Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 1 | /* |
| 2 | * jquant1.c |
| 3 | * |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 4 | * Copyright (C) 1991-1994, Thomas G. Lane. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 5 | * This file is part of the Independent JPEG Group's software. |
| 6 | * For conditions of distribution and use, see the accompanying README file. |
| 7 | * |
| 8 | * This file contains 1-pass color quantization (color mapping) routines. |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 9 | * These routines provide mapping to a fixed color map using equally spaced |
| 10 | * color values. Optional Floyd-Steinberg or ordered dithering is available. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 11 | */ |
| 12 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 13 | #define JPEG_INTERNALS |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 14 | #include "jinclude.h" |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 15 | #include "jpeglib.h" |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 16 | |
| 17 | #ifdef QUANT_1PASS_SUPPORTED |
| 18 | |
| 19 | |
| 20 | /* |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 21 | * The main purpose of 1-pass quantization is to provide a fast, if not very |
| 22 | * high quality, colormapped output capability. A 2-pass quantizer usually |
| 23 | * gives better visual quality; however, for quantized grayscale output this |
| 24 | * quantizer is perfectly adequate. Dithering is highly recommended with this |
| 25 | * quantizer, though you can turn it off if you really want to. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 26 | * |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 27 | * In 1-pass quantization the colormap must be chosen in advance of seeing the |
| 28 | * image. We use a map consisting of all combinations of Ncolors[i] color |
| 29 | * values for the i'th component. The Ncolors[] values are chosen so that |
| 30 | * their product, the total number of colors, is no more than that requested. |
| 31 | * (In most cases, the product will be somewhat less.) |
| 32 | * |
| 33 | * Since the colormap is orthogonal, the representative value for each color |
| 34 | * component can be determined without considering the other components; |
| 35 | * then these indexes can be combined into a colormap index by a standard |
| 36 | * N-dimensional-array-subscript calculation. Most of the arithmetic involved |
| 37 | * can be precalculated and stored in the lookup table colorindex[]. |
| 38 | * colorindex[i][j] maps pixel value j in component i to the nearest |
| 39 | * representative value (grid plane) for that component; this index is |
| 40 | * multiplied by the array stride for component i, so that the |
| 41 | * index of the colormap entry closest to a given pixel value is just |
| 42 | * sum( colorindex[component-number][pixel-component-value] ) |
| 43 | * Aside from being fast, this scheme allows for variable spacing between |
| 44 | * representative values with no additional lookup cost. |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 45 | * |
| 46 | * If gamma correction has been applied in color conversion, it might be wise |
| 47 | * to adjust the color grid spacing so that the representative colors are |
| 48 | * equidistant in linear space. At this writing, gamma correction is not |
| 49 | * implemented by jdcolor, so nothing is done here. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 50 | */ |
| 51 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 52 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 53 | /* Declarations for ordered dithering. |
| 54 | * |
| 55 | * We use a standard 4x4 ordered dither array. The basic concept of ordered |
| 56 | * dithering is described in many references, for instance Dale Schumacher's |
| 57 | * chapter II.2 of Graphics Gems II (James Arvo, ed. Academic Press, 1991). |
| 58 | * In place of Schumacher's comparisons against a "threshold" value, we add a |
| 59 | * "dither" value to the input pixel and then round the result to the nearest |
| 60 | * output value. The dither value is equivalent to (0.5 - threshold) times |
| 61 | * the distance between output values. For ordered dithering, we assume that |
| 62 | * the output colors are equally spaced; if not, results will probably be |
| 63 | * worse, since the dither may be too much or too little at a given point. |
| 64 | * |
| 65 | * The normal calculation would be to form pixel value + dither, range-limit |
| 66 | * this to 0..MAXJSAMPLE, and then index into the colorindex table as usual. |
