| J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1996 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | /* |
| 27 | * This file contains macro definitions for the Encoding category of |
| 28 | * the macros used by the generic scaleloop function. |
| 29 | * |
| 30 | * This implementation uses a Floyd-Steinberg error diffusion technique |
| 31 | * to produce a very high quality version of an image with only an 8-bit |
| 32 | * (or less) RGB colormap. The error diffusion technique requires that |
| 33 | * the input color information be delivered in a special order from the |
| 34 | * top row to the bottom row and then left to right within each row, thus |
| 35 | * it is only valid in cases where the ImageProducer has specified the |
| 36 | * TopDownLeftRight delivery hint. If the data is not read in that order, |
| 37 | * no mathematical or memory access errors should occur, but the dithering |
| 38 | * error will be spread through the pixels of the output image in an |
| 39 | * unpleasant manner. |
| 40 | */ |
| 41 | |
| 42 | #include "img_fsutil.h" |
| 43 | |
| 44 | /* |
| 45 | * These definitions vector the standard macro names to the "Color" |
| 46 | * versions of those macros only if the "DitherDeclared" keyword has |
| 47 | * not yet been defined elsewhere. The "DitherDeclared" keyword is |
| 48 | * also defined here to claim ownership of the primary implementation |
| 49 | * even though this file does not rely on the definitions in any other |
| 50 | * files. |
| 51 | */ |
| 52 | #ifndef DitherDeclared |
| 53 | #define DitherDeclared |
| 54 | #define DeclareDitherVars DeclareColorDitherVars |
| 55 | #define InitDither InitColorDither |
| 56 | #define StartDitherLine StartColorDitherLine |
| 57 | #define DitherPixel ColorDitherPixel |
| 58 | #define DitherBufComplete ColorDitherBufComplete |
| 59 | #endif |
| 60 | |
| 61 | typedef struct { |
| 62 | int r, g, b; |
| 63 | } ColorDitherError; |
| 64 | |
| 65 | #define DeclareColorDitherVars \ |
| 66 | int er, eg, eb; \ |
| 67 | ColorDitherError *cep; |
| 68 | |
| 69 | #define InitColorDither(cvdata, clrdata, dstTW) \ |
| 70 | do { \ |
| 71 | if (cvdata->fserrors == 0) { \ |
| 72 | int size = (dstTW + 2) * sizeof(ColorDitherError); \ |
| 73 | cep = (ColorDitherError *) sysMalloc(size); \ |
| 74 | if (cep == 0) { \ |
| 75 | SignalError(0, JAVAPKG "OutOfMemoryError", 0); \ |
| 76 | return SCALEFAILURE; \ |
| 77 | } \ |
| 78 | memset(cep, 0, size); \ |
| 79 | cvdata->fserrors = (void *) cep; \ |
| 80 | } \ |
| 81 | } while (0) |
| 82 | |
| 83 | #define StartColorDitherLine(cvdata, dstX1, dstY) \ |
| 84 | do { \ |
| 85 | cep = (ColorDitherError *) cvdata->fserrors; \ |
| 86 | if (dstX1) { \ |
| 87 | er = cep[0].r; \ |
| 88 | eg = cep[0].g; \ |
| 89 | eb = cep[0].b; \ |
| 90 | cep += dstX1; \ |
| 91 | } else { \ |
| 92 | er = eg = eb = 0; \ |
| 93 | } \ |
| 94 | } while (0) |
| 95 | |
| 96 | #define ColorDitherPixel(dstX, dstY, pixel, red, green, blue) \ |
| 97 | do { \ |
| 98 | int e1, e2, e3; \ |
| 99 | \ |
| 100 | /* add previous errors */ \ |
| 101 | red += cep[1].r; \ |
| 102 | green += cep[1].g; \ |
| 103 | blue += cep[1].b; \ |
| 104 | \ |
| 105 | /* bounds checking */ \ |
| 106 | e1 = ComponentBound(red); \ |
| 107 | e2 = ComponentBound(green); \ |
| 108 | e3 = ComponentBound(blue); \ |
| 109 | \ |
| 110 | /* Store the closest color in the destination pixel */ \ |
| 111 | pixel = ColorCubeFSMap(e1, e2, e3); \ |
| 112 | GetPixelRGB(pixel, red, green, blue); \ |
| 113 | \ |
| 114 | /* Set the error from the previous lap */ \ |
| 115 | cep[1].r = er; cep[1].g = eg; cep[1].b = eb; \ |
| 116 | \ |
| 117 | /* compute the errors */ \ |
| 118 | er = e1 - red; eg = e2 - green; eb = e3 - blue; \ |
| 119 | \ |
| 120 | /* distribute the errors */ \ |
| 121 | DitherDist(cep, e1, e2, e3, er, r); \ |
| 122 | DitherDist(cep, e1, e2, e3, eg, g); \ |
| 123 | DitherDist(cep, e1, e2, e3, eb, b); \ |
| 124 | cep++; \ |
| 125 | } while (0) |
| 126 | |
| 127 | #define ColorDitherBufComplete(cvdata, dstX1) \ |
| 128 | do { \ |
| 129 | if (dstX1) { \ |
| 130 | cep = (ColorDitherError *) cvdata->fserrors; \ |
| 131 | cep[0].r = er; \ |
| 132 | cep[0].g = eg; \ |
| 133 | cep[0].b = eb; \ |
| 134 | } \ |
| 135 | } while (0) |