <tr><th valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr>
1257 <tr><td valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1258 <tr><td valign="middle">S=distance from axis outward</td></tr>
1259 <tr><td valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <var>intensity-like</var></td></tr>
1260
1261 <tr><th valign="middle">HSL — Hue, Saturation, Lightness; like a double cone end-to-end with peaks at very top and bottom</th></tr>
1262 <tr><td valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
1263 <tr><td valign="middle">S=distance from axis outward</td></tr>
1264 <tr><td valign="middle">L=distance along axis from bottom upward; L=0.5*max(R,G,B) + 0.5*min(R,G,B); <var>intensity-like</var></td></tr>
1265
1266 <tr><th valign="middle">HWB — Hue, Whiteness, Blackness</th></tr>
1267 <tr><td valign="middle">Hue (complicated equation)</td></tr>
1268 <tr><td valign="middle">Whiteness (complicated equation)</td></tr>
1269 <tr><td valign="middle">Blackness (complicated equation)</td></tr>
1270
1271 <tr><th valign="middle">LAB</th></tr>
1272 <tr><td valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
1273 <tr><td valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
1274 <tr><td valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
1275
1276 <tr><th valign="middle">LOG</th></tr>
1277 <tr><td valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
1278 <tr><td valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
1279 <tr><td valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
1280
1281 <tr><th valign="middle">OHTA — approximates principal components transformation</th></tr>
1282 <tr><td valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <var>intensity-like</var></td></tr>
1283 <tr><td valign="middle">I2=(0.50000*R+0.00000*G−0.50000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1284 <tr><td valign="middle">I3=(−0.25000*R+0.50000*G−0.25000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1285
1286 <tr><th valign="middle">Rec601Luma</th></tr>
1287 <tr><td valign="middle">Gray = 0.298839*R+0.586811*G+0.114350*B</td></tr>
1288
1289 <tr><th valign="middle">Rec601YCbCr</th></tr>
1290 <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr>
1291 <tr><td valign="middle">Cb=(−0.168736*R-0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1292 <tr><td valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1293
1294 <tr><th valign="middle">Rec709Luma</th></tr>
1295 <tr><td valign="middle">Gray=0.212656*R+0.715158*G+0.072186*B</td></tr>
1296
1297 <tr><th valign="middle">Rec709YCbCr</th></tr>
1298 <tr><td valign="middle">Y=0.212656*R+0.715158*G+0.072186*B; <var>intensity-like</var></td></tr>
1299 <tr><td valign="middle">Cb=(−0.114572*R−0.385428*G+0.500000*B)+(<var>QuantumRange</var>+1)/2</td></tr>
1300 <tr><td valign="middle">Cr=(0.500000*R−0.454153*G−0.045847*B)+(<var>QuantumRange</var>+1)/2</td></tr>
1301
1302 <tr><th valign="middle">sRGB</th></tr>
1303 <tr><td valign="middle">if R ≤ .0.0031308 then Rs=R/12.92 else Rs=1.055 R ^ (1.0 / 2.4) ? 0.055</td></tr>
1304 <tr><td valign="middle">if G ≤ .0.0031308 then Gs=B/12.92 else Gs=1.055 R ^ (1.0 / 2.4) ? 0.055</td></tr>
1305 <tr><td valign="middle">if B ≤ .0.0031308 then Bs=B/12.92 else Bs=1.055 R ^ (1.0 / 2.4) ? 0.055</td></tr>
1306
1307 <tr><th valign="middle">XYZ</th></tr>
1308 <tr><td valign="middle">X=0.4124564*R+0.3575761*G+0.1804375*B</td></tr>
1309 <tr><td valign="middle">Y=0.2126729*R+0.7151522*G+0.0721750*B</td></tr>
1310 <tr><td valign="middle">Z=0.0193339*R+0.1191920*G+0.9503041*B</td></tr>
1311
1312 <tr><th valign="middle">YCC</th></tr>
1313 <tr><td valign="middle">Y=(0.298839*R+0.586811*G+0.114350*B) (with complicated scaling); <var>intensity-like</var></td></tr>
1314 <tr><td valign="middle">C1=(−0.298839*R−0.586811*G+0.88600*B) (with complicated scaling)</td></tr>
1315 <tr><td valign="middle">C2=(0.70100*R−0.586811*G−0.114350*B) (with complicated scaling)</td></tr>
1316
1317 <tr><th valign="middle">YCbCr</th></tr>
1318 <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr>
1319 <tr><td valign="middle">Cb=(−0.168736*R−0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1320 <tr><td valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1321
1322 <tr><th valign="middle">YIQ</th></tr>
1323 <tr><td valign="middle">Y=0.298839*R+0.586811*G+0.114350*B; <var>intensity-like</var></td></tr>
1324 <tr><td valign="middle">I=(0.59600*R−0.27400*G−0.32200*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1325 <tr><td valign="middle">Q=(0.21100*R−0.52300*G+0.31200*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1326
1327 <tr><th valign="middle">YPbPr</th></tr>
1328 <tr><td valign="middle">Y=0.2988390*R+0.5868110*G+0.1143500*B; <var>intensity-like</var></td></tr>
1329 <tr><td valign="middle">Pb=(−0.168736*R−0.331264*G+0.500000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1330 <tr><td valign="middle">Pr=(0.500000*R−0.418688*G−0.081312*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1331
1332 <tr><th valign="middle">YUV</th></tr>
1333 <tr><td valign="middle">Y=0.298839*R+0.586811*G+0.114350*B; <var>intensity-like</var></td></tr>
1334 <tr><td valign="middle">U=(−0.14740*R−0.28950*G+0.43690*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1335 <tr><td valign="middle">V=(0.61500*R−0.51500*G−0.10000*B)*(<var>QuantumRange</var>+1)/2</td></tr>
1336</table>
1337
1338<p>Note the scRGB colorspace requires HDRI support otherwise it behaves just like linear RGB.</p>
1339
1340<div style="margin: auto;">
1341 <h4><a id="combine"></a>-combine</h4>
1342</div>
1343
1344<p class="magick-description">Combine one or more images into a single image.</p>
1345
1346<p>The channels (previously set by <a href="command-line-options.html#channel">-channel</a>) of the
1347combined image are taken from the grayscale values of each image in the
1348sequence, in order. For the default -channel setting of <code>RGB</code>, this
1349means the first image is assigned to the <code>Red</code> channel, the second
1350to the <code>Green</code> channel, the third to the <code>Blue</code>.</p>
1351
1352<p>This option can be thought of as the inverse to <a href="command-line-options.html#separate">-separate</a>, so long as the channel settings are the same.
1353Thus, in the following example, the final image should be a copy of the
1354original. </p>
1355
1356<pre>
1357convert original.png -channel RGB -separate sepimage.png
1358convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB \
1359 -combine imagecopy.png
1360</pre>
1361
1362<div style="margin: auto;">
1363 <h4><a id="comment"></a>-comment <var>string</var></h4>
1364</div>
1365
1366<p class="magick-description">Embed a comment in an image.</p>
1367
1368<p>This option sets the comment meta-data of an image read in after this
1369option has been given. To modify a comment of images already in memory use
1370"<code><a href="command-line-options.html#set">-set</a> comment</code>". </p>
1371
1372<p>The comment can contain special format characters listed in the <a href="escape.html">Format and
1373Print Image Properties</a>. These attributes are expanded when the comment
1374is finally assigned to the individual images. </p>
1375
1376<p>If the first character of <var>string</var> is <var>@</var>, the image comment is read from a file titled by the
1377remaining characters in the string. Comments read in from a file are literal;
1378no embedded formatting characters are recognized.</p>
1379
1380<p>Comment meta-data are not visible on the image itself. To do that use the
1381<a href="command-line-options.html#annotate">-annotate</a> or <a href="command-line-options.html#draw">-draw</a> options
1382instead.</p>
1383
1384<p>For example,</p>
1385
1386<p class="crtsnip">
1387 -comment "%m:%f %wx%h" bird.miff
1388</p>
1389
1390<p>produces an image comment of <code>MIFF:bird.miff 512x480</code> (assuming
1391that the image <code>bird.miff</code> has a width of 512 and a height of
1392480.</p>
1393
1394<div style="margin: auto;">
1395 <h4><a id="compare"></a>-compare</h4>
1396</div>
1397
1398<p class="magick-description">mathematically and visually annotate the difference between an image and its reconstruction</p>
1399
1400<p>This is a convert version of "<code>compare</code>" for two same sized images. The syntax is as follows, but other metrics are allowed.</p>
1401
1402<pre>
1403convert image.png reference.png -metric RMSE -compare \ <br> difference.png
1404</pre>
1405
1406<p>To get the metric value use the string format "%[distortion]".</p>
1407
1408<pre>
1409convert image.png reference.png -metric RMSE -compare -format \
1410 "%[distortion]" info:
1411</pre>
1412
1413<div style="margin: auto;">
1414 <h4><a id="complex"></a>-complex <var>operator</var></h4>
1415</div>
1416
1417<p class="magick-description">perform complex mathematics on an image sequence</p>
1418
1419Choose from these operators:
1420
1421<pre>
1422 add
1423 conjugate
1424 divide
1425 magnuitude-phase
1426 multiply
1427 real-imaginary
1428 subtract
1429</pre>
1430
1431<p>Optionally specify the <code>divide</code> operator SNR with <code><a href="command-line-options.html#define">-define</a> complex:snr=float</code>.</p>
1432
1433<div style="margin: auto;">
1434 <h4><a id="compose"></a>-compose <var>operator</var></h4>
1435</div>
1436
1437<p class="magick-description">Set the type of image composition.</p>
1438
1439<p>See <a href="compose.html">Alpha Compositing</a> for
1440a detailed discussion of alpha compositing.</p>
1441
1442<p>This setting effects image processing operators that merge two (or more)
1443images together in some way. This includes the operators,
1444<a href="command-line-options.html#composite">-compare</a>,
1445<a href="command-line-options.html#composite">-composite</a>,
1446<a href="command-line-options.html#layers">-layers</a> composite,
1447<a href="command-line-options.html#flatten">-flatten</a>,
1448<a href="command-line-options.html#mosaic">-mosaic</a>,
1449<a href="command-line-options.html#layers">-layers</a> merge,
1450<a href="command-line-options.html#border">-border</a>,
1451<a href="command-line-options.html#frame">-frame</a>,
1452and <a href="command-line-options.html#extent">-extent</a>. </p>
1453
1454<p>It is also one of the primary options for the "<code>composite</code>"
1455command. </p>
1456
1457
1458<div style="margin: auto;">
1459 <h4><a id="composite"></a>-composite</h4>
1460</div>
1461
1462<p class="magick-description">Perform alpha composition on two images and an optional mask</p>
1463
1464<p>Take the first image 'destination' and overlay the second 'source' image
1465according to the current <a href="command-line-options.html#compose">-compose</a> setting. The location
1466of the 'source' or 'overlay' image is controlled according to <a href="command-line-options.html#geometry">-geometry</a>, and <a href="command-line-options.html#geometry">-geometry</a>
1467settings. </p>
1468
1469<p>If a third image is given this is treated as a gray-scale blending 'mask' image
1470relative to the first 'destination' image. This mask is blended with the
1471source image. However for the '<code>displace</code>' compose method, the
1472mask is used to provide a separate Y-displacement image instead. </p>
1473
1474<p>If a <a href="command-line-options.html#compose">-compose</a> method requires extra numerical
1475arguments or flags these can be provided by setting the <a href="command-line-options.html#set">-set</a> '<code>option:compose:args</code>'
1476appropriately for the compose method. </p>
1477
1478<p>Some <a href="command-line-options.html#compose">-compose</a> methods can modify the 'destination'
1479image outside the overlay area. You can disable this by setting the special <a href="command-line-options.html#set">-set</a> '<code>option:compose:outside-overlay</code>'
1480to '<code>false</code>'. </p>
1481
1482<p>The SVG compositing specification requires that color and opacity values range between zero and QuantumRange inclusive. You can permit values outside this range with this option: <a href="command-line-options.html#set">-set</a> '<code>option:compose:clamp=false</code></p>
1483
1484
1485<div style="margin: auto;">
1486 <h4><a id="compress"></a>-compress <var>type</var></h4>
1487</div>
1488
1489<p class="magick-description">Use pixel compression specified by <var>type</var> when writing the image.</p>
1490
1491<p>Choices are: <code>None</code>, <code>BZip</code>, <code>Fax</code>, <code>Group4</code>, <code>JPEG</code>, <code>JPEG2000</code>, <code>Lossless</code>, <code>LZW</code>, <code>RLE</code> or <code>Zip</code>.</p>
1492
1493<p>To print a complete list of compression types, use <a href="command-line-options.html#list">-list
1494compress</a>.</p>
1495
1496<p>Specify <a href="command-line-options.html#compress">+compress</a> to store the binary image in an
1497uncompressed format. The default is the compression type of the specified
1498image file.</p>
1499
1500<p>If <code>LZW</code> compression is specified but LZW compression has not been
1501enabled, the image data is written in an uncompressed LZW format that can be
1502read by LZW decoders. This may result in larger-than-expected GIF files.</p>
1503
1504<p><code>Lossless</code> refers to lossless JPEG, which is only available if the
1505JPEG library has been patched to support it. Use of lossless JPEG is generally
1506not recommended.</p>
1507
1508<p>
1509When writing an ICO file, you may request that the images be encoded in
1510PNG format, by specifying <code>Zip</code> compression.</p>
1511
1512<p>
1513When writing a JNG file, specify <code>Zip</code> compression to request that
1514the alpha channel be encoded in PNG "IDAT" format, or <code>JPEG</code>
1515to request that it be encoded in JPG "JDAA" format.</p>
1516
1517<p>Use the <a href="command-line-options.html#quality">-quality</a> option to set the compression level
1518to be used by JPEG, PNG, MIFF, and MPEG encoders.
1519Use the <a href="command-line-options.html#sampling-factor">-sampling-factor</a> option to set the
1520sampling factor to be used by JPEG, MPEG, and YUV encoders for down-sampling
1521the chroma channels.</p>
1522
1523<div style="margin: auto;">
1524 <h4><a id="connected-components"></a>-connected-components <var>connectivity</var></h4>
1525</div>
1526
1527<p class="magick-description">connected-components uniquely labeled, choose from 4 or 8 way connectivity.</p>
1528
1529<p>Use <code><a href="command-line-options.html#define">-define</a> connected-components:verbose=true</code> to output statistics associated with each unique label.</p>
1530
1531<div style="margin: auto;">
1532 <h4><a id="contrast"></a>-contrast</h4>
1533</div>
1534
1535<p class="magick-description">Enhance or reduce the image contrast.</p>
1536
1537<p>This option enhances the intensity differences between the lighter and
1538darker elements of the image. Use <a href="command-line-options.html#contrast">-contrast</a> to enhance
1539the image or <a href="command-line-options.html#contrast">+contrast</a> to reduce the image
1540contrast.</p>
1541
1542<p>For a more pronounced effect you can repeat the option:</p>
1543
1544<pre>
1545convert rose: -contrast -contrast rose_c2.png
1546</pre>
1547
1548<div style="margin: auto;">
1549 <h4><a id="contrast-stretch"></a>-contrast-stretch <var>black-point</var><br>-contrast-stretch <var>black-point</var>{x<var>white-point</var>}{<var>%</var>}}</h4>
1550</div>
1551
1552<p class="magick-description">Increase the contrast in an image by <var>stretching</var> the range of intensity values.</p>
1553
1554<p>While performing the stretch, black-out at most <var>black-point</var> pixels and white-out at most <var>white-point</var> pixels. Or, if percent is used, black-out at most
1555<var>black-point %</var> pixels and white-out at most <var>white-point %</var> pixels.</p>
1556
1557<p>Prior to ImageMagick 6.4.7-0, <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a> will black-out at most <var>black-point</var> pixels and white-out at most <var>total pixels
1558minus white-point</var> pixels. Or, if percent is used, black-out at most <var>black-point %</var> pixels and white-out at most <var>100% minus white-point %</var> pixels.</p>
1559
1560<p>Note that <code>-contrast-stretch 0</code> will modify the image such that
1561the image's min and max values are stretched to 0 and <var>QuantumRange</var>, respectively, without any loss of data due to burn-out or
1562clipping at either end. This is not the same as <a href="command-line-options.html#normalize">-normalize</a>, which is equivalent to <code>-contrast-stretch 0.15x0.05%</code> (or
1563prior to ImageMagick 6.4.7-0, <code>-contrast-stretch 2%x99%</code>).</p>
1564
1565<p>Internally operator works by creating a histogram bin, and then uses that
1566bin to modify the image. As such some colors may be merged together when they
1567originally fell into the same 'bin'. </p>
1568
1569<p>All the channels are normalized in concert by the came amount so as to
1570preserve color integrity, when the default <a href="command-line-options.html#channel">+channel</a>
1571setting is in use. Specifying any other <a href="command-line-options.html#channel">-channel</a>
1572setting will normalize the RGB channels independently.</p>
1573
1574<p>See also <a href="command-line-options.html#auto-level">-auto-level</a> for a 'perfect'
1575normalization of mathematical images. </p>
1576
1577<p>This operator is under review for re-development. </p>
1578
1579
1580<div style="margin: auto;">
1581 <h4><a id="convolve"></a>-convolve <var>kernel</var></h4>
1582</div>
1583
1584<p class="magick-description">Convolve an image with a user-supplied convolution kernel.</p>
1585
1586<p>The <var>kernel</var> is a matrix specified as
1587a comma-separated list of integers (with no spaces), ordered left-to right,
1588starting with the top row. Presently, only odd-dimensioned kernels are
1589supported, and therefore the number of entries in the specified <var>kernel</var> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25,
15907<sup>2</sup>=49, etc. </p>
1591
1592<p>Note that the <a href="command-line-options.html#convolve">‑convolve</a> operator supports the <a href="command-line-options.html#bias">‑bias</a> setting. This option shifts the convolution so that
1593positive and negative results are relative to a user-specified bias value.
1594This is important for non-HDRI compilations of ImageMagick when dealing with
1595convolutions that contain negative as well as positive values. This is
1596especially the case with convolutions involving high pass filters or edge
1597detection. Without an output bias, the negative values is clipped at zero.
1598</p>
1599
1600<p>When using an ImageMagick with the HDRI compile-time setting, <a href="command-line-options.html#bias">‑bias</a> is not needed, as ImageMagick is able to store/handle any
1601negative results without clipping to the color value range (0..QuantumRange).
1602See the discussion on HDRI implementations of ImageMagick on the page <a href="high-dynamic-range.html">High
1603Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this
1604<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
1605entry. </p>
1606
1607
1608<div style="margin: auto;">
1609 <h4><a id="crop"></a>-crop <var>geometry</var>{<var>@</var>}{<var>!</var>}</h4>
1610</div>
1611
1612<p class="magick-description">Cut out one or more rectangular regions of the image.</p>
1613
1614<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
1615
1616<p>The <var>width</var> and <var>height</var> of the <var>geometry</var> argument give the size of the image that remains
1617after cropping, and <var>x</var> and <var>y</var> in the
1618<var>offset</var> (if present) gives the location of the top left
1619corner of the cropped image with respect to the original image. To specify the
1620amount to be removed, use <a href="command-line-options.html#shave">-shave</a> instead.</p>
1621
1622<p>If the <var>x</var> and <var>y</var> offsets are
1623present, a single image is generated, consisting of the pixels from the
1624cropping region. The offsets specify the location of the upper left corner of
1625the cropping region measured downward and rightward with respect to the upper
1626left corner of the image. If the <a href="command-line-options.html#gravity">-gravity</a> option is
1627present with <code>NorthEast</code>, <code>East</code>, or <code>SouthEast</code>
1628gravity, it gives the distance leftward from the right edge of the image to
1629the right edge of the cropping region. Similarly, if the <a href="command-line-options.html#gravity">-gravity</a> option is present with <code>SouthWest</code>,
1630<code>South</code>, or <code>SouthEast</code> gravity, the distance is measured
1631upward between the bottom edges.</p>
1632
1633<p>If the <var>x</var> and <var>y</var> offsets are
1634omitted, a set of tiles of the specified geometry, covering the entire input
1635image, is generated. The rightmost tiles and the bottom tiles are smaller if
1636the specified geometry extends beyond the dimensions of the input image.</p>
1637
1638<p>You can add the <var>@</var> to the geometry argument to equally divide the image into the number of tiles generated.</p>
1639
1640<p>By adding a exclamation character flag to the geometry argument, the
1641cropped images virtual canvas page size and offset is set as if the
1642geometry argument was a viewport or window. This means the canvas page size
1643is set to exactly the same size you specified, the image offset set
1644relative top left corner of the region cropped. </p>
1645
1646<p>If the cropped image 'missed' the actual image on its virtual canvas, a
1647special single pixel transparent 'missed' image is returned, and a 'crop
1648missed' warning given. </p>
1649
1650<p>It might be necessary to <a href="command-line-options.html#repage">+repage</a> the image prior to
1651cropping the image to ensure the crop coordinate frame is relocated to the
1652upper-left corner of the visible image.
1653
1654Similarly you may want to use <a href="command-line-options.html#repage">+repage</a> after cropping to
1655remove the page offset that will be left behind. This is especially true when
1656you are going to write to an image format such as PNG that supports an image
1657offset.</p>
1658
1659<div style="margin: auto;">
1660 <h4><a id="cycle"></a>-cycle <var>amount</var></h4>
1661</div>
1662
1663<p class="magick-description">displace image colormap by amount.</p>
1664
1665<p><var>Amount</var> defines the number of positions each
1666colormap entry is shifted.</p>
1667
1668
1669<div style="margin: auto;">
1670 <h4><a id="debug"></a>-debug <var>events</var></h4>
1671</div>
1672
1673<p class="magick-description">enable debug printout.</p>
1674
1675<p>The <code>events</code> parameter specifies which events are to be logged. It
1676can be either <code>None</code>, <code>All</code>, <code>Trace</code>, or
1677a comma-separated list consisting of one or more of the following domains:
1678<code>Accelerate</code>, <code>Annotate</code>, <code>Blob</code>, <code>Cache</code>,
1679<code>Coder</code>, <code>Configure</code>, <code>Deprecate</code>,
1680<code>Exception</code>, <code>Locale</code>, <code>Render</code>,
1681<code>Resource</code>, <code>Security</code>, <code>TemporaryFile</code>,
1682<code>Transform</code>, <code>X11</code>, or <code>User</code>. </p>
1683
1684
1685<p>For example, to log cache and blob events, use.</p>
1686
1687<pre>
1688convert -debug "Cache,Blob" rose: rose.png
1689</pre>
1690
1691<p>The <code>User</code> domain is normally empty, but developers can log user
1692events in their private copy of ImageMagick.</p>
1693
1694<p>To print the complete list of debug methods, use <a href="command-line-options.html#list">-list
1695debug</a>.</p>
1696
1697<p>Use the <a href="command-line-options.html#log">-log</a> option to specify the format for debugging
1698output.</p>
1699
1700<p>Use <a href="command-line-options.html#debug">+debug</a> to turn off all logging.</p>
1701
1702<p>Debugging may also be set using the <code>MAGICK_DEBUG</code> <a href="resources.html#environment">environment variable</a>. The allowed values for the <code>MAGICK_DEBUG</code>
1703environment variable are the same as for the <a href="command-line-options.html#debug">-debug</a>
1704option.</p>
1705
1706
1707<div style="margin: auto;">
1708 <h4><a id="decipher"></a>-decipher <var>filename</var></h4>
1709</div>
1710
1711<p class="magick-description">Decipher and restore pixels that were previously transformed by <a href="command-line-options.html#encipher">-encipher</a>.</p>
1712
1713<p>Get the passphrase from the file specified by <var>filename</var>.</p>
1714
cristy44443b92015-05-05 00:06:07 +0000[diff] [blame]1715<p>For more information, see the webpage, <a href="../www/cipher.html">ImageMagick: Encipher or
cristyd2432012015-05-04 23:15:15 +0000[diff] [blame]1716Decipher an Image</a>.</p>
1717
1718
1719<div style="margin: auto;">
1720 <h4><a id="deconstruct"></a>-deconstruct</h4>
1721</div>
1722
1723<p class="magick-description">find areas that has changed between images </p>
1724
1725<p>Given a sequence of images all the same size, such as produced by <a href="command-line-options.html#coalesce">-coalesce</a>, replace the second and later images, with
1726a smaller image of just the area that changed relative to the previous image.
1727</p>
1728
1729<p>The resulting sequence of images can be used to optimize an animation
1730sequence, though will not work correctly for GIF animations when parts of the
1731animation can go from opaque to transparent. </p>
1732
1733<p>This option is actually equivalent to the <a href="command-line-options.html#layers">-layers</a>
1734method '<code>compare-any</code>'. </p>
1735
1736
1737<div style="margin: auto;">
1738 <h4><a id="define"></a>-define <var>key</var>{<var>=value</var>}<var>...</var></h4>
1739</div>
1740
1741<p class="magick-description">add specific global settings generally used to control coders and image processing operations.</p>
1742
1743<p>This option creates one or more definitions for coders and decoders to use
1744while reading and writing image data. Definitions are generally used to
1745control image file format coder modules, and image processing operations,
1746beyond what is provided by normal means. Defined settings are listed in <a href="command-line-options.html#verbose">-verbose</a> information ("<code>info:</code>" output format)
1747as "Artifacts". </p>
1748
1749<p>If <var>value</var> is missing for a definition, an empty-valued
1750definition of a flag is created with that name. This used to control on/off
1751options. Use <a href="command-line-options.html#define">+define key</a> to remove definitions
1752previously created. Use <a href="command-line-options.html#define">+define "*"</a> to remove all
1753existing definitions.</p>
1754
1755<p>The same 'artifact' settings can also be defined using the <a href="command-line-options.html#set">-set "option:<var>key</var>" "<var>value</var>"</a> option, which also allows the use of <a href="escape.html">Format and Print Image
1756Properties</a> in the defined value. </p>
1757
1758<p>The <var>option</var> and <var>key</var> are case-independent (they are
1759converted to lowercase for use within the decoders) while the <var>value</var>
1760is case-dependent.</p>
1761
1762<p>Such settings are global in scope, and affect all images and operations. </p>
1763
1764<p>The following definitions are just some of the artifacts that are
1765available:</p>
1766
1767<dl>
1768
1769<dt>bmp:format=<var>value</var></dt>
1770 <dd> valid values are <var>bmp2</var>, <var>bmp3</var>,
1771 and <var>bmp4</var>. This option can be useful when the
1772 method of prepending "BMP2:" to the output filename is inconvenient or
1773 is not available, such as when using the <a href="mogrify.html">mogrify</a> utility.</dd>
1774
1775<dt>complex:snr=<var>value</var></dt>
1776 <dd>Set the divide SNR constant<a href="command-line-options.html#complex">-complex</a></dd>
1777
1778<dt>compose:args=<var>arguments</var></dt>
1779 <dd>Sets certain compose argument values when using convert ... -compose ...
cristy44443b92015-05-05 00:06:07 +0000[diff] [blame]1780 -composite. See <a href="compose.html">Image Composition</a></dd>
cristyd2432012015-05-04 23:15:15 +0000[diff] [blame]1781
1782<dt>convolve:scale=<var>{kernel_scale}[!^] [,{origin_addition}] [%]</var></dt>
1783 <dd>Defines the kernel scaling. The special flag ! automatically scales to
1784 full dynamic range. The ! flag can be used in combination with a factor or
1785 percent. The factor or percent is then applied after the automatic scaling.
1786 An example is 50%!. This produces a result 50% darker than full dynamic
1787 range scaling. The ^ flag assures the kernel is 'zero-summing', for
1788 example when some values are positive and some are negative as in edge
1789 detection kernels. The origin addition adds that value to the center
1790 pixel of the kernel. This produces and effect that is like adding the image
1791 that many times to the result of the filtered image. The typical value
1792 is 1 so that the original image is added to the result of the convolution.
1793 The default is 0.</dd>
1794
1795<dt>convolve:showkernel=<var>1</var></dt>
1796 <dd>Outputs (to 'standard error') all the information about a specified <a href="command-line-options.html#morphology">-morphology convolve</a> kernel.</dd>
1797
1798<dt>dcm:display-range=<var>reset</var></dt>
1799 <dd>Sets the display range to the minimum and maximum pixel values for the
1800 DCM image format.</dd>
1801
1802<dt>dds:cluster-fit=<var>true|false</var></dt>
1803 <dd>Enables the dds cluster-fit.</dd>
1804
1805<dt>dds:compression=<var>dxt1|dxt5|none</var></dt>
1806 <dd>Sets the dds compression.</dd>
1807
1808<dt>dds:mipmaps=<var>value</var></dt>
1809 <dd>Sets the dds number of mipmaps.</dd>
1810
1811<dt>dds:weight-by-alpha=<var>true|false</var></dt>
1812 <dd>Enables the dds alpha weighting.</dd>
1813
1814<dt>delegate:bimodal=<var>true</var></dt>
1815 <dd>Specifies direct conversion from Postscript to PDF.</dd>
1816
1817<dt>distort:scale=<var>value</var></dt>
1818 <dd>Sets the output scaling factor for use with <a href="command-line-options.html#distort">-distort</a></dd>
1819
1820<dt>distort:viewport=<var>WxH+X+Y</var></dt>
1821 <dd>Sets the viewport for use with <a href="command-line-options.html#distort">-distort</a></dd>
1822
1823<dt>dot:layout-engine=<var>value</var></dt>
1824 <dd>Specifies the layout engine for the DOT image format (e.g.
1825 <code>neato</code>).</dd>
1826
1827<dt>filter:option=<var>value</var></dt>
1828 <dd>Set a filter option for use with <a href="command-line-options.html#resize">-resize</a>.
1829 See <a href="command-line-options.html#filter">-filter</a> for details.</dd>
1830
1831<dt>fourier:normalize=<var>inverse</var></dt>
1832 <dd>Sets the location for the FFT/IFT normalization as use by
1833 <a href="command-line-options.html#fft">+-fft</a> and <a href="command-line-options.html#ift">+-ift</a>. The default is
1834 forward.</dd>
1835
1836<dt>icon:auto-resize</dt>
1837 <dd>Automatically stores multiple sizes when writing an ico image
1838 (requires a 256x256 input image).</dd>
1839
1840<dt>jp2:layer-number=<var>value</var></dt>
1841 <dd>Sets the maximum number of quality layers to decode. Same for JPT, JC2,
1842 and J2K</dd>
1843
1844<dt>jp2:number-resolutions=<var>value</var></dt>
1845 <dd>Sets the number of resolutions to encode.Same for JPT, JC2, and J2K</dd>
1846
1847<dt>jp2:progression-order=<var>value</var></dt>
1848 <dd>choose from LRCP, RLCP, RPCL, PCRL or CPRL. Same for JPT, JC2, and
1849 J2K</dd>
1850
1851<dt>jp2:quality=<var>value,value...</var></dt>
1852 <dd>Sets the quality layer PSNR, given in dB. The order is from left to
1853 right in ascending order. The default is a single lossless quality layer.
1854 Same for JPT, JC2, and J2K</dd>
1855
1856<dt>jp2:rate=<var>value</var></dt>
1857 <dd>Specify the compression factor to use while writing JPEG-2000 files. The
1858 compression factor is the reciprocal of the compression ratio. The valid
1859 range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined,
1860 this value overrides the -quality setting. A quality setting of 75
1861 results in a rate value of 0.06641. Same for JPT, JC2, and J2K</dd>
1862
1863<dt>jp2:reduce-factor=<var>value</var></dt>
1864 <dd>Sets the number of highest resolution levels to be discarded.Same for
1865 JPT, JC2, and J2K</dd>
1866
1867<dt>jpeg:block-smoothing=<var>on|off</var></dt>
1868
1869<dt>jpeg:colors=<var>value</var></dt>
1870 <dd>Set the desired number of colors and let the JPEG encoder do the
1871 quantizing.</dd>
1872
1873<dt>jpeg:dct-method=<var>value</var></dt>
1874 <dd>Choose from <code>default</code>, <code>fastest</code>,
1875 <code>float</code>, <code>ifast</code>, and <code>islow</code>.</dd>
1876
1877<dt>jpeg:extent=<var>value</var></dt>
1878 <dd>Restrict the maximum JPEG file size, for example <code>-define
1879 jpeg:extent=400KB</code>. The JPEG encoder will search for the highest
1880 compression quality level that results in an output file that does not
1881 exceed the value. The <code>-quality</code> option is ignored if it
1882 is also present.</dd>
1883
1884<dt>jpeg:fancy-upsampling=<var>on|off</var></dt>
1885
1886<dt>jpeg:optimize-coding=<var>on|off</var></dt>
1887
1888<dt>jpeg:q-table=<var>table</var></dt>
1889
1890<dt>jpeg:sampling-factor=<var>sampling-factor-string</var></dt>
1891
1892<dt>jpeg:size=<var>geometry</var></dt>
1893 <dd>Set the size hint of a JPEG image, for
1894 example, <code>-define jpeg:size=128x128</code>.
1895 It is most useful for increasing performance and reducing the memory
1896 requirements when reducing the size of a large JPEG image.</dd>
1897
1898<dt>json:features</dt>
1899 <dd>includes features in verbose information</dd>
1900
1901<dt>json:limit</dt>
1902
1903<dt>json:locate</dt>
1904
1905<dt>json:moments</dt>
1906 <dd>includes image moments in verbose information</dd>
1907
1908<dt>mng:need-cacheoff</dt>
1909 <dd>turn playback caching off for streaming MNG.</dd>
1910
1911<dt>morphology:compose=<var>compose-method</var></dt>
1912 <dd>Specifies how to merge results generated by multiple<a href="command-line-options.html#morphology">-morphology</a> kernel. The default is none. One
1913 typical value is 'lighten' as used, for example, with the sobel edge
1914 kernels. </dd>
1915
1916<dt>morphology:showkernel=<var>1</var></dt>
1917 <dd>Outputs (to 'standard error') all the information about a generated <a href="command-line-options.html#morphology">-morphology</a> kernel.</dd>
1918
1919<dt>pcl:fit-to-page=<var>true</var></dt>
1920
1921<dt>pdf:fit-page=<var>geometry</var></dt>
1922 <dd> geometry specifies the scaling dimensions for resizing when the PDF is
1923 being read. The geometry is either WxH{%} or page size. No offsets are
1924 allowed. (introduced in IM 6.8.8-8)</dd>
1925
1926<dt>pdf:fit-to-page=<var>true</var></dt>
1927
1928<dt>pdf:use-cropbox=<var>true</var></dt>
1929
1930<dt>pdf:use-trimbox=<var>true</var></dt>
1931
1932<dt>png:bit-depth=<var>value</var></dt>
1933<dt>png:color-type=<var>value</var></dt>
1934 <dd>desired bit-depth and color-type for PNG output. You can force the PNG
1935 encoder to use a different bit-depth and color-type than it would have
1936 normally selected, but only if this does not cause any loss of image
1937 quality. Any attempt to reduce image quality is treated as an error and no
1938 PNG file is written. E.g., if you have a 1-bit black-and-white image, you
1939 can use these "defines" to cause it to be written as an 8-bit grayscale,
1940 indexed, or even a 64-bit RGBA. But if you have a 16-million color image,
1941 you cannot force it to be written as a grayscale or indexed PNG. If you
1942 wish to do this, you must use the appropriate <a href="command-line-options.html#depth">-depth</a>,
1943 <a href="command-line-options.html#colors">-colors</a>, or <a href="command-line-options.html#type">-type</a> directives to
1944 reduce the image quality prior to using the PNG encoder. Note that in
1945 indexed PNG files, "bit-depth" refers to the number of bits per index,
1946 which can be 1, 2, 4, or 8. In such files, the color samples always have
1947 8-bit depth.</dd>
1948
1949<dt>png:compression-filter=<var>value</var></dt>
1950 <dd> valid values are 0 through 9. 0-4 are the corresponding PNG filters,
1951 5 means adaptive filtering except for images with a colormap, 6 means
1952 adaptive filtering for all images, 7 means MNG "loco" compression, 8 means
1953 Z_RLE strategy with adaptive filtering, and 9 means Z_RLE strategy with no
1954 filtering.</dd>
1955
1956<dt>png:compression-level=<var>value</var></dt>
1957 <dd> valid values are 0 through 9, with 0 providing the least but fastest
1958 compression and 9 usually providing the best and always the slowest.</dd>
1959
1960<dt>png:compression-strategy=<var>value</var></dt>
1961 <dd> valid values are 0 through 4, meaning default, filtered, huffman_only,
1962 rle, and fixed ZLIB compression strategy. If you are using an old zlib
1963 that does not support Z_RLE (before 1.2.0) or Z_FIXED (before 1.2.2.2),
1964 values 3 and 4, respectively, will use the zlib default strategy
1965 instead.</dd>
1966
1967<dt>png:format=<var>value</var></dt>
1968 <dd> valid values are <var>png8</var>, <var>png24</var>,
1969 <var>png32</var>, <var>png48</var>,
1970 <var>png64</var>, and <var>png00</var>.