| 67 | * We can skip the separate range-limiting step by extending the colorindex |
| 68 | * table in both directions. |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 69 | */ |
| 70 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 71 | #define ODITHER_SIZE 4 /* dimension of dither matrix */ |
| 72 | #define ODITHER_CELLS (4*4) /* number of cells in dither matrix */ |
| 73 | #define ODITHER_MASK 3 /* mask for wrapping around dither counters */ |
| 74 | |
| 75 | typedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE]; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 76 | |
| 77 | |
| 78 | /* Declarations for Floyd-Steinberg dithering. |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 79 | * |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 80 | * Errors are accumulated into the array fserrors[], at a resolution of |
| 81 | * 1/16th of a pixel count. The error at a given pixel is propagated |
| 82 | * to its not-yet-processed neighbors using the standard F-S fractions, |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 83 | * ... (here) 7/16 |
| 84 | * 3/16 5/16 1/16 |
| 85 | * We work left-to-right on even rows, right-to-left on odd rows. |
| 86 | * |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 87 | * We can get away with a single array (holding one row's worth of errors) |
| 88 | * by using it to store the current row's errors at pixel columns not yet |
| 89 | * processed, but the next row's errors at columns already processed. We |
| 90 | * need only a few extra variables to hold the errors immediately around the |
| 91 | * current column. (If we are lucky, those variables are in registers, but |
| 92 | * even if not, they're probably cheaper to access than array elements are.) |
| 93 | * |
| 94 | * The fserrors[] array is indexed [component#][position]. |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 95 | * We provide (#columns + 2) entries per component; the extra entry at each |
| 96 | * end saves us from special-casing the first and last pixels. |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 97 | * |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 98 | * Note: on a wide image, we might not have enough room in a PC's near data |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 99 | * segment to hold the error array; so it is allocated with alloc_large. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 100 | */ |
| 101 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 102 | #if BITS_IN_JSAMPLE == 8 |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 103 | typedef INT16 FSERROR; /* 16 bits should be enough */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 104 | typedef int LOCFSERROR; /* use 'int' for calculation temps */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 105 | #else |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 106 | typedef INT32 FSERROR; /* may need more than 16 bits */ |
| 107 | typedef INT32 LOCFSERROR; /* be sure calculation temps are big enough */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 108 | #endif |
| 109 | |
| 110 | typedef FSERROR FAR *FSERRPTR; /* pointer to error array (in FAR storage!) */ |
| 111 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 112 | |
| 113 | /* Private subobject */ |
| 114 | |
| 115 | #define MAX_Q_COMPS 4 /* max components I can handle */ |
| 116 | |
| 117 | typedef struct { |
| 118 | struct jpeg_color_quantizer pub; /* public fields */ |
| 119 | |
| 120 | JSAMPARRAY colorindex; /* Precomputed mapping for speed */ |
| 121 | /* colorindex[i][j] = index of color closest to pixel value j in component i, |
| 122 | * premultiplied as described above. Since colormap indexes must fit into |
| 123 | * JSAMPLEs, the entries of this array will too. |
| 124 | */ |
| 125 | |
| 126 | /* Variables for ordered dithering */ |
| 127 | int row_index; /* cur row's vertical index in dither matrix */ |
| 128 | ODITHER_MATRIX *odither; /* one dither array per component */ |
| 129 | |
| 130 | /* Variables for Floyd-Steinberg dithering */ |
| 131 | FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */ |
| 132 | boolean on_odd_row; /* flag to remember which row we are on */ |
| 133 | } my_cquantizer; |
| 134 | |
| 135 | typedef my_cquantizer * my_cquantize_ptr; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 136 | |
| 137 | |
| 138 | /* |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 139 | * Policy-making subroutines for create_colormap: these routines determine |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 140 | * the colormap to be used. The rest of the module only assumes that the |
| 141 | * colormap is orthogonal. |
| 142 | * |
| 143 | * * select_ncolors decides how to divvy up the available colors |
| 144 | * among the components. |
| 145 | * * output_value defines the set of representative values for a component. |
| 146 | * * largest_input_value defines the mapping from input values to |
| 147 | * representative values for a component. |
| 148 | * Note that the latter two routines may impose different policies for |
| 149 | * different components, though this is not currently done. |
| 150 | */ |
| 151 | |
| 152 | |
| 153 | LOCAL int |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 154 | select_ncolors (j_decompress_ptr cinfo, int Ncolors[]) |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 155 | /* Determine allocation of desired colors to components, */ |
| 156 | /* and fill in Ncolors[] array to indicate choice. */ |
| 157 | /* Return value is total number of colors (product of Ncolors[] values). */ |
| 158 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 159 | int nc = cinfo->out_color_components; /* number of color components */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 160 | int max_colors = cinfo->desired_number_of_colors; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 161 | int total_colors, iroot, i, j; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 162 | long temp; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 163 | static const int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE }; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 164 | |
| 165 | /* We can allocate at least the nc'th root of max_colors per component. */ |
| 166 | /* Compute floor(nc'th root of max_colors). */ |
| 167 | iroot = 1; |
| 168 | do { |
| 169 | iroot++; |
| 170 | temp = iroot; /* set temp = iroot ** nc */ |
| 171 | for (i = 1; i < nc; i++) |
| 172 | temp *= iroot; |
| 173 | } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */ |
| 174 | iroot--; /* now iroot = floor(root) */ |
| 175 | |
| 176 | /* Must have at least 2 color values per component */ |
| 177 | if (iroot < 2) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 178 | ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int) temp); |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 179 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 180 | /* Initialize to iroot color values for each component */ |
| 181 | total_colors = 1; |
| 182 | for (i = 0; i < nc; i++) { |
| 183 | Ncolors[i] = iroot; |
| 184 | total_colors *= iroot; |
| 185 | } |
| 186 | /* We may be able to increment the count for one or more components without |
| 187 | * exceeding max_colors, though we know not all can be incremented. |
| 188 | * In RGB colorspace, try to increment G first, then R, then B. |
| 189 | */ |
| 190 | for (i = 0; i < nc; i++) { |
| 191 | j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i); |
| 192 | /* calculate new total_colors if Ncolors[j] is incremented */ |
| 193 | temp = total_colors / Ncolors[j]; |
| 194 | temp *= Ncolors[j]+1; /* done in long arith to avoid oflo */ |
| 195 | if (temp > (long) max_colors) |
| 196 | break; /* won't fit, done */ |
| 197 | Ncolors[j]++; /* OK, apply the increment */ |
| 198 | total_colors = (int) temp; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 199 | } |
| 200 | |
| 201 | return total_colors; |
| 202 | } |
| 203 | |
| 204 | |
| 205 | LOCAL int |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 206 | output_value (j_decompress_ptr cinfo, int ci, int j, int maxj) |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 207 | /* Return j'th output value, where j will range from 0 to maxj */ |
| 208 | /* The output values must fall in 0..MAXJSAMPLE in increasing order */ |
| 209 | { |
| 210 | /* We always provide values 0 and MAXJSAMPLE for each component; |
| 211 | * any additional values are equally spaced between these limits. |
| 212 | * (Forcing the upper and lower values to the limits ensures that |
| 213 | * dithering can't produce a color outside the selected gamut.) |
| 214 | */ |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 215 | return (int) (((INT32) j * MAXJSAMPLE + maxj/2) / maxj); |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 216 | } |
| 217 | |
| 218 | |
| 219 | LOCAL int |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 220 | largest_input_value (j_decompress_ptr cinfo, int ci, int j, int maxj) |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 221 | /* Return largest input value that should map to j'th output value */ |
| 222 | /* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */ |
| 223 | { |