1971 This property can be useful for specifying
1972 the specific PNG format to be used, when the usual method of prepending the
1973 format name to the output filename is inconvenient, such as when writing
1974 a PNG-encoded ICO file or when using <a href="mogrify.html">mogrify</a>.
1975 Value = <var>png8</var> reduces the number of colors to 256,
1976 only one of which may be fully transparent, if necessary. The other
1977 values do not force any reduction of quality; it is an error to request
1978 a format that cannot represent the image data without loss (except that
1979 it is allowed to reduce the bit-depth from 16 to 8 for all formats).
1980 Value = <var>png24</var> and <var>png48</var>
1981 allow transparency, only if a single color is fully transparent and that
1982 color does not also appear in an opaque pixel; such transparency is
1983 written in a PNG <code>tRNS</code> chunk.
1984 Value = <var>png00</var> causes the image to inherit its
1985 color-type and bit-depth from the input image, if the input was also
1986 a PNG.</dd>
1987
1988<dt>png:exclude-chunk=<var>value</var></dt>
1989
1990<dt>png:include-chunk=<var>value</var></dt>
1991 <dd>ancillary chunks to be excluded from or included in PNG output.
1992
1993 <p>The <var>value</var> can be the name of a PNG chunk-type such
1994 as <var>bKGD</var>, a comma-separated list of chunk-names
1995 (which can include the word <var>date</var>, the word
1996 <var>all</var>, or the word <var>none</var>).
1997 Although PNG chunk-names are case-dependent, you can use all lowercase
1998 names if you prefer.</p>
1999
2000 <p>The "include-chunk" and "exclude-chunk" lists only affect the behavior
2001 of the PNG encoder and have no effect on the PNG decoder.</p>
2002
2003 <p>As a special case, if the <code>sRGB</code> chunk is excluded and
2004 the <code>gAMA</code> chunk is included, the <code>gAMA</code> chunk will
2005 only be written if gamma is not 1/2.2, since most decoders assume
2006 sRGB and gamma=1/2.2 when no colorspace information is included in
2007 the PNG file. Because the list is processed from left to right, you
2008 can achieve this with a single define:</p>
2009
2010<pre>
2011 -define png:include-chunk=none,gAMA
2012</pre>
2013
2014 <p>As a special case, if the <code>sRGB</code> chunk is not excluded and
2015 the PNG encoder recognizes that the image contains the sRGB ICC profile,
2016 the PNG encoder will write the <code>sRGB</code> chunk instead of the
2017 entire ICC profile. To force the PNG encoder to write the sRGB
2018 profile as an <code>iCCP</code> chunk in the output PNG instead of the
2019 <code>sRGB</code> chunk, exclude the <code>sRGB</code> chunk.</p>
2020
2021 <p>The critical PNG chunks <code>IHDR</code>, <code>PLTE</code>,
2022 <code>IDAT</code>, and <code>IEND</code> cannot be excluded. Any such
2023 entries appearing in the list will be ignored.</p>
2024
2025 <p>If the ancillary PNG <code>tRNS</code> chunk is excluded and the
2026 image has transparency, the PNG colortype is forced to be 4 or 6
2027 (GRAY_ALPHA or RGBA). If the image is not transparent, then the
2028 <code>tRNS</code> chunk isn't written anyhow, and there is no effect
2029 on the PNG colortype of the output image.</p>
2030
2031 <p>The <a href="command-line-options.html#strip">-strip</a> option does the equivalent of the
2032 following for PNG output:</p>
2033
2034<pre>
2035 -define png:exclude-chunk=EXIF,iCCP,iTXt,sRGB,tEXt,zCCP,zTXt,date
2036</pre>
2037
2038 <p>The default behavior is to include all known PNG ancillary chunks
2039 plus ImageMagick's private <code>vpAg</code> ("virtual page") chunk,
2040 and to exclude all PNG chunks that are unknown to ImageMagick,
2041 regardless of their PNG "copy-safe" status as described in the
2042 PNG specification.</p>
2043
2044 <p>Any chunk names that are not known to ImageMagick are ignored
2045 if they appear in either the "include-chunk" or "exclude-chunk" list.
2046 The ancillary chunks currently known to ImageMagick are
2047 <code>bKGD</code>, <code>cHRM</code>, <code>gAMA</code>, <code>iCCP</code>,
2048 <code>oFFs</code>, <code>pHYs</code>, <code>sRGB</code>, <code>tEXt</code>,
2049 <code>tRNS</code>, <code>vpAg</code>, and <code>zTXt</code>.</p>
2050
2051 <p>You can also put <code>date</code> in the list to include or exclude
2052 the "Date:create" and "Date:modify" text chunks that ImageMagick normally
2053 inserts in the output PNG.</p></dd>
2054
2055<dt>png:preserve-colormap[=<var>true</var>]</dt>
2056 <dd>Use the existing image-&gt;colormap. Normally the PNG encoder will
2057 try to optimize the palette, eliminating unused entries and putting
2058 the transparent colors first. If this flag is set, that behavior
2059 is suppressed.</dd>
2060
2061<dt>png:preserve-iCCP[=<var>true</var>]</dt>
2062 <dd>By default, the PNG decoder and encoder examine any ICC profile
2063 that is present, either from an <code>iCCP</code> chunk in the PNG
2064 input or supplied via an option, and if the profile is recognized
2065 to be the sRGB profile, converts it to the <code>sRGB</code> chunk.
2066 You can use <code>-define png:preserve-iCCP</code> to prevent
2067 this from happening; in such cases the <code>iCCP</code> chunk
2068 will be read or written and no <code>sRGB</code> chunk will be
2069 written. There are some ICC profiles that claim to be sRGB but
2070 have various errors that cause them to be rejected by libpng16; such
2071 profiles are recognized anyhow and converted to the <code>sRGB</code>
2072 chunk, but are rejected if the <code>-define png:preserve-iCCP</code>
2073 is present. Note that not all "sRGB" ICC profiles are recognized
2074 yet; we will add them to the list as we encounter them.</dd>
2075
2076<dt>png:swap-bytes[=<var>true</var>]</dt>
2077 <dd>The PNG specification requires that any multi-byte integers be stored in
2078 network byte order (MSB-LSB endian). This option allows you to
2079 fix any invalid PNG files that have 16-bit samples stored incorrectly
2080 in little-endian order (LSB-MSB). The "-define png:swap-bytes" option
2081 must appear before the input filename on the commandline. The swapping
2082 is done during the libpng decoding operation.</dd>
2083
2084<dt>profile:skip=<var>name1,name2,...</var></dt>
2085 <dd>Skip the named profile[s] when reading the image. Use skip="*" to
2086 skip all named profiles in the image. Many named profiles exist,
2087 including ICC, EXIF, APP1, IPTC, XMP, and others.</dd>
2088
2089<dt>ps:imagemask</dt>
2090 <dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create
2091 Postscript files that render bilevel images with the Postscript imagemask
2092 operator instead of the image operator.</dd>
2093
2094<dt>quantum:format=<var>type</var></dt>
2095 <dd>Set the type to <code>floating-point</code> to specify a floating-point
2096 format for raw files (e.g. GRAY:) or for MIFF and TIFF images in HDRI mode
2097 to preserve negative values. If <a href="command-line-options.html#depth">-depth</a> 16 is
2098 included, the result is a single precision floating point format.
2099 If <a href="command-line-options.html#depth">-depth</a> 32 is included, the result is
2100 double precision floating point format.</dd>
2101
2102<dt>quantum:polarity=<var>photometric-interpretation</var></dt>
2103 <dd>Set the photometric-interpretation of an image (typically for TIFF image
2104 file format) to either <code>min-is-black</code> (default) or
2105 <code>min-is-white</code>.</dd>
2106
2107<dt>sample:offset=<var>geometry</var></dt>
2108 <dd>Location of the sampling point within the sub-region being sampled,
2109 expressed as percentages (see <a href="command-line-options.html#sample">-sample</a>).</dd>
2110
2111<dt>showkernel=<var>1</var></dt>
2112 <dd>Outputs (to 'standard error') all the information about a generated <a href="command-line-options.html#morphology">-morphology</a> kernel.</dd>
2113
2114<dt>stream:buffer-size=<var>value</var></dt>
2115 <dd>Set the stream buffer size. Select 0 for unbuffered I/O.</dd>
2116
2117<dt>tiff:alpha=<var>associated|unassociated|unspecified</var></dt>
2118 <dd>Specify the alpha extra samples as associated, unassociated or unspecified </dd>
2119
2120<dt>tiff:endian=<var>msb|lsb</var></dt>
2121
2122<dt>tiff:exif-properties=<var>false</var></dt>
2123 <dd>Skips reading the EXIF properties.</dd>
2124
2125<dt>tiff:fill-order=<var>msb|lsb</var></dt>
2126
2127<dt>tiff:ignore-tags=<var>comma-separate-list-of-tag-IDs</var></dt>
2128 <dd>Allows one or more tag ID values to be ignored.</dd>
2129
2130<dt>tiff:rows-per-strip=<var>value</var></dt>
2131 <dd>Sets the number of rows per strip</dd>
2132
2133<dt>tiff:tile-geometry=<var>WxH</var></dt>
2134 <dd>Sets the tile size for pyramid tiffs. Requires the suffix
2135 PTIF: before the outputname</dd>
2136</dl>
2137
2138<p>For example, to create a postscript file that will render only the black
2139pixels of a bilevel image, use:</p>
2140
2141<pre>
2142convert bilevel.tif -define ps:imagemask eps3:stencil.ps
2143</pre>
2144
2145<p>Set attributes of the image registry by prefixing the value with
2146<code>registry:</code>. For example, to set a temporary path to put work files,
2147use:</p>
2148
2149<p class="crtsnip">
2150-define registry:temporary-path=/data/tmp
2151</p>
2152
2153<div style="margin: auto;">
2154 <h4><a id="delay"></a>-delay <var>ticks</var> <br>-delay <var>ticks</var>x<var>ticks-per-second</var> {<var>&lt;</var>} {<var>&gt;</var>}</h4>
2155</div>
2156
2157<p class="magick-description">display the next image after pausing.</p>
2158
2159<p>This option is useful for regulating the animation of image sequences
2160<var>ticks/ticks-per-second</var> seconds must expire before the display of the
2161next image. The default is no delay between each showing of the image
2162sequence. The default ticks-per-second is 100.</p>
2163
2164<p>Use <code>&gt;</code> to change the image delay <var>only</var> if its current
2165value exceeds the given delay. <code>&lt;</code> changes the image delay
2166<var>only</var> if current value is less than the given delay. For example, if
2167you specify <code>30&gt;</code> and the image delay is 20, the image delay does
2168not change. However, if the image delay is 40 or 50, the delay it is changed
2169to 30. Enclose the given delay in quotation marks to prevent the
2170<code>&lt;</code> or <code>&gt;</code> from being interpreted by your shell as
2171a file redirection.</p>
2172
2173
2174<div style="margin: auto;">
2175 <h4><a id="delete"></a>-delete <var>indexes</var></h4>
2176</div>
2177
2178<p class="magick-description">delete the images specified by index, from the image sequence.</p>
2179
2180<p>Specify the image by its index in the sequence. The first image is index
21810. Negative indexes are relative to the end of the sequence, for example, -1
2182represents the last image of the sequence. Specify a range of images with
2183a dash (e.g. 0-4). Separate indexes with a comma (e.g. 0,2). Use
2184<code>+delete</code> to delete the last image in the current image sequence.</p>
2185
2186
2187<div style="margin: auto;">
2188 <h4><a id="density"></a>-density <var>width</var><br>-density <var>width</var>x<var>height</var></h4>
2189</div>
2190
2191<p class="magick-description">Set the horizontal and vertical resolution of an image for rendering to devices.</p>
2192
2193<p>This option specifies the image resolution to store while encoding a raster
2194image or the canvas resolution while rendering (reading) vector formats such
2195as Postscript, PDF, WMF, and SVG into a raster image. Image resolution
2196provides the unit of measure to apply when rendering to an output device or
2197raster image. The default unit of measure is in dots per inch (DPI). The <a href="command-line-options.html#units">-units</a> option may be used to select dots per centimeter
2198instead.</p>
2199
2200<p>The default resolution is 72 dots per inch, which is equivalent to one
2201point per pixel (Macintosh and Postscript standard). Computer screens are
2202normally 72 or 96 dots per inch, while printers typically support 150, 300,
2203600, or 1200 dots per inch. To determine the resolution of your display, use
2204a ruler to measure the width of your screen in inches, and divide by the
2205number of horizontal pixels (1024 on a 1024x768 display).</p>
2206
2207<p>If the file format supports it, this option may be used to update the
2208stored image resolution. Note that Photoshop stores and obtains image
2209resolution from a proprietary embedded profile. If this profile is not
2210stripped from the image, then Photoshop will continue to treat the image using
2211its former resolution, ignoring the image resolution specified in the standard
2212file header.</p>
2213
2214<p>The <a href="command-line-options.html#density">-density</a> option sets an <var>attribute</var> and
2215does not alter the underlying raster image. It may be used to adjust the
2216rendered size for desktop publishing purposes by adjusting the scale applied
2217to the pixels. To resize the image so that it is the same size at a different
2218resolution, use the <a href="command-line-options.html#resample">-resample</a> option.</p>
2219
2220<div style="margin: auto;">
2221 <h4><a id="depth"></a>-depth <var>value</var></h4>
2222</div>
2223
2224<p class="magick-description">depth of the image.</p>
2225
2226<p>This the number of bits in a color sample within a pixel. Use this option
2227to specify the depth of raw images whose depth is unknown such as GRAY, RGB,
2228or CMYK, or to change the depth of any image after it has been read.</p>
2229
2230<div style="margin: auto;">
2231 <h4><a id="descend"></a>-descend</h4>
2232</div>
2233
2234<p class="magick-description">obtain image by descending window hierarchy.</p>
2235
2236<div style="margin: auto;">
2237 <h4><a id="deskew"></a>-deskew <var>threshold</var></h4>
2238</div>
2239
2240<p class="magick-description">straighten an image. A threshold of 40% works for most images.</p>
2241
2242<p>Use <a href="command-line-options.html#set">-set</a> <code>option:deskew:auto-crop
2243<var>width</var></code> to auto crop the image. The set argument is the pixel
2244width of the image background (e.g 40).</p>
2245
2246<div style="margin: auto;">
2247 <h4><a id="despeckle"></a>-despeckle</h4>
2248</div>
2249
2250<p class="magick-description">reduce the speckles within an image.</p>
2251
2252<div style="margin: auto;">
2253 <h4><a id="direction"></a>-direction <var>type</var></h4>
2254</div>
2255
2256<p class="magick-description">render text right-to-left or left-to-right.</p>
2257
2258<div style="margin: auto;">
2259 <h4><a id="displace"></a>-displace <var>horizontal-scale</var><br>-displace <var>horizontal-scale</var>x<var>vertical-scale</var></h4>
2260</div>
2261
2262<p class="magick-description">shift image pixels as defined by a displacement map.</p>
2263
2264<p>With this option, the 'overlay' image, and optionally the 'mask' image,
2265is used as a displacement map, which is used to displace the lookup of
2266what part of the 'background' image is seen at each point of the overlaid
2267area. Much like the displacement map is a 'lens' that redirects light shining
2268through it so as to present a distorted view the original 'background' image
2269behind it. </p>
2270
2271<p>Any perfect grey areas of the displacement map produce a zero
2272displacement of the image. Black areas produce the given maximum negative
2273displacement of the lookup point, while white produce a maximum positive
2274displacement of the lookup. </p>
2275
2276<p>Note that it is the lookup of the 'background' that is displaced, not a
2277displacement of the image itself. As such an area of the displacement map
2278containing 'white' will have the lookup point 'shifted' by a positive amount,
2279and thus generating a copy of the destination image to the right/downward from
2280the correct position. That is the image will look like it may have been
2281'shifted' in a negative left/upward direction. Understanding this is a very
2282important in understanding how displacement maps work. </p>
2283
2284<p>The given arguments define the maximum amount of displacement in pixels
2285that a particular map can produce. If the displacement scale is large enough
2286it is also possible to lookup parts of the 'background' image that lie well
2287outside the bounds of the displacement map itself. That is you could very
2288easily copy a section of the original image from outside the overlay area
2289into the overlay area. </p>
2290
2291<p>The '%' flag makes the displacement scale relative to the size of the
2292overlay image (100% = half width/height of image). Using '!' switches
2293percentage arguments to refer to the destination image size instead.
2294these flags were added as of IM v6.5.3-5.</p>
2295
2296<p>Normally a single grayscale displacement map is provided, which with the
2297given scaling values will determine a single direction (vector) in which
2298displacements can occur (positively or negatively). However, if you also
2299specify a third image which is normally used as a <var>mask</var>,
2300the <var>composite image</var> is used for horizontal X
2301displacement, while the <var>mask image</var> is used for vertical Y
2302displacement. This allows you to define completely different displacement
2303values for the X and Y directions, and allowing you to lookup any point within
2304the <var>scale</var> bounds. In other words each pixel can lookup
2305any other nearby pixel, producing complex 2 dimensional displacements, rather
2306than a simple 1 dimensional vector displacements. </p>
2307
2308<p>Alternatively rather than supplying two separate images, as of IM v6.4.4-0,
2309you can use the 'red' channel of the overlay image to specify the horizontal
2310or X displacement, and the 'green' channel for the vertical or Y displacement.
2311</p>
2312
2313<p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a
2314mask the transparency of the destination image. However areas outside the
2315overlaid areas will not be effected. </p>
2316
2317
2318<div style="margin: auto;">
2319 <h4><a id="display"></a>-display <var>host:display[.screen]</var></h4>
2320</div>
2321
2322<p class="magick-description">Specifies the X server to contact.</p>
2323
2324<p>This option is used with convert for obtaining image or font from this
2325X server. See <var>X(1)</var>.</p>
2326
2327<div style="margin: auto;">
2328 <h4><a id="dispose"></a>-dispose <var>method</var></h4>
2329</div>
2330
2331<p class="magick-description">define the GIF disposal image setting for images that are being created or read in. </p>
2332
2333<p>The layer disposal method defines the way each the displayed image is to be
2334modified after the current 'frame' of an animation has finished being
2335displayed (after its 'delay' period), but before the next frame on an
2336animation is to be overlaid onto the display. </p>
2337
2338<p>Here are the valid methods:</p>
2339
2340<pre>
2341 Undefined 0 No disposal specified (equivalent to '<code>none</code>').
2342 None 1 Do not dispose, just overlay next frame image.
2343 Background 2 Clear the frame area with the background color.
2344 Previous 3 Clear to the image prior to this frames overlay.
2345</pre>
2346
2347<p>You can also use the numbers given above, which is what the GIF format
2348uses internally to represent the above settings. </p>
2349
2350<p>To print a complete list of dispose methods, use <a href="command-line-options.html#list">-list dispose</a>.</p>
2351
2352<p>Use <a href="command-line-options.html#dispose">+dispose</a>, turn off the setting and prevent
2353resetting the layer disposal methods of images being read in. </p>
2354
2355<p>Use <a href="command-line-options.html#set">-set</a> '<code>dispose</code>' method to set the image
2356disposal method for images already in memory.</p>
2357
2358<div style="margin: auto;">
2359 <h4><a id="dissimilarity-threshold"></a>-dissimilarity-threshold <var>value</var></h4>
2360</div>
2361
2362<p class="magick-description">maximum RMSE for subimage match (default 0.2).</p>
2363
2364
2365<div style="margin: auto;">
2366 <h4><a id="dissolve"></a>-dissolve <var>src_percent</var>[x<var>dst_percent</var>]</h4>
2367</div>
2368
2369<p class="magick-description">dissolve an image into another by the given percent.</p>
2370
2371<p>The opacity of the composite image is multiplied by the given percent, then
2372it is composited 'over' the main image. If <var>src_percent</var>
2373is greater than 100, start dissolving the main image so it becomes
2374transparent at a value of '<code>200</code>'. If both percentages
2375are given, each image are dissolved to the percentages given. </p>
2376
2377<p>Note that dissolve percentages do not add, two opaque images dissolved
2378'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
2379images, you would need to use dissolve values of '50,100'. </p>
2380
2381<div style="margin: auto;">
2382 <h4><a id="distort"></a>-distort <var>method arguments</var></h4>
2383</div>
2384
2385<p class="magick-description">distort an image, using the given <var>method</var> and its required <var>arguments</var>.</p>
2386
2387<p>The <var>arguments</var> is a single string containing a list
2388of floating point numbers separated by commas or spaces. The number of
2389and meaning of the floating point values depends on the distortion <var>method</var> being used. </p>
2390
2391<p>Choose from these distortion types:</p>
2392
2393<table class="table table-condensed table-striped">
2394 <tr>
2395 <th style="width: 8%">Method</th>
2396 <th>Description</th>
2397 </tr>
2398
2399 <tr>
2400 <td><code>ScaleRotateTranslate</code>
2401 <br>or <code>SRT</code></td>
2402 <td>
2403 Distort image by first scaling and rotating about a given 'center',
2404 before translating that 'center' to the new location, in that order. It
2405 is an alternative method of specifying a '<code>Affine</code>' type of
2406 distortion, but without shearing effects. It also provides a good way
2407 of rotating and displacing a smaller image for tiling onto a larger
2408 background (IE 2-dimensional animations). <br>
2409
2410 The number of arguments determine the specific meaning of each
2411 argument for the scales, rotation, and translation operations. <br>
2412
2413 <table style="margin-left:auto; margin-right:auto;">
2414 <tr><td># </td><td>arguments meaning</td></tr>
2415 <tr><td>1:</td><td><var>Angle_of_Rotation</var></td></tr>
2416 <tr><td>2:</td><td><var>Scale Angle</var></td></tr>
2417 <tr><td>3:</td><td><var>X,Y Angle</var></td></tr>
2418 <tr><td>4:</td><td><var>X,Y Scale Angle</var></td></tr>
2419 <tr><td>5:</td>
2420 <td><var>X,Y ScaleX,ScaleY Angle</var></td></tr>
2421 <tr><td>6:</td>
2422 <td><var>X,Y Scale Angle NewX,NewY</var></td></tr>
2423 <tr><td>7:</td>
2424 <td><var>X,Y ScaleX,ScaleY Angle
2425 NewX,NewY</var></td></tr>
2426 </table>
2427
2428 This is actually an alternative way of specifying a 2 dimensional linear
2429 '<code>Affine</code>' or '<code>AffineProjection</code>' distortion. </td> </tr>
2430
2431 <tr>
2432 <td><code>Affine</code></td>
2433 <td>
2434 Distort the image linearly by moving a list of at least 3 or more sets
2435 of control points (as defined below). Ideally 3 sets or 12 floating
2436 point values are given allowing the image to be linearly scaled,
2437 rotated, sheared, and translated, according to those three points. See
2438 also the related '<code>AffineProjection</code>' and '<code>SRT</code>'
2439 distortions. <br>
2440
2441 More than 3 sets given control point pairs (12 numbers) is least
2442 squares fitted to best match a linear affine distortion. If only 2
2443 control point pairs (8 numbers) are given a two point image translation
2444 rotation and scaling is performed, without any possible shearing,
2445 flipping or changes in aspect ratio to the resulting image. If only one
2446 control point pair is provides the image is only translated, (which may
2447 be a floating point non-integer translation). <br>
2448
2449 This distortion does not include any form of perspective distortion.
2450 </td>
2451
2452 </tr>
2453
2454 <tr>
2455 <td><code>AffineProjection</code></td>
2456 <td>
2457 Linearly distort an image using the given Affine Matrix of 6
2458 pre-calculated coefficients forming a set of Affine Equations to map
2459 the source image to the destination image.
2460
2461 <div style="text-align: center"><var>
2462 s<sub>x</sub>, r<sub>x</sub>,
2463 r<sub>y</sub>, s<sub>y</sub>,
2464 t<sub>x</sub>, t<sub>y</sub>
2465 </var></div>
2466
2467 See <a href="command-line-options.html#affine">-affine</a> setting for more detail, and
2468 meanings of these coefficients. <br>
2469
2470 The distortions '<code>Affine</code>' and '<code>SRT</code>' provide
2471 alternative methods of defining this distortion, with ImageMagick doing
2472 the calculations needed to generate the required coefficients. You can
2473 see the internally generated coefficients, by using a <a href="command-line-options.html#verbose">-verbose</a> setting with those other variants. </td>
2474
2475 </tr>
2476
2477 <tr>
2478 <td><code>BilinearForward</code><br>
2479 <code>BilinearReverse</code></td>
2480 <td>
2481 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or
2482 16 values (see below). Not that lines may not appear straight after
2483 distortion, though the distance between coordinates will remain
2484 consistent. <br>
2485
2486 The '<code>BilinearForward</code>' is used to map rectangles to any
2487 quadrilateral, while the '<code>BilinearReverse</code>' form maps any
2488 quadrilateral to a rectangle, while preserving the straight line edges
2489 in each case. <br>
2490
2491 Note that '<code>BilinearForward</code>' can generate invalid pixels
2492 which will be colored using the <a href="command-line-options.html#mattecolor">-mattecolor</a>
2493 color setting. Also if the quadrilateral becomes 'flipped' the image
2494 may disappear. <br>
2495
2496 There are future plans to produce a true Bilinear distortion that will
2497 attempt to map any quadrilateral to any other quadrilateral, while
2498 preserving edges (and edge distance ratios).
2499
2500 </td>
2501 </tr>
2502
2503 <tr>
2504 <td><code>Perspective</code></td>
2505 <td>
2506 Perspective distort the images, using a list of 4 or more sets of
2507 control points (as defined below). More that 4 sets (16 numbers) of
2508 control points provide least squares fitting for more accurate
2509 distortions (for the purposes of image registration and panorama
2510 effects). Less than 4 sets will fall back to a '<code>Affine</code>'
2511 linear distortion. <br>
2512
2513 Perspective Distorted images ensures that straight lines remain
2514 straight, but the scale of the distorted image will vary. The horizon
2515 is anti-aliased, and the 'sky' color may be set using the
2516 <a href="command-line-options.html#mattecolor">-mattecolor</a> setting. </td>
2517 </tr>
2518
2519 <tr>
2520 <td><code>PerspectiveProjection</code> </td>
2521 <td>
2522 Do a '<code>Perspective</code>' distortion biased on a set of 8
2523 pre-calculated coefficients. You can get these coefficients by looking
2524 at the <a href="command-line-options.html#verbose">-verbose</a> output of a
2525 '<code>Perspective</code>' distortion, or by calculating them yourself.
2526 If the last two perspective scaling coefficients are zero, the
2527 remaining 6 represents a transposed 'Affine Matrix'. </td>
2528
2529 </tr>
2530
2531 <tr>
2532 <td><code>Arc</code></td>
2533 <td>
2534 Arc the image (variation of polar mapping) over the angle given around
2535 a circle. <br>
2536 <table width="90%" style="margin-left: auto; margin-right: auto;">
2537 <tr><td>Argument</td>
2538 <td>Meaning</td></tr>
2539 <tr><td><var>arc_angle</var></td>
2540 <td>The angle over which to arc the image side-to-side</td></tr>
2541 <tr><td><var>rotate_angle</var></td>
2542 <td>Angle to rotate resulting image from vertical center</td></tr>
2543 <tr><td><var>top_radius</var></td>
2544 <td>Set top edge of source image at this radius</td></tr>
2545 <tr><td><var>bottom_radius</var> </td>
2546 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2547 </table>
2548
2549 The resulting image is always resized to best fit the resulting image,
2550 (as if using <a href="command-line-options.html#distort">+distort</a>) while attempting to
2551 preserve scale and aspect ratio of the original image as much as
2552 possible with the arguments given by the user. All four arguments will
2553 be needed to change the overall aspect ratio of an 'Arc'ed image. <br>
2554
2555 This a variation of a polar distortion designed to try to preserve the
2556 aspect ratio of the image rather than direct Cartesian to Polar
2557 conversion. </td>
2558 </tr>
2559
2560 <tr>
2561 <td><code>Polar</code></td>
2562 <td>
2563 Like '<code>Arc</code>' but do a complete Cartesian to Polar mapping of
2564 the image. that is the height of the input image is mapped to the
2565 radius limits, while the width is wrapped around between the
2566 angle limits. <br>
2567
2568 Arguments: <var>Rmax,Rmin CenterX,CenterY, start,end_angle</var> <br>
2569
2570 All arguments are optional. With <var>Rmin</var> defaulting to zero, the
2571 center to the center of the image, and the angles going from -180 (top)
2572 to +180 (top). If <var>Rmax</var> is given the special value of
2573 '<code>0</code>', the the distance from the center to the nearest edge
2574 is used for the radius of the output image, which will ensure the whole
2575 image is visible (though scaled smaller). However a special value of
2576 '<code>-1</code>' will use the distance from the center to the furthest
2577 corner, This may 'clip' the corners from the input rectangular image,
2578 but will generate the exact reverse of a '<code>DePolar</code>' with
2579 the same arguments. <br>
2580
2581 If the plus form of distort (<a href="command-line-options.html#distort">+distort</a>) is used
2582 output image center will default to <code>0,0</code> of the virtual
2583 canvas, and the image size adjusted to ensure the whole input image is
2584 made visible in the output image on the virtual canvas. </td>
2585
2586 </tr>
2587
2588 <tr>
2589 <td><code>DePolar</code></td>
2590 <td>
2591 Uses the same arguments and meanings as a '<code>Polar</code>' distortion
2592 but generates the reverse Polar to Cartesian distortion. <br>
2593
2594 The special <var>Rmax</var> setting of '<code>0</code>' may however clip
2595 the corners of the input image. However using the special
2596 <var>Rmax</var> setting of '<code>-1</code>' (maximum center to corner
2597 distance) will ensure the whole distorted image is preserved in the
2598 generated result, so that the same argument to '<code>Polar</code>' will
2599 reverse the distortion re-producing the original.
2600
2601 Note that as this distortion requires the area resampling of a circular
2602 arc, which can not be handled by the builtin EWA resampling function.
2603 As such the normal EWA filters are turned off. It is recommended some
2604 form of 'super-sampling' image processing technique be used to produce
2605 a high quality result. </td>
2606
2607 </tr>
2608
2609 <tr>
2610 <td><code>Barrel</code></td>
2611 <td>
2612 Given the four coefficients (A,B,C,D) as defined by <a href="http://wiki.panotools.org/Lens_correction_model">Helmut
2613 Dersch</a>, perform a barrel or pin-cushion distortion appropriate to
2614 correct radial lens distortions. That is in photographs, make straight
2615 lines straight again. <br>
2616
2617 Arguments: <var>A B C</var> [ <var>D</var> [
2618 <var>X</var> , <var>Y</var> ] ] <br>
2619 or <var>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub>
2620 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></var>
2621 [ <var>X</var> , <var>Y</var> ] <br>
2622 So that it forms the function <br>
2623 Rsrc = r * ( <var>A</var>*r<sup>3</sup> + <var>B</var>*r<sup>2</sup> +
2624 <var>C</var>*r + <var>D</var> )<br>
2625
2626 Where <var>X</var>,<var>Y</var> is the optional center of the distortion
2627 (defaulting to the center of the image). <br>
2628 The second form is typically used to distort images, rather than
2629 correct lens distortions. <br>
2630 </td>
2631
2632 </tr>
2633
2634 <tr>
2635 <td><code>BarrelInverse</code></td>
2636 <td>
2637 This is very similar to '<code>Barrel</code>' with the same set of
2638 arguments, and argument handling. However it uses the inverse
2639 of the radial polynomial,
2640 so that it forms the function <br>
2641 Rsrc = r / ( <var>A</var>*r<sup>3</sup> + <var>B</var>*r<sup>2</sup> +
2642 <var>C</var>*r + <var>D</var> )<br>
2643 Note that this is not the reverse of the '<code>Barrel</code>'
2644 distortion, just a different barrel-like radial distortion method.
2645
2646 </td>
2647 </tr>
2648
2649 <tr>
2650 <td><code>Shepards</code></td>
2651 <td>
2652 Distort the given list control points (any number) using an Inverse
2653 Squared Distance Interpolation Method (<a href="http://en.wikipedia.org/wiki/Shepard%27s_method">Shepards
2654 Method</a>). The control points in effect do 'localized' displacement
2655 of the image around the given control point (preserving the look and
2656 the rotation of the area near the control points. For best results
2657 extra control points should be added to 'lock' the positions of the
2658 corners, edges and other unchanging parts of the image, to prevent
2659 their movement. <br>
2660
2661 The distortion has been likened to 'taffy pulling' using nails, or
2662 pins' stuck in a block of 'jelly' which is then moved to the new
2663 position, distorting the surface of the jelly. <br>
2664
2665 Internally it is equivalent to generating a displacement map (see <a href="command-line-options.html#displace">-displace</a>) for source image color look-up using
2666 the <a href="command-line-options.html#sparse-color">-sparse-color</a> method of the same name.
2667
2668 </td>
2669 </tr>
2670
2671</table>
2672
2673<p>To print a complete list of distortion methods, use <a href="command-line-options.html#list">-list
2674distort</a>.</p>
2675
2676<p>Many of the above distortion methods such as '<code>Affine</code>',
2677'<code>Perspective</code>', and '<code>Shepards</code>' use a list control points
2678defining how these points in the given image should be distorted in the
2679destination image. Each set of four floating point values represent a source
2680image coordinate, followed immediately by the destination image coordinate.
2681This produces a list of values such as...</p>
2682<div style="text-align: center"><var>
2683 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub>
2684 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub>
2685 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub>
2686 ...