| 224 | /* Breakpoints are halfway between values returned by output_value */ |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 225 | return (int) (((INT32) (2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj)); |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 226 | } |
| 227 | |
| 228 | |
| 229 | /* |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 230 | * Create the colormap and color index table. |
| 231 | * Also creates the ordered-dither tables, if required. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 232 | */ |
| 233 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 234 | LOCAL void |
| 235 | create_colormap (j_decompress_ptr cinfo) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 236 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 237 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
| 238 | JSAMPARRAY colormap; /* Created colormap */ |
| 239 | JSAMPROW indexptr; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 240 | int total_colors; /* Number of distinct output colors */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 241 | int Ncolors[MAX_Q_COMPS]; /* # of values alloced to each component */ |
| 242 | ODITHER_MATRIX *odither; |
| 243 | int i,j,k, nci, blksize, blkdist, ptr, val, pad; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 244 | |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 245 | /* Select number of colors for each component */ |
| 246 | total_colors = select_ncolors(cinfo, Ncolors); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 247 | |
| 248 | /* Report selected color counts */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 249 | if (cinfo->out_color_components == 3) |
| 250 | TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS, |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 251 | total_colors, Ncolors[0], Ncolors[1], Ncolors[2]); |
| 252 | else |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 253 | TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors); |
| 254 | |
| 255 | /* For ordered dither, we pad the color index tables by MAXJSAMPLE in |
| 256 | * each direction (input index values can be -MAXJSAMPLE .. 2*MAXJSAMPLE). |
| 257 | * This is not necessary in the other dithering modes. |
| 258 | */ |
| 259 | pad = (cinfo->dither_mode == JDITHER_ORDERED) ? MAXJSAMPLE*2 : 0; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 260 | |
| 261 | /* Allocate and fill in the colormap and color index. */ |
| 262 | /* The colors are ordered in the map in standard row-major order, */ |
| 263 | /* i.e. rightmost (highest-indexed) color changes most rapidly. */ |
| 264 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 265 | colormap = (*cinfo->mem->alloc_sarray) |
| 266 | ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 267 | (JDIMENSION) total_colors, (JDIMENSION) cinfo->out_color_components); |
| 268 | cquantize->colorindex = (*cinfo->mem->alloc_sarray) |
| 269 | ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 270 | (JDIMENSION) (MAXJSAMPLE+1 + pad), |
| 271 | (JDIMENSION) cinfo->out_color_components); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 272 | |
| 273 | /* blksize is number of adjacent repeated entries for a component */ |
| 274 | /* blkdist is distance between groups of identical entries for a component */ |
| 275 | blkdist = total_colors; |
| 276 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 277 | for (i = 0; i < cinfo->out_color_components; i++) { |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 278 | /* fill in colormap entries for i'th color component */ |
| 279 | nci = Ncolors[i]; /* # of distinct values for this color */ |
| 280 | blksize = blkdist / nci; |
| 281 | for (j = 0; j < nci; j++) { |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 282 | /* Compute j'th output value (out of nci) for component */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 283 | val = output_value(cinfo, i, j, nci-1); |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 284 | /* Fill in all colormap entries that have this value of this component */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 285 | for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) { |
| 286 | /* fill in blksize entries beginning at ptr */ |
| 287 | for (k = 0; k < blksize; k++) |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 288 | colormap[i][ptr+k] = (JSAMPLE) val; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 289 | } |
| 290 | } |
| 291 | blkdist = blksize; /* blksize of this color is blkdist of next */ |
| 292 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 293 | /* adjust colorindex pointers to provide padding at negative indexes. */ |
| 294 | if (pad) |
| 295 | cquantize->colorindex[i] += MAXJSAMPLE; |
| 296 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 297 | /* fill in colorindex entries for i'th color component */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 298 | /* in loop, val = index of current output value, */ |
| 299 | /* and k = largest j that maps to current val */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 300 | indexptr = cquantize->colorindex[i]; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 301 | val = 0; |
| 302 | k = largest_input_value(cinfo, i, 0, nci-1); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 303 | for (j = 0; j <= MAXJSAMPLE; j++) { |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 304 | while (j > k) /* advance val if past boundary */ |
| 305 | k = largest_input_value(cinfo, i, ++val, nci-1); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 306 | /* premultiply so that no multiplication needed in main processing */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 307 | indexptr[j] = (JSAMPLE) (val * blksize); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 308 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 309 | /* Pad at both ends if necessary */ |
| 310 | if (pad) |
| 311 | for (j = 1; j <= MAXJSAMPLE; j++) { |
| 312 | indexptr[-j] = indexptr[0]; |
| 313 | indexptr[MAXJSAMPLE+j] = indexptr[MAXJSAMPLE]; |
| 314 | } |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 315 | } |
| 316 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 317 | /* Make the colormap available to the application. */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 318 | cinfo->colormap = colormap; |
| 319 | cinfo->actual_number_of_colors = total_colors; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 320 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 321 | if (cinfo->dither_mode == JDITHER_ORDERED) { |
| 322 | /* Allocate and fill in the ordered-dither tables. */ |
| 323 | odither = (ODITHER_MATRIX *) |
| 324 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 325 | cinfo->out_color_components * SIZEOF(ODITHER_MATRIX)); |
| 326 | cquantize->odither = odither; |
| 327 | for (i = 0; i < cinfo->out_color_components; i++) { |
| 328 | nci = Ncolors[i]; /* # of distinct values for this color */ |
| 329 | /* The inter-value distance for this color is MAXJSAMPLE/(nci-1). |
| 330 | * Hence the dither value for the matrix cell with fill order j |
| 331 | * (j=1..N) should be (N+1-2*j)/(2*(N+1)) * MAXJSAMPLE/(nci-1). |
| 332 | */ |
| 333 | val = 2 * (ODITHER_CELLS + 1) * (nci - 1); /* denominator */ |
| 334 | /* Macro is coded to ensure round towards zero despite C's |
| 335 | * lack of consistency in integer division... |
| 336 | */ |
| 337 | #define ODITHER_DIV(num,den) ((num)<0 ? -((-(num))/(den)) : (num)/(den)) |
| 338 | #define ODITHER_VAL(j) ODITHER_DIV((ODITHER_CELLS+1-2*j)*MAXJSAMPLE, val) |
| 339 | /* Traditional fill order for 4x4 dither; see Schumacher's figure 4. */ |
| 340 | odither[0][0][0] = ODITHER_VAL(1); |
| 341 | odither[0][0][1] = ODITHER_VAL(9); |
| 342 | odither[0][0][2] = ODITHER_VAL(3); |
| 343 | odither[0][0][3] = ODITHER_VAL(11); |
| 344 | odither[0][1][0] = ODITHER_VAL(13); |
| 345 | odither[0][1][1] = ODITHER_VAL(5); |
| 346 | odither[0][1][2] = ODITHER_VAL(15); |
| 347 | odither[0][1][3] = ODITHER_VAL(7); |
| 348 | odither[0][2][0] = ODITHER_VAL(4); |
| 349 | odither[0][2][1] = ODITHER_VAL(12); |
| 350 | odither[0][2][2] = ODITHER_VAL(2); |
| 351 | odither[0][2][3] = ODITHER_VAL(10); |
| 352 | odither[0][3][0] = ODITHER_VAL(16); |
| 353 | odither[0][3][1] = ODITHER_VAL(8); |
| 354 | odither[0][3][2] = ODITHER_VAL(14); |
| 355 | odither[0][3][3] = ODITHER_VAL(6); |
| 356 | odither++; /* advance to next matrix */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 357 | } |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 358 | } |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 359 | } |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 360 | |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 361 | |
| 362 | /* |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 363 | * Map some rows of pixels to the output colormapped representation. |
| 364 | */ |
| 365 | |
| 366 | METHODDEF void |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 367 | color_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf, |
| 368 | JSAMPARRAY output_buf, int num_rows) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 369 | /* General case, no dithering */ |
| 370 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 371 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