2687 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub>
2688</var></div>
2689<p>where <var>U,V</var> on the source image is mapped to <var>X,Y</var> on the
2690destination image. </p>
2691
2692<p>For example, to warp an image using '<code>perspective</code>' distortion,
2693needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2694perspective distortion of the built-in "rose:" image. Note how spaces were
2695used to group the 4 sets of coordinate pairs, to make it easier to read and
2696understand.</p>
2697
2698<pre>
2699convert rose: -virtual-pixel black \
2700 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \
2701 rose_3d_rotated.gif"
2702</pre>
2703
2704<p>If more that the required number of coordinate pairs are given for
2705a distortion, the distortion method is 'least squares' fitted to produce the
2706best result for all the coordinate pairs given. If less than the ideal number
2707of points are given, the distort will generally fall back to a simpler form of
2708distortion that can handles the smaller number of coordinates (usually a linear
2709'<code>Affine</code>' distortion). </p>
2710
2711<p>By using more coordinates you can make use of image registration tool to
2712find matching coordinate pairs in overlapping images, so as to improve the
2713'fit' of the distortion. Of course a bad coordinate pair can also make the
2714'fit' worse. Caution is always advised. </p>
2715
2716<p>Colors are acquired from the source image according to a cylindrical
2717resampling <a href="command-line-options.html#filter">-filter</a>, using a special technique known as
2718EWA resampling. This produces very high quality results, especially when
2719images become smaller (minified) in the output, which is very common when
2720using '<code>perspective</code>' distortion. For example here we view
2721a infinitely tiled 'plane' all the way to the horizon. </p>
2722
2723<pre>
2724convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \
2725 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \
2726 checks_tiled.jpg
2727</pre>
2728
2729<p>Note that a infinitely tiled perspective images involving the horizon can
2730be very slow, because of the number of pixels that are compressed to generate
2731each individual pixel close to the 'horizon'. You can turn off EWA
2732resampling, by specifing the special <a href="command-line-options.html#filter">-filter</a> setting of
2733'<code>point</code>' (recommended if you plan to use super-sampling instead).
2734</p>
2735
2736<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2737example, <a href="command-line-options.html#distort">-distort</a> will use the current <a href="command-line-options.html#mattecolor">-mattecolor</a> setting for these pixels. If you do not
2738what these pixels to be visible, set the color to match the rest of the
2739ground. </p>
2740
2741<p>The output image size will by default be the same as the input image. This
2742means that if the part of the distorted image falls outside the viewed area of
2743the 'distorted space', those parts is clipped and lost. However if you use
2744the plus form of the operator (<a href="command-line-options.html#distort">+distort</a>) the operator
2745will attempt (if possible) to show the whole of the distorted image, while
2746retaining a correct 'virtual canvas' offset, for image layering. This offset
2747may need to be removed using <a href="command-line-options.html#repage">+repage</a>, to remove if it
2748is unwanted. </p>
2749
2750<p>Setting <a href="command-line-options.html#verbose">-verbose</a> setting, will cause <a href="command-line-options.html#distort">-distort</a> to attempt to output the internal coefficients,
2751and the <a href="command-line-options.html#fx">-fx</a> equivalent to the distortion, for expert study,
2752and debugging purposes. This many not be available for all distorts. </p>
2753
2754<p>You can alternatively specify a special "<code><a href="command-line-options.html#define">-define</a> distort:viewport={geometry_string}</code>" setting which will
2755specify the size and the offset of the generated 'viewport' image of the
2756distorted image space.</p>
2757
2758<p>Setting a "<code><a href="command-line-options.html#define">-define</a>
2759distort:scale={scale_factor}</code>" will scale the output image (viewport or
2760otherwise) by that factor without changing the viewed contents of the
2761distorted image. This can be used either for 'super-sampling' the image for
2762a higher quality result, or for panning and zooming around the image (with
2763appropriate viewport changes, or post-distort cropping and resizing). </p>
2764
2765<p>Setting "<code><a href="command-line-options.html#define">-define</a> resample:verbose=1</code>"
2766will output the cylindrical filter lookup table created by the EWA (Elliptical
2767Weighted Average) resampling algorithm. Note this table uses a squared radius
2768lookup value. This is typically only used for debugging EWA resampling. </p>
2769
2770
2771<div style="margin: auto;">
2772 <h4><a id="distribute-cache"></a>-distribute-cache <var>port</var></h4>
2773</div>
2774
2775<p class="magick-description">launch a distributed pixel cache server. </p>
2776
2777<div style="margin: auto;">
2778 <h4><a id="dither"></a>-dither <var>method</var></h4>
2779</div>
2780
2781<p class="magick-description">Apply a Riemersma or Floyd-Steinberg error diffusion dither to
2782images when general color reduction is applied via an option, or automagically
2783when saving to specific formats. This enabled by default.</p>
2784
2785<p>Dithering places two or more colors in neighboring pixels so that to the
2786eye a closer approximation of the images original color is reproduced. This
2787reduces the number of colors needed to reproduce the image but at the cost of
2788a lower level pattern of colors. Error diffusion dithers can use any set of
2789colors (generated or user defined) to an image. </p>
2790
2791<p>Dithering is turned on by default, to turn it off use the plus form of the
2792setting, <a href="command-line-options.html#dither">+dither</a>. This will also also render PostScript
2793without text or graphic aliasing. Disabling dithering often (but not always)
2794leads to faster process, a smaller number of colors, but more cartoon like
2795image coloring. Generally resulting in 'color banding' effects in areas with
2796color gradients. </p>
2797
2798<p>The color reduction operators <a href="command-line-options.html#colors">-colors</a>, <a href="command-line-options.html#monochrome">-monochrome</a>, <a href="command-line-options.html#remap%20">-remap</a>, and <a href="command-line-options.html#posterize">-posterize</a>, apply dithering to images using the reduced
2799color set they created. These operators are also used as part of automatic
2800color reduction when saving images to formats with limited color support, such
2801as <code>GIF:</code>, <code>XBM:</code>, and others, so dithering may also be used
2802in these cases. </p>
2803
2804<p>Alternatively you can use <a href="command-line-options.html#random-threshold">-random-threshold</a>
2805to generate purely random dither. Or use <a href="command-line-options.html#ordered-dither">-ordered-dither</a> to apply threshold mapped dither
2806patterns, using uniform color maps, rather than specific color maps. </p>
2807
2808
2809<div style="margin: auto;">
2810 <h4><a id="draw"></a>-draw <var>string</var></h4>
2811</div>
2812
2813<p class="magick-description">Annotate an image with one or more graphic primitives.</p>
2814
2815<p>Use this option to annotate or decorate an image with one or more graphic
2816primitives. The primitives include shapes, text, transformations, and pixel
2817operations.</p>
2818
2819<p>The shape primitives:</p>
2820
2821<pre>
2822 point x,y
2823 line x0,y0 x1,y1
2824 rectangle x0,y0 x1,y1
2825 roundRectangle x0,y0 x1,y1 wc,hc
2826 arc x0,y0 x1,y1 a0,a1
2827 ellipse x0,y0 rx,ry a0,a1
2828 circle x0,y0 x1,y1
2829 polyline x0,y0 ... xn,yn
2830 polygon x0,y0 ... xn,yn
2831 bezier x0,y0 ... xn,yn
2832 path path specification
2833 image operator x0,y0 w,h filename
2834</pre>
2835
2836<p>The text primitive:</p>
2837
2838<pre>
2839 text x0,y0 string
2840</pre>
2841<p>The text gravity primitive:</p>
2842
2843<pre>
2844 gravity NorthWest, North, NorthEast, West, Center,
2845 East, SouthWest, South, or SouthEast
2846</pre>
2847
2848<p>The text gravity primitive only affects the placement of text and does not
2849interact with the other primitives. It is equivalent to using the <a href="command-line-options.html#gravity">-gravity</a> command-line option, except that it is limited in
2850scope to the <a href="command-line-options.html#draw">-draw</a> option in which it appears.</p>
2851
2852<p>The transformation primitives:</p>
2853
2854<pre>
2855 rotate degrees
2856 translate dx,dy
2857 scale sx,sy
2858 skewX degrees
2859 skewY degrees
2860</pre>
2861
2862<p>The pixel operation primitives:</p>
2863
2864<pre>
2865 color x0,y0 method
2866 matte x0,y0 method
2867</pre>
2868
2869<p>The shape primitives are drawn in the color specified by the preceding <a href="command-line-options.html#fill">-fill</a> setting. For unfilled shapes, use <a href="command-line-options.html#fill">-fill none</a>. You can optionally control the stroke (the
2870"outline" of a shape) with the <a href="command-line-options.html#stroke">-stroke</a> and <a href="command-line-options.html#strokewidth">-strokewidth</a> settings.</p>
2871
2872<p>A <code>point</code> primitive is specified by a single <var>point</var> in the
2873pixel plane, that is, by an ordered pair of integer coordinates,
2874<var>x</var>,<var>y</var>. (As it involves only a single pixel, a <code>point</code>
2875primitive is not affected by <a href="command-line-options.html#stroke">-stroke</a> or <a href="command-line-options.html#strokewidth">-strokewidth</a>.)</p>
2876
2877<p>A <code>line</code> primitive requires a start point and end point.</p>
2878
2879<p>A <code>rectangle</code> primitive is specified by the pair of points at the
2880upper left and lower right corners.</p>
2881
2882<p>A <code>roundRectangle</code> primitive takes the same corner points as
2883a <code>rectangle</code> followed by the width and height of the rounded corners
2884to be removed.</p>
2885
2886<p>The <code>circle</code> primitive makes a disk (filled) or circle (unfilled).
2887Give the center and any point on the perimeter (boundary).</p>
2888
2889<p>The <code>arc</code> primitive is used to inscribe an elliptical segment in
2890to a given rectangle. An <code>arc</code> requires the two corners used for
2891<code>rectangle</code> (see above) followed by the start and end angles of the
2892arc of the segment segment (e.g. 130,30 200,100 45,90). The start and end
2893points produced are then joined with a line segment and the resulting segment
2894of an ellipse is filled.</p>
2895
2896<p>Use <code>ellipse</code> to draw a partial (or whole) ellipse. Give the
2897center point, the horizontal and vertical "radii" (the <var>semi-axes</var> of
2898the ellipse) and start and end angles in degrees (e.g. 100,100 100,150
28990,360).</p>
2900
2901<p>The <code>polyline</code> and <code>polygon</code> primitives require three or
2902more points to define their perimeters. A <code>polyline</code> is simply
2903a <code>polygon</code> in which the final point is not stroked to the start
2904point. When unfilled, this is a <var>polygonal line</var>. If the <a href="command-line-options.html#stroke">-stroke</a> setting is <code>none</code> (the default), then
2905a <code>polyline</code> is identical to a <code>polygon</code>. </p>
2906
2907<p>A <var>coordinate</var> is a pair of integers separated by a space or
2908optional comma. </p>
2909
2910<p>As an example, to define a circle centered at 100,100 that extends to
2911150,150 use:</p>
2912
2913<p class="crtsnip">
2914 -draw 'circle 100,100 150,150'
2915</p>
2916
2917<p>The <code>Bezier</code> primitive creates a spline curve and requires three
2918or points to define its shape. The first and last points are the
2919<var>knots</var> and these points are attained by the curve, while any
2920intermediate coordinates are <var>control points</var>. If two control points
2921are specified, the line between each end knot and its sequentially respective
2922control point determines the tangent direction of the curve at that end. If
2923one control point is specified, the lines from the end knots to the one
2924control point determines the tangent directions of the curve at each end. If
2925more than two control points are specified, then the additional control points
2926act in combination to determine the intermediate shape of the curve. In order
2927to draw complex curves, it is highly recommended either to use the
2928<code>path</code> primitive or to draw multiple four-point bezier segments with
2929the start and end knots of each successive segment repeated. For example:</p>
2930
2931<p class="crtsnip">
2932 -draw 'bezier 20,50 45,100 45,0 70,50'
2933</p>
2934<p class="crtsnip">
2935 -draw 'bezier 70,50 95,100 95,0 120,50'
2936</p>
2937
2938
2939<p>A <code>path</code> represents an outline of an object, defined in terms of
2940moveto (set a new current point), lineto (draw a straight line), curveto (draw
2941a Bezier curve), arc (elliptical or circular arc) and closepath (close the
2942current shape by drawing a line to the last moveto) elements. Compound paths
2943(i.e., a path with subpaths, each consisting of a single moveto followed by
2944one or more line or curve operations) are possible to allow effects such as
2945<var>donut holes</var> in objects. (See <a href="http://www.w3.org/TR/SVG/paths.html">Paths</a>.)</p>
2946
2947<p>Use <code>image</code> to composite an image with another image. Follow the
2948image keyword with the composite operator, image location, image size, and
2949filename:</p>
2950
2951<p class="crtsnip">
2952 -draw 'image SrcOver 100,100 225,225 image.jpg'
2953</p>
2954
2955<p>You can use 0,0 for the image size, which means to use the actual
2956dimensions found in the image header. Otherwise, it is scaled to the given
2957dimensions. See <a href="compose.html">Alpha Compositing</a> for
2958a detailed discussion of alpha composition methods that are available. </p>
2959
2960<p>The "special augmented compose operators" such as "dissolve" that require
2961arguments cannot be used at present with the <code>-draw image</code> option.
2962 </p>
2963
2964<p>Use <code>text</code> to annotate an image with text. Follow the text
2965coordinates with a string. If the string has embedded spaces, enclose it in
2966single or double quotes.</p>
2967
2968<p>For example, the following annotates the image with <code>Works like
2969magick!</code> for an image titled <code>bird.miff</code>. </p>
2970
2971<p class="crtsnip">
2972 -draw "text 100,100 'Works like magick!' "
2973</p>
2974
2975<p>See the <a href="command-line-options.html#annotate">-annotate</a> option for another convenient way
2976to annotate an image with text.</p>
2977
2978<p>The <code>rotate</code> primitive rotates subsequent shape primitives and
2979text primitives about the origin of the main image. If the <a href="command-line-options.html#region">-region</a> option precedes the <a href="command-line-options.html#draw">-draw</a>
2980option, the origin for transformations is the upper left corner of the
2981region.</p>
2982
2983<p>The <code>translate</code> primitive translates subsequent shape and text
2984primitives.</p>
2985
2986<p>The <code>scale</code> primitive scales them.</p>
2987
2988<p>The <code>skewX</code> and <code>skewY</code> primitives skew them with respect
2989to the origin of the main image or the region.</p>
2990
2991<p>The transformations modify the current affine matrix, which is initialized
2992from the initial affine matrix defined by the <a href="command-line-options.html#affine">-affine</a>
2993option. Transformations are cumulative within the <a href="command-line-options.html#draw">-draw</a>
2994option. The initial affine matrix is not affected; that matrix is only changed
2995by the appearance of another <a href="command-line-options.html#affine">-affine</a> option. If another
2996<a href="command-line-options.html#draw">-draw</a> option appears, the current affine matrix is
2997reinitialized from the initial affine matrix.</p>
2998
2999<p>Use the <code>color</code> primitive to change the color of a pixel to the
3000fill color (see <a href="command-line-options.html#fill">-fill</a>). Follow the pixel coordinate with
3001a method:</p>
3002
3003<pre>
3004 point
3005 replace
3006 floodfill
3007 filltoborder
3008 reset
3009</pre>
3010
3011<p>Consider the target pixel as that specified by your coordinate. The
3012<code>point</code> method recolors the target pixel. The <code>replace</code>
3013method recolors any pixel that matches the color of the target pixel.
3014<code>Floodfill</code> recolors any pixel that matches the color of the target
3015pixel and is a neighbor, whereas <code>filltoborder</code> recolors any neighbor
3016pixel that is not the border color. Finally, <code>reset</code> recolors all
3017pixels.</p>
3018
3019<p>Use <code>matte</code> to the change the pixel matte value to transparent.
3020Follow the pixel coordinate with a method (see the <code>color</code> primitive
3021for a description of methods). The <code>point</code> method changes the matte
3022value of the target pixel. The <code>replace</code> method changes the matte
3023value of any pixel that matches the color of the target pixel.
3024<code>Floodfill</code> changes the matte value of any pixel that matches the
3025color of the target pixel and is a neighbor, whereas <code>filltoborder</code>
3026changes the matte value of any neighbor pixel that is not the border color (<a href="command-line-options.html#bordercolor">-bordercolor</a>). Finally <code>reset</code> changes the
3027matte value of all pixels.</p>
3028
3029<p>You can set the primitive color, font, and font bounding box color with <a href="command-line-options.html#fill">-fill</a>, <a href="command-line-options.html#font">-font</a>, and <a href="command-line-options.html#box">-box</a>
3030respectively. Options are processed in command line order so be sure to use
3031these options <var>before</var> the <a href="command-line-options.html#draw">-draw</a> option.</p>
3032
3033<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather
3034than 1.png).</p>
3035
3036<p>Drawing primitives conform to the <a href="magick-vector-graphics.html">Magick
3037Vector Graphics</a> format.</p>
3038
3039
3040<div style="margin: auto;">
3041 <h4><a id="duplicate"></a>-duplicate <var>count,indexes</var></h4>
3042</div>
3043
3044<p class="magick-description">duplicate an image one or more times.</p>
3045
3046<p>Specify the count and the image to duplicate by its index in the sequence.
3047The first image is index 0. Negative indexes are relative to the end of the
3048sequence, for example, -1 represents the last image of the sequence. Specify
3049a range of images with a dash (e.g. 0-4). Separate indexes with a comma (e.g.
30500,2). Use <code>+duplicate</code> to duplicate the last image in the current
3051image sequence.</p>
3052
3053<div style="margin: auto;">
3054 <h4><a id="edge"></a>-edge <var>radius</var></h4>
3055</div>
3056
3057<p class="magick-description">detect edges within an image.</p>
3058
3059<div style="margin: auto;">
3060 <h4><a id="emboss"></a>-emboss <var>radius</var></h4>
3061</div>
3062
3063<p class="magick-description">emboss an image.</p>
3064
3065<div style="margin: auto;">
3066 <h4><a id="encipher"></a>-encipher <var>filename</var></h4>
3067</div>
3068
3069<p class="magick-description">Encipher pixels for later deciphering by <a href="command-line-options.html#decipher">-decipher</a>.</p>
3070
3071<p>Get the passphrase from the file specified by <var>filename</var>.</p>
3072
cristy44443b92015-05-05 00:06:07 +0000[diff] [blame]3073<p>For more information, see the webpage, <a href="../www/cipher.html">ImageMagick: Encipher or
cristyd2432012015-05-04 23:15:15 +0000[diff] [blame]3074Decipher an Image</a>.</p>
3075
3076
3077
3078<div style="margin: auto;">
3079 <h4><a id="encoding"></a>-encoding <var>type</var></h4>
3080</div>
3081
3082<p class="magick-description">specify the text encoding.</p>
3083
3084<p>Choose from <code>AdobeCustom</code>, <code>AdobeExpert</code>,
3085<code>AdobeStandard</code>, <code>AppleRoman</code>, <code>BIG5</code>,
3086<code>GB2312</code>, <code>Latin 2</code>, <code>None</code>, <code>SJIScode</code>,
3087<code>Symbol</code>, <code>Unicode</code>, <code>Wansung</code>.</p>
3088
3089<div style="margin: auto;">
3090 <h4><a id="endian"></a>-endian <var>type</var></h4>
3091</div>
3092
3093<p class="magick-description">Specify endianness (<code>MSB</code> or <code>LSB</code>) of the image.</p>
3094
3095<p>To print a complete list of endian types, use the <a href="command-line-options.html#list">-list endian</a> option.</p>
3096
3097<p>Use <a href="command-line-options.html#endian">+endian</a> to revert to unspecified endianness.</p>
3098
3099
3100<div style="margin: auto;">
3101 <h4><a id="enhance"></a>-enhance</h4>
3102</div>
3103
3104<p class="magick-description">Apply a digital filter to enhance a noisy image.</p>
3105
3106
3107<div style="margin: auto;">
3108 <h4><a id="equalize"></a>-equalize</h4>
3109</div>
3110
3111<p class="magick-description">perform histogram equalization on the image channel-by-channel.</p>
3112
3113<p>To perform histogram equalization on all channels in concert, transform the
3114image into some other color space, such as HSL, OHTA, YIQ or YUV, then
3115equalize the appropriate intensity-like channel, then convert back to RGB.</p>
3116
3117<p>For example using HSL, we have: ... <code>-colorspace HSL -channel lightness
3118-equalize -colorspace RGB</code> ...</p>
3119
3120<p>For YIQ, YUV and OHTA use the red channel. For example, OHTA is a principal
3121components transformation that puts most of the information in the first
3122channel. Here we have ... <code>-colorspace OHTA -channel red -equalize
3123-colorspace RGB</code> ...</p>
3124
3125<div style="margin: auto;">
3126 <h4><a id="evaluate"></a>-evaluate <var>operator value</var></h4>
3127</div>
3128
3129<p class="magick-description">Alter channel pixels by evaluating an arithmetic, relational, or logical expression.</p>
3130
3131<p>(See the <a href="command-line-options.html#function">-function</a> operator for some
3132multi-parameter functions. See the <a href="command-line-options.html#fx">-fx</a> operator if more
3133elaborate calculations are needed.)</p>
3134
3135<p>The behaviors of each <var>operator</var> are summarized in the
3136following list. For brevity, the numerical value of a "pixel" referred to
3137below is the value of the corresponding channel of that pixel, while
3138a "normalized pixel" is that number divided by the maximum
3139(installation-dependent) value <var>QuantumRange</var>. (If
3140normalized pixels are used, they are restored, following the other
3141calculations, to the full range by multiplying by <var>QuantumRange</var>.)</p>
3142
3143<table class="table table-condensed table-striped">
3144 <col width="25%">
3145 <col width="75%">
3146 <thead>
3147 <tr>
3148 <th><var>operator</var></th>
3149 <th>Summary (see further below for details)</th>
3150 </tr>
3151 </thead>
3152 <tbody>
3153
3154 <tr><td>Abs </td> <td>Add <var>value</var> to pixels and return absolute value. </td></tr>
3155 <tr><td>Add </td> <td>Add <var>value</var> to pixels. </td></tr>
3156 <tr><td>AddModulus </td> <td>Add <var>value</var> to pixels modulo <var>QuantumRange</var>.</td></tr>
3157 <tr><td>And </td> <td>Binary AND of pixels with <var>value</var>.</td></tr>
3158 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <var>value</var> with 50% bias added.</td></tr>
3159 <tr><td>Divide </td> <td>Divide pixels by <var>value</var>.</td></tr>
3160 <tr><td>Exp </td> <td>base-e exponential function</td></tr>
3161 <tr><td>Exponential </td> <td>base-e exponential function</td></tr>
3162 <tr><td>LeftShift </td> <td>Shift the pixel values left by <var>value</var> bits (i.e., multiply pixels by 2<sup><var>value</var></sup>).</td></tr>
3163 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
3164 <tr><td>Max </td> <td>Clip pixels at lower bound <var>value</var>.</td></tr>
3165 <tr><td>Mean </td> <td>Add the <var>value</var> and divide by 2.</td></tr>
3166 <tr><td>Median </td> <td>Choose the median value from an image sequence.</td></tr>
3167 <tr><td>Min </td> <td>Clip pixels at upper bound <var>value</var>.</td></tr>
3168 <tr><td>Multiply </td> <td>Multiply pixels by <var>value</var>.</td></tr>
3169 <tr><td>Or </td> <td>Binary OR of pixels with <var>value</var>.</td></tr>
3170 <tr><td>Pow </td> <td>Raise normalized pixels to the power <var>value</var>.</td></tr>
3171 <tr><td>RightShift </td> <td>Shift the pixel values right by <var>value</var> bits (i.e., divide pixels by 2<sup><var>value</var></sup>).</td></tr>
3172 <tr><td>RMS</td> <td>Square the pixel and add the <var>value</var>.</td></tr>
3173 <tr><td>RootMeanSquare</td> <td>Square the pixel and add the <var>value</var>.</td></tr>
3174 <tr><td>Set </td> <td>Set pixel equal to <var>value</var>.</td></tr>
3175 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <var>value</var> with 50% bias added.</td></tr>
3176 <tr><td>Subtract </td> <td>Subtract <var>value</var> from pixels.</td></tr>
3177 <tr><td>Xor </td> <td>Binary XOR of pixels with <var>value.</var></td></tr>
3178
3179 <tr><td> </td></tr>
3180
3181 <tr><td>Gaussian-noise</td></tr>
3182 <tr><td>Impulse-noise</td></tr>
3183 <tr><td>Laplacian-noise</td></tr>
3184 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="command-line-options.html#noise">-noise</a> operators.)</td></tr>
3185 <tr><td>PoissonNoise</td></tr>
3186 <tr><td>Uniform-noise</td></tr>
3187
3188 <tr><td> </td></tr>
3189
3190 <tr><td>Threshold </td> <td>Threshold pixels larger than <var>value</var>.</td></tr>
3191 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <var>value</var>.</td></tr>
3192 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <var>value</var>. </td></tr>
3193 </tbody>
3194 </table>
3195
3196<p>The specified functions are applied only to each previously set <a href="command-line-options.html#channel">-channel</a> in the image. If necessary, the results of the
3197calculations are truncated (clipped) to fit in the interval [0, <var>QuantumRange</var>]. The transparency channel of the image is
3198represented as a 'alpha' values (0 = fully transparent), so, for example, a
3199<code>Divide</code> by 2 of the alpha channel will make the image
3200semi-transparent. Append the percent symbol '<code>%</code>' to specify a value
3201as a percentage of the <var>QuantumRange</var>.</p>
3202
3203<p>To print a complete list of <a href="command-line-options.html#evaluate">-evaluate</a> operators, use
3204<a href="command-line-options.html#list">-list evaluate</a>.</p>
3205
3206<p>The results of the <code>Add</code>, <code>Subtract</code> and
3207<code>Multiply</code> methods can also be achieved using either the <a href="command-line-options.html#level">-level</a> or the <a href="command-line-options.html#level">+level</a> operator, with
3208appropriate argument, to linearly modify the overall range of color values.
3209Please note, however, that <a href="command-line-options.html#level">-level</a> treats transparency as
3210'matte' values (0 = opaque), while <a href="command-line-options.html#level">-evaluate</a> works with
3211'alpha' values.</p>
3212
3213<p><code>AddModulus</code> has been added as of ImageMagick 6.4.8-4 and provides
3214addition modulo the <var>QuantumRange</var>. It is therefore
3215equivalent to <code>Add</code> unless the resulting pixel value is outside the
3216interval [0, <var>QuantumRange</var>]. </p>
3217
3218<p><code>Exp or Exponential</code> has been added as of ImageMagick 6.6.5-1 and
3219works on normalized pixel values. The <var>value</var> used with
3220<code>Exp</code> should be negative so as to produce a decaying exponential
3221function. Non-negative values will always produce results larger unity and
3222thus outside the interval [0, <var>QuantumRange</var>]. The
3223formula is expressed below. </p>
3224
3225 <div style="text-align:center;">
3226 exp(<var>value</var> × <b><var>u</var></b>)
3227 </div>
3228
3229<p> If the input image is squared, for example, using <a href="command-line-options.html#-function">-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be
3230the result.</p>
3231
3232<p><code>Log</code> has been added as of ImageMagick 6.4.2-1 and works on
3233normalized pixel values. This a <var>scaled</var> log function. The <var>value</var> used with <code>Log</code> provides a <var>scaling
3234factor</var> that adjusts the curvature in the graph of the log function. The
3235formula applied to a normalized value <b><var>u</var></b> is below. </p>
3236
3237 <div style="text-align:center;">
3238 log(<var>value</var> × <b><var>u</var></b> + 1) / log(<var>value</var> + 1)
3239 </div>
3240
3241<p><code>Pow</code> has been added as of ImageMagick 6.4.1-9, and works on
3242normalized pixel values. Note that <code>Pow</code> is related to the <a href="command-line-options.html#gamma">-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
3243to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
3244with <a href="command-line-options.html#gamma">-gamma</a> is simply the reciprocal of the value used
3245with <code>Pow</code>.</p>
3246
3247<p><code>Cosine</code> and <code>Sine</code> was added as of IM v6.4.8-8 and
3248converts the image values into a value according to a (co)sine wave function.
3249The synonyms <code>Cos</code> and <code>Sin</code> may also be used. The output
3250is biased 50% and normalized by 50% so as to fit in the respective color value
3251range. The <var>value</var> scaling of the <var>period</var> of the
3252function (its frequency), and thus determines the number of 'waves' that will
3253be generated over the input color range. For example, if the <var>value</var> is 1, the effective period is simply the <var>QuantumRange</var>; but if the <var>value</var> is 2,
3254then the effective period is the <var>half</var> the <var>QuantumRange</var>.</p>
3255
3256 <div style="text-align:center;">
3257 0.5 + 0.5 × cos(2 π <b><var>u</var></b> × <var>value</var>).
3258 </div>
3259
3260<p>See also the <a href="command-line-options.html#function">-function</a> operator, which is a
3261multi-value version of evaluate. </p>
3262
3263<div style="margin: auto;">
3264 <h4><a id="evaluate-sequence"></a>-evaluate-sequence <var>operator</var></h4>
3265</div>
3266
3267<p class="magick-description">Alter channel pixels by evaluating an arithmetic, relational, or
3268logical expression over a sequence of images.</p>
3269
3270<p>To print a complete list of <a href="command-line-options.html#evaluate-sequence">-evaluate-sequence</a> operators, use <a href="command-line-options.html#list">-list evaluate</a>.</p>
3271
3272<div style="margin: auto;">
3273 <h4><a id="extent"></a>-extent <var>geometry</var></h4>
3274</div>
3275
3276<p class="magick-description">Set the image size and offset.</p>
3277
3278<p>If the image is enlarged, unfilled areas are set to the background color.
3279To position the image, use offsets in the <var>geometry</var>
3280specification or precede with a <a href="command-line-options.html#gravity">-gravity</a> setting. To
3281specify how to compose the image with the background, use <a href="command-line-options.html#compose">-compose</a>.</p>
3282
3283<p>This command reduces or expands a JPEG image to fit on an 800x600
3284display. If the aspect ratio of the input image isn't exactly 4:3, then the
3285image is centered on an 800x600 black canvas: </p>
3286
3287<pre>
3288convert input.jpg -resize 800x600 -background black -compose Copy \
3289 -gravity center -extent 800x600 -quality 92 output.jpg
3290</pre>
3291
3292<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3293
3294<div style="margin: auto;">
3295 <h4><a id="extract"></a>-extract <var>geometry</var></h4>
3296</div>
3297
3298<p class="magick-description">Extract the specified area from image.</p>
3299
3300<p>This option is most useful for extracting a subregion of a very large raw
3301image. Note that these two commands are equivalent:</p>
3302
3303<pre>
3304convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 \
3305 image.rgb image.png",
3306convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' \
3307 image.rgb image.png"
3308</pre>
3309
3310<p>If you omit the offsets, as in</p>
3311
3312<pre>
3313convert -size 16000x16000 -depth 8 -extract 640x480 \
3314 image.rgb image.png
3315</pre>
3316
3317<p>the image is <var>resized</var> to the specified dimensions instead,
3318equivalent to:</p>
3319
3320<pre>
3321convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png
3322</pre>
3323
3324<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
3325
3326<div style="margin: auto;">
3327 <h4><a id="family"></a>-family <var>fontFamily</var></h4>
3328</div>
3329
3330<p class="magick-description">Set a font family for text.</p>
3331
3332<p>This setting suggests a font family that ImageMagick should try to use for
3333rendering text. If the family can be found it is used; if not, a default font
3334(e.g., "Arial") or a family known to be similar is substituted (e.g.,
3335"Courier" might be used if "System" is requested but not found). </p>
3336
3337<p>For other settings that affect fonts, see the options <a href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#stretch">-stretch</a>, <a href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
3338
3339<div style="margin: auto;">
3340 <h4><a id="features"></a>-features <var>distance</var></h4>
3341</div>
3342
3343<p class="magick-description">display (cooccurrence matrix) texture measure features for each channel in the image in each of four directions (horizontal, vertical, left and right diagonals) for the specified distance.</p>
3344
3345<pre>
3346 Angular Second Moment
3347 Contrast
3348 Correlation
3349 Sum of Squares Variance
3350 Inverse Difference Moment
3351 Sum Average
3352 Sum Variance
3353 Sum Entropy
3354 Entropy
3355 Difference Variance
3356 Difference Entropy
3357 Information Measure of Correlation 1
3358 Information Measure of Correlation 2
3359 Maximum Correlation Coefficient
3360</pre>
3361
3362
3363<div style="margin: auto;">
3364 <h4><a id="fft"></a>-fft</h4>
3365</div>
3366
3367<p class="magick-description">implements the forward discrete Fourier transform (DFT).</p>
3368
3369<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows
3370users in ImageMagick 6.6.0-9). It transforms an image from the normal
3371(spatial) domain to the frequency domain. In the frequency domain, an image is
3372represented as a superposition of complex sinusoidal waves of varying
3373amplitudes. The image x and y coordinates are the possible frequencies along
3374the x and y directions, respectively, and the pixel intensity values are
3375complex numbers that correspond to the sinusoidal wave amplitudes. See for
3376example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier
3377Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier
3378Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier
3379Transform</a>.</p>
3380
3381<p>A single image name is provided as output for this option. However, the
3382output result will have two components. It is either a two-frame image or two
3383separate images, depending upon whether the image format specified supports
3384multi-frame images. The reason that we get a dual output result is because the
3385frequency domain represents an image using complex numbers, which cannot be
3386visualized directly. Therefore, the complex values are automagically separated
3387into a two-component image representation. The first component is the
3388magnitude of the complex number and the second is the phase of the complex
3389number. See for example, <a href="http://en.wikipedia.org/wiki/Complex_numbers">Complex Numbers</a>.</p>
3390
3391<p>The magnitude and phase component images must be specified using image
3392formats that do not limit the color or compress the image. Thus, MIFF, TIF,
3393PFM, EXR and PNG are the recommended image formats to use. All of these
3394formats, except PNG support multi-frame images. So for example,</p>
3395
3396<pre>
3397convert image.png -fft fft_image.miff
3398</pre>
3399
3400<p>generates a magnitude image as <code>fft_image.miff[0]</code> and a phase
3401image as <code>fft_image.miff[1]</code>. Similarly,</p>
3402
3403<pre>
3404convert image.png -fft fft_image.png
3405</pre>
3406
3407<p>generates a magnitude image as <code>fft_image-0.png</code> and a phase image
3408as <code>fft_image-1.png</code>. If you prefer this representation, then you can
3409force any of the other formats to produce two output images by including <a href="command-line-options.html#adjoin">+adjoin</a> following -fft in the command line.</p>
3410
3411<p>The input image can be any size, but if not square and even-dimensioned, it
3412is padded automagically to the larger of the width or height of the input
3413image and to an even number of pixels. The padding will occur at the bottom
3414and/or right sides of the input image. The resulting output magnitude and
3415phase images is square at this size. The kind of padding relies on the <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting.</p>
3416
3417<p>Both output components will have dynamic ranges that fit within
3418[0, <var>QuantumRange</var>], so that HDRI need not be enabled.