| 372 | JSAMPARRAY colorindex = cquantize->colorindex; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 373 | register int pixcode, ci; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 374 | register JSAMPROW ptrin, ptrout; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 375 | int row; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 376 | JDIMENSION col; |
| 377 | JDIMENSION width = cinfo->output_width; |
| 378 | register int nc = cinfo->out_color_components; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 379 | |
| 380 | for (row = 0; row < num_rows; row++) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 381 | ptrin = input_buf[row]; |
| 382 | ptrout = output_buf[row]; |
| 383 | for (col = width; col > 0; col--) { |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 384 | pixcode = 0; |
| 385 | for (ci = 0; ci < nc; ci++) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 386 | pixcode += GETJSAMPLE(colorindex[ci][GETJSAMPLE(*ptrin++)]); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 387 | } |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 388 | *ptrout++ = (JSAMPLE) pixcode; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 389 | } |
| 390 | } |
| 391 | } |
| 392 | |
| 393 | |
| 394 | METHODDEF void |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 395 | color_quantize3 (j_decompress_ptr cinfo, JSAMPARRAY input_buf, |
| 396 | JSAMPARRAY output_buf, int num_rows) |
| 397 | /* Fast path for out_color_components==3, no dithering */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 398 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 399 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 400 | register int pixcode; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 401 | register JSAMPROW ptrin, ptrout; |
| 402 | JSAMPROW colorindex0 = cquantize->colorindex[0]; |
| 403 | JSAMPROW colorindex1 = cquantize->colorindex[1]; |
| 404 | JSAMPROW colorindex2 = cquantize->colorindex[2]; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 405 | int row; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 406 | JDIMENSION col; |
| 407 | JDIMENSION width = cinfo->output_width; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 408 | |
| 409 | for (row = 0; row < num_rows; row++) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 410 | ptrin = input_buf[row]; |
| 411 | ptrout = output_buf[row]; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 412 | for (col = width; col > 0; col--) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 413 | pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*ptrin++)]); |
| 414 | pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*ptrin++)]); |
| 415 | pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*ptrin++)]); |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 416 | *ptrout++ = (JSAMPLE) pixcode; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 417 | } |
| 418 | } |
| 419 | } |
| 420 | |
| 421 | |
| 422 | METHODDEF void |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 423 | quantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, |
| 424 | JSAMPARRAY output_buf, int num_rows) |
| 425 | /* General case, with ordered dithering */ |
| 426 | { |
| 427 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
| 428 | register JSAMPROW input_ptr; |
| 429 | register JSAMPROW output_ptr; |
| 430 | JSAMPROW colorindex_ci; |
| 431 | int * dither; /* points to active row of dither matrix */ |
| 432 | int row_index, col_index; /* current indexes into dither matrix */ |
| 433 | int nc = cinfo->out_color_components; |
| 434 | int ci; |
| 435 | int row; |
| 436 | JDIMENSION col; |
| 437 | JDIMENSION width = cinfo->output_width; |
| 438 | |
| 439 | for (row = 0; row < num_rows; row++) { |
| 440 | /* Initialize output values to 0 so can process components separately */ |
| 441 | jzero_far((void FAR *) output_buf[row], |
| 442 | (size_t) (width * SIZEOF(JSAMPLE))); |
| 443 | row_index = cquantize->row_index; |
| 444 | for (ci = 0; ci < nc; ci++) { |
| 445 | input_ptr = input_buf[row] + ci; |
| 446 | output_ptr = output_buf[row]; |
| 447 | colorindex_ci = cquantize->colorindex[ci]; |
| 448 | dither = cquantize->odither[ci][row_index]; |
| 449 | col_index = 0; |
| 450 | |
| 451 | for (col = width; col > 0; col--) { |
| 452 | /* Form pixel value + dither, range-limit to 0..MAXJSAMPLE, |
| 453 | * select output value, accumulate into output code for this pixel. |
| 454 | * Range-limiting need not be done explicitly, as we have extended |
| 455 | * the colorindex table to produce the right answers for out-of-range |
| 456 | * inputs. The maximum dither is +- MAXJSAMPLE; this sets the |
| 457 | * required amount of padding. |
| 458 | */ |