3419Phase values nominally range from 0 to 2*π, but is scaled to span the full
3420dynamic range. (The first few releases had non-HDRI scaled but HDRI not
3421scaled). The magnitude image is not scaled and thus generally will contain
3422very small values. As such, the image normally will appear totally black. In
3423order to view any detail, the magnitude image typically is enhanced with a log
3424function into what is usually called the spectrum. A log function is used to
3425enhance the darker values more in comparison to the lighter values. This can
3426be done, for example, as follows:</p>
3427
3428<pre>
3429convert fft_image.miff[0] -contrast-stretch 0 \
3430 -evaluate log 1000 fft_image_spectrum.png"
3431</pre>
3432
3433<p>where either <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a> 0 or <a href="command-line-options.html#auto-level">-auto-level</a> is used to scale the image to full dynamic
3434range, first. The argument to the <a href="command-line-options.html#evaluate">-evaluate</a> log
3435typically is specified between 100 and 10,000, depending upon the amount of
3436detail that one wants to bring out in the spectrum. Larger values produce more
3437visible detail. Too much detail, however, may hide the important features.</p>
3438
3439<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to
3440use <a href="command-line-options.html#fft">-fft</a>.</p>
3441
3442<p>Use <a href="command-line-options.html#fft">+fft</a> to produce two output images that are the real
3443and imaginary components of the complex valued Fourier transform.</p>
3444
3445<p>However, as the real and imaginary components can contain negative values,
3446this requires that IM be configured with HDRI enabled. In this case, you must
3447use either MIFF, TIF, PFM or MPC formats for the real and imaginary component
3448results, since they are formats that preserve both negative and fractional
3449values without clipping them or truncating the fractional part. With either
3450MIFF or TIF, one should add -define quantum:format=32, to allow those image
3451types to work properly in HDRI mode without clipping.</p>
3452
3453<p>The real and imaginary component images resulting from <a href="command-line-options.html#fft">+fft</a> are also square, even dimensioned images due to the same
3454padding that was discussed above for the magnitude and phase component
3455images.</p>
3456
3457<p>See the discussion on HDRI implementations of ImageMagick on the page <a href="high-dynamic-range.html">High Dynamic-Range Images</a>. For more
3458about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages, <a href="http://www.fmwconcepts.com/imagemagick/fourier_transforms/fourier.html">Fred's Fourier Processing With ImageMagick page</a> or this <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a>
3459 entry. </p>
3460
3461<p>By default the FFT is normalized (and the IFT is not). Use "<code><a href="command-line-options.html#define">-define</a> fourier:normalize=forward</code> to explicityly normalize the FFT and unnormalize the IFT.</p>
3462
3463
3464<div style="margin: auto;">
3465 <h4><a id="fill"></a>-fill <var>color</var></h4>
3466</div>
3467
3468<p class="magick-description">color to use when filling a graphic primitive.</p>
3469
3470<p>This option accepts a color name, a hex color, or a numerical RGB, RGBA,
3471HSL, HSLA, CMYK, or CMYKA specification. See <a href="color.html">Color Names</a> for
3472a description of how to properly specify the color argument.</p>
3473
3474<p>Enclose the color specification in quotation marks to prevent the "#" or
3475the parentheses from being interpreted by your shell.</p>
3476
3477<p>For example,</p>
3478
3479<p class="crtsnip">
3480 -fill blue
3481</p>
3482<p class="crtsnip">
3483 -fill "#ddddff"
3484</p>
3485<p class="crtsnip">
3486 -fill "rgb(255,255,255)"
3487</p>
3488
3489<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
3490
3491<p>To print a complete list of color names, use the <a href="command-line-options.html#list">-list color</a> option.</p>
3492
3493<div style="margin: auto;">
3494 <h4><a id="filter"></a>-filter <var>type</var></h4>
3495</div>
3496
3497<p class="magick-description">Use this <var>type</var> of filter when resizing or distorting an image.</p>
3498
3499<p>Use this option to affect the resizing operation of an image during
3500operations such as <a href="command-line-options.html#resize">-resize</a> and <a href="command-line-options.html#distort">-distort</a>. For example you can use a simple resize filter such as:</p>
3501
3502<pre>
3503 Point Hermite Cubic
3504 Box Gaussian Catrom
3505 Triangle Quadratic Mitchell
3506</pre>
3507
3508<p>The <code>Bessel</code> and <code>Sinc</code> filter is also provided (as well
3509as a faster <code>SincFast</code> equivalent form). However these filters are
3510generally useless on their own as they are infinite filters that are being
3511clipped to the filters support size. Their direct use is not recommended
3512except via expert settings (see below). </p>
3513
3514<p>Instead these special filter functions are typically windowed by a windowing
3515function that the <a href="command-line-options.html#filter">-filter</a> setting defines. That is
3516using these functions will define a 'Windowed' filter, appropriate to the
3517operator involved. Windowed filters include: </p>
3518
3519<pre>
3520 Lanczos Hamming Parzen
3521 Blackman Kaiser Welsh
3522 Hanning Bartlett Bohman
3523</pre>
3524
3525<p>Also one special self-windowing filter is also provided
3526<code>Lagrange</code>, which will automagically re-adjust its function depending
3527on the current 'support' or 'lobes' expert settings (see below).</p>
3528
3529<p>If you do not select a filter with this option, the filter defaults to
3530<code>Mitchell</code> for a colormapped image, an image with a matte channel, or
3531if the image is enlarged. Otherwise the filter default to
3532<code>Lanczos</code>.</p>
3533
3534<p>To print a complete list of resize filters, use the <a href="command-line-options.html#list">-list
3535filter</a> option.</p>
3536
3537<p>You can modify how the filter behaves as it scales your image through the
3538use of these expert settings (see also <a href="command-line-options.html#define">-define</a> and <a href="command-line-options.html#set">-set</a>):-</p>
3539
3540<dl>
3541<dt>-define filter:blur=<var>factor</var></dt>
3542<dd>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
3543 blurry or &lt; 1.0 for sharp. This should only be used with Gaussian and
3544 Gaussian-like filters simple filters, or you may not get the expected
3545 results. </dd>
3546
3547<dt>-define filter:support=<var>radius</var></dt>
3548<dd>Set the filter support radius. Defines how large the filter should be and
3549 thus directly defines how slow the filtered resampling process is. All
3550 filters have a default 'prefered' support size. Some filters like
3551 <code>Lagrange</code> and windowed filters adjust themselves depending on
3552 this value. With simple filters this value either does nothing (but slow
3553 the resampling), or will clip the filter function in a detrimental way.
3554 </dd>
3555
3556<dt>-define filter:lobes=<var>count</var></dt>
3557<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an
3558 alternative way of specifying the 'support' range of the filter, that is
3559 designed to be more suited to windowed filters, especially when used for
3560 image distorts.</dd>
3561
3562<dt>-define filter:sigma=<var>value</var></dt>
3563<dd>The 'sigma' value used to define the <code>Gaussian</code> filter. Default
3564 sigma value is '<code>0.5</code>'. It only effects <code>Gaussian</code> but
3565 does not shrink (but may enlarge) the filter's 'support'. It can be used
3566 to generate very small blurs but without the filter 'missing' pixels due
3567 to using a small support setting. A larger value of '<code>0.707</code>'
3568 (a value of '1/sqrt(2)') is another common setting. </dd>
3569
3570<dt>-define filter:b=<var>b-spline_factor</var></dt>
3571<dt>-define filter:c=<var>keys_alpha_factor</var></dt>
3572<dd>Redefine the values used for cubic filters such as <code>Cubic</code>,
3573 <code>Catrom</code>, <code>Mitchel</code>, and <code>Hermite</code>, as well as
3574 the <code>Parzen</code> cubic windowing function. If only one of the values
3575 are defined, the other is set so as to generate a 'Cubic-Keys' filter.
3576 The values meaning was defined by a research paper by
3577 Mitchell-Netravali.</dd>
3578
3579<dt>-define filter:kaiser-beta=<var>value</var></dt>
3580<dd>The 'alpha' value used to as part of the Kaiser Windowing function.
3581 Default value is '6.5'. It only effects Kaiser windowing function, and
3582 does not effect any other attributes.</dd>
3583
3584<dd>Before IM v6.7.6-10, this option was known as "filter:alpha", (an
3585 inheritance from the very old "zoom" program). It was changed to bring the
3586 function in line with more modern academic research usage, and better
3587 assign it be more definitive. </dd>
3588
3589<dt>-define filter:kaiser-alpha=<var>value</var></dt>
3590<dd>This value when multiplied by 'PI' is equivalent to "kaiser-beta", and
3591 will override that setting. It only effects Kaiser windowing function,
3592 and does not effect any other attributes. </dd>
3593
3594<dt>-define filter:filter=<var>filter_function</var></dt>
3595<dd>Use this function directly as the weighting filter. This will allow
3596 you to directly use a windowing function such as <code>Blackman</code>,
3597 as a resampling filter, rather than as its normal usage as a windowing
3598 function. </dd>
3599
3600<dd>If defined, no windowing function also defined, the window function is set
3601 to <code>Box</code>). Directly specifying <code>Sinc</code> or <code>Jinc</code>
3602 as a filter will also do this. </dd>
3603
3604<dt>-define filter:window=<var>filter_function</var></dt>
3605<dd>The IIR (infinite impulse response) filters <code>Sinc</code> and
3606 <code>Jinc</code> are windowed (brought down to zero over the defined
3607 support range) with the given filter. This allows you to specify a filter
3608 function to be used as a windowing function for these IIR filters. </dd>
3609
3610<dd>Many of the defined filters are actually windowing functions for these IIR
3611 filters. A typical choices is <code>Box</code>, (which effectively turns
3612 off the windowing function). </dd>
3613
3614<dt>-define filter:win-support=<var>radius</var></dt>
3615<dd>Scale windowing function to this size instead. This causes the windowing
3616 (or self-windowing Lagrange filter) to act is if the support window is
3617 larger than what is actually supplied to the calling operator. The filter
3618 however is still clipped to the real support size given. If unset this
3619 will equal the normal filter support size. </dd>
3620
3621<dt>-define filter:verbose=<var>1</var></dt>
3622<dd>This causes IM to print information on the final internal filter
3623 selection to standard output. This includes a commented header on the
3624 filter settings being used, and data allowing the filter weights to be
3625 easily graphed. </dd>
3626
3627<dd>Note however that some filters are internally defined in terms of other
3628 filters. The <code>Lanczos</code> filter for example is defined in terms of
3629 a <code>SincFast</code> windowed <code>SincFast</code> filter, while
3630 <code>Mitchell</code> is defined as a general <code>Cubic</code> family filter
3631 with specific 'B' and 'C' settings. </dd>
3632
3633</dl>
3634
3635<p>For example, to get a 8 lobe jinc windowed sinc filter (Genseng filter?):</p>
3636
3637<pre>
3638convert image.png \
3639 -filter sinc \
3640 -set filter:window=jinc \
3641 -set filter:lobes=8 \
3642 -resize 150% image.jpg"
3643</pre>
3644
3645<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
3646
3647<pre>
3648convert image.png \
3649 -set filter:filter=sinc \
3650 -set filter:lobes=4 \
3651 -resize 150% image.jpg"
3652</pre>
3653
3654<p>To extract the data for a raw windowing function, combine it with
3655a '<code>Box</code>' filter. For example the '<code>Welch</code> parabolic
3656windowing function. </p>
3657
3658<pre>
3659convert null: -define filter:filter=Box \
3660 -define filter:window=Welch \
3661 -define filter:support=1.0 \
3662 -define filter:verbose=1 \
3663 -resize 2 null: &gt; window_welch.dat
3664gnuplot
3665 set grid
3666 plot \"window_welch.dat\" with lines
3667</pre>
3668
3669<p>Note that the use of expert options is provided for image processing experts
3670who have studied and understand how resize filters work. Without this
3671knowledge, and an understanding of the definition of the actual filters
3672involved, using expert settings are more likely to be detrimental to your image
3673resizing.</p>
3674
3675
3676<div style="margin: auto;">
3677 <h4><a id="flatten"></a>-flatten</h4>
3678</div>
3679
3680<p class="magick-description">This is a simple alias for the <a href="command-line-options.html#layers">-layers</a> method "flatten".</p>
3681
3682
3683<div style="margin: auto;">
3684 <h4><a id="flip"></a>-flip</h4>
3685</div>
3686
3687<p class="magick-description">create a <var>mirror image</var></p>
3688
3689<p>reflect the scanlines in the vertical direction. The image will be mirrored
3690upside-down. </p>
3691
3692
3693<div style="margin: auto;">
3694 <h4><a id="floodfill"></a>-floodfill {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var> <var>color</var></h4>
3695</div>
3696
3697<p class="magick-description">floodfill the image with color at the specified offset.</p>
3698
3699<p>Flood fill starts from the given 'seed point' which is not gravity effected.
3700Any color that matches within <a href="command-line-options.html#fuzz">-fuzz</a> color distance of the
3701given <var>color</var> argument, connected to that 'seed point'
3702will be replaced with the current <a href="command-line-options.html#fill">-fill</a> color. </p>
3703
3704<p>Note that if the pixel at the 'seed point' does not itself match the given
3705<var>color</var> (according to <a href="command-line-options.html#fuzz">-fuzz</a>), then no
3706action will be taken. </p>
3707
3708<p>This operator works more like the <a href="command-line-options.html#opaque">-opaque</a> option, than
3709a more general flood fill that reads the matching color directly at the 'seed
3710point'. For this form of flood fill, look at <a href="command-line-options.html#draw">-draw</a> and
3711its 'color floodfill' drawing method. </p>
3712
3713
3714<div style="margin: auto;">
3715 <h4><a id="flop"></a>-flop</h4>
3716</div>
3717
3718<p class="magick-description">create a <var>mirror image</var>.</p>
3719
3720<p>Reflect the scanlines in the horizontal direction, just like the image in
3721a vertical mirror. </p>
3722
3723
3724<div style="margin: auto;">
3725 <h4><a id="font"></a>-font <var>name</var></h4>
3726</div>
3727
3728<p class="magick-description">set the font to use when annotating images with text, or creating labels.</p>
3729
3730<p>To print a complete list of fonts, use the <a href="command-line-options.html#list">-list font</a>
3731option (for versions prior to 6.3.6, use 'type' instead of 'font').</p>
3732
3733<p>In addition to the fonts specified by the above pre-defined list, you can
3734also specify a font from a specific source. For example <code>Arial.ttf</code>
3735is a TrueType font file, <code>ps:helvetica</code> is PostScript font, and
3736<code>x:fixed</code> is X11 font.</p>
3737
3738<p>For other settings that affect fonts, see the options <a href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#stretch">-stretch</a>, <a href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
3739
3740
3741<div style="margin: auto;">
3742 <h4><a id="foreground"></a>-foreground <var>color</var></h4>
3743</div>
3744
3745<p class="magick-description">Define the foreground color for menus.", "display</p>
3746
3747<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
3748
3749<p>The default foreground color is black.</p>
3750
3751<div style="margin: auto;">
3752 <h4><a id="format"></a>-format <var>type</var></h4>
3753</div>
3754
3755<p class="magick-description">the image format type.</p>
3756
3757<p>When used with the <code>mogrify</code> utility, this option converts any
3758image to the image <a href="formats.html">format</a> you specify.
3759For a list of image format types supported by ImageMagick, use <a href="command-line-options.html#list">-list format</a>.</p>
3760
3761<p>By default the file is written to its original name. However, if the
3762filename extension matches a supported format, the extension is replaced with
3763the image format type specified with <a href="command-line-options.html#format">-format</a>. For
3764example, if you specify <var>tiff</var> as the format type and the
3765input image filename is <var>image.gif</var>, the output image
3766filename becomes <var>image.tiff</var>.</p>
3767
3768<div style="margin: auto;">
3769 <h4><a id="format_identify_"></a>-format <var>string</var></h4>
3770</div>
3771
3772<p class="magick-description">output formatted image characteristics.</p>
3773
3774<p>See <a href="escape.html">Format and Print Image
3775Properties</a> for an explanation on how to specify the argument to this
3776option.</p>
3777
3778<div style="margin: auto;">
3779 <h4><a id="frame"></a>-frame <var>geometry</var></h4>
3780</div>
3781
3782<p class="magick-description">Surround the image with a border or beveled frame.</p>
3783
3784<p>The color of the border is specified with the <a href="command-line-options.html#mattecolor">-mattecolor</a> command line option. </p>
3785
3786<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <var>size</var> portion of the <var>geometry</var> argument indicates the amount of extra width and
3787height that is added to the dimensions of the image. If no offsets are given
3788in the <var>geometry</var> argument, then the border added is
3789a solid color. Offsets <var>x</var> and <var>y</var>, if present, specify that
3790the width and height of the border is partitioned to form an outer bevel of
3791thickness <var>x</var> pixels and an inner bevel of thickness
3792<var>y</var> pixels. Negative offsets make no sense as frame arguments.
3793</p>
3794
3795<p>The <a href="command-line-options.html#frame">-frame</a> option is affected by the current <a href="command-line-options.html#compose">-compose</a> setting and assumes that this is using the default
3796'<code>Over</code>' composition method. It generates an image of the appropriate
3797size with the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting, and then
3798draws the frame of four distinct colors close to the current <a href="command-line-options.html#mattecolor">-mattecolor</a>. The original image is then overlaid onto
3799center of this image. This means that with the default compose method of
3800'<code>Over</code>' any transparent parts may be replaced by the current <a href="command-line-options.html#bordercolor">-bordercolor</a> setting.</p>
3801
3802<p>The image composition is not
3803affected by the <a href="command-line-options.html#gravity">-gravity</a> option.</p>
3804
3805
3806<div style="margin: auto;">
3807 <h4><a id="frame_import_"></a>-frame</h4>
3808</div>
3809
3810<p class="magick-description">include the X window frame in the imported image. </p>
3811<div style="margin: auto;">
3812 <h4><a id="function"></a>-function <var>function</var> <var>parameters</var></h4>
3813</div>
3814
3815<p class="magick-description">Apply a function to channel values.</p>
3816
3817<p>This operator performs calculations based on the given arguments to modify
3818each of the color values for each previously set <a href="command-line-options.html#channel">-channel</a> in the image. See <a href="command-line-options.html#evaluate">-evaluate</a> for details concerning how the results of the
3819calculations are handled.</p>
3820
3821<p>This is can be considered a multi-argument version of the <a href="command-line-options.html#evaluate">-evaluate</a> operator. (Added in
3822ImageMagick 6.4.8−8.)</p>
3823
3824<p>Here, <var>parameters</var> is a comma-separated list of
3825numerical values. The number of values varies depending on which <var>function</var> is selected. Choose the <var>function</var> from:</p>
3826
3827<pre>
3828 Polynomial
3829 Sinusoid
3830 Arcsin
3831 Arctan
3832</pre>
3833
3834<p>To print a complete list of <a href="command-line-options.html#function">-function</a> operators,
3835use <a href="command-line-options.html#list">-list function</a>. Descriptions follow.</p>
3836
3837<dl>
3838<dt><code>Polynomial</code></dt>
3839<dd>
3840
3841<p>The <code>Polynomial</code> function takes an arbitrary number of parameters,
3842these being the coefficients of a polynomial, in decreasing order of degree.
3843That is, entering</p>
3844
3845<div style="text-align: center">
3846 -function Polynomial <var>a</var><sub><var>n</var></sub>,<var>a</var><sub><var>n</var>-1</sub>,...<var>a</var><sub>1</sub>,<var>a</var><sub>0</sub>
3847</div>
3848
3849<p>will invoke a polynomial function given by</p>
3850
3851<div style="text-align: center">
3852 <var>a</var><sub><var>n</var></sub> <b><var>u</var></b><sup><var>n</var></sup> +
3853 <var>a</var><sub><var>n</var>-1</sub> <b><var>u</var></b><sup><var>n</var>-1</sup> +
3854 ··· <var>a</var><sub>1</sub> <b><var>u</var></b> + <var>a</var><sub>0</sub>,
3855</div>
3856
3857<p>where <b><var>u</var></b> is pixel's original normalized channel value.</p>
3858
3859<p>The <code>Polynomial</code> function can be used in place of <code>Set</code>
3860(the <var>constant</var> polynomial) and <code>Add</code>, <code>Divide</code>,
3861<code>Multiply</code>, and <code>Subtract</code> (some <var>linear</var>
3862polynomials) of the <a href="command-line-options.html#evaluate">-evaluate</a> operator. The <a href="command-line-options.html#level">-level</a> operator also affects channels linearly. Some
3863correspondences follow.</p>
3864
3865<table class="table table-condensed table-striped">
3866 <col width="35%">
3867 <col width="35%">
3868 <col width="30%">
3869 <tr>
3870 <td>-evaluate Set <var>value</var> </td>
3871 <td>-function Polynomial <var>value</var></td>
3872 <td>(Constant functions; set <var>value</var>×100% gray when channels are RGB.)</td>
3873 </tr>
3874 <tr>
3875 <td>-evaluate Add <var>value</var> </td>
3876 <td>-function Polynomial 1,<var>value</var></td>
3877 </tr>
3878 <tr>
3879 <td>-evaluate Subtract <var>value</var> </td>
3880 <td>-function Polynomial 1,−<var>value</var></td>
3881 </tr>
3882 <tr>
3883 <td>-evaluate Multiply <var>value</var> </td>
3884 <td>-function Polynomial <var>value</var>,0</td>
3885 </tr>
3886 <tr>
3887 <td>+level black% x white%</td>
3888 <td>-function Polynomial A,B</td>
3889 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
3890 </tr>
3891</table>
3892
3893<p>The <code>Polynomial</code> function gives great versatility, since
3894polynomials can be used to fit any continuous curve to any degree of accuracy
3895desired.</p>
3896
3897</dd>
3898
3899<dt><code>Sinusoid</code></dt>
3900<dd>
3901<p>The <code>Sinusoid</code> function can be used to vary the channel values
3902sinusoidally by setting frequency, phase shift, amplitude, and a bias. These
3903values are given as one to four parameters, as follows,</p>
3904
3905<div style="text-align: center">
3906 -function <code>Sinusoid</code> <var>freq</var>,[<var>phase</var>,[<var>amp</var>,[<var>bias</var>]]]
3907</div>
3908
3909<p>where <var>phase</var> is in degrees. (The domain [0,1] of the function
3910corresponds to 0 through <var>freq</var>×360 degrees.)
3911The result is that if a pixel's normalized channel value is originally
3912<b><var>u</var></b>, its resulting normalized value is given by </p>
3913
3914<div style="text-align: center">
3915<var>amp</var> * sin(2*π* (<var>freq</var> * <b><var>u</var></b> + <var>phase</var> / 360)) + <var>bias</var>
3916</div>
3917
3918<p> For example, the following generates a curve that starts and ends at 0.9
3919(when <b><var>u</var></b>=0 and 1, resp.), oscillating three times between
3920.7−.2=.5 and .7+.2=.9. </p>
3921
3922<p class="crtsnip">
3923 -function Sinusoid 3,-90,.2,.7
3924</p>
3925
3926<p>The default values of <var>amp</var> and <var>bias</var> are both .5. The default for <var>phase</var>
3927is 0.</p>
3928
3929<p>The <code>Sinusoid</code> function generalizes <code>Sin</code> and
3930<code>Cos</code> of the <a href="command-line-options.html#evaluate">-evaluate</a> operator by allowing
3931varying amplitude, phase and bias. The correspondence is as follows.</p>
3932
3933<table class="table table-condensed table-striped">
3934 <tr>
3935 <td>-evaluate Sin <var>freq</var> </td>
3936 <td>-function Sinusoid <var>freq</var>,0 </td>
3937 </tr>
3938 <tr>
3939 <td>-evaluate Cos <var>freq</var> </td>
3940 <td>-function Sinusoid <var>freq</var>,90 </td>
3941 </tr>
3942</table>
3943</dd>
3944
3945<dt><code>ArcSin</code></dt>
3946<dd>
3947<p>The <code>ArcSin</code> function generates the inverse curve of a Sinusoid,
3948and can be used to generate cylindrical distortion and displacement maps.
3949The curve can be adjusted relative to both the input values and output range
3950of values.</p>
3951
3952<p style="text-align: center">
3953 -function <code>ArcSin</code> <var>width</var>,[<var>center</var>,[<var>range</var>,[<var>bias</var>]]]
3954</p>
3955
3956<p>with all values given in terms of normalized color values (0.0 for black,
39571.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
3958for bout input (<var>width</var>), and output (<var>width</var>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
3959
3960<p style="text-align: center">
3961<var>range</var>/π * asin( 2/<var>width</var> * ( <b><var>u</var></b> - <var>center</var> ) ) + <var>bias</var>
3962</p>
3963
3964</dd>
3965
3966<dt><code>ArcTan</code></dt>
3967<dd>
3968<p>The <code>ArcTan</code> function generates a curve that smooth crosses from
3969limit values at infinities, though a center using the given slope value.
3970All these values can be adjusted via the arguments.</p>
3971
3972<p style="text-align: center">
3973 -function <code>ArcTan</code> <var>slope</var>,[<var>center</var>,[<var>range</var>,[<var>bias</var>]]]
3974</p>
3975
3976<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3977</p>
3978
3979<p style="text-align: center">
3980<var>range</var>/π * atan( <var>slope</var>*π * ( <b><var>u</var></b> - <var>center</var> ) ) + <var>bias</var>
3981</p>
3982
3983</dd>
3984
3985</dl>
3986
3987
3988<div style="margin: auto;">
3989 <h4><a id="fuzz"></a>-fuzz <var>distance</var>{<var>%</var>}</h4>
3990</div>
3991
3992<p class="magick-description">Colors within this <var>distance</var> are considered equal.</p>
3993
3994<p>A number of algorithms search for a target color. By default the color must
3995be exact. Use this option to match colors that are close to the target color
3996in RGB space. For example, if you want to automagically trim the edges of an
3997image with <a href="command-line-options.html#trim">-trim</a> but the image was scanned and the target
3998background color may differ by a small amount. This option can account for
3999these differences.</p>
4000
4001<p>The <var>distance</var> can be in absolute intensity units or, by
4002appending <code>%</code> as a percentage of the maximum possible intensity (255,
400365535, or 4294967295).</p>
4004
4005<p>Use <a href="command-line-options.html#fuzz">+fuzz</a> to reset the fuzz value to 0.</p>
4006
4007
4008<div style="margin: auto;">
4009 <h4><a id="fx"></a>-fx <var>expression</var></h4>
4010</div>
4011
4012<p class="magick-description">apply a mathematical expression to an image or image channels.</p>
4013
4014<p>If the first character of <var>expression</var> is <code>@</code>,
4015the expression is read from a file titled by the remaining characters in the
4016string.</p>
4017
4018<p>See <a href="fx.html">FX,
4019The Special Effects Image Operator</a> for a detailed discussion of this
4020option.</p>
4021
4022
4023<div style="margin: auto;">
4024 <h4><a id="gamma"></a>-gamma <var>value</var></h4>
4025</div>
4026
4027<p class="magick-description">level of gamma correction.</p>
4028
4029<p>The same color image displayed on two different workstations may look
4030different due to differences in the display monitor. Use gamma correction to
4031adjust for this color difference. Reasonable values extend from
4032<code>0.8</code> to <code>2.3</code>. Gamma less than 1.0 darkens the image and
4033gamma greater than 1.0 lightens it. Large adjustments to image gamma may
4034result in the loss of some image information if the pixel quantum size is only
4035eight bits (quantum range 0 to 255).</p>
4036
4037<p>Gamma adjusts the image's channel values pixel-by-pixel according to
4038a power law, namely, pow(pixel,1/gamma) or pixel^(1/gamma), where pixel is the
4039normalized or 0 to 1 color value. For example, using a value of gamma=2 is the
4040same as taking the square root of the image.</p>
4041
4042<p>You can apply separate gamma values to the red, green, and blue channels of
4043the image with a gamma value list delimited with commas (e.g.,
4044<code>1.7,2.3,1.2</code>).</p>
4045
4046<p>Use <a href="command-line-options.html#gamma">+gamma <var>value</var></a> to set the
4047image gamma level without actually adjusting the image pixels. This option
4048is useful if the image is of a known gamma but not set as an image attribute
4049(e.g. PNG images). Write the "file gamma" which is the reciprocal of the
4050display gamma; e.g., if your image is sRGB and you want to write a PNG gAMA
4051chunk, use</p>
4052
4053<pre>
4054convert input.png +gamma .45455 output.png
4055</pre>
4056
4057<p>(0.45455 is 1/2.2)</p>
4058
4059<p>Note that gamma adjustments are also available via the <a href="command-line-options.html#level">-level</a> operator.</p>
4060
4061<div style="margin: auto;">
4062 <h4><a id="gaussian-blur"></a>-gaussian-blur <var>radius</var><br>-gaussian-blur <var>radius</var>x<var>sigma</var></h4>
4063</div>
4064
4065<p class="magick-description">Blur the image with a Gaussian operator.</p>
4066
4067<p>Convolve the image with a Gaussian or normal distribution using the given
4068<var>Sigma</var> value. The formula is:</p>
4069
4070<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png">
4071</div>
4072
4073<p>The <var>Sigma</var> value is the important argument, and
4074determines the actual amount of blurring that will take place. </p>
4075
4076<p>The <var>Radius</var> is only used to determine the size of the
4077array which will hold the calculated Gaussian distribution. It should be an
4078integer. If not given, or set to zero, IM will calculate the largest possible
4079radius that will provide meaningful results for the Gaussian distribution.
4080</p>
4081
4082<p>The larger the <var>Radius</var> the radius the slower the
4083operation is. However too small a <var>Radius</var>, and sever
4084aliasing effects may result. As a guideline, <var>Radius</var>
4085should be at least twice the <var>Sigma</var> value, though three
4086times will produce a more accurate result. </p>
4087
4088<p>This differs from the faster <a href="command-line-options.html#blur">-blur</a> operator in that a
4089full 2-dimensional convolution is used to generate the weighted average of the
4090neighboring pixels. </p>
4091
4092<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
4093pixels which are outside the image proper are blurred into the final result.
4094</p>
4095
4096
4097<div style="margin: auto;">
4098 <h4><a id="geometry"></a>-geometry <var>geometry</var></h4>
4099</div>
4100
4101<p class="magick-description">Set the preferred size and location of the image.</p>
4102
4103<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4104
4105<div style="margin: auto;">
4106 <h4><a id="gravity"></a>-gravity <var>type</var></h4>
4107</div>
4108
4109<p class="magick-description">Sets the current gravity suggestion for various other settings and options.</p>
4110
4111<p>Choices include: <code>NorthWest</code>, <code>North</code>,
4112<code>NorthEast</code>, <code>West</code>, <code>Center</code>, <code>East</code>,
4113<code>SouthWest</code>, <code>South</code>, <code>SouthEast</code>. Use <a href="command-line-options.html#list">-list gravity</a> to get a complete list of <a href="command-line-options.html#gravity">-gravity</a> settings available in your ImageMagick
4114installation.</p>
4115
4116<p>The direction you choose specifies where to position text or subimages. For
4117example, a gravity of <code>Center</code> forces the text to be centered within
4118the image. By default, the image gravity is <code>NorthWest</code>. See <a href="command-line-options.html#draw">-draw</a> for more details about graphic primitives. Only the
4119text primitive of <a href="command-line-options.html#draw">-draw</a> is affected by the <a href="command-line-options.html#gravity">-gravity</a> option.</p>
4120
4121<p>The <a href="command-line-options.html#gravity">-gravity</a> option is also used in concert with the
4122<a href="command-line-options.html#geometry">-geometry</a> setting and other settings or options that
4123take <var>geometry</var> as an argument, such as the <a href="command-line-options.html#crop">-crop</a> option. </p>
4124
4125<p>If a <a href="command-line-options.html#gravity">-gravity</a> setting occurs before another option
4126or setting having a <var>geometry</var> argument that specifies an
4127offset, the offset is usually applied to the point within the image suggested
4128by the <a href="command-line-options.html#gravity">-gravity</a> argument. Thus, in the following
4129command, for example, suppose the file <code>image.png</code> has dimensions
4130200x100. The offset specified by the argument to <a href="command-line-options.html#region">-region</a>
4131is (−40,+20). The argument to <a href="command-line-options.html#gravity">-gravity</a> is
4132<code>Center</code>, which suggests the midpoint of the image, at the point
4133(100,50). The offset (−40,20) is applied to that point, giving
4134(100−40,50+20)=(60,70), so the specified 10x10 region is located at
4135that point. (In addition, the <a href="command-line-options.html#gravity">-gravity</a> affects the
4136region itself, which is <var>centered</var> at the pixel
4137coordinate (60,70). (See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.)</p>
4138
4139<pre>
4140convert image.png -gravity Center -region 10x10-40+20 \
4141 -negate output.png
4142</pre>
4143
4144<p>When used as an option to <a href="composite.html">composite</a>, <a href="command-line-options.html#gravity">-gravity</a> gives the direction that the image gravitates
4145within the composite.</p>
4146
4147<p>When used as an option to <a href="montage.html">montage</a>, <a href="command-line-options.html#gravity">-gravity</a> gives the direction that an image gravitates
4148within a tile. The default gravity is <code>Center</code> for this purpose.</p>
4149
4150
4151<div style="margin: auto;">
4152 <h4><a id="grayscale"></a>-grayscale <var>method</var></h4>
4153</div>
4154
4155<p class="magick-description">convert image to grayscale.</p>
4156
4157<p>This will use one of the <a href="command-line-options.html#intensity">-intensity</a> methods to
4158convert the given image into a linear-grayscale image. </p>
4159
4160<p>For example, to convert an image to (linear) Rec709Luminance grayscale, type:</p>
4161
4162<pre>
4163convert in.png -grayscale Rec709Luminance out.png
4164</pre>
4165
4166<p>which is equivalent to:</p>
4167
4168<pre>
4169convert in.png -colorspace gray out.png
4170</pre>
4171
4172<p>Similarly, to convert an image to (non-linear) Rec709Luma grayscale, type:</p>
4173
4174<pre>
4175convert in.png -grayscale Rec709Luma out.png
4176</pre>
4177
4178<p>which is equivalent to:</p>
4179
4180<pre>
4181convert in.png -set colorspace RGB -colorspace gray out.png
4182</pre>
4183
4184<p>Note that a 'colorspace' intensity method will produce the same result
4185regardless of the current colorpsace of the image. But a 'mathematical'
4186intensity method will depend on the current colorspace the image is currently
4187using. </p>
4188
4189<p>While this operation uses an <a href="command-line-options.html#intensity">-intensity</a> method,
4190it does not use or set the <a href="command-line-options.html#intensity">-intensity</a> setting, so
4191will not effect other operations that may use that setting.</p>
4192
4193
4194<div style="margin: auto;">
4195 <h4><a id="green-primary"></a>-green-primary <var>x,y</var></h4>
4196</div>
4197
4198<p class="magick-description">green chromaticity primary point.</p>
4199
4200
4201<div style="margin: auto;">
4202 <h4><a id="hald-clut"></a>-hald-clut</h4>
4203</div>
4204
4205<p class="magick-description">apply a Hald color lookup table to the image.</p>
4206
4207<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
4208dimensions. Create it with the <code>HALD:</code> prefix (e.g. HALD:8). You
4209can apply any color transformation to the Hald image and then use this option
4210to apply the transform to the image. </p>
4211
4212<pre>
4213convert image.png hald.png -hald-clut transform.png
4214</pre>
4215
4216<p>This option provides a convenient method for you to use Gimp or Photoshop
4217to make color corrections to the Hald CLUT image and subsequently apply them
4218to multiple images using an ImageMagick script. </p>
4219
4220<p>Note that the representation is only of the normal RGB color space and that
4221the whole color value triplet is used for the interpolated lookup of the
4222represented Hald color cube image. Because of this the operation is not <a href="command-line-options.html#channel">-channel</a> setting effected, nor can it adjust or modify an
4223images transparency or alpha/matte channel.</p>
4224
4225<p>See also <a href="command-line-options.html#clut">-clut</a> which provides color value replacement
4226of the individual color channels, usually involving a simpler gray-scale
4227image. E.g: gray-scale to color replacement, or modification by a histogram
4228mapping. </p>
4229
4230
4231<div style="margin: auto;">
4232 <h4><a id="help"></a>-help</h4>
4233</div>
4234
4235<p class="magick-description">print usage instructions.</p>
4236
4237<div style="margin: auto;">
4238 <h4><a id="highlight-color"></a>-highlight-color <var>color</var></h4>
4239</div>
4240
4241<p class="magick-description">when comparing images, emphasize pixel differences with this color.</p>
4242
4243<div style="margin: auto;">
4244 <h4><a id="hough-lines"></a>-hough-lines <var>width</var>x<var>height</var>{<var>+threshold</var>}</h4>
4245</div>
4246
4247<p class="magick-description">identify straight lines in the image (e.g. -hough-lines 9x9+195).</p>
4248
4249<p>Use the Hough line detector with any binary edge extracted image to locate and draw any straight lines that it finds.</p>
4250
4251<p>The process accumulates counts for every white pixel in the binary edge image for every possible orientation (for angles from 0 to 179 in 1 deg increments) and distance from the center of the image to the corners (in 1 px increments). It stores the counts in an accumulator matrix of angle vs distance. The size of the accumulator will be 180x(diagonal/2). Next it searches the accumulator for peaks in counts and converts the locations of the peaks to slope and intercept in the normal x,y input image space. The algorithm uses slope/intercepts to find the endpoints clipped to the bounds of the image. The lines are drawn from the given endpoints. The counts are a measure of the length of the lines.</p>.
4252
4253<p>The WxH arguments specify the filter size for locating the peaks in the Hough accumulator. The threshold excludes lines whose counts are less than the threshold value.</p>
4254
4255<p>Use <code><a href="command-line-options.html#background">-background</a></code> to specify the color of the background onto which the lines will be drawn. The default is black.</p>
4256
4257<p>Use <code><a href="command-line-options.html#fill">-fill</a></code> to specify the color of the lines. The default is black.</p>
4258
4259<p>Use <code><a href="command-line-options.html#stroke">-stroke</a></code> and <code><a href="command-line-options.html#strokewidth">-strokewidth</a></code> to specify the thickness of the lines. The default is black and no strokewidth.</p>
4260
4261<p>A text file listing the endpoints and counts may be created by using the suffix, .mvg, for the output image.</p>
4262
4263<p>Use <code><a href="command-line-options.html#define">-define</a> hough-lines:accumulator=true</code> to return the accumulator image in addition to the lines image.</p>
4264
4265<div style="margin: auto;">
4266 <h4><a id="iconGeometry"></a>-iconGeometry <var>geometry</var></h4>
4267</div>
4268
4269<p class="magick-description">specify the icon geometry.</p>
4270
4271<p>Offsets, if present in the geometry specification, are handled in the same
4272manner as the <a href="command-line-options.html#geometry">-geometry</a> option, using X11 style to
4273handle negative offsets.</p>
4274
4275<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
4276
4277<div style="margin: auto;">
4278 <h4><a id="iconic"></a>-iconic</h4>
4279</div>
4280
4281<p class="magick-description">start in icon mode in X Windows", 'animate', 'display</p>
4282
4283<div style="margin: auto;">
4284 <h4><a id="identify"></a>-identify</h4>
4285</div>
4286
4287<p class="magick-description">identify the format and characteristics of the image.</p>
4288
4289<p>This information is printed: image scene number; image name; image size;
4290the image class (<var>DirectClass</var> or <var>PseudoClass</var>); the total number of unique colors; and the
4291number of seconds to read and transform the image. Refer to <a href="miff.html">MIFF</a> for
4292a description of the image class.</p>
4293
4294<p>If <a href="command-line-options.html#colors">-colors</a> is also specified, the total unique colors
4295in the image and color reduction error values are printed. Refer to <a href="quantize.html">color
4296reduction algorithm</a> for a description of these values.</p>
4297
4298<p>If <a href="command-line-options.html#verbose">-verbose</a> precedes this option, copious
4299amounts of image properties are displayed including image statistics, profiles,
4300image histogram, and others.</p>
4301
4302<div style="margin: auto;">
4303 <h4><a id="ift"></a>-ift</h4>
4304</div>
4305
4306<p class="magick-description">implements the inverse discrete Fourier transform (DFT).</p>
4307
4308<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows
4309users in ImageMagick 6.6.0-9). It transforms a pair of magnitude and phase
4310images from the frequency domain to a single image in the normal or spatial
4311domain. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier Transform</a>,
4312<a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier Transform</a> and
4313<a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier Transform</a>.</p>
4314
4315<p>For example, depending upon the image format used to store the result of
4316the <a href="command-line-options.html#fft">-fft</a>, one would use either</p>
4317
4318<pre>
4319convert fft_image.miff -ift fft_image_ift.png
4320</pre>
4321
4322<p>or</p>
4323
4324<pre>
4325convert fft_image-0.png fft_image-1.png -ift fft_image_ift.png
4326</pre>
4327
4328<p>The resulting image may need to be cropped due to padding introduced when
4329the original image, prior to the <a href="command-line-options.html#fft">-fft</a> or <a href="command-line-options.html#fft">+fft</a>, was not square or even dimensioned. Any padding is at
4330the right and/or bottom sides of the image.</p>
4331
4332<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to
4333use <a href="command-line-options.html#ift">-ift</a>.</p>
4334
4335<p>Use <a href="command-line-options.html#ift">+ift</a> (with HDRI enabled) to transform a pair of real
4336and imaginary images from the frequency domain to a single image in the normal
4337(spatial) domain.</p>
4338
4339<p>By default the IFT is not normalized (and the FFT is). Use "<code><a href="command-line-options.html#define">-define</a> fourier:normalize=inverse</code> to explictly normalize the IFT and unnormalize the FFT.</p>
4340
4341<div style="margin: auto;">
4342 <h4><a id="immutable"></a>-immutable</h4>
4343</div>
4344
4345<p class="magick-description">make image immutable.</p>
4346
4347<div style="margin: auto;">
4348 <h4><a id="implode"></a>-implode <var>factor</var></h4>
4349</div>
4350
4351<p class="magick-description">implode image pixels about the center.</p>
4352
4353<div style="margin: auto;">
4354 <h4><a id="insert"></a>-insert <var>index</var></h4>
4355</div>
4356
4357<p class="magick-description">insert the last image into the image sequence.</p>
4358
4359<p>This option takes last image in the current image sequence and inserts it
4360at the given index. If a negative index is used, the insert position is
4361calculated before the last image is removed from the sequence. As such
4362<code>-insert -1</code> will result in no change to the image sequence.</p>
4363
4364<p>The <code>+insert</code> option is equivalent to <code>-insert -1</code>. In
4365other words, insert the last image, at the end of the current image sequence.
4366Consequently this has no effect on the image sequence order.</p>
4367
4368<div style="margin: auto;">
4369 <h4><a id="intensity"></a>-intensity <var>method</var></h4>
4370</div>
4371
4372<p class="magick-description">method to generate intensity value from pixel.</p>
4373
4374<p>ImageMagick provides a number of methods used in situations where an
4375operatory needs to determine a single grayscale value for some purpose, from
4376an image with red, green, and blue pixel components. Typically the linear
4377<code>Rec709Luminance</code> formula is used, which is the same formula used when
4378converting images to <code>-colorspace gray</code>. </p>
4379
4380<p>The following formulas are currently provided, and will first convert
4381the pixel values to linear-RGB or non-linear sRGB colorspace before
4382being applied to calulate the final greyscale value. </p>
4383
4384<pre>
4385 Rec601Luma 0.298839R' + 0.586811G'+ 0.114350B'
4386 Rec601Luminance 0.298839R + 0.586811G + 0.114350B
4387 Rec709Luma 0.212656R' + 0.715158G' + 0.072186B'
4388 Rec709Luminance 0.212656R + 0.715158G + 0.072186B
4389 Brightness max(R', G', B')
4390 Lightness (min(R', G', B') + max(R', G', B')) / 2.0
4391</pre>
4392<p>Note that the above R,G,B values is the image's linear-RGB values, while
4393R',G',B' are sRGB non-linear values. </p>
4394
4395<p>These intensity methods are mathematical in nature and will use the
4396current value in the images respective R,G,B channel regardless of
4397what that is, or what colorspace the image is currently using.</p>
4398
4399<pre>
4400 Average (R + G + B) / 3.0
4401 MS (R^2 + G^2 + B^2) / 3.0
4402 RMS sqrt( (R^2 + G^2 + B^2) / 3.0 )
4403</pre>
4404
4405<p>These methods are often used for other purposes, such as generating a
4406grayscale difference image between two color images (using <a href="command-line-options.html#compose">-compose</a> '<code>Difference</code>' composition. </p>
4407
4408<p> For example The 'MS' (Mean Squared) setting is good for minimizing color
4409error comparisions. While... The method 'RMS' (Root Mean Squared) for
4410example is appropriate for calculating color vector distance, from a color
4411difference image. This is equivalent to the color only component of the <a href="command-line-options.html#fuzz">-fuzz</a> factor color compare setting. </p>
4412
4413<p>See also <a href="command-line-options.html#grayscale">-grayscale</a> which applies one of the above
4414grayscaling formula directly to an image without setting the <a href="command-line-options.html#intensity">-intensity</a> setting.</p>
4415
4416<p>The <a href="command-line-options.html#colorspace">-colorspace gray</a> image conversion also uses
4417the current intensity setting, but will always convert the image to the
4418appropriate sRGB or linear-RGB colorspace before appling the above
4419function.</p>
4420
4421<p>To print a complete list of posible pixel intensity setting methods, use <a href="command-line-options.html#list">-list intensity</a>.</p>
4422
4423<p>Operators affected by the <a href="command-line-options.html#intensity">-intensity</a> setting include:</p>
4424
4425<pre>
4426-adaptive-blur
4427-adaptive-sharpen
4428-black-threshold
4429-clut (when mapping greyscale CLUT image to alpha channel if set by -channels)
4430-colors for gray colorspace
4431-compose {LightenIntensity, DarkenIntensity, CopyOpacity, CopyBlack}
4432-contrast-stretch
4433-distort {ErodeIntensity, DilateIntensity}
4434-normalize
4435-random-threshold
4436-selective-blur
4437-shade
4438-threshold
4439-tint
4440-white-threshold
4441</pre>
4442
4443<div style="margin: auto;">
4444 <h4><a id="intent"></a>-intent <var>type</var></h4>
4445</div>
4446
4447<p class="magick-description">use this type of rendering intent when managing the image color.</p>
4448
4449<p>Use this option to affect the color management operation of an image (see
4450<a href="command-line-options.html#profile">-profile</a>). Choose from these intents: <code>Absolute,
4451Perceptual, Relative, Saturation</code>.</p>
4452
4453<p>The default intent is Perceptual for the sRGB colorspace and undefined for the RGB and gray colorspaces.</p>
4454
4455<p>To print a complete list of rendering intents, use <a href="command-line-options.html#list">-list intent</a>.</p>
4456
4457<div style="margin: auto;">
4458 <h4><a id="interlace"></a>-interlace <var>type</var></h4>
4459</div>
4460
4461<p class="magick-description">the type of interlacing scheme.</p>
4462
4463<p>Choose from:</p>
4464
4465<pre>
4466 none
4467 line
4468 plane
4469 partition
4470 JPEG
4471 GIF
4472 PNG
4473</pre>
4474
4475<p>This option is used to specify the type of interlacing scheme for raw image
4476formats such as <code>RGB</code> or <code>YUV</code>.</p>
4477
4478<p><code>None</code> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
4479
4480<p><code>Line</code> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
4481
4482<p><code>Plane</code> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
4483
4484<p><code>Partition</code> is like plane except the different planes are saved to
4485individual files (e.g. image.R, image.G, and image.B).</p>
4486
4487<p>Use <code>Line</code> or <code>Plane</code> to create an <code>interlaced
4488PNG</code> or <code>GIF</code> or <code>progressive JPEG</code> image.</p>
4489
4490<p>To print a complete list of interlacing schemes, use <a href="command-line-options.html#list">-list
4491interlace</a>.</p>
4492
4493<div style="margin: auto;">
4494 <h4><a id="interpolate"></a>-interpolate <var>type</var></h4>
4495</div>
4496
4497<p class="magick-description">Set the pixel color interpolation method to use when looking up a color based on a floating point or real value.</p>
4498
4499<p>When looking up the color of a pixel using a non-integer floating point
4500value, you typically fall in between the pixel colors defined by the source
4501image. This setting determines how the color is determined from the colors of
4502the pixels surrounding that point. That is how to determine the color of a
4503point that falls between two, or even four different colored pixels. </p>
4504
4505<pre>
4506 integer The color of the top-left pixel (floor function)
4507 nearest-neighbor The nearest pixel to the lookup point (rounded function)
4508 average The average color of the surrounding four pixels
4509 bilinear A double linear interpolation of pixels (the default)
4510 mesh Divide area into two flat triangular interpolations
4511 bicubic Fitted bicubic-spines of surrounding 16 pixels
4512 spline Direct spline curves (colors are blurred)
4513 filter Use resize <a href="command-line-options.html#filter">-filter</a> settings
4514</pre>
4515
4516<p>This most important for distortion operators such as <a href="command-line-options.html#distort">-distort</a>, <a href="command-line-options.html#implode">-implode</a>, <a href="command-line-options.html#transform">-transform</a> and <a href="command-line-options.html#fx">-fx</a>. </p>
4517
4518<p>To print a complete list of interpolation methods, use <a href="command-line-options.html#list">-list interpolate</a>.</p>
4519
4520<p>See also <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a>, for control of the
4521lookup for positions outside the boundaries of the image. </p>
4522
4523
4524<div style="margin: auto;">
4525 <h4><a id="interline-spacing"></a>-interline-spacing <var>value</var></h4>
4526</div>
4527
4528<p class="magick-description">the space between two text lines.</p>
4529
4530<div style="margin: auto;">
4531 <h4><a id="interword-spacing"></a>-interword-spacing <var>value</var></h4>
4532</div>
4533
4534<p class="magick-description">the space between two words.</p>
4535
4536<div style="margin: auto;">
4537 <h4><a id="kerning"></a>-kerning <var>value</var></h4>
4538</div>
4539
4540<p class="magick-description">the space between two letters.</p>
4541
4542<div style="margin: auto;">
4543 <h4><a id="kuwahara"></a>-kuwahara <var>radius</var><br>-kuwahara <var>radius</var>x<var>sigma</var></h4>
4544</div>
4545
4546<p class="magick-description">edge preserving noise reduction filter.</p>
4547
4548<p>The <var>radius</var> is more important than the <var>sigma</var>. If <var>sigma</var> is left off, it will be computed automatically from the <var>radius</var> as <var>sigma</var>=<var>radius</var>-0.5. The <var>sigma</var> provides a bit of additional smoothing control.</p>
4549
4550
4551<div style="margin: auto;">
4552 <h4><a id="label"></a>-label <var>name</var></h4>
4553</div>
4554
4555<p class="magick-description">assign a label to an image.</p>
4556
4557<p>Use this option to assign a specific label to the image, as it is read in
4558or created. You can use the <a href="command-line-options.html#set">-set</a> operation to re-assign
4559a the labels of images already read in. Image formats such as TIFF, PNG,
4560MIFF, supports saving the label information with the image.</p>
4561
4562<p>When saving an image to a <var>PostScript</var> file, any label
4563assigned to an image is used as a header string to print above the postscript
4564image. </p>
4565
4566<p>You can include the image filename, type, width, height, or other image
4567attribute by embedding special format character. See <a href="escape.html">Format and Print Image
4568Properties</a> for details of the percent escape codes.</p>
4569
4570<p>For example,</p>
4571
4572<p class="crtsnip">
4573 -label "%m:%f %wx%h" bird.miff
4574</p>
4575
4576<p>assigns an image label of <code>MIFF:bird.miff 512x480</code> to the
4577"<code>bird.miff</code>" image and whose width is 512 and height is 480, as it
4578is read in. If a <a href="command-line-options.html#label">+label</a> option was used instead, any
4579existing label present in the image would be used. You can remove all labels
4580from an image by assigning the empty string. </p>
4581
4582<p>A label is not drawn on the image, but is embedded in the image datastream
4583via <var>Label</var> tag or similar mechanism. If you want the label to be
4584visible on the image itself, use the <a href="command-line-options.html#draw">-draw</a> option, or
4585during the final processing in the creation of an image montage.</p>
4586
4587<p>If the first character of <var>string</var> is <var>@</var>, the image label is read from a file titled by the
4588remaining characters in the string. Labels in a file are literal, no embedded
4589formatting characters are recognized.</p>
4590
4591
4592<div style="margin: auto;">
4593 <h4><a id="lat"></a>-lat <var>width</var><br>-lat <var>width</var>x<var>height</var>{<var>+-</var>}<var>offset</var>{<var>%</var>}</h4>
4594</div>
4595
4596<p class="magick-description">perform local adaptive threshold.</p>
4597
4598<p>Adaptively threshold each pixel based on the value of pixels in a
4599surrounding window. If the current pixel is lighter than this average plus
4600the optional <code>offset</code>, then it is made white, otherwise it is made
4601black. Small variations in pixel values such as found in scanned documents
4602can be ignored if offset is positive. A negative offset will make it more
4603sensitive to those small variations. </p>
4604
4605<p>This is commonly used to threshold images with an uneven background. It is
4606based on the assumption that average color of the small window is the
4607the local background color, from which to separate the foreground color. </p>
4608
4609
4610<div style="margin: auto;">
4611 <h4><a id="layers"></a>-layers <var>method</var></h4>
4612</div>
4613
4614<p class="magick-description">handle multiple images forming a set of image layers or animation frames.</p>
4615
4616<p>Perform various image operation methods to a ordered sequence of images
4617which may represent either a set of overlaid 'image layers', a GIF disposal
4618animation, or a fully-'coalesced' animation sequence. </p>
4619
4620<table class="table table-condensed table-striped">
4621 <tbody>
4622 <tr>
4623 <th style="width: 8%">Method</th>
4624 <th>Description</th>
4625 </tr>
4626
4627 <tr>
4628 <td>compare-any</td>
4629 <td>Crop the second and later frames to the smallest rectangle
4630 that contains all the differences between the two images. No GIF <a href="command-line-options.html#dispose">-dispose</a> methods are taken into account. </td>
4631 </tr>
4632
4633 <tr><td></td><td>This exactly the same as the <a href="command-line-options.html#deconstruct">-deconstruct</a> operator, and does not preserve animations normal
4634 working, especially when animation used layer disposal methods such as
4635 '<code>Previous</code>' or '<code>Background</code>'. </td>
4636 </tr>
4637
4638 <tr>
4639 <td>compare-clear</td>
4640 <td>As '<code>compare-any</code>' but crop to the bounds of any
4641 opaque pixels which become transparent in the second frame. That is the
4642 smallest image needed to mask or erase pixels for the next frame. </td>
4643 </tr>
4644
4645 <tr>
4646 <td>compare-overlay</td>
4647 <td>As '<code>compare-any</code>' but crop to pixels that add
4648 extra color to the next image, as a result of overlaying color pixels.
4649 That is the smallest single overlaid image to add or change colors. </td>
4650 </tr>
4651
4652 <tr><td></td><td>This can be used with the <a href="command-line-options.html#compose">-compose</a> alpha
4653 composition method '<code>change-mask</code>', to reduce the image to
4654 just the pixels that need to be overlaid. </td>
4655 </tr>
4656
4657 <tr>
4658 <td>coalesce</td>
4659 <td>Equivalent to a call to the <a href="command-line-options.html#coalesce">-coalesce</a> operator. Apply the layer disposal methods set in the
4660 current image sequence to form a fully defined animation sequence, as
4661 it should be displayed. Effectively converting a GIF animation into a
4662 'film strip'-like animation. </td>
4663 </tr>
4664
4665 <tr>
4666 <td>composite</td>
4667 <td>Alpha Composition of two image lists, separated by a
4668 "<code>null:</code>" image, with the destination image list first, and
4669 the source images last. An image from each list are composited
4670 together until one list is finished. The separator image and source
4671 image lists are removed. </td>
4672 </tr>
4673
4674
4675 <tr><td></td>
4676 <td>The <a href="command-line-options.html#geometry">-geometry</a> offset is adjusted according
4677 to <a href="command-line-options.html#gravity">-gravity</a> in accordance of the virtual
4678 canvas size of the first image in each list. Unlike a normal <a href="command-line-options.html#composite">-composite</a> operation, the canvas offset is also
4679 added to the final composite positioning of each image. </td> </tr>
4680
4681 <tr><td></td>
4682 <td>If one of the image lists only contains one image, that image is
4683 applied to all the images in the other image list, regardless of which
4684 list it is. In this case it is the image meta-data of the list which
4685 preserved. </td>
4686 </tr>
4687
4688
4689 <tr>
4690 <td>dispose</td>
4691 <td>This like '<code>coalesce</code>' but shows the look of
4692 the animation after the layer disposal method has been applied, before
4693 the next sub-frame image is overlaid. That is the 'dispose' image that
4694 results from the application of the GIF <a href="command-line-options.html#dispose">-dispose</a> method. This allows you to check what
4695 is going wrong with a particular animation you may be developing.
4696 </td>
4697 </tr>
4698
4699 <tr>
4700 <td>flatten</td>
4701 <td>Create a canvas the size of the first images virtual
4702 canvas using the current <a href="command-line-options.html#background">-background</a> color,
4703 and <a href="command-line-options.html#compose">-compose</a> each image in turn onto that
4704 canvas. Images falling outside that canvas is clipped. Final
4705 image will have a zero virtual canvas offset. </td>
4706 </tr>
4707
4708 <tr><td></td>
4709 <td>This usually used as one of the final 'image layering' operations
4710 overlaying all the prepared image layers into a final image. </td>
4711 </tr>
4712
4713 <tr><td></td>
4714 <td>For a single image this method can also be used to fillout a virtual
4715 canvas with real pixels, or to underlay an opaque color to remove
4716 transparency from an image.</td>
4717 </tr>
4718
4719
4720 <tr>
4721 <td>merge</td>
4722 <td>As 'flatten' method but merging all the given image
4723 layers to create a new layer image just large enough to hold all the
4724 image without clipping or extra space. The new images virtual offset
4725 will preserve the position of the new layer, even if this offset is
4726 negative. The virtual canvas size of the first image is preserved.
4727 </td>
4728 </tr>
4729
4730 <tr><td></td><td>Caution is advised when handling image layers with
4731 negative offsets as few image file formats handle them correctly.
4732 Following this operation method with <a href="command-line-options.html#repage">+repage</a>
4733 will remove the layer offset, and create an image in which all the
4734 overlaid image positions relative to each other is preserved, though
4735 not necessarily exactly where you specified them.
4736 </td>
4737 </tr>
4738
4739 <tr><td></td><td>See also 'trim-bounds' below which is closely related but
4740 without doing the'flatten' to merge the images together. </td>
4741 </tr>
4742
4743 <tr>
4744 <td>mosaic</td>
4745 <td>As 'flatten' method but expanding the initial canvas size
4746 of the first image in a positive direction only so as to hold all the
4747 image layers. However as a virtual canvas is 'locked' to the origin,
4748 by its own definition, image layers with a negative offsets will still
4749 become clipped by the top and left edges. See 'merge' or 'trim-bounds'
4750 if this could be a problem. </td>
4751
4752 </tr>
4753
4754 <tr><td></td><td>This method is commonly used to layout individual image
4755 using various offset but without knowing the final canvas size. The
4756 resulting image will, like 'flatten' not have any virtual offset, so
4757 can be saved to any image file format. </td>
4758 </tr>
4759
4760
4761 <tr>
4762 <td>optimize</td>
4763 <td>Optimize a coalesced animation, into GIF animation using
4764 a number of general techniques. This currently a short cut to
4765 apply both the '<code>optimize-frame</code>', and
4766 '<code>optimize-transparency</code>' methods but may be expanded to
4767 include other optimization methods as they are developed. </td>
4768 </tr>
4769
4770 <tr>
4771 <td>optimize-frame</td>
4772 <td>Optimize a coalesced animation, into GIF animation by
4773 reducing the number of pixels per frame as much as possible by
4774 attempting to pick the best layer disposal method to use, while ensuring
4775 the result will continue to animate properly. </td>
4776 </tr>
4777
4778 <tr><td></td><td> There is no guarantee that the best optimization is found.
4779 But then no reasonably fast GIF optimization algorithm can do this.
4780 However this does seem to do better than most other GIF frame
4781 optimizers seen. </td>
4782 </tr>
4783
4784 <tr>
4785 <td>optimize-plus</td>
4786 <td>As '<code>optimize-frame</code>' but attempt to improve the
4787 overall optimization by adding extra frames to the animation, without
4788 changing the final look or timing of the animation. The frames are
4789 added to attempt to separate the clearing of pixels from the
4790 overlaying of new additional pixels from one animation frame to the
4791 next. If this does not improve the optimization (for the next frame
4792 only), it will fall back to the results of the previous normal
4793 '<code>optimize-frame</code>' technique. </td>
4794 </tr>
4795
4796 <tr><td></td><td>There is the possibility that the change in the disposal
4797 style will result in a worsening in the optimization of later frames,
4798 though this is unlikely. In other words there no guarantee that it is
4799 better than the normal '<code>optimize-frame</code>' technique. For some
4800 animations however you can get a vast improvement in the final
4801 animation size. </td>
4802 </tr>
4803
4804 <tr>
4805 <td>optimize-transparency</td>
4806 <td>Given a GIF animation, replace any pixel in the sub-frame
4807 overlay images with transparency, if it does not change the resulting
4808 animation by more than the current <a href="command-line-options.html#fuzz">-fuzz</a> factor.
4809 </td>
4810 </tr>
4811
4812 <tr><td></td><td>This should allow a existing frame optimized GIF animation
4813 to compress into a smaller file size due to larger areas of one
4814 (transparent) color rather than a pattern of multiple colors repeating
4815 the current disposed image of the last frame. </td>
4816 </tr>
4817
4818 <tr>
4819 <td>remove-dups</td>
4820 <td>Remove (and merge time delays) of duplicate consecutive
4821 images, so as to simplify layer overlays of coalesced animations.
4822 </td>
4823 </tr>
4824
4825 <tr><td></td><td>Usually this a result of using a constant time delay
4826 across the whole animation, or after a larger animation was split into
4827 smaller sub-animations. The duplicate frames could also have been
4828 used as part of some frame optimization methods. </td>
4829 </tr>
4830
4831 <tr>
4832 <td>remove-zero</td>
4833 <td>Remove any image with a zero time delay, unless ALL the
4834 images have a zero time delay (and is not a proper timed animation, a
4835 warning is then issued). </td>
4836 </tr>
4837
4838 <tr><td></td><td>In a GIF animation, such images are usually frames which
4839 provide partial intermediary updates between the frames that are
4840 actually displayed to users. These frames are usually added for
4841 improved frame optimization in GIF animations. </td>
4842 </tr>
4843
4844 <tr>
4845 <td>trim-bounds</td>
4846 <td>Find the bounds of all the images in the current
4847 image sequence, then adjust the offsets so all images are contained on
4848 a minimal positive canvas. None of the image data is modified or
4849 merged, only the individual image virtual canvas size and offset.
4850 All the images is given the same canvas size, and and will have
4851 a positive offset, but will remain in the same position relative to
4852 each other. As a result of the minimal canvas size at least one image
4853 will touch every edge of that canvas. The image data touching those
4854 edges however may be transparent. </td>
4855 </tr>
4856
4857 <tr><td></td><td>The result is much like if you used 'merge' followed by a
4858 <a href="command-line-options.html#repage">+repage</a> option, except that all the images
4859 have been kept separate. If 'flatten' is used after using
4860 'trim-bounds' you will get the same result. </td>
4861 </tr>
4862
4863 </tbody>
4864</table>
4865
4866<p>To print a complete list of layer types, use <a href="command-line-options.html#list">-list layers</a>.</p>
4867
4868<p>The operators <a href="command-line-options.html#coalesce">-coalesce</a>, <a href="command-line-options.html#deconstruct">-deconstruct</a>, <a href="command-line-options.html#flatten">-flatten</a>, and <a href="command-line-options.html#mosaic">-mosaic</a> are only aliases for the above methods and may be depreciated in
4869the future. Also see <a href="command-line-options.html#page">-page</a>, <a href="command-line-options.html#repage">-repage</a> operators, the <a href="command-line-options.html#compose">-compose</a> setting, and the
4870GIF <a href="command-line-options.html#dispose">-dispose</a> and <a href="command-line-options.html#delay">-delay</a>
4871settings. </p>
4872
4873
4874<div style="margin: auto;">
4875 <h4><a id="level"></a>-level <var>black_point</var>{,<var>white_point</var>}{<var>%</var>}{,<var>gamma</var>}</h4>
4876</div>
4877
4878<p class="magick-description">adjust the level of image channels.</p>
4879
4880<p>Given one, two or three values delimited with commas: black-point,
4881white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
4882white points range from 0 to <var>QuantumRange</var>, or from 0 to
4883100%; if the white point is omitted it is set to (<var>QuantumRange</var> - black_point), so as to center contrast changes.
4884If a <code>%</code> sign is present anywhere in the string, both black and white
4885points are percentages of the full color range. Gamma will do a <a href="command-line-options.html#gamma">-gamma</a> adjustment of the values. If it is omitted, the
4886default of 1.0 (no gamma correction) is assumed.</p>
4887
4888<p>In normal usage (<code>-level</code>) the image values are stretched so that
4889the given '<code>black_point</code>' value in the original image is set to zero
4890(or black), while the given '<code>white_point</code>' value is set to <var>QuantumRange</var> (or white). This provides you with direct
4891contrast adjustments to the image. The '<code>gamma</code>' of the resulting
4892image will then be adjusted. </p>
4893
4894<p>From ImageMagick v6.4.1-9 using the plus form of the operator
4895(<code>+level</code>) or adding the special '!' flag anywhere in the argument
4896list, will cause the operator to do the reverse of the level adjustment. That
4897is a zero, or <var>QuantumRange</var> value (black, and white, resp.)
4898in the original image, is adjusted to the given level values, allowing you to
4899de-contrast, or compress the channel values within the image. The
4900'<code>gamma</code>' is adjusted before the level adjustment to de-contrast the
4901image is made. </p>
4902
4903<p>Only the channels defined by the current <a href="command-line-options.html#channel">-channel</a>
4904setting are adjusted (defaults to RGB color channels only), allowing you to
4905limit the effect of this operator. </p>
4906
4907<p>Please note that the transparency channel is treated as 'matte'
4908values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
4909
4910
4911<div style="margin: auto;">
4912 <h4><a id="level-colors"></a>-level-colors {<var>black_color</var>}{,}{<var>white_color</var>}</h4>
4913</div>
4914
4915<p class="magick-description">adjust the level of an image using the provided dash separated colors.</p>
4916
4917<p>This function is exactly like <a href="command-line-options.html#level">-level</a>, except that the
4918value value for each color channel is determined by the
4919'<code>black_color</code>' and '<code>white_color</code>' colors given (as
4920described under the <a href="command-line-options.html#fill">-fill</a> option). </p>
4921
4922<p>This effectually means the colors provided to <code>-level-colors</code>
4923is mapped to become 'black' and 'white' respectively, with all the other
4924colors linearly adjusted (or clipped) to match that change. Each channel is
4925adjusted separately using the channel values of the colors specified. </p>
4926
4927<p>On the other hand the plus form of the operator (<code>+level-colors</code>)
4928will map the image color 'black' and 'white' to the given colors
4929respectively, resulting in a gradient (de-contrasting) tint of the image to
4930those colors. This can also be used to convert a plain gray-scale image into a
4931one using the gradient of colors specified. </p>
4932
4933<p>By supplying a single color with a comma separator either before or after
4934that color, will just replace the respective 'black' or 'white' point
4935respectively. But if no comma separator is provided, the given color is
4936used for both the black and white color points, making the operator either
4937threshold the images around that color (- form) or set all colors to that
4938color (+ form). </p>
4939
4940
4941<div style="margin: auto;">
4942 <h4><a id="limit"></a>-limit <var>type value</var></h4>
4943</div>
4944
4945<p class="magick-description">Set the pixel cache resource limit.</p>
4946
4947<p>Choose from: <code>area</code>, <code>disk</code>, <code>file</code>,
4948<code>map</code>, <code>memory</code>, <code>thread</code>, or <code>time</code>.</p>
4949
4950<p>The value for <code>file</code> is in number of files. The other limits are
4951in bytes. Define arguments for the memory, map, area, and disk resource limits
4952with SI prefixes (.e.g 100MB).</p>
4953
4954<p>By default the limits are 768 files, 3GB of image area, 1.5GiB memory, 3GiB
4955memory map, and 18.45EB of disk. These limits are adjusted relative to the
4956available resources on your computer if this information is available. When
4957any limit is reached, ImageMagick fails in some fashion but attempts to take
4958compensating actions, if possible. For example, the following limits
4959memory:</p>
4960
4961<p class="crtsnip">
4962 -limit memory 32MiB -limit map 64MiB
4963</p>
4964
4965<p>Use <a href="command-line-options.html#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
4966
4967<pre>
4968-&gt; identify -list resource
4969Resource limits:
4970 Width: 100MP
4971 Height: 100MP
4972 Area: 25.181GB
4973 Memory: 11.726GiB
4974 Map: 23.452GiB
4975 Disk: unlimited
4976 File: 768
4977 Thread: 12
4978 Throttle: 0
4979 Time: unlimited
4980</pre>
4981
4982<p>Requests for pixel storage to keep intermediate images are satisfied by one
4983of three resource categories: in-memory pool, memory-mapped files pool, and
4984disk pool (in that order) depending on the <a href="command-line-options.html#limit">‑limit</a> settings
4985and whether the system honors a resource request. If the total size of
4986allocated pixel storage in the given pool reaches the corresponding limit, the
4987request is passed to the next pool. Additionally, requests that exceed the
4988<code>area</code> limit automagically are allocated on disk.</p>
4989
4990<p>To illustrate how ImageMagick utilizes resource limits, consider a typical
4991image resource request. First, ImageMagick tries to allocate the pixels in
4992memory. The request might be denied if the resource request exceeds the
4993<code>memory</code> limit or if the system does not honor the request. If
4994a memory request is not honored, the pixels are allocated to disk and the file
4995is memory-mapped. However, if the allocation request exceeds the
4996<code>map</code> limit, the resource allocation goes to disk. In all cases, if
4997the resource request exceeds the <code>area</code> limit, the pixels are
4998automagically cached to disk. If the disk has a hard limit, the program
4999fails.</p>
5000
5001<p>In most cases you simply do not need to concern yourself with resource
5002limits. ImageMagick chooses reasonable defaults and most images do not tax
5003your computer resources. Where limits do come in handy is when you process
5004images that are large or on shared systems where ImageMagick can consume all
5005or most of the available memory. In this case, the ImageMagick workflow slows
5006other processes or, in extreme cases, brings the system to a halt. Under
5007these circumstances, setting limits give some assurances that the ImageMagick
5008workflow will not interfere with other concurrent uses of the computer. For
5009example, assume you have a web interface that processes images uploaded from
5010the Internet. To assure ImageMagick does not exceed 10MiB of memory you can
5011simply set the area limit to 10MiB:</p>
5012
5013<p class="crtsnip">
5014-limit area 10MB
5015</p>
5016
5017<p>Now whenever a large image is processed, the pixels are automagically
5018cached to disk instead of memory. This of course implies that large images
5019typically process very slowly, simply because pixel processing in memory can
5020be an order of magnitude faster than on disk. Because your web site users
5021might inadvertently upload a huge image to process, you should set a disk
5022limit as well:</p>
5023
5024<p class="crtsnip">
5025-limit area 10MB -limit disk 500MB
5026</p>
5027
5028<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
5029
5030<p>In addition to command-line resource limit option, resources can be set
5031with <a href="resources.html#environment">environment variables</a>. Set the
5032environment variables <code>MAGICK_AREA_LIMIT</code>,
5033<code>MAGICK_DISK_LIMIT</code>, <code>MAGICK_FILE_LIMIT</code>,
5034<code>MAGICK_MEMORY_LIMIT</code>, <code>MAGICK_MAP_LIMIT</code>,
5035<code>MAGICK_THREAD_LIMIT</code>, <code>MAGICK_TIME_LIMIT</code> for limits of
5036image area, disk space, open files, heap memory, memory map, number of threads
5037of execution, and maximum elapsed time in seconds respectively.</p>
5038
5039<p> Inquisitive users can try adding <a href="command-line-options.html#debug">-debug cache</a> to
5040their commands and then scouring the generated output for references to the
5041pixel cache, in order to determine how the pixel cache was allocated and how
5042resources were consumed. Advanced Unix/Linux users can pipe that output
5043through <code>grep memory|open|destroy|disk</code> for more readable sifting.
5044</p>
5045
5046<p>For more about ImageMagick's use of resources, see the section <b>Cache
5047Storage and Resource Requirements</b> on the <a href="architecture.html#cache%20">Architecture</a> page. </p>
5048
5049<div style="margin: auto;">
5050 <h4><a id="linear-stretch"></a>-linear-stretch <var>black-point</var><br>-linear-stretch <var>black-point</var>{x<var>white-point</var>}{<var>%</var>}}</h4>
5051</div>
5052
5053<p class="magick-description">Linear with saturation stretch.</p>
5054
5055<p>This is very similar to <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a>,
5056and uses a 'histogram bin' to determine the range of color values that needs to
5057be stretched. However it then stretches those colors using the <a href="command-line-options.html#level">-level</a> operator.</p>
5058
5059<p>As such while the initial determination may have 'binning' round off
5060effects, the image colors are stretched mathematically, rather than using the
5061histogram bins. This makes the operator more accurate. </p>
5062
5063<p>note however that a <a href="command-line-options.html#linear-stretch">-linear-stretch</a> of
5064'<code>0</code>' does nothing, while a value of '<code>1</code>' does a near
5065perfect stretch of the color range. </p>
5066
5067<p>See also <a href="command-line-options.html#auto-level">-auto-level</a> for a 'perfect'
5068normalization of mathematical images. </p>
5069
5070<p>This operator is under review for re-development. </p>
5071
5072
5073<div style="margin: auto;">
5074 <h4><a id="linewidth"></a>-linewidth</h4>
5075</div>
5076
5077<p class="magick-description">the line width for subsequent draw operations.</p>
5078
5079<div style="margin: auto;">
5080 <h4><a id="liquid-rescale"></a>-liquid-rescale <var>geometry</var></h4>
5081</div>
5082
5083<p class="magick-description">rescale image with seam-carving.</p>
5084
5085<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5086
5087<div style="margin: auto;">
5088 <h4><a id="list"></a>-list <var>type</var></h4>
5089</div>
5090
5091<p class="magick-description">Print a list of supported arguments for various options or settings. Choose from these list types:</p>
5092
5093<pre>
5094 Align Alpha Boolean Channel
5095 Class ClipPath Coder Color
5096 Colorspace Command Compose Compress
5097 Configure DataType Debug Decoration
5098 Delegate Direction Dispose Distort
5099 Dither Endian Evaluate FillRule
5100 Filter Font Format Function
5101 Gravity ImageList Intent Interlace
5102 Interpolate Kernel Layers LineCap
5103 LineJoin List Locale LogEvent
5104 Log Magic Method Metric
5105 Mime Mode Morphology Module
5106 Noise Orientation Policy PolicyDomain
5107 PolicyRights Preview Primitive QuantumFormat
5108 Resource SparseColor Storage Stretch
5109 Style Threshold Type Units
5110 Validate VirtualPixel
5111</pre>
5112
5113<p>These lists vary depending on your version of ImageMagick. Use "<code>-list
5114list</code>" to get a complete listing of all the "<code>-list</code>" arguments
5115available:</p>
5116
5117<pre>
5118identify -list list
5119</pre>
5120
5121<div style="margin: auto;">
5122 <h4><a id="log"></a>-log <var>string</var></h4>
5123</div>
5124
5125<p class="magick-description">Specify format for debug log.</p>
5126
5127<p>This option specifies the format for the log printed when the <a href="command-line-options.html#debug">-debug</a> option is active.</p>
5128
5129<p>You can display the following components by embedding special format
5130characters:</p>
5131
5132<pre>
5133 %d domain
5134 %e event
5135 %f function
5136 %l line
5137 %m module
5138 %p process ID
5139 %r real CPU time
5140 %t wall clock time
5141 %u user CPU time
5142 %% percent sign
5143 \n newline
5144 \r carriage return
5145</pre>
5146
5147<p>For example:</p>
5148
5149<pre>
5150convert -debug coders -log "%u %m:%l %e" in.gif out.png
5151</pre>
5152
5153<p>The default behavior is to print all of the components.</p>
5154
5155<div style="margin: auto;">
5156 <h4><a id="loop"></a>-loop <var>iterations</var></h4>
5157</div>
5158
5159<p class="magick-description">add Netscape loop extension to your GIF animation.</p>
5160
5161<p>Set iterations to zero to repeat the animation an infinite number of times,
5162otherwise the animation repeats itself up to <var>iterations</var>
5163times.</p>
5164
5165<div style="margin: auto;">
5166 <h4><a id="lowlight-color"></a>-lowlight-color <var>color</var></h4>
5167</div>
5168
5169<p class="magick-description">when comparing images, de-emphasize pixel differences with this color.</p>
5170
5171<div style="margin: auto;">
5172 <h4><a id="magnify"></a>-magnify</h4>
5173</div>
5174
5175<p class="magick-description">double the size of the image with pixel art scaling.</p>
5176
5177
5178<div style="margin: auto;">
5179 <h4><a id="map"></a>-map <var>type</var></h4>
5180</div>
5181
5182<p class="magick-description">Display image using this <var>type</var>.</p>
5183
5184<p>Choose from these <var>Standard Colormap</var> types:</p>
5185
5186<pre>
5187 best
5188 default
5189 gray
5190 red
5191 green
5192 blue
5193</pre>
5194
5195<p>The <var>X server</var> must support the <var>Standard
5196Colormap</var> you choose, otherwise an error occurs. Use <code>list</code> as
5197the type and <code>display</code> searches the list of colormap types in
5198<code>top-to-bottom</code> order until one is located. See <var>xstdcmap(1)</var> for one way of creating Standard Colormaps.</p>
5199
5200
5201<div style="margin: auto;">
5202 <h4><a id="map_stream_"></a>-map <var>components</var></h4>
5203</div>
5204
5205<p class="magick-description">pixel map.</p>
5206
5207<p>Here are the valid components of a map:</p>
5208
5209<pre>
5210 r red pixel component
5211 g green pixel component
5212 b blue pixel component
5213 a alpha pixel component (0 is transparent)
5214 o opacity pixel component (0 is opaque)
5215 i grayscale intensity pixel component
5216 c cyan pixel component
5217 m magenta pixel component
5218 y yellow pixel component
5219 k black pixel component
5220 p pad component (always 0)
5221</pre>
5222
5223<p>You can specify as many of these components as needed in any order (e.g.
5224bgr). The components can repeat as well (e.g. rgbr).</p>
5225
5226
5227<div style="margin: auto;">
5228 <h4><a id="mask"></a>-mask
5229<var>filename</var></h4>
5230</div>
5231
5232<p class="magick-description">Prevent updates to image pixels specified by the mask.</p>
5233
5234<p>This the same as using a mask used for composite masking operations, with
5235grayscale values causing blended updates of the image the mask is attached to.
5236</p>
5237
5238<p>Use <a href="command-line-options.html#mask">+mask</a> to remove the mask from images.</p>
5239
5240<p>Also see <a href="command-line-options.html#clip-mask">-clip-mask</a> which work in the same way,
5241but with strict boolean masking. </p>
5242
5243<div style="margin: auto;">
5244 <h4><a id="mattecolor"></a>-mattecolor <var>color</var></h4>
5245</div>
5246
5247<p class="magick-description">Specify the color to be used with the <a href="command-line-options.html#frame">-frame</a> option.</p>
5248
5249<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
5250
5251<p>The default matte color is <code>#BDBDBD</code>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p>
5252
5253<div style="margin: auto;">
5254 <h4><a id="maximum"></a>-maximum</h4>
5255</div>
5256
5257<p class="magick-description">return the maximum intensity of an image sequence.</p>
5258
5259<p>Select the 'maximum' value from all the surrounding pixels. </p>
5260
5261<p>This is legacy option from the <a href="command-line-options.html#statistic">method</a> of the same
5262name. </p>
5263
5264<div style="margin: auto;">
5265 <h4><a id="median"></a>-median <var>geometry</var></h4>
5266</div>
5267
5268<p class="magick-description">apply a median filter to the image.</p>
5269
5270<p>Select the 'middle' value from all the surrounding pixels. </p>
5271
5272<p>This is legacy option from the <a href="command-line-options.html#statistic">method</a> of the same
5273name. </p>
5274
5275<div style="margin: auto;">
5276 <h4><a id="mean-shift"></a>-mean-shift <var>width</var>x<var>height</var>{<var>+distance</var>{%}}</h4>
5277</div>
5278
5279<p class="magick-description">image noise removal and color reduction/segmentation (e.g. -mean-shift 7x7+10%).</p>
5280
5281<p><var>width</var>x<var>height</var> is the window size and <var>distance</var> is the color distance measured in the range 0 to 1 or 0 to 100%</p>
5282
5283<p>The mean shift algorithm is iterative and thus slower the larger the window size. For each pixel, it gets all the pixels in the window centered at the pixel and excludes those that are outside the radius=sqrt((width-1)(height-1)/4) surrounding the pixel. From those pixels, it finds which of them are within the specified squared color distance from the current mean. It then computes a new x,y centroid from those coordinates and a new mean. This new x,y centroid is used as the center for a new window. This process is iterated until it converges and the final mean is then used to replace the original pixel value. It repeats this process for the next pixel, etc, until it processes all pixels in the image. Results are better when using other colorspaces rather than RGB. Recommend YIQ, YUV or YCbCr, which seem to give equivalent results.</p>
5284
5285<div style="margin: auto;">
5286 <h4><a id="metric"></a>-metric <var>type</var></h4>
5287</div>
5288
5289<p class="magick-description">Output to STDERR a measure of the differences between images according to the <var>type</var> given metric.</p>
5290
5291<p>Choose from:</p>
5292
5293<pre>
5294 AE absolute error count, number of different pixels (-fuzz effected)
5295 FUZZ mean color distance
5296 MAE mean absolute error (normalized), average channel error distance
5297 MEPP mean error per pixel (normalized mean error, normalized peak error)
5298 MSE mean error squared, average of the channel error squared
5299 NCC normalized cross correlation
5300 PAE peak absolute (normalized peak absolute)
5301 PHASH perceptual hash
5302 PSNR peak signal to noise ratio
5303 RMSE root mean squared (normalized root mean squared)
5304</pre>
5305
5306<p>Control the '<code>AE</code>', or absolute count of pixels that are different,
5307with the <a href="command-line-options.html#fuzz">-fuzz</a> factor (ignore pixels which
5308only changed by a small amount). Use '<code>PAE</code>' to find the
5309size of the <a href="command-line-options.html#fuzz">-fuzz</a> factor needed to make all pixels
5310'similar', while '<code>MAE</code>' determines the factor needed
5311for about half the pixels to be similar. </p>
5312
5313<p>The '<code>MEPP</code>' metric returns three different metrics
5314('<code>MAE</code>', '<code>MAE</code>' normalized, and '<code>PAE</code>'
5315normalized) from a single comparison run. </p>
5316
5317<p>To print a complete list of metrics, use the <a href="command-line-options.html#list">-list
5318metric</a> option.</p>
5319
5320
5321<div style="margin: auto;">
5322 <h4><a id="minimum"></a>-minimum</h4>
5323</div>
5324
5325<p class="magick-description">return the minimum intensity of an image sequence.</p>
5326
5327<p>Select the 'minimal' value from all the surrounding pixels. </p>
5328
5329<p>This is legacy option from the <a href="command-line-options.html#statistic">method</a> of the same
5330name. </p>
5331
5332
5333
5334<div style="margin: auto;">
5335 <h4><a id="mode"></a>-mode <var>geometry</var></h4>
5336</div>
5337
5338<p class="magick-description">make each pixel the \'predominant color\' of the neighborhood.'</p>
5339
5340<div style="margin: auto;">
5341 <h4>-mode <var>value</var></h4>
5342</div>
5343
5344<p class="magick-description">Mode of operation.</p>
5345
5346<p>Choose the <var>value</var> from these styles: <code>Frame,
5347Unframe, or Concatenate</code></p>
5348
5349<p>Use the <a href="command-line-options.html#list">-list</a> option with a '<code>Mode</code>' argument
5350for a list of <a href="command-line-options.html#mode">-mode</a> arguments available in your
5351ImageMagick installation.</p>
5352
5353
5354<div style="margin: auto;">
5355 <h4><a id="modulate"></a>-modulate <var>brightness</var>[,<var>saturation</var>,<var>hue</var>]</h4>
5356</div>
5357
5358<p class="magick-description">Vary the <var>brightness</var>, <var>saturation</var>, and <var>hue</var> of an image.</p>
5359
5360<p>The arguments are given as a percentages of variation. A value of 100 means
5361no change, and any missing values are taken to mean 100.</p>
5362
5363<p>The <var>brightness</var> is a multiplier of the overall
5364brightness of the image, so 0 means pure black, 50 is half as bright, 200 is
5365twice as bright. To invert its meaning <a href="command-line-options.html#negate">-negate</a> the image
5366before and after. </p>
5367
5368<p>The <var>saturation</var> controls the amount of color in an
5369image. For example, 0 produce a grayscale image, while a large value such as
5370200 produce a very colorful, 'cartoonish' color.</p>
5371
5372<p>The <var>hue</var> argument causes a "rotation" of the colors
5373within the image by the amount specified. For example, 50 results in
5374a counter-clockwise rotation of 90, mapping red shades to purple, and so on.
5375A value of either 0 or 200 results in a complete 180 degree rotation of the
5376image. Using a value of 300 is a 360 degree rotation resulting in no change to
5377the original image. </p>
5378
5379<p>For example, to increase the color brightness by 20% and decrease the color
5380saturation by 10% and leave the hue unchanged, use <a href="command-line-options.html#modulate">-modulate 120,90</a>.</p>
5381
5382<p>Use <a href="command-line-options.html#set">-set</a> attribute of '<code>option:modulate:colorspace</code>' to specify which colorspace to
5383modulate. Choose from <code>HCL</code>, <code>HCLp</code>, <code>HSB</code>, <code>HSI</code>, <code>HSL</code> (the default), <code>HSV</code>, <code>HWB</code>, or <code>LCH</code> (LCHuv). For example,</p>
5384
5385<pre>
5386convert image.png -set option:modulate:colorspace hsb -modulate 120,90 modulate.png
5387</pre>
5388
5389<div style="margin: auto;">
5390 <h4><a id="moments"></a>-moments</h4>
5391</div>
5392
5393<p class="magick-description">report image moments and perceptual hash.</p>
5394
5395
5396<div style="margin: auto;">
5397 <h4><a id="monitor"></a>-monitor</h4>
5398</div>
5399
5400<p class="magick-description">monitor progress.</p>
5401
5402
5403<div style="margin: auto;">
5404 <h4><a id="monochrome"></a>-monochrome</h4>
5405</div>
5406
5407<p class="magick-description">transform the image to black and white.</p>
5408
5409<div style="margin: auto;">
5410 <h4><a id="morph"></a>-morph <var>frames</var></h4>
5411</div>
5412
5413<p class="magick-description">morphs an image sequence.</p>
5414
5415<p>Both the image pixels and size are linearly interpolated to give the
5416appearance of a metamorphosis from one image to the next, over all the images
5417in the current image list. The added images are the equivalent of a <a href="command-line-options.html#blend">-blend</a> composition. The <var>frames</var>
5418argument determine how many images to interpolate between each image. </p>
5419
5420
5421<div style="margin: auto;">
5422 <h4><a id="morphology"></a>-morphology</h4>
5423 <h4>-morphology <var>method</var> <var>kernel</var></h4>
5424</div>
5425
5426<p class="magick-description">apply a morphology method to the image.</p>
5427
5428<p>Until I get around to writing an option summary for this, see <a href="http://www.imagemagick.org/Usage/morphology/">IM Usage Examples,
5429Morphology</a>. </p>
5430
5431
5432<div style="margin: auto;">
5433 <h4><a id="mosaic"></a>-mosaic</h4>
5434</div>
5435
5436<p class="magick-description">an simple alias for the <a href="command-line-options.html#layers">-layers</a> method "mosaic"</p>
5437
5438
5439<div style="margin: auto;">
5440 <h4><a id="motion-blur"></a>-motion-blur <var>radius</var><br>-motion-blur <var>radius</var>x<var>sigma</var>+<var>angle</var></h4>
5441</div>
5442
5443<p class="magick-description">simulate motion blur.</p>
5444
5445<p>Blur with the given radius, standard deviation (sigma), and angle. The
5446angle given is the angle toward which the image is blurred. That is the
5447direction people would consider the object is coming from. </p>
5448
5449<p>Note that the blur is not uniform distribution, giving the motion a
5450definite sense of direction of movement. </p>
5451
5452<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
5453pixels which are outside the image proper are blurred into the final result.
5454</p>
5455
5456<div style="margin: auto;">
5457 <h4><a id="name"></a>-name</h4>
5458</div>
5459
5460<p class="magick-description">name an image.</p>
5461<div style="margin: auto;">
5462 <h4><a id="negate"></a>-negate</h4>
5463</div>
5464
5465<p class="magick-description">replace each pixel with its complementary color.</p>
5466
5467<p>The red, green, and blue intensities of an image are negated. White becomes
5468black, yellow becomes blue, etc. Use <a href="command-line-options.html#negate">+negate</a> to only
5469negate the grayscale pixels of the image.</p>
5470
5471<div style="margin: auto;">
5472 <h4><a id="noise"></a>-noise <var>geometry</var><br>
5473 +noise <var>type</var></h4>
5474</div>
5475
5476<p class="magick-description">Add or reduce noise in an image.</p>
5477
5478<p>The principal function of noise peak elimination filter is to smooth the
5479objects within an image without losing edge information and without creating
5480undesired structures. The central idea of the algorithm is to replace a pixel
5481with its next neighbor in value within a pixel window, if this pixel has been
5482found to be noise. A pixel is defined as noise if and only if this pixel is
5483a maximum or minimum within the pixel window.</p>
5484
5485<p>Use <code><a href="command-line-options.html#noise">-noise</a> <var>radius</var></code> to
5486specify the width of the neighborhood when reducing noise. This is equivalent
5487to using a <code><a href="command-line-options.html#statistic">-statistic</a> NonPeak</code> operation,
5488which should be used in preference.</p>
5489
5490<p>Use <a href="command-line-options.html#noise">+noise</a> followed by a noise <var>type</var> to add noise to an image. Choose from these noise
5491types:</p>
5492
5493<pre>
5494 Gaussian
5495 Impulse
5496 Laplacian
5497 Multiplicative
5498 Poisson
5499 Random
5500 Uniform
5501</pre>
5502
5503<p>The amount of noise added can be controled by the <code><a href="command-line-options.html#attunuuate">-attenuate</a></code> setting. If unset the value is
5504equivalent to 1.0, or a maximum noise addition.</p>
5505
5506<p>Note that Random will replace the image with noise rather than add noise to the image. Use Uniform, if you wish to add random noise to the image.</p>
5507
5508<p>To print a complete list of noises, use the <a href="command-line-options.html#list">-list noise</a> option.</p>
5509
5510<p>Also see the <a href="command-line-options.html#evaluate">-evaluate</a> noise functions that allows
5511the use of a controlling value to specify the amount of noise that should be
5512added to an image. </p>
5513
5514
5515<div style="margin: auto;">
5516 <h4><a id="normalize"></a>-normalize</h4>
5517</div>
5518
5519<p class="magick-description">Increase the contrast in an image by <var>stretching</var> the range of intensity values.</p>
5520
5521<p>The intensity values are stretched to cover the entire range of possible
5522values. While doing so, black-out at most <var>2%</var> of the pixels and
5523white-out at most <var>1%</var> of the pixels.</p>
5524
5525<p>Note that as of ImageMagick 6.4.7-0, <a href="command-line-options.html#normalize">-normalize</a>
5526is equivalent to <a href="command-line-options.html#contrast-stretch">-contrast-stretch 2%x1%</a>.
5527(Before this version, it was equivalent to <a href="command-line-options.html#contrast-stretch">-contrast-stretch 2%x99%</a>).</p>
5528
5529<p>All the channels are normalized in concert by the came amount so as to
5530preserve color integrity, when the default <a href="command-line-options.html#channel">+channel</a>
5531setting is in use. Specifying any other <a href="command-line-options.html#channel">-channel</a>
5532setting will normalize the RGB channels independently.</p>
5533
5534<p>See <a href="command-line-options.html#contrast-stretch">-contrast-stretch</a> for more details.
5535Also see <a href="command-line-options.html#auto-level">-auto-level</a> for a 'perfect' normalization
5536that is better suited to mathematically generated images. </p>
5537
5538<p>This operator is under review for re-development. </p>
5539
5540
5541<div style="margin: auto;">
5542 <h4><a id="opaque"></a>-opaque <var>color</var></h4>
5543</div>
5544
5545<p class="magick-description">change this color to the fill color within the image.</p>
5546
5547<p>The <var>color</var> argument is defined using the format
5548described under the <a href="command-line-options.html#fill">-fill</a> option. The <a href="command-line-options.html#fuzz">-fuzz</a> setting can be used to match and replace colors similar to the one
5549given.</p>
5550
5551<p>Use <a href="command-line-options.html#opaque">+opaque</a> to paint any pixel that does not match
5552the target color. </p>
5553
5554<p>The <a href="command-line-options.html#transparent">-transparent</a> operator is exactly the same
5555as <a href="command-line-options.html#opaque">-opaque</a> but replaces the matching color with
5556transparency rather than the current <a href="command-line-options.html#fill">-fill</a> color setting.
5557To ensure that it can do this it also ensures that the image has an alpha
5558channel enabled, as per "<code><a href="command-line-options.html#alpha">-alpha</a> set</code>", for
5559the new transparent colors, and does not require you to modify the <a href="command-line-options.html#channel">-channel</a> to enable alpha channel handling. </p>
5560
5561
5562<div style="margin: auto;">
5563 <h4><a id="ordered-dither"></a>-ordered-dither <var>threshold_map</var>{,<var>level</var>...}</h4>
5564</div>
5565
5566<p class="magick-description">dither the image using a pre-defined ordered dither <var>threshold map</var> specified, and a uniform color map with the
5567given number of <var>levels</var> per color channel.</p>
5568
5569<p>You can choose from these standard threshold maps:</p>
5570
5571<pre>
5572 threshold 1x1 Threshold 1x1 (non-dither)
5573 checks 2x1 Checkerboard 2x1 (dither)
5574 o2x2 2x2 Ordered 2x2 (dispersed)
5575 o3x3 3x3 Ordered 3x3 (dispersed)
5576 o4x4 4x4 Ordered 4x4 (dispersed)
5577 o8x8 8x8 Ordered 8x8 (dispersed)
5578 h4x4a 4x1 Halftone 4x4 (angled)
5579 h6x6a 6x1 Halftone 6x6 (angled)
5580 h8x8a 8x1 Halftone 8x8 (angled)
5581 h4x4o Halftone 4x4 (orthogonal)
5582 h6x6o Halftone 6x6 (orthogonal)
5583 h8x8o Halftone 8x8 (orthogonal)
5584 h16x16o Halftone 16x16 (orthogonal)
5585 c5x5b c5x5 Circles 5x5 (black)
5586 c5x5w Circles 5x5 (white)
5587 c6x6b c6x6 Circles 6x6 (black)
5588 c6x6w Circles 6x6 (white)
5589 c7x7b c7x7 Circles 7x7 (black)
5590 c7x7w Circles 7x7 (white)
5591</pre>
5592
5593<p> The <code>threshold</code> generated a simple 50% threshold of the image.
5594This could be used with <var>level</var> to do the equivalent of <a href="command-line-options.html#posterize">-posterize</a> to reduce an image to basic primary colors.
5595</p>
5596
5597<p>The <code>checks</code> pattern produces a 3 level checkerboard dither
5598pattern. That is a grayscale will become a pattern of solid black, solid
5599white, and mid-tone colors into a checkerboard pattern of black and white.
5600</p>
5601
5602<p>You can define your own <var>threshold map</var> for ordered
5603dithering and halftoning your images, in either personal or system
5604<code>thresholds.xml</code> XML file. See <a href="resources.html">Resources</a>
5605for more details of configuration files. </p>
5606
5607<p>To print a complete list of the thresholds that have been defined, use the
5608<a href="command-line-options.html#list">-list threshold</a> option.</p>
5609
5610<p>Note that at this time the same threshold dithering map is used for all
5611color channels, no attempt is made to offset or rotate the map for different
5612channels is made, to create an offset printing effect. Also as the maps are
5613simple threshold levels, the halftone and circle maps will create incomplete
5614circles along the edges of a colored area. Also all the effects are purely
5615on/off boolean effects, without anti-aliasing to make the circles smooth
5616looking. Large dots can be made to look better with a small amount of blurring
5617after being created. </p>
5618
5619
5620<div style="margin: auto;">
5621 <h4><a id="orient"></a>-orient <var>image orientation</var></h4>
5622</div>
5623
5624<p class="magick-description">specify orientation of a digital camera image.</p>
5625
5626<p>Choose from these orientations:</p>
5627
5628<pre>
5629 bottom-left
5630 bottom-right
5631 left-bottom
5632 left-top
5633 right-bottom
5634 right-top
5635 top-left
5636 top-right
5637 undefined
5638</pre>
5639
5640<p>To print a complete list of orientations, use the <a href="command-line-options.html#list">-list
5641orientation</a> option.</p>
5642
5643
5644<div style="margin: auto;">
5645 <h4><a id="page"></a>-page <var>geometry</var><br>
5646 -page <var>media</var>[<var>offset</var>][{<var>^!&lt;&gt;</var>}]<br>
5647 +page
5648 </h4>
5649</div>
5650
5651<p class="magick-description">Set the size and location of an image on the larger virtual canvas.</p>
5652
5653<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
5654
5655<p>For convenience you can specify the page size using <var>media</var> (see below). Offsets can then be added as with other
5656<var>geometry</var> arguments (e.g. <a href="command-line-options.html#page">-page</a> <code>Letter+43+43</code>).</p>
5657
5658<p>Use <var>media</var> as shorthand to specify the dimensions (<var>width</var>x<var>height</var>) of the <var>PostScript</var> page in dots per inch or a TEXT page in pixels.
5659The choices for a PostScript page are:</p>
5660
5661<div class="table-responsive">
5662<table class="table table-condensed table-striped">
5663 <tr>
5664 <td><var>media</var></td>
5665 <td><var>width</var></td>
5666 <td><var>height</var></td>
5667 </tr>
5668<tr><td> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
5669<tr><td> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
5670<tr><td> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
5671<tr><td> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
5672<tr><td> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
5673<tr><td> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
5674<tr><td> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
5675<tr><td> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
5676<tr><td> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
5677<tr><td> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
5678<tr><td> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
5679<tr><td> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
5680<tr><td> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
5681<tr><td> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
5682<tr><td> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
5683<tr><td> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
5684<tr><td> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
5685<tr><td> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
5686<tr><td> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
5687<tr><td> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
5688<tr><td> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
5689<tr><td> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
5690<tr><td> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
5691<tr><td> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
5692<tr><td> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
5693<tr><td> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
5694<tr><td> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
5695<tr><td> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
5696<tr><td> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
5697<tr><td> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
5698<tr><td> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
5699<tr><td> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
5700<tr><td> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
5701<tr><td> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
5702<tr><td> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
5703<tr><td> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
5704<tr><td> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
5705<tr><td> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
5706</table></div>
5707
5708<p>This option is also used to place subimages when writing to a multi-image
5709format that supports offsets, such as GIF89 and MNG. When used for this
5710purpose the offsets are always measured from the top left corner of the canvas
5711and are not affected by the <a href="command-line-options.html#gravity">-gravity</a> option. To
5712position a GIF or MNG image, use <a href="command-line-options.html#page">-page</a><var>{+-}x{+-}y</var> (e.g. -page +100+200). When writing to a MNG
5713file, a <a href="command-line-options.html#page">-page</a> option appearing ahead of the first image in
5714the sequence with nonzero width and height defines the width and height values
5715that are written in the <code>MHDR</code> chunk. Otherwise, the MNG width and
5716height are computed from the bounding box that contains all images in the
5717sequence. When writing a GIF89 file, only the bounding box method is used to
5718determine its dimensions.</p>
5719
5720<p>For a PostScript page, the image is sized as in <a href="command-line-options.html#geometry">-geometry</a> but positioned relative to the <var>lower
5721left-hand corner</var> of the page by {+-}<code>x</code><var>offset</var>{+-}<code>y</code> <var>offset</var>. Use <a href="command-line-options.html#page">-page 612x792</a>, for example, to center the image within the
5722page. If the image size exceeds the PostScript page, it is reduced to fit the
5723page. The default gravity for the <a href="command-line-options.html#page">-page</a> option is <var>NorthWest</var>, i.e., positive <code>x</code> and <code>y</code> <var>offset</var> are measured rightward and downward from the top left
5724corner of the page, unless the <a href="command-line-options.html#gravity">-gravity</a> option is
5725present with a value other than <var>NorthWest</var>.</p>
5726
5727<p>The default page dimensions for a TEXT image is 612x792.</p>
5728
5729<p>This option is used in concert with <a href="command-line-options.html#density">-density</a>.</p>
5730
5731<p>Use <a href="command-line-options.html#page">+page</a> to remove the page settings for an image.</p>
5732
5733<div style="margin: auto;">
5734 <h4><a id="paint"></a>-paint <var>radius</var></h4>
5735</div>
5736
5737<p class="magick-description">simulate an oil painting.</p>
5738
5739<p>Each pixel is replaced by the most frequent color in a circular
5740neighborhood whose width is specified with <var>radius</var>.</p>
5741
5742<div style="margin: auto;">
5743 <h4><a id="path"></a>-path <var>path</var></h4></div>
5744
5745<p class="magick-description">write images to this path on disk.</p>
5746
5747<div style="margin: auto;">
5748 <h4><a id="pause_animate_"></a>-pause <var>seconds</var></h4>
5749</div>
5750
5751<p class="magick-description">Pause between animation loops</p>
5752
5753<p>Pause for the specified number of seconds before repeating the animation.</p>
5754
5755<div style="margin: auto;">
5756 <h4><a id="pause_import_"></a>-pause <var>seconds</var></h4>
5757</div>
5758
5759<p class="magick-description">Pause between snapshots.</p>
5760
5761<p>Pause for the specified number of seconds before taking the next snapshot.</p>
5762
5763<div style="margin: auto;">
5764 <h4><a id="perceptible"></a>-perceptible <var>epsilon</var></h4>
5765</div>
5766
5767<p class="magick-description">set each pixel whose value is less than |<var>epsilon</var>| to <var>-epsilon</var> or <var>epsilon</var> (whichever is closer) otherwise the pixel value remains unchanged.</p>
5768
5769<div style="margin: auto;">
5770 <h4><a id="ping"></a>-ping</h4>
5771</div>
5772
5773<p class="magick-description">efficiently determine image characteristics.</p>
5774
5775<div style="margin: auto;">
5776 <h4><a id="pointsize"></a>-pointsize <var>value</var></h4>
5777</div>
5778
5779<p class="magick-description">pointsize of the PostScript, OPTION1, or TrueType font.</p>
5780
5781<div style="margin: auto;">
5782 <h4><a id="polaroid"></a>-polaroid <var>angle</var></h4>
5783</div>
5784
5785<p class="magick-description">simulate a Polaroid picture.</p>
5786
5787<p>Use <code>+polaroid</code> to rotate the image at a random angle between -15 and +15 degrees.</p>
5788
5789<div style="margin: auto;">
5790 <h4><a id="poly"></a>-poly <var>"wt,exp ..."</var></h4>
5791</div>
5792
5793<p class="magick-description">combines multiple images according to a weighted sum of polynomials; one floating point weight (coefficient) and one floating point polynomial exponent (power) for each image expressed as comma separated pairs.</p>
5794
5795<p> The weights should typically be fractions between -1 and 1. But the sum of weights should be 1 or at least between 0 and 1 to avoid clamping in non-hdri mode at black and white.</p>
5796
5797<p>The exponents may be positive, negative or zero. A negative exponent is equivalent to 1 divided by the image raised to the corresponding positive exponent. A zero exponent always produces 1 scaled by quantumrange to white, i.e. wt*white, no matter what the image.</p>
5798
5799<p>The format is: output = wt1*image1^exp1 + wt2*image2^exp2 ...</p>
5800
5801<p>Some simple uses are:</p>
5802<ul>
5803<li>A weighted sum of each image provided all weights add to unity and all exponents=1. If the the weights are all equal to 1/(number of images), then this is equivalent to <a href="command-line-options.html#profile">-evaluate-sequence</a> <var>mean</var>.</li>
5804<li>The sum of squares of two or more images, provided the weights are equal (and sum to 1 to avoid clamping) and the exponents equal 2.</li>
5805</ul>
5806
5807<p>Note that one may add a constant color to the expression simply by using xc:somecolor for one of the images and specifying the desired weight and exponent equal to 0.</p>
5808
5809<p>Similarly one may add white to the expression by simply using null: (or xc:white) for one of the images with the appropriate weight and exponent equal to 0.</p>
5810
5811
5812<div style="margin: auto;">
5813 <h4><a id="posterize"></a>-posterize <var>levels</var></h4>
5814</div>
5815
5816<p class="magick-description">reduce the image to a limited number of color levels per channel.</p>
5817
5818<p>Very low values of <var>levels</var>, e.g., 2, 3, 4, have the most
5819visible effect.</p>
5820
5821<div style="margin: auto;">
5822 <h4><a id="precision"></a>-precision <var>value</var></h4>
5823</div>
5824
5825<p class="magick-description">set the maximum number of significant digits to be printed.</p>
5826
5827<div style="margin: auto;">
5828 <h4><a id="preview"></a>-preview <var>type</var></h4>
5829</div>
5830
5831<p class="magick-description">image preview type.</p>
5832
5833<p>Use this option to affect the preview operation of an image (e.g.
5834<code>convert file.png -preview Gamma Preview:gamma.png</code>). Choose from
5835these previews:</p>
5836
5837<pre>
5838 Rotate Shear Roll Hue
5839 Saturation Brightness Gamma Spiff
5840 Dull Grayscale Quantize Despeckle
5841 ReduceNoise Add Noise Sharpen Blur
5842 Threshold EdgeDetect Spread Shade
5843 Raise Segment Solarize Swirl
5844 Implode Wave OilPaint CharcoalDrawing
5845 JPEG
5846</pre>
5847
5848<p>To print a complete list of previews, use the <a href="command-line-options.html#list">-list preview</a> option.</p>
5849
5850<p>The default preview is <code>JPEG</code>.</p>
5851
5852<div style="margin: auto;">
5853 <h4><a id="print"></a>-print <var>string</var></h4>
5854</div>
5855
5856<p class="magick-description">interpret string and print to console.</p>
5857
5858<div style="margin: auto;">
5859 <h4><a id="process"></a>-process <var>command</var></h4>
5860</div>
5861
5862<p class="magick-description">process the image with a custom image filter.</p>
5863
5864<p>The command arguments has the form <code>"module arg1 arg2 arg3 ...
5865argN"</code> where <code>module</code> is the name of the module to invoke (e.g.
5866"Analyze") and arg1 arg2 arg3 ... argN are an arbitrary number of arguments to
5867pass to the process module.</p>
5868
5869<div style="margin: auto;">
5870 <h4><a id="profile"></a>-profile <var>filename</var><br>
5871 +profile <var>profile_name</var></h4>
5872</div>
5873
5874<p class="magick-description">Manage ICM, IPTC, or generic profiles in an image.</p>
5875
5876<p>Using <a href="command-line-options.html#profile">-profile</a> <var>filename</var> adds an
5877ICM (ICC color management), IPTC (newswire information), or a generic profile
5878to the image.</p>
5879
5880<p>Use <a href="command-line-options.html#profile">+profile <var>profile_name</var></a> to
5881remove the indicated profile. ImageMagick uses standard filename globbing, so
5882wildcard expressions may be used to remove more than one profile. Here we
5883remove all profiles from the image except for the XMP profile: <code>+profile
5884"!xmp,*"</code>. </p>
5885
5886<p>Use <code>identify -verbose</code> to find out which profiles are in the
5887image file. Use <a href="command-line-options.html#strip">-strip</a> to remove all profiles (and
5888comments).</p>
5889
5890<p>To extract a profile, the <a href="command-line-options.html#profile">-profile</a> option is not
5891used. Instead, simply write the file to an image format such as <var>APP1, 8BIM, ICM,</var> or <var>IPTC</var>.</p>
5892
5893<p>For example, to extract the Exif data (which is stored in JPEG files in the
5894<var>APP1</var> profile), use.</p>
5895
5896<pre>
5897convert cockatoo.jpg profile.exif
5898</pre>
5899
5900<p>It is important to note that results may depend on whether or not the
5901original image already has an included profile. Also, keep in mind that <a href="command-line-options.html#profile">-profile</a> is an "operator" (as opposed to a "setting") and
5902therefore a conversion is made each time it is encountered, in order, in the
5903command-line. For instance, in the following example, if the original image is
5904CMYK with profile, a CMYK-CMYK-RGB conversion results.</p>
5905
5906<pre>
5907convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff
5908</pre>
5909
5910<p>Furthermore, since ICC profiles are not necessarily symmetric, extra
5911conversion steps can yield unwanted results. CMYK profiles are often very
5912asymmetric since they involve 3−&gt;4 and 4−&gt;3 channel mapping.
5913</p>
5914
5915<div style="margin: auto;">
5916 <h4><a id="quality"></a>-quality <var>value</var></h4>
5917</div>
5918
5919<p class="magick-description">JPEG/MIFF/PNG compression level.</p>
5920
5921<p>For the JPEG and MPEG image formats, quality is 1 (lowest image quality and
5922highest compression) to 100 (best quality but least effective compression).
5923The default is to use the estimated quality of your input image if it can
5924be determined, otherwise 92. When the quality is greater than 90, then the
5925chroma channels are not downsampled.
5926Use the <a href="command-line-options.html#sampling-factor">-sampling-factor</a> option to specify the
5927factors for chroma downsampling.</p>
5928
5929<p>For the MIFF image format, quality/10 is the zlib compression level, which
5930is 0 (worst but fastest compression) to 9 (best but slowest). It has no effect
5931on the image appearance, since the compression is always lossless.</p>
5932
5933<p>For the JPEG-2000 image format, quality is mapped using a non-linear
5934equation to the compression ratio required by the Jasper library. This
5935non-linear equation is intended to loosely approximate the quality provided by
5936the JPEG v1 format. The default quality value 100, a request for non-lossy
5937compression. A quality of 75 results in a request for 16:1 compression.</p>
5938
5939<p>For the MNG and PNG image formats, the quality value sets the zlib
5940compression level (quality / 10) and filter-type (quality % 10). The default
5941PNG "quality" is 75, which means compression level 7 with adaptive PNG
5942filtering, unless the image has a color map, in which case it means
5943compression level 7 with no PNG filtering.</p>
5944
5945<p>For compression level 0 (quality value less than 10), the Huffman-only
5946strategy is used, which is fastest but not necessarily the worst
5947compression.</p>
5948
5949<p>If filter-type is 4 or less, the specified PNG filter-type is used for
5950all scanlines:</p>
5951
5952<pre>
5953 0: none
5954 1: sub
5955 2: up
5956 3: average
5957 4: Paeth
5958</pre>
5959
5960<p>If filter-type is 5, adaptive filtering is used when quality is greater
5961than 50 and the image does not have a color map, otherwise no filtering is
5962used.</p>
5963
5964<p>If filter-type is 6, adaptive filtering
5965with <var>minimum-sum-of-absolute-values</var> is used.</p>
5966
5967<p>Only if the output is MNG, if filter-type is 7, the LOCO color
5968transformation (intrapixel differencing) and adaptive filtering
5969with <var>minimum-sum-of-absolute-values</var> are used.</p>
5970
5971<p>If the filter-type is 8 the zlib Z_RLE compression strategy (or the
5972Z_HUFFMAN_ONLY strategy, when compression level is 0) is used with
5973adaptive PNG filtering.</p>
5974
5975<p>If the filter-type is 9 the zlib Z_RLE compression strategy (or the
5976Z_HUFFMAN_ONLY strategy, when compression level is 0) is used with
5977no PNG filtering.</p>
5978
5979<p>The quality setting has no effect on the appearance or signature of PNG
5980and MNG images, since the compression is always lossless.</p>
5981
5982<p>Not all combinations of compression level, strategy, and PNG filter type
5983can be obtained using the -quality option. For more precise control,
5984you can use the PNG:compression-level=N, PNG:compression-strategy=N, and
5985PNG:compression-filter=N defines, respectively, instead.
5986See <a href="command-line-options.html#define">-define</a>. Values from the defines take precedence
5987over values from the -quality option.</p>
5988
5989<p>For further information, see
5990the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
5991
5992<div style="margin: auto;">
5993 <h4><a id="quantize"></a>-quantize <var>colorspace</var></h4>
5994</div>
5995
5996<p class="magick-description">reduce colors using this colorspace.</p>
5997
5998<p>This setting defines the colorspace used to sort out and reduce the number
5999of colors needed by an image (for later dithering) by operators such as <a href="command-line-options.html#colors">-colors</a>, Note that color reduction also happens
6000automatically when saving images to color-limited image file formats, such as
6001GIF, and PNG8.</p>
6002
6003
6004<div style="margin: auto;">
6005 <h4><a id="quiet"></a>-quiet</h4>
6006</div>
6007
6008<p class="magick-description">suppress all warning messages. Error messages are still reported.</p>
6009
6010<div style="margin: auto;">
6011 <h4><a id="radial-blur"></a>-radial-blur <var>angle</var></h4>
6012</div>
6013
6014<p class="magick-description">Blur around the center of the image.</p>
6015
6016<p>Note that this is actually a rotational blur rather than a radial and as
6017such actually mis-named. </p>
6018
6019<p>The <a href="command-line-options.html#virtual-pixel">-virtual-pixel</a> setting will determine how
6020pixels which are outside the image proper are blurred into the final result.
6021</p>
6022
6023
6024<div style="margin: auto;">
6025 <h4><a id="raise"></a>-raise <var>thickness</var></h4>
6026</div>
6027
6028<p class="magick-description">Lighten or darken image edges.</p>
6029
6030<p>This will create a 3-D effect. Use <a href="command-line-options.html#raise">-raise</a> to create
6031a raised effect, otherwise use <a href="command-line-options.html#raise">+raise</a>. </p>
6032
6033<p>Unlike the similar <a href="command-line-options.html#frame">-frame</a> option, <a href="command-line-options.html#raise">-raise</a> does not alter the dimensions of the image.</p>
6034
6035<div style="margin: auto;">
6036 <h4><a id="random-threshold"></a>-random-threshold <var>low</var>x<var>high</var></h4>
6037</div>
6038
6039<p class="magick-description">Apply a random threshold to the image.</p>
6040
6041<div style="margin: auto;">
6042 <h4><a id="red-primary"></a>-red-primary <var>x,y</var></h4>
6043</div>
6044
6045<p class="magick-description">Set the red chromaticity primary point.</p>
6046
6047<div style="margin: auto;">
6048 <h4><a id="regard-warnings"></a>-regard-warnings</h4>
6049</div>
6050
6051<p class="magick-description">Pay attention to warning messages.</p>
6052
6053<p>This option causes some warnings in some image formats to be treated
6054as errors. </p>
6055
6056<div style="margin: auto;">
6057 <h4><a id="remap"></a>-remap <var>filename</var></h4>
6058</div>
6059
6060<p class="magick-description">Reduce the number of colors in an image to the colors used by this image.</p>
6061
6062<p>If the <a href="command-line-options.html#dither">-dither</a> setting is enabled (the default) then
6063the given colors are dithered over the image as necessary, otherwise the closest
6064color (in RGB colorspace) is selected to replace that pixel in the image. </p>
6065
6066<p>As a side effect of applying a <a href="command-line-options.html#remap">-remap</a> of colors across all
6067images in the current image sequence, all the images will have the same color
6068table. That means that when saved to a file format such as GIF, it will use
6069that color table as a single common or global color table, for all the images,
6070without requiring extra local color tables. </p>
6071
6072<p>Use <a href="command-line-options.html#remap">+remap</a> to reduce all images in the current image
6073sequence to use a common color map over all the images. This equivalent to
6074appending all the images together (without extra background colors) and color
6075reducing those images using <a href="command-line-options.html#colors">-colors</a> with a 256 color
6076limit, then <a href="command-line-options.html#remap">-remap</a> those colors over the original list of
6077images. This ensures all the images follow a single color map. </p>
6078
6079<p>If the number of colors over all the images is less than 256, then <a href="command-line-options.html#remap">+remap</a> should not perform any color reduction or dithering, as
6080no color changes are needed. In that case, its only effect is to force the use
6081of a global color table. This recommended after using either <a href="command-line-options.html#colors">-colors</a> or <a href="command-line-options.html#ordered-dither">-ordered-dither</a> to
6082reduce the number of colors in an animated image sequence. </p>
6083
6084<p>Note, the remap image colormap has at most 8-bits of precision. Deeper color maps are automagically coalesced with other colors to meet this requirement.</p>
6085
6086<div style="margin: auto;">
6087 <h4><a id="region"></a>-region <var>geometry</var></h4>
6088</div>
6089
6090<p class="magick-description">Set a region in which subsequent operations apply.</p>
6091
6092<p>The <var>x</var> and <var>y</var> offsets are treated
6093in the same manner as in <a href="command-line-options.html#crop">-crop</a>.</p>
6094
6095<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6096
6097<div style="margin: auto;">
6098 <h4><a id="remote"></a>-remote</h4>
6099</div>
6100
6101<p class="magick-description">perform a remote operation.</p>
6102
6103<p>The only command recognized is the name of an image file to load.</p>
6104
6105<p>If you have more than one <a href="display.html">display</a> application
6106running simultaneously, use the <a href="command-line-options.html#window"> window</a> option to
6107specify which application to control.</p>
6108
6109<div style="margin: auto;">
6110 <h4><a id="render"></a>-render</h4>
6111</div>
6112
6113<p class="magick-description">render vector operations.</p>
6114
6115<p>Use <a href="command-line-options.html#render">+render</a> to turn off rendering vector operations.
6116This useful when saving the result to vector formats such as MVG or SVG.</p>
6117
6118<div style="margin: auto;">
6119<h4><a id="repage"></a>-repage <var>geometry</var></h4>
6120</div>
6121
6122<p class="magick-description">Adjust the canvas and offset information of the image.</p>
6123
6124<p>This option is like <a href="command-line-options.html#page">-page</a> but acts as an image operator
6125rather than a setting. You can separately set the canvas size or the offset
6126of the image on that canvas by only providing those components. </p>
6127
6128<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6129
6130<p>If a <code>!</code> flag is given the offset given is added to the existing
6131offset to move the image relative to its previous position. This useful for
6132animation sequences. </p>
6133
6134<p>A given a canvas size of zero such as '<code>0x0</code>' forces it to
6135recalculate the canvas size so the image (at its current offset) will appear
6136completely on that canvas (unless it has a negative offset).</p>
6137
6138<p>Use <a href="command-line-options.html#repage">+repage</a> to completely remove/reset the virtual
6139canvas meta-data from the images. </p>
6140
6141<p>The <a href="command-line-options.html#set">-set</a> '<code>page</code>' option can be used to
6142directly assign virtual canvas meta-data. </p>
6143
6144
6145<div style="margin: auto;">
6146 <h4><a id="resample"></a>-resample <var>horizontal</var>x<var>vertical</var></h4>
6147</div>
6148
6149<p class="magick-description">Resample image to specified horizontal and vertical resolution.</p>
6150
6151<p>Resize the image so that its rendered size remains the same as the original
6152at the specified target resolution. For example, if a 300 DPI image renders at
61533 inches by 2 inches on a 300 DPI device, when the image has been resampled to
615472 DPI, it will render at 3 inches by 2 inches on a 72 DPI device. Note that
6155only a small number of image formats (e.g. JPEG, PNG, and TIFF) are capable of
6156storing the image resolution. For formats which do not support an image
6157resolution, the original resolution of the image must be specified via <a href="command-line-options.html#density">-density</a> on the command line prior to specifying the
6158resample resolution.</p>
6159
6160<p>Note that Photoshop stores and obtains image resolution from a proprietary
6161embedded profile. If this profile exists in the image, then Photoshop will
6162continue to treat the image using its former resolution, ignoring the image
6163resolution specified in the standard file header.</p>
6164
6165<div style="margin: auto;">
6166 <h4><a id="resize"></a>-resize <var>geometry</var></h4>
6167</div>
6168
6169<p class="magick-description">Resize an image.</p>
6170
6171<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are
6172ignored, and the <a href="command-line-options.html#gravity">-gravity</a> option has no effect.</p>
6173
6174<p>If the <a href="command-line-options.html#filter">-filter</a> option
6175or <code>-define filter:option=value</code> precedes the <a href="command-line-options.html#resize">-resize</a> option, the image is resized with the specified
6176filter.</p>
6177
6178<p>Many image processing algorithms assume your image is in a linear-light
6179coding. If your image is gamma-corrected, you can remove the nonlinear gamma
6180correction, apply the transform, then restore it like this:</p>
6181
6182<pre>
6183convert portrait.jpg -gamma .45455 -resize 25% -gamma 2.2 \ <br> -quality 92 passport.jpg
6184</pre>
6185
6186<div style="margin: auto;">
6187 <h4><a id="respect-parentheses"></a>-respect-parentheses</h4>
6188</div>
6189
6190<p class="magick-description">settings remain in effect until parenthesis boundary.</p>
6191
6192<div style="margin: auto;">
6193 <h4><a id="reverse"></a>-reverse</h4>
6194</div>
6195
6196<p class="magick-description">Reverse the order of images in the current image list.</p>
6197
6198
6199<div style="margin: auto;">
6200 <h4><a id="roll"></a>-roll {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var></h4>
6201</div>
6202
6203<p class="magick-description">roll an image vertically or horizontally by the amount given.</p>
6204
6205<p>A negative <var>x</var> offset rolls the image right-to-left.
6206A negative <var>y</var> offset rolls the image bottom-to-top.</p>
6207
6208
6209<div style="margin: auto;">
6210 <h4><a id="rotate"></a>-rotate <var>degrees</var>{<var>&lt;</var>}{<var>&gt;</var>}</h4>
6211</div>
6212
6213<p class="magick-description">Apply Paeth image rotation (using shear operations) to the image.</p>
6214
6215<p>Use <code>&gt;</code> to rotate the image only if its width exceeds the
6216height. <code>&lt;</code> rotates the image <var>only</var> if its width is less
6217than the height. For example, if you specify <code>-rotate "-90&gt;"</code> and
6218the image size is 480x640, the image is not rotated. However, if the image is
6219640x480, it is rotated by -90 degrees. If you use <code>&gt;</code> or
6220<code>&lt;</code>, enclose it in quotation marks to prevent it from being
6221misinterpreted as a file redirection.</p>
6222
6223<p>Empty triangles in the corners, left over from rotating the image, are
6224filled with the <code>background</code> color. </p>
6225
6226<p>See also the <a href="command-line-options.html#distort">-distort</a> operator and specifically the
6227'<code>ScaleRotateTranslate</code>' distort method. </p>
6228
6229
6230<div style="margin: auto;">
6231 <h4><a id="sample"></a>-sample <var>geometry</var></h4>
6232</div>
6233
6234<p class="magick-description">minify / magnify the image with pixel subsampling and pixel replication, respectively.</p>
6235
6236<p>Change the image size simply by directly sampling the pixels original
6237from the image. When magnifying, pixels are replicated in blocks. When
6238minifying, pixels are sub-sampled (i.e., some rows and columns are skipped
6239over). </p>
6240
6241<p>The results are thus equivalent to using <a href="command-line-options.html#resize">-resize</a> with
6242a <a href="command-line-options.html#filter">-filter</a> setting of <code>point</code> (nearest
6243neighbour), though <a href="command-line-options.html#sample">-sample</a> is a lot faster, as it
6244avoids all the filter processing of the image. As such it completely ignores
6245the current <a href="command-line-options.html#filter">-filter</a> setting. </p>
6246
6247<p>The key feature of the <a href="command-line-options.html#sample">-sample</a> is that no new colors
6248will be added to the resulting image, though some colors may disappear. </p>
6249
6250<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are
6251ignored, unlike <a href="command-line-options.html#resize">-resize</a>. </p>
6252
6253
6254<p>The actual sampling point is the middle of the sub-region being sampled.
6255As such a single pixel sampling of an image will take the middle pixel, (or
6256top-left-middle if image has even dimensions). However the <a href="command-line-options.html#define">-define</a> '<code>sample:offset</code>' can be set to modify
6257this position some other location within each sub-region being sampled, as
6258a percentage offset.</p>
6259
6260<p>By default this value is '<code>50</code>' for the midpoint, but could be set
6261to '<code>0</code>' for top-left, '<code>100</code>' for bottom-right, or with
6262separate X and Y offsets such as '<code>0x50</code>' for left-middle edge of
6263sampling sub-region.</p>
6264
6265
6266<div style="margin: auto;">
6267 <h4><a id="sampling-factor"></a>-sampling-factor <var>horizontal-factor</var>x<var>vertical-factor</var></h4>
6268</div>
6269
6270<p class="magick-description">sampling factors used by JPEG or MPEG-2 encoder and YUV decoder/encoder.</p>
6271
6272<p>This option specifies the sampling factors to be used by the JPEG encoder
6273for chroma downsampling. If this option is omitted, the JPEG library will use
6274its own default values. When reading or writing the YUV format and when
6275writing the M2V (MPEG-2) format, use <a href="command-line-options.html#sampling-factor">-sampling-factor 2x1</a> or <a href="command-line-options.html#sampling-factor">-sampling-factor 4:2:2</a> to specify the 4:2:2
6276downsampling method.</p>
6277
6278<div style="margin: auto;">
6279 <h4><a id="scale"></a>-scale <var>geometry</var></h4>
6280</div>
6281
6282<p class="magick-description">minify / magnify the image with pixel block averaging and pixel replication, respectively.</p>
6283
6284<p>Change the image size simply by replacing pixels by averaging pixels
6285together when minifying, or replacing pixels when magnifying. </p>
6286
6287<p>The results are thus equivalent to using <a href="command-line-options.html#resize">-resize</a> with
6288a <a href="command-line-options.html#filter">-filter</a> setting of <code>box</code>. Though it is a lot
6289faster, as it avoids all the filter processing of the image. As such it
6290completely ignores the current <a href="command-line-options.html#filter">-filter</a> setting. </p>
6291
6292<p>If when shrinking (minifying) images the original image is some integer
6293multiple of the new image size, the number of pixels averaged together to
6294produce the new pixel color is the same across the whole image. This is
6295a special case known as 'binning' and is often used as a method of reducing
6296noise in image such as those generated by digital cameras, especially in low
6297light conditions. </p>
6298
6299
6300<div style="margin: auto;">
6301 <h4><a id="scene"></a>-scene <var>value</var></h4>
6302</div>
6303
6304<p class="magick-description">set scene number.</p>
6305
6306<p>This option sets the scene number of an image or the first image in an image sequence.</p>
6307
6308<div style="margin: auto;">
6309 <h4><a id="screen"></a>-screen</h4>
6310</div>
6311
6312<p class="magick-description">specify the screen to capture.</p>
6313
6314<p>This option indicates that the GetImage request used to obtain the image
6315should be done on the root window, rather than directly on the specified
6316window. In this way, you can obtain pieces of other windows that overlap the
6317specified window, and more importantly, you can capture menus or other popups
6318that are independent windows but appear over the specified window.</p>
6319
6320<div style="margin: auto;">
6321 <h4><a id="seed"></a>-seed</h4>
6322</div>
6323
6324<p class="magick-description">seed a new sequence of pseudo-random numbers</p>
6325
6326<div style="margin: auto;">
6327 <h4><a id="segment"></a>-segment <var>cluster-threshold</var>x<var>smoothing-threshold</var></h4>
6328</div>
6329
6330<p class="magick-description">segment the colors of an image.</p>
6331
6332<p>Segment an image by analyzing the histograms of the color components and
6333identifying units that are homogeneous with the fuzzy c-means technique. This
6334is part of the ImageMagick color quantization routines. </p>
6335
6336<p>Specify <var>cluster threshold</var> as the number of pixels in
6337each cluster that must exceed the cluster threshold to be considered valid.
6338<var>Smoothing threshold</var> eliminates noise in the second
6339derivative of the histogram. As the value is increased, you can expect
6340a smoother second derivative. The default is 1.5.</p>
6341
6342<p>If the <a href="command-line-options.html#verbose">-verbose</a> setting is defined, a detailed report
6343of the color clusters is returned.</p>
6344
6345
6346<div style="margin: auto;">
6347 <h4><a id="selective-blur"></a>-selective-blur <var>radius</var><br>-selective-blur <var>radius</var>x<var>sigma</var>{<var>+threshold</var>}</h4>
6348</div>
6349
6350<p class="magick-description">Selectively blur pixels within a contrast threshold.</p>
6351
6352<p>Blurs those pixels that are less than or equal to the threshold in
6353contrast. The threshold may be expressed as a fraction of <var>QuantumRange</var> or as a percentage.</p>
6354
6355<div style="margin: auto;">
6356 <h4><a id="separate"></a>-separate</h4>
6357</div>
6358
6359<p class="magick-description">separate an image channel into a grayscale image. Specify the channel with <a href="command-line-options.html#channel">-channel</a>.</p>
6360
6361<div style="margin: auto;">
6362 <h4><a id="sepia-tone"></a>-sepia-tone <var>threshold</var></h4>
6363</div>
6364
6365<p class="magick-description">simulate a sepia-toned photo.</p>
6366
6367<p>Specify <var>threshold</var> as the percent threshold of the intensity (0 - 99.9%).</p>
6368
6369<p>This option applies a special effect to the image, similar to the effect
6370achieved in a photo darkroom by sepia toning. Threshold ranges from 0 to <var>QuantumRange</var> and is a measure of the extent of the sepia
6371toning. A threshold of 80% is a good starting point for a reasonable
6372tone.</p>
6373
6374
6375
6376<div style="margin: auto;">
6377 <h4><a id="set"></a>-set <var>key value</var></h4>
6378 <h4>+set <var>key</var></h4>
6379</div>
6380
6381<p class="magick-description">sets image attributes and properties for images in the current image sequence.</p>
6382
6383<p>This will assign (or modify) specific settings attached to all the images
6384in the current image sequence. Using the <a href="command-line-options.html#set">+set</a> form of the
6385option will either remove, or reset that setting to a default state, as
6386appropriate. </p>
6387
6388<p>For example, it will modify specific well known image meta-data
6389'attributes' such as those normally overridden by: the options <a href="command-line-options.html#delay">-delay</a>, <a href="command-line-options.html#dispose">-dispose</a>, and <a href="command-line-options.html#page">-page</a>, <a href="command-line-options.html#colorspace">-colorspace</a>; generally
6390assigned before the image is read in, by using a <var>key</var> of
6391the same name. </p>
6392
6393<p>If the given <var>key</var> does not match a specific known
6394'attribute ', such as shown above, the setting is stored as a a free form
6395'property' string. Such settings are listed in <a href="command-line-options.html#verbose">-verbose</a> information ("<code>info:</code>" output format) as "Properties".
6396</p>
6397
6398<p>This includes string 'properties' that are set by and assigned to images
6399using the options <a href="command-line-options.html#comment">-comment</a>, <a href="command-line-options.html#label">-label</a>, <a href="command-line-options.html#caption">-caption</a>. These options actually assign
6400a global 'artifact' which are automatically assigned (and any <a href="escape.html">Format Percent
6401Escapes</a> expanded) to images as they are read in. For example:</p>
6402
6403<pre>
6404convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png
6405identify -format %c rose.png
6406Rose is a rose is a rose is a rose
6407</pre>
6408
6409<p>The set value can also make use of <a href="escape.html">Format and Print Image
6410Properties</a> in the defined value. For example:</p>
6411
6412<pre>
6413convert rose: -set origsize '%wx%h' -resize 50% \
6414 -format 'Old size = %[origsize] New size = %wx%h' info:
6415Old size = 70x46 New size = 35x23
6416</pre>
6417
6418<p>Other well known 'properties' that are availible include:
6419'<code>date:create</code>' and '<code>date:modify</code>' and
6420'<code>signature</code>'. </p>
6421
6422<p>The <a href="command-line-options.html#repage">-repage</a> operator will also allow you to modify
6423the '<code>page</code>' attribute of an image for images already in memory (also
6424see <a href="command-line-options.html#repage">-page</a>). However it is designed to provide a finer
6425control of the sub-parts of this 'attribute'. The <a href="command-line-options.html#set">-set page</a>
6426option will only provide a direct, unmodified assignment of '<code>page</code>'
6427attribute. </p>
6428
6429<p>This option can also associate a colorspace or profile with your image.
6430For example,</p>
6431
6432<pre>
6433convert image.psd -set profile ISOcoated_v2_eci.icc image-icc.psd
6434</pre>
6435
6436<p>Some 'properties' must be defined in a specific way to be used. For
6437example only 'properties' prefixed with "<code>filename:</code>" can be used to
6438modify the output filename of an image. For example</p>
6439
6440<pre>
6441convert rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png'
6442</pre>
6443
6444<p>If the setting value is prefixed with "<code>option:</code>" the setting will
6445be saved as a global "Artifact" exactly as if it was set using the <a href="command-line-options.html#define">-define</a> option. As such settings are global in scope, they
6446can be used to pass 'attributes' and 'properties' of one specific image,
6447in a way that allows you to use them in a completely different image, even if
6448the original image has long since been modified or destroyed. For example: </p>
6449
6450<pre>
6451convert rose: -set option:rosesize '%wx%h' -delete 0 \
6452 label:'%[rosesize]' label_size_of_rose.gif"
6453</pre>
6454
6455<p>Note that <a href="escape.html">Format Percent Escapes</a> will only match
6456a 'artifact' if the given <var>key</var> does not match an existing
6457'attribute' or 'property'. </p>
6458
6459<p>You can set the attributes of the image registry by prefixing the value
6460with <code>registry:</code>.</p>
6461
6462<p>The <a href="command-line-options.html#set">-set profile</a> option can also be used to inject
6463previously-formatted ancillary chunks into the output PNG file, using
6464the commandline option as shown below or by setting the profile via a
6465programming interface:</p>
6466
6467<pre>
6468convert in.png -set profile PNG-chunk-x:&lt;filename&gt; out.png
6469</pre>
6470
6471<p>where <var>x</var> is a location flag and
6472<var>filename</var> is a file containing the chunk
6473name in the first 4 bytes, then a colon (":"), followed by the chunk data.
6474This encoder will compute the chunk length and CRC, so those must not
6475be included in the file.</p>
6476
6477<p>"x" can be "b" (before PLTE), "m" (middle, i.e., between PLTE and IDAT),
6478or "e" (end, i.e., after IDAT). If you want to write multiple chunks
6479of the same type, then add a short unique string after the "x" to prevent
6480subsequent profiles from overwriting the preceding ones, e.g.,</p>
6481
6482
6483<pre>
6484convert in.png -set profile PNG-chunk-b01:file01 \
6485 -profile PNG-chunk-b02:file02 out.png
6486</pre>
6487
6488<div style="margin: auto;">
6489 <h4><a id="shade"></a>-shade <var>azimuth</var>x<var>elevation</var></h4>
6490</div>
6491
6492<p class="magick-description">shade the image using a distant light source.</p>
6493
6494<p>Specify <var>azimuth</var> and <var>elevation</var> as
6495the position of the light source. Use <a href="command-line-options.html#shade">+shade</a> to return
6496the shading results as a grayscale image.</p>
6497
6498<div style="margin: auto;">
6499 <h4><a id="shadow"></a>-shadow <var>percent-opacity</var>{x<var>sigma</var>}{<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var>{<var>%</var>}</h4>
6500</div>
6501
6502<p class="magick-description">simulate an image shadow.</p>
6503
6504<div style="margin: auto;">
6505 <h4><a id="shared-memory"></a>-shared-memory</h4>
6506</div>
6507
6508<p class="magick-description">use shared memory.</p>
6509
6510<p>This option specifies whether the utility should attempt to use shared
6511memory for pixmaps. ImageMagick must be compiled with shared memory support,
6512and the display must support the <var>MIT-SHM</var> extension.
6513Otherwise, this option is ignored. The default is <code>True</code>.</p>
6514
6515<div style="margin: auto;">
6516 <h4><a id="sharpen"></a>-sharpen <var>radius</var><br>-sharpen <var>radius</var>x<var>sigma</var></h4>
6517</div>
6518
6519<p class="magick-description">sharpen the image.</p>
6520
6521<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
6522
6523<div style="margin: auto;">
6524 <h4><a id="shave"></a>-shave <var>geometry</var></h4>
6525</div>
6526
6527<p class="magick-description">Shave pixels from the image edges.</p>
6528
6529<p>The <var>size</var> portion of the <var>geometry</var>
6530argument specifies the width of the region to be removed from both sides of
6531the image and the height of the regions to be removed from top and bottom.
6532Offsets are ignored.</p>
6533
6534<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
6535
6536<div style="margin: auto;">
6537 <h4><a id="shear"></a>-shear <var>Xdegrees</var>[x<var>Ydegrees</var>]</h4>
6538</div>
6539
6540<p class="magick-description">Shear the image along the x-axis and/or y-axis.</p>
6541
6542<p>The shear angles may be positive, negative, or zero. When <var>Ydegrees</var> is omitted it defaults to 0. When both angles are
6543given, the horizontal component of the shear is performed before the vertical
6544component.</p>
6545
6546<p>Shearing slides one edge of an image along the x-axis or y-axis (i.e.,
6547horizontally or vertically, respectively),creating a parallelogram. The amount
6548of each is controlled by the respective shear angle. For horizontal shears,
6549<var>Xdegrees</var> is measured clockwise relative to "up" (the
6550negative y-axis), sliding the top edge to the right when 0°&lt;<var>Xdegrees</var>&lt;90° and to the left when 90°&lt;<var>Xdegrees</var>&lt;180°. For vertical shears <var>Ydegrees</var> is measured clockwise relative to "right" (the
6551positive x-axis), sliding the right edge down when 0°&lt;<var>Ydegrees</var>&lt;90° and up when 90°&lt;<var>Ydegrees</var>&lt;180°.</p>
6552
6553<p>Empty triangles left over from shearing the image are filled with the color
6554defined by the <a href="command-line-options.html#fill">-background</a> option. The color is specified
6555using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
6556
6557<p>The horizontal shear is performed before the vertical part. This is
6558important to note, since horizontal and vertical shears do not
6559<var>commute</var>, i.e., the order matters in a sequence of shears. For
6560example, the following two commands are not equivalent.</p>
6561
6562<pre>
6563convert logo: -shear 20x0 -shear 0x60 logo-sheared.png
6564convert logo: -shear 0x60 -shear 20x0 logo-sheared.png
6565</pre>
6566
6567<p>The first of the two commands above is equivalent to the following, except
6568for the amount of empty space created; the command that follows generates
6569a smaller image, and so is a better choice in terms of time and space.</p>
6570
6571<pre>
6572convert logo: -shear 20x60 logo-sheared.png
6573</pre>
6574
6575<div style="margin: auto;">
6576 <h4><a id="sigmoidal-contrast"></a>-sigmoidal-contrast <var>contrast</var>x<var>mid-point</var></h4>
6577</div>
6578
6579<p class="magick-description">increase the contrast without saturating highlights or shadows.</p>
6580
6581<p>Increase the contrast of the image using a sigmoidal transfer function
6582without saturating highlights or shadows. <var>Contrast</var>
6583indicates how much to increase the contrast. For example, 0 is none, 3 is
6584typical and 20 is a lot.
6585</p>
6586
6587<p>The <var>mid-point</var> indicates where the maximum change
6588'slope' in contrast should fall in the resultant image (0 is white; 50% is
6589middle-gray; 100% is black). </p>
6590
6591<p>By default the image contrast is increased, use <var>+sigmoidal-contrast</var> to decrease the contrast.</p>
6592
6593<p>To achieve the equivalent of a sigmoidal brightness change (similar to
6594a gamma adjustment), you would use <var>-sigmoidal-contrast
6595{brightness}x0%</var> to increase brightness and <var>+sigmoidal-contrast {brightness}x0%</var> to decrease brightness.
6596Note the use of '0' fo rthe mid-point of the sigmoidal curve. </p>
6597
6598<p>Using a very high <var>contrast</var> will produce a sort of
6599'smoothed thresholding' of the image. Not as sharp (with high aliasing
6600effects) of a true threshold, but with tapered gray-levels around the threshold
6601<var>mid-point</var>. </p>
6602
6603<div style="margin: auto;">
6604 <h4><a id="silent"></a>-silent</h4>
6605</div>
6606
6607<p class="magick-description">operate silently.</p>
6608
6609<div style="margin: auto;">
6610 <h4><a id="similarity-threshold"></a>-similarity-threshold <var>value</var></h4>
6611</div>
6612
6613<p class="magick-description">minimum RMSE for subimage match.</p>
6614
6615<p>If this setting is used, then the search will stop as soon as it finds a match whose metric is less than or equal to the value. A partially filled second output image will result. Using a value of zero, will cause the search to stop at the first perfect match it finds. If this setting is left off, then the search will proceed to completion or as limited by <var>-dissimilarity-threshold</var>.</p>
6616
6617<div style="margin: auto;">
6618 <h4><a id="size"></a>-size <var>width</var>[x<var>height</var>][<var>+offset</var>]</h4>
6619</div>
6620
6621<p class="magick-description">set the width and height of the image.</p>
6622
6623<p>Use this option to specify the width and height of raw images whose
6624dimensions are unknown such as <code>GRAY</code>, <code>RGB</code>, or
6625<code>CMYK</code>. In addition to width and height, use <a href="command-line-options.html#size">-size</a> with an offset to skip any header information in the
6626image or tell the number of colors in a <code>MAP</code> image file, (e.g. -size
6627640x512+256).</p>
6628
6629<p>For Photo CD images, choose from these sizes:</p>
6630
6631<pre>
6632 192x128
6633 384x256
6634 768x512
6635 1536x1024
6636 3072x2048
6637</pre>
6638
6639<div style="margin: auto;">
6640 <h4><a id="sketch"></a>-sketch <var>radius</var><br>-sketch <var>radius</var>x<var>sigma</var>+<var>angle</var></h4>
6641</div>
6642
6643<p class="magick-description">simulate a pencil sketch.</p>
6644
6645<p>Sketch with the given radius, standard deviation (sigma), and angle. The
6646angle given is the angle toward which the image is sketched. That is the
6647direction people would consider the object is coming from. </p>
6648
6649<div style="margin: auto;">
6650 <h4><a id="smush"></a>-smush <var>offset</var></h4>
6651</div>
6652
6653<p class="magick-description">smush an image sequence together.</p>
6654
6655<div style="margin: auto;">
6656 <h4><a id="snaps"></a>-snaps <var>value</var></h4>
6657</div>
6658
6659<p class="magick-description">Set the number of screen snapshots.</p>
6660
6661<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
6662
6663<div style="margin: auto;">
6664 <h4><a id="solarize"></a>-solarize <var>threshold</var></h4>
6665</div>
6666
6667<p class="magick-description">negate all pixels above the threshold level.</p>
6668
6669<p>Specify <var>factor</var> as the percent threshold of the intensity (0 - 99.9%).</p>
6670
6671<p>This option produces a <var>solarization</var> effect seen when
6672exposing a photographic film to light during the development process.</p>
6673
6674<div style="margin: auto;">
6675 <h4><a id="sparse-color"></a>-sparse-color <var>method</var> '<var>x</var>,<var>y</var> <var>color</var> ...'</h4>
6676</div>
6677
6678<p class="magick-description"> color the given image using the specified points of color, and filling the other intervening colors using the given methods. </p>
6679
6680
6681<table class="table table-condensed table-striped">
6682 <tbody>
6683 <tr>
6684 <th style="width: 8%">Method</th>
6685 <th>Description</th>
6686 </tr>
6687
6688 <tr>
6689 <td>barycentric</td>
6690 <td>three point triangle of color given 3 points.
6691 Giving only 2 points will form a linear gradient between those points.
6692 The gradient generated extends beyond the triangle created by those
6693 3 points. </td>
6694 </tr>
6695
6696 <tr>
6697 <td>bilinear</td>
6698 <td>Like barycentric but for 4 points. Less than 4 points
6699 fall back to barycentric. </td>
6700 </tr>
6701 <tr>
6702 <td>voronoi</td>
6703 <td>Simply map each pixel to the to nearest color point
6704 given. The result are polygonal 'cells' of solid color. </td>
6705 </tr>
6706
6707 <tr>
6708 <td>shepards</td>
6709 <td>Colors points biased on the ratio of inverse distance
6710 squared. Generating spots of color in a sea of the average of
6711 colors. </td>
6712 </tr>
6713
6714 <tr>
6715 <td>inverse</td>
6716 <td>Colors points biased on the ratio of inverse distance.
6717 This generates sharper points of color rather than rounded spots of
6718 '<code>shepards</code>' Generating spots of color in a sea of the
6719 average of colors. </td>
6720 </tr>
6721
6722 </tbody>
6723</table>
6724
6725<p>The points are placed according to the images location on the virtual
6726canvas (<a href="command-line-options.html#page">-page</a> or <a href="command-line-options.html#repage">-repage</a>
6727offset), and do not actually have to exist on the given image, but may be
6728some point beyond the edge of the image. All points are floating point values.
6729</p>
6730
6731<p>Only the color channels defined by the <a href="command-line-options.html#channel">-channel</a> are
6732modified, which means that by default matte/alpha transparency channel is not
6733effected. Typically transparency channel is turned off either before or after
6734the operation. </p>
6735
6736<p>Of course if some color points are transparent to generate a transparent
6737gradient, then the image also requires transparency enabled to store the
6738values. </p>
6739
6740<p>All the above methods when given a single point of color will replace all
6741the colors in the image with the color given, regardless of the point. This is
6742logical, and provides an alternative technique to recolor an image to some
6743default value. </p>
6744
6745
6746<div style="margin: auto;">
6747 <h4><a id="splice"></a>-splice <var>geometry</var></h4>
6748</div>
6749
6750<p class="magick-description">Splice the current background color into the image.</p>
6751
6752<p>This will add rows and columns of the current <a href="command-line-options.html#background">-background</a> color into the given image according to the
6753given <a href="command-line-options.html#gravity">-gravity</a> geometry setting. See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Essentially <a href="command-line-options.html#splice">-splice</a> will divide the
6754image into four quadrants, separating them by the inserted rows and columns.
6755</p>
6756
6757<p>If a dimension of geometry is zero no rows or columns will be added for that
6758dimension. Similarly using a zero offset with the appropriate <a href="command-line-options.html#gravity">-gravity</a> setting will add rows and columns to the edges of
6759the image, padding the image only along that one edge. Edge padding is what <a href="command-line-options.html#splice">-splice</a> is most commonly used for. </p>
6760
6761<p>If the exact same <var>geometry</var> and <a href="command-line-options.html#gravity">-gravity</a> is later used with <a href="command-line-options.html#chop">-chop</a> the
6762added added all splices removed. </p>
6763
6764<div style="margin: auto;">
6765 <h4><a id="spread"></a>-spread <var>amount</var></h4>
6766</div>
6767
6768<p class="magick-description">displace image pixels by a random amount.</p>
6769
6770<p>The argument <var>amount</var> defines the size of the
6771neighborhood around each pixel from which to choose a candidate pixel to
6772swap.</p>
6773
6774<div style="margin: auto;">
6775 <h4><a id="statistic"></a>-statistic <var>type</var> <var>geometry</var></h4>
6776</div>
6777
6778<p class="magick-description">replace each pixel with corresponding statistic from the neighborhood.</p>
6779
6780<p>Choose from these statistic types:</p>
6781<pre>
6782 Gradient maximum difference (max - min) value in neighborhood
6783 Maximum maximum value per channel in neighborhood
6784 Minimum minimum value per channel in neighborhood
6785 Mean average value per channel in neighborhood
6786 Median median value per channel in neighborhood
6787 Mode mode (most frequent) value per channel in neighborhood
6788 Nonpeak value just before or after the median value per channel in neighborhood
6789 RMS root mean square value per channel in neighborhood
6790 StandardDeviation standard deviation value per channel in neighborhood
6791</pre>
6792
6793<div style="margin: auto;">
6794 <h4><a id="stegano"></a>-stegano <var>offset</var></h4>
6795</div>
6796
6797<p class="magick-description">hide watermark within an image.</p>
6798
6799<p>Use an offset to start the image hiding some number of pixels from the
6800beginning of the image. Note this offset and the image size. You will need
6801this information to recover the steganographic image (e.g. display -size
6802320x256+35 stegano:image.png).</p>
6803
6804<div style="margin: auto;">
6805 <h4><a id="stereo"></a>-stereo <var>+x</var>{<var>+y</var>}</h4>
6806</div>
6807
6808<p class="magick-description">composite two images to create a red / cyan stereo anaglyph.</p>
6809
6810<p>The left side of the stereo pair (second image) is saved as the red channel of the output image. The right side (first image) is saved as the green and blue channels. Red-green stereo glasses are required to properly view the stereo image.</p>
6811
6812<div style="margin: auto;">
6813 <h4><a id="storage-type"></a>-storage-type <var>type</var></h4>
6814</div>
6815
6816<p class="magick-description">pixel storage type. Here are the valid types:</p>
6817
6818<pre>
6819 char unsigned characters
6820 double doubles
6821 float floats
6822 integer integers
6823 long longs
6824 quantum pixels in the native depth of your ImageMagick distribution
6825 short unsigned shorts
6826</pre>
6827
6828<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
6829values range from 0 to the maximum value the storage type can support.</p>
6830
6831<div style="margin: auto;">
6832 <h4><a id="stretch"></a>-stretch <var>fontStretch</var></h4>
6833</div>
6834
6835<p class="magick-description">Set a type of stretch style for fonts.</p>
6836
6837<p>This setting suggests a type of stretch that ImageMagick should try to
6838apply to the currently selected font family. Select <var>fontStretch</var> from the following.</p>
6839
6840<pre>
6841 Any
6842 Condensed
6843 Expanded
6844 ExtraCondensed
6845 ExtraExpanded
6846 Normal
6847 SemiCondensed
6848 SemiExpanded
6849 UltraCondensed
6850 UltraExpanded
6851</pre>
6852
6853<p>To print a complete list of stretch types, use <a href="command-line-options.html#list">-list
6854stretch</a>.</p>
6855
6856<p>For other settings that affect fonts, see the options <a href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#style">-style</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
6857
6858<div style="margin: auto;">
6859 <h4><a id="strip"></a>-strip</h4>
6860</div>
6861
6862<p class="magick-description">strip the image of any profiles or comments.</p>
6863
6864<div style="margin: auto;">
6865 <h4><a id="stroke"></a>-stroke <var>color</var></h4>
6866</div>
6867
6868<p class="magick-description">color to use when stroking a graphic primitive.</p>
6869
6870<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
6871
6872<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
6873
6874<div style="margin: auto;">
6875 <h4><a id="strokewidth"></a>-strokewidth <var>value</var></h4>
6876</div>
6877
6878<p class="magick-description">set the stroke width.</p>
6879
6880<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
6881
6882<div style="margin: auto;">
6883 <h4><a id="style"></a>-style <var>fontStyle</var></h4>
6884</div>
6885
6886<p class="magick-description">Set a font style for text.</p>
6887
6888<p>This setting suggests a font style that ImageMagick should try to apply to
6889the currently selected font family. Select <var>fontStyle</var> from
6890the following.</p>
6891
6892<pre>
6893 Any
6894 Italic
6895 Normal
6896 Oblique
6897</pre>
6898
6899<p>For other settings that affect fonts, see the options <a href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#stretch">-stretch</a>, and <a href="command-line-options.html#weight">-weight</a>. </p>
6900
6901<div style="margin: auto;">
6902 <h4><a id="subimage-search"></a>-subimage-search</h4>
6903</div>
6904
6905<p class="magick-description">search for subimage.</p>
6906
6907<p>This option is required to have compare search for the best match location
6908of a small image within a larger image. This search will produce two images
6909(or two frames). The first is the "difference" image and the second will
6910be the "match score" image.</p>
6911
6912<p>The "match-score" image is smaller containing a pixel for ever possible
6913position of the top-left corner of the given sub-image. that is its size will
6914be the size of the larger_image - sub_image + 1. The brightest location in
6915this image is the location s the locate on the best match that is also
6916reported. Note that this may or may not be a perfect match, and the actual
6917brightness will reflect this. Other bright 'peaks' can be used to locate other
6918possible matching locations. </p>
6919
6920<p>Note that the search will try to compare the sub-image at every possible
6921location in the larger image, as such it can be very slow. The smaller the
6922sub-image the faster this search is. </p>
6923
6924
6925<div style="margin: auto;">
6926 <h4><a id="swap"></a>-swap <var>index,index</var></h4>
6927</div>
6928
6929<p class="magick-description">Swap the positions of two images in the image sequence.</p>
6930
6931<p>For example, <a href="command-line-options.html#swap">-swap 0,2</a> swaps the first and the third
6932images in the current image sequence. Use <a href="command-line-options.html#swap">+swap</a> to switch
6933the last two images in the sequence.</p>
6934
6935<div style="margin: auto;">
6936 <h4><a id="swirl"></a>-swirl <var>degrees</var></h4>
6937</div>
6938
6939<p class="magick-description">swirl image pixels about the center.</p>
6940
6941<p><var>Degrees</var> defines the tightness of the swirl.</p>
6942
6943<div style="margin: auto;">
6944 <h4><a id="synchronize"></a>-synchronize</h4>
6945</div>
6946
6947<p class="magick-description">synchronize image to storage device.</p>
6948
6949<p>Set to "true" to ensure all image data is fully flushed and synchronized
6950to disk. There is a performance penalty, but the benefits include ensuring a
6951valid image file in the event of a system crash and early reporting if there
6952is not enough disk space for the image pixel cache.</p>
6953
6954<div style="margin: auto;">
6955 <h4><a id="taint"></a>-taint</h4>
6956</div>
6957
6958<p class="magick-description">Mark the image as modified.</p>
6959
6960<div style="margin: auto;">
6961 <h4><a id="text-font"></a>-text-font <var>name</var></h4>
6962</div>
6963
6964<p class="magick-description">font for writing fixed-width text.</p>
6965
6966<p>Specifies the name of the preferred font to use in fixed (typewriter style)
6967formatted text. The default is 14 point <var>Courier</var>.</p>
6968
6969<p>You can tag a font to specify whether it is a PostScript, TrueType, or
6970OPTION1 font. For example, <code>Courier.ttf</code> is a TrueType font and
6971<code>x:fixed</code> is OPTION1.</p>
6972
6973<div style="margin: auto;">
6974 <h4><a id="texture"></a>-texture <var>filename</var></h4>
6975</div>
6976
6977<p class="magick-description">name of texture to tile onto the image background.</p>
6978
6979<div style="margin: auto;">
6980 <h4><a id="threshold"></a>-threshold <var>value</var>{<var>%</var>}</h4>
6981</div>
6982
6983<!-- {<var>green,blue,opacity</var>}
6984<p>If the green or blue value is omitted, these channels use the same value as
6985the first one provided. If all three color values are the same, the result is
6986a bi-level image. If the opacity threshold is omitted, OpaqueOpacity is used
6987and any partially transparent pixel becomes fully transparent.</p>
6988-->
6989
6990<p class="magick-description">Apply simultaneous black/white threshold to the image.</p>
6991
6992<p>Any pixel values (more specifically, those channels set using <a href="command-line-options.html#channel">‑channel</a>) that exceed the specified threshold are reassigned the
6993maximum channel value, while all other values are assigned the minimum.</p>
6994
6995<p> The threshold value can be given as a percentage or as an absolute integer
6996value corresponding to the desired channel value. When given as an integer,
6997the minimum attainable value is 0 (corresponding to black when all channels
6998are affected), but the maximum value (corresponding to white) is that of the
6999<code>quantum depth</code> of the particular build of ImageMagick, and is
7000therefore dependent on the installation. For that reason, a reasonable
7001recommendation for most applications is to specify the threshold values as
7002a percentage. </p>
7003
7004<p> The following would force pixels with red values above 50% to have 100%
7005red values, while those at or below 50% red would be set to 0 in the red
7006channel. The green, blue, and alpha channels (if present) would be unchanged.
7007</p>
7008
7009<pre>
7010convert in.png -channel red -threshold 50% out.png
7011</pre>
7012
7013<p>As (possibly) impractical but instructive examples, the following would
7014generate an all-black and an all-white image with the same dimensions as the
7015input image.</p>
7016
7017
7018<pre>
7019convert in.png -threshold 100% black.png
7020convert in.png -threshold -1 white.png
7021</pre>
7022
7023<p>Note that the values of the transparency channel is treated as 'matte'
7024values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
7025
7026<p> See also <a href="command-line-options.html#black-threshold">‑black‑threshold</a> and <a href="command-line-options.html#white-threshold">‑white‑threshold</a>.
7027</p>
7028
7029<div style="margin: auto;">
7030 <h4><a id="thumbnail"></a>-thumbnail <var>geometry</var></h4>
7031</div>
7032
7033<p class="magick-description">Create a thumbnail of the image.</p>
7034
7035<p>This is similar to <a href="command-line-options.html#resize">-resize</a>, except it is optimized
7036for speed and any image profile, other than a color profile, is removed to
7037reduce the thumbnail size. To strip the color profiles as well, add <a href="command-line-options.html#strip">-strip</a> just before of after this option.</p>
7038
7039<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
7040
7041<div style="margin: auto;">
7042 <h4><a id="tile"></a>-tile <var>filename</var></h4>
7043</div>
7044
7045<p class="magick-description">Set the tile image used for filling a subsequent graphic primitive.</p>
7046
7047<div style="margin: auto;">
7048 <h4>-tile <var>geometry</var></h4>
7049</div>
7050
7051<p class="magick-description">Specify the layout of images.</p>
7052
7053<p>See <a href="command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p>
7054
7055<div style="margin: auto;">
7056 <h4>-tile</h4>
7057</div>
7058
7059<p class="magick-description">Specifies that a subsequent composite operation is repeated across and down image.</p>
7060
7061<div style="margin: auto;">
7062 <h4><a id="tile-offset"></a>-tile-offset {<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var></h4>
7063</div>
7064
7065<p class="magick-description">Specify the offset for tile images, relative to the background image it is tiled on.</p>
7066
7067<p>This should be set before the tiling image is set by <a href="command-line-options.html#tile">-tile</a> or <a href="command-line-options.html#texture">-texture</a>, or directly applied for
7068creating a tiled canvas using <code>TILE:</code> or <code>PATTERN:</code> input
7069formats. </p>
7070
7071<p>Internally ImageMagick does a <a href="command-line-options.html#roll">-roll</a> of the tile image
7072by the arguments given when the tile image is set. </p>
7073
7074<div style="margin: auto;">
7075 <h4><a id="tint"></a>-tint <var>value</var></h4>
7076</div>
7077
7078<p class="magick-description">Tint the image with the fill color.</p>
7079
7080<p>Tint the image with the fill color.</p>
7081
7082<p>Specify the amount of tinting as a percentage. Pure colors like black,
7083white red, yellow, will not be affected by -tint. Only mid-range colors such
7084as the various shades of grey.</p>
7085
7086<div style="margin: auto;">
7087 <h4><a id="title"></a>-title <var>string</var></h4>
7088</div>
7089
7090<p class="magick-description">Assign a title to displayed image.", "animate", "display", "montage</p>
7091
7092<p>Use this option to assign a specific title to the image. This assigned to
7093the image window and is typically displayed in the window title bar.
7094Optionally you can include the image filename, type, width, height, Exif data,
7095or other image attribute by embedding special format characters described
7096under the <a href="command-line-options.html#format">-format</a> option.</p>
7097
7098<p>For example,</p>
7099
7100<p class="crtsnip">
7101 -title "%m:%f %wx%h"
7102</p>
7103
7104<p>produces an image title of <code>MIFF:bird.miff 512x480</code> for an image
7105titled <code>bird.miff</code> and whose width is 512 and height is 480.</p>
7106
7107
7108<div style="margin: auto;">
7109 <h4><a id="transform"></a>-transform</h4>
7110</div>
7111
7112<p class="magick-description">transform the image.</p>
7113
7114<p>This option applies the transformation matrix from a previous <a href="command-line-options.html#affine">-affine</a> option.</p>
7115
7116<pre>
7117convert -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg
7118</pre>
7119
7120
7121<p>This operator has been now been superseded by the <a href="command-line-options.html#distort">-distort</a> '<code>AffineProjection</code>' method. </p>
7122
7123
7124<div style="margin: auto;">
7125 <h4><a id="transparent"></a>-transparent <var>color</var></h4>
7126</div>
7127
7128<p class="magick-description">Make this color transparent within the image.</p>
7129
7130<p>The <var>color</var> argument is defined using the format
7131described under the <a href="command-line-options.html#fill">-fill</a> option. The <a href="command-line-options.html#fuzz">-fuzz</a> setting can be used to match and replace colors similar to the one
7132given. </p>
7133
7134<p>Use <a href="command-line-options.html#transparent">+transparent</a> to invert the pixels matched.
7135that is make all non-matching colors transparent. </p>
7136
7137<p>The <a href="command-line-options.html#opaque">-opaque</a> operator is exactly the same as <a href="command-line-options.html#transparent">-transparent</a> but replaces the matching color with the
7138current <a href="command-line-options.html#fill">-fill</a> color setting, rather than transparent.
7139However the <a href="command-line-options.html#transparent">-transparent</a> operator also ensures
7140that the image has an alpha channel enabled, as per "<code><a href="command-line-options.html#alpha">-alpha</a> set</code>", and does not require you to modify the <a href="command-line-options.html#channel">-channel</a> to enable alpha channel handling. </p>
7141
7142<p>Note that this does not define the color as being the 'transparency color'
7143used for color-mapped image formats, such as GIF. For that use <a href="command-line-options.html#transparent-color">-transparent-color</a> </p>
7144
7145
7146<div style="margin: auto;">
7147 <h4><a id="transparent-color"></a>-transparent-color <var>color</var></h4>
7148</div>
7149
7150<p class="magick-description">Set the transparent color.</p>
7151
7152<p>Sometimes this is used for saving to image formats such as
7153GIF and PNG8 which uses this color to represent boolean transparency. This
7154does not make a color transparent, it only defines what color the transparent
7155color is in the color palette of the saved image. Use <a href="command-line-options.html#transparent">-transparent</a> to make an opaque color transparent.</p>
7156
7157<p>This option allows you to have both an opaque visible color, as well as a
7158transparent color of the same color value without conflict. That is, you can
7159use the same color for both the transparent and opaque color areas within an
7160image. This, in turn, frees to you to select a transparent color that is
7161appropriate when an image is displayed by an application that does not handle a
7162transparent color index, while allowing ImageMagick to correctly handle images of this
7163type. </p>
7164
7165<p>The default transparent color is <code>#00000000</code>, which is fully transparent black.</p>
7166
7167<div style="margin: auto;">
7168 <h4><a id="transpose"></a>-transpose</h4>
7169</div>
7170
7171<p class="magick-description">Mirror the image along the top-left to bottom-right diagonal.</p>
7172
7173<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <code>-flip -rotate 90</code>.
7174</p>
7175
7176<div style="margin: auto;">
7177 <h4><a id="transverse"></a>-transverse</h4>
7178</div>
7179
7180<p class="magick-description">Mirror the image along the images bottom-left top-right diagonal. Equivalent to the operations <code>-flop -rotate 90</code>.</p>
7181
7182
7183<div style="margin: auto;">
7184 <h4><a id="treedepth"></a>-treedepth <var>value</var></h4>
7185</div>
7186
7187<p class="magick-description">tree depth for the color reduction algorithm.</p>
7188
7189<p>Normally, this integer value is zero or one. A value of zero or one causes
7190the use of an optimal tree depth for the color reduction algorithm.</p>
7191
7192<p>An optimal depth generally allows the best representation of the source
7193image with the fastest computational speed and the least amount of memory.
7194However, the default depth is inappropriate for some images. To assure the
7195best representation, try values between 2 and 8 for this parameter. Refer to
7196the <a href="quantize.html">color reduction algorithm</a> for more details.</p>
7197
7198<p>The <a href="command-line-options.html#colors">-colors</a> or <a href="command-line-options.html#monochrome">-monochrome</a>
7199option, or writing to an image format which requires color reduction, is
7200required for this option to take effect.</p>
7201
7202<div style="margin: auto;">
7203 <h4><a id="trim"></a>-trim</h4>
7204</div>
7205
7206<p class="magick-description">trim an image.</p>
7207
7208<p>This option removes any edges that are exactly the same color as the corner
7209pixels. Use <a href="command-line-options.html#fuzz">-fuzz</a> to make <a href="command-line-options.html#trim">-trim</a> remove
7210edges that are nearly the same color as the corner pixels.</p>
7211
7212<p>The page or virtual canvas information of the image is preserved allowing
7213you to extract the result of the <a href="command-line-options.html#trim">-trim</a> operation from the
7214image. Use a <a href="command-line-options.html#repage">+repage</a> to remove the virtual canvas page
7215information if it is unwanted.</p>
7216
7217<p>If the trimmed image 'disappears' an warning is produced, and a special
7218single pixel transparent 'missed' image is returned, in the same way as when a
7219<a href="command-line-options.html#crop">-crop</a> operation 'misses' the image proper. </p>
7220
7221
7222<div style="margin: auto;">
7223 <h4><a id="type"></a>-type <var>type</var></h4>
7224</div>
7225
7226<p class="magick-description">the image type.</p> <p>Choose from: <code>Bilevel</code>,
7227<code>Grayscale</code>, <code>GrayscaleMatte</code>, <code>Palette</code>,
7228<code>PaletteMatte</code>, <code>TrueColor</code>, <code>TrueColorMatte</code>,
7229<code>ColorSeparation</code>, or <code>ColorSeparationMatte</code>.</p>
7230
7231<p>Normally, when a format supports different subformats such as grayscale and
7232truecolor, the encoder will try to choose an efficient subformat. The <a href="command-line-options.html#type">-type</a> option can be used to override this behavior. For
7233example, to prevent a JPEG from being written in grayscale format even though
7234only gray pixels are present, use.</p>
7235
7236<pre>
7237convert bird.png -type TrueColor bird.jpg
7238</pre>
7239
7240<p>Similarly, use <a href="command-line-options.html#type">-type TrueColorMatte</a> to force the
7241encoder to write an alpha channel even though the image is opaque, if the
7242output format supports transparency.</p>
7243
7244<p>Use <a href="command-line-options.html#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
7245
7246<div style="margin: auto;">
7247 <h4><a id="undercolor"></a>-undercolor <var>color</var></h4>
7248</div>
7249
7250<p class="magick-description">set the color of the annotation bounding box.</p>
7251
7252<p>The color is specified using the format described under the <a href="command-line-options.html#fill">-fill</a> option.</p>
7253
7254<p>See <a href="command-line-options.html#draw">-draw</a> for further details.</p>
7255
7256
7257<div style="margin: auto;">
7258 <h4><a id="update"></a>-update <var>seconds</var></h4>
7259</div>
7260
7261<p class="magick-description">detect when image file is modified and redisplay.</p>
7262
7263<p>Suppose that while you are displaying an image the file that is currently
7264displayed is over-written. <code>display</code> will automagically detect that
7265the input file has been changed and update the displayed image
7266accordingly.</p>
7267
7268
7269<div style="margin: auto;">
7270 <h4><a id="unique-colors"></a>-unique-colors</h4>
7271</div>
7272
7273<p class="magick-description">discard all but one of any pixel color.</p>
7274
7275
7276<div style="margin: auto;">
7277 <h4><a id="units"></a>-units <var>type</var></h4>
7278</div>
7279
7280<p class="magick-description">the units of image resolution.</p>
7281
7282<p>Choose from: <code>Undefined</code>, <code>PixelsPerInch</code>, or
7283<code>PixelsPerCentimeter</code>. This option is normally used in conjunction
7284with the <a href="command-line-options.html#density">-density</a> option.</p>
7285
7286
7287<div style="margin: auto;">
7288 <h4><a id="unsharp"></a>-unsharp <var>radius</var><br>-unsharp <var>radius</var>x<var>sigma</var>{<var>+gain</var>}{<var>+threshold</var>}</h4>
7289</div>
7290
7291<p class="magick-description">sharpen the image with an unsharp mask operator.</p>
7292
7293<p>The <a href="command-line-options.html#unsharp">-unsharp</a> option sharpens an image. The image is
7294convolved with a Gaussian operator of the given radius and standard deviation
7295(sigma). For reasonable results, radius should be larger than sigma. Use
7296a radius of 0 to have the method select a suitable radius.</p>
7297
7298<p>The parameters are:</p>
7299
7300<pre>
7301 radius The radius of the Gaussian, in pixels, not counting the center
7302 pixel (default 0).
7303 sigma The standard deviation of the Gaussian, in pixels (default 1.0).
7304 gain The fraction of the difference between the original and the blur
7305 image that is added back into the original (default 1.0).
7306 threshold The threshold, as a fraction of <var>QuantumRange</var>, needed to apply the
7307 difference amount (default 0.05).
7308</pre>
7309
7310
7311<div style="margin: auto;">
7312 <h4><a id="verbose"></a>-verbose</h4>
7313</div>
7314
7315<p class="magick-description">print detailed information about the image when this option precedes the <a href="command-line-options.html#identify">-identify</a> option or <code>info:</code>.</p>
7316
7317
7318<div style="margin: auto;">
7319 <h4><a id="version"></a>-version</h4>
7320</div>
7321
7322<p class="magick-description">print ImageMagick version string and exit.</p>
7323
7324
7325<div style="margin: auto;">
7326 <h4><a id="view"></a>-view <var>string</var></h4>
7327</div>
7328
7329<p class="magick-description">FlashPix viewing parameters.</p>
7330
7331
7332<div style="margin: auto;">
7333 <h4><a id="vignette"></a>-vignette <var>radius</var>{x<var>sigma</var>}{<var>+-</var>}<var>x</var>{<var>+-</var>}<var>y</var>{<var>%</var>}</h4>
7334</div>
7335
7336<p class="magick-description">soften the edges of the image in vignette style.</p>
7337
7338<p>The vignette effect rolloff is controlled by radiusxsigma. For nominal rolloff, this would be set to 0xsigma. A value of 0x0 will produce a circle/ellipse with no rolloff. The arguments x and y control the size of the circle. Larger values decrease the radii and smaller values increase the radii. Values of +0+0 will generate a circle/ellipse the same size as the image. The default values for x and y are 10% of the corresponding image dimension. Thus, the radii will be decreased by 10%, i.e., the diameters of the circle/ellipse will be 80% of the corresponding image dimension.</p>
7339
7340<div style="margin: auto;">
7341 <h4><a id="virtual-pixel"></a>-virtual-pixel <var>method</var></h4>
7342</div>
7343
7344<p class="magick-description">Specify contents of <var>virtual pixels</var>.</p>
7345
7346<p>This option defines what color source should be used if and when a color
7347lookup completely 'misses' the source image. The color(s) that appear to
7348surround the source image. Generally this color is derived from the source
7349image, but could also be set to a specify background color. </p>
7350
7351<p>Choose from these methods:</p>
7352
7353<pre>
7354 background the area surrounding the image is the background color
7355 black the area surrounding the image is black
7356 checker-tile alternate squares with image and background color
7357 dither non-random 32x32 dithered pattern
7358 edge extend the edge pixel toward infinity
7359 gray the area surrounding the image is gray
7360 horizontal-tile horizontally tile the image, background color above/below
7361 horizontal-tile-edge horizontally tile the image and replicate the side edge pixels
7362 mirror mirror tile the image
7363 random choose a random pixel from the image
7364 tile tile the image (default)
7365 transparent the area surrounding the image is transparent blackness
7366 vertical-tile vertically tile the image, sides are background color
7367 vertical-tile-edge vertically tile the image and replicate the side edge pixels
7368 white the area surrounding the image is white
7369</pre>
7370
7371<p>The default value is "edge".</p>
7372
7373<p>This most important for distortion operators such as <a href="command-line-options.html#distort">-distort</a>, <a href="command-line-options.html#implode">-implode</a>, and <a href="command-line-options.html#fx">-fx</a>.
7374However it also effects operations that may access pixels just outside the
7375image proper, such as <a href="command-line-options.html#convolve">-convolve</a>, <a href="command-line-options.html#blur">-blur</a>, and <a href="command-line-options.html#sharpen">-sharpen</a>. </p>
7376
7377<p>To print a complete list of virtual pixel types, use the <a href="command-line-options.html#list">-list virtual-pixel</a> option.</p>
7378
7379
7380<div style="margin: auto;">
7381 <h4><a id="visual"></a>-visual <var>type</var></h4>
7382</div>
7383
7384<p class="magick-description">Animate images using this X visual type.", 'animate', 'display'</p>
7385
7386<p>Choose from these visual classes:</p>
7387
7388<pre>
7389 StaticGray
7390 GrayScale
7391 StaticColor
7392 PseudoColor
7393 TrueColor
7394 DirectColor
7395 default
7396 visual id
7397</pre>
7398
7399<p>The X server must support the visual you choose, otherwise an error occurs.
7400If a visual is not specified, the visual class that can display the most
7401simultaneous colors on the default screen is chosen.</p>
7402
7403
7404<div style="margin: auto;">
7405 <h4><a id="watermark"></a>-watermark <var>brightness</var>x<var>saturation</var></h4>
7406</div>
7407
7408<p class="magick-description">Watermark an image using the given percentages of brightness and saturation.</p>
7409
7410<p>Take a grayscale image (with alpha mask) and modify the destination image's
7411brightness according to watermark image's grayscale value and the
7412<var>brightness</var> percentage. The destinations color saturation
7413attribute is just direct modified by the <var>saturation</var>
7414percentage, which defaults to 100 percent (no color change). </p>
7415
7416
7417<div style="margin: auto;">
7418 <h4><a id="wave"></a>-wave <var>amplitude</var><br>-wave <var>amplitude</var>x<var>wavelength</var></h4>
7419</div>
7420
7421<p class="magick-description">Shear the columns of an image into a sine wave.</p>
7422
7423<p>Specify <var>amplitude</var> and <var>wavelength</var>
7424of the wave.</p>
7425
7426<div style="margin: auto;">
7427 <h4><a id="weight"></a>-weight <var>fontWeight</var></h4>
7428</div>
7429
7430<p class="magick-description">Set a font weight for text.</p>
7431
7432<p>This setting suggests a font weight that ImageMagick should try to apply to
7433the currently selected font family. Use a positive integer for
7434<var>fontWeight</var> or select from the following.</p>
7435
7436<table class="table table-condensed table-striped">
7437 <col width="25%">
7438 <col width="75%">
7439 <thead>
7440 <tr>
7441 <th><var>fontWeight</var></th>
7442 <th>Description</th>
7443 </tr>
7444 </thead>
7445 <tbody>
7446 <tr><td>All </td>
7447 <td>No effect. </td></tr>
7448 <tr><td>Bold </td>
7449 <td>Same as <var>fontWeight</var> = 700.</td></tr>
7450 <tr><td>Bolder </td>
7451 <td>Add 100 to font weight if currently ≤ 800.</td></tr>
7452 <tr><td>Lighter </td>
7453 <td>Subtract 100 to font weight if currently ≤ 100.</td></tr>
7454 <tr><td>Normal </td>
7455 <td>Same as <var>fontWeight</var> = 400.</td></tr>
7456 </tbody>
7457 </table>
7458
7459<p>To print a complete list of weight types, use <a href="command-line-options.html#list">-list
7460weight</a>.</p>
7461
7462<p>For other settings that affect fonts, see the options <a href="command-line-options.html#font">-font</a>, <a href="command-line-options.html#family">-family</a>, <a href="command-line-options.html#stretch">-stretch</a>, and <a href="command-line-options.html#style">-style</a>. </p>
7463
7464<div style="margin: auto;">
7465 <h4><a id="white-point"></a>-white-point <var>x,y</var></h4>
7466</div>
7467
7468<p class="magick-description">chromaticity white point.</p>
7469
7470<div style="margin: auto;">
7471 <h4><a id="white-threshold"></a>-white-threshold <var>value</var>{<var>%</var>}</h4>
7472</div>
7473
7474<p class="magick-description">Force to white all pixels above the threshold while leaving all pixels at or below the threshold unchanged.</p>
7475
7476<p> The threshold value can be given as a percentage or as an absolute integer
7477value within [0, <var>QuantumRange</var>] corresponding to the
7478desired <a href="command-line-options.html#channel">‑channel</a> value. See <a href="command-line-options.html#threshold">‑threshold</a>for more details on thresholds and resulting values. </p>
7479
7480<div style="margin: auto;">
7481 <h4><a id="window"></a>-window <var>id</var></h4>
7482</div>
7483
7484<p class="magick-description">Make the image the background of a window.", 'animate', 'display'</p>
7485
7486<p><var>id</var> can be a window id or name. Specify <code>root</code>
7487to select X's root window as the target window.</p>
7488
7489<p>By default the image is tiled onto the background of the target window. If
7490<code>backdrop</code> or <a href="command-line-options.html#geometry">-resize</a> are specified, the
7491image is surrounded by the background color. Refer to <code>X RESOURCES</code>
7492for details.</p>
7493
7494<p>The image will not display on the root window if the image has more unique
7495colors than the target window colormap allows. Use <a href="command-line-options.html#colors">-colors</a> to reduce the number of colors.</p>
7496
7497<div style="margin: auto;">
7498 <h4><a id="window-group"></a>-window-group</h4>
7499</div>
7500
7501<p class="magick-description">specify the window group.</p>
7502
7503<div style="margin: auto;">
7504 <h4><a id="write"></a>-write <var>filename</var></h4>
7505</div>
7506
7507<p class="magick-description">write an image sequence.</p>
7508
7509<p>The image sequence preceding the <a href="command-line-options.html#write">-write</a> <var>filename</var> option is written out, and processing continues with the same image in its current state if there are additional options. To restore the image to its original state after writing it, use the <a href="command-line-options.html#write">+write</a> <var>filename</var> option.</p>
7510
7511<p>Use <a href="command-line-options.html#compress">-compress</a> to specify the type of image compression.</p>
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