| 459 | *output_ptr += colorindex_ci[GETJSAMPLE(*input_ptr)+dither[col_index]]; |
| 460 | input_ptr += nc; |
| 461 | output_ptr++; |
| 462 | col_index = (col_index + 1) & ODITHER_MASK; |
| 463 | } |
| 464 | } |
| 465 | /* Advance row index for next row */ |
| 466 | row_index = (row_index + 1) & ODITHER_MASK; |
| 467 | cquantize->row_index = row_index; |
| 468 | } |
| 469 | } |
| 470 | |
| 471 | |
| 472 | METHODDEF void |
| 473 | quantize3_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, |
| 474 | JSAMPARRAY output_buf, int num_rows) |
| 475 | /* Fast path for out_color_components==3, with ordered dithering */ |
| 476 | { |
| 477 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
| 478 | register int pixcode; |
| 479 | register JSAMPROW input_ptr; |
| 480 | register JSAMPROW output_ptr; |
| 481 | JSAMPROW colorindex0 = cquantize->colorindex[0]; |
| 482 | JSAMPROW colorindex1 = cquantize->colorindex[1]; |
| 483 | JSAMPROW colorindex2 = cquantize->colorindex[2]; |
| 484 | int * dither0; /* points to active row of dither matrix */ |
| 485 | int * dither1; |
| 486 | int * dither2; |
| 487 | int row_index, col_index; /* current indexes into dither matrix */ |
| 488 | int row; |
| 489 | JDIMENSION col; |
| 490 | JDIMENSION width = cinfo->output_width; |
| 491 | |
| 492 | for (row = 0; row < num_rows; row++) { |
| 493 | row_index = cquantize->row_index; |
| 494 | input_ptr = input_buf[row]; |
| 495 | output_ptr = output_buf[row]; |
| 496 | dither0 = cquantize->odither[0][row_index]; |
| 497 | dither1 = cquantize->odither[1][row_index]; |
| 498 | dither2 = cquantize->odither[2][row_index]; |
| 499 | col_index = 0; |
| 500 | |
| 501 | for (col = width; col > 0; col--) { |
| 502 | pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*input_ptr++) + |
| 503 | dither0[col_index]]); |
| 504 | pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*input_ptr++) + |
| 505 | dither1[col_index]]); |
| 506 | pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*input_ptr++) + |
| 507 | dither2[col_index]]); |
| 508 | *output_ptr++ = (JSAMPLE) pixcode; |
| 509 | col_index = (col_index + 1) & ODITHER_MASK; |
| 510 | } |
| 511 | row_index = (row_index + 1) & ODITHER_MASK; |
| 512 | cquantize->row_index = row_index; |
| 513 | } |
| 514 | } |
| 515 | |
| 516 | |
| 517 | METHODDEF void |
| 518 | quantize_fs_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, |
| 519 | JSAMPARRAY output_buf, int num_rows) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 520 | /* General case, with Floyd-Steinberg dithering */ |
| 521 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 522 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 523 | register LOCFSERROR cur; /* current error or pixel value */ |
| 524 | LOCFSERROR belowerr; /* error for pixel below cur */ |
| 525 | LOCFSERROR bpreverr; /* error for below/prev col */ |
| 526 | LOCFSERROR bnexterr; /* error for below/next col */ |
| 527 | LOCFSERROR delta; |
| 528 | register FSERRPTR errorptr; /* => fserrors[] at column before current */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 529 | register JSAMPROW input_ptr; |
| 530 | register JSAMPROW output_ptr; |
| 531 | JSAMPROW colorindex_ci; |
| 532 | JSAMPROW colormap_ci; |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 533 | int pixcode; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 534 | int nc = cinfo->out_color_components; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 535 | int dir; /* 1 for left-to-right, -1 for right-to-left */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 536 | int dirnc; /* dir * nc */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 537 | int ci; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 538 | int row; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 539 | JDIMENSION col; |
| 540 | JDIMENSION width = cinfo->output_width; |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 541 | JSAMPLE *range_limit = cinfo->sample_range_limit; |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 542 | SHIFT_TEMPS |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 543 | |
| 544 | for (row = 0; row < num_rows; row++) { |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 545 | /* Initialize output values to 0 so can process components separately */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 546 | jzero_far((void FAR *) output_buf[row], |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 547 | (size_t) (width * SIZEOF(JSAMPLE))); |
| 548 | for (ci = 0; ci < nc; ci++) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 549 | input_ptr = input_buf[row] + ci; |
| 550 | output_ptr = output_buf[row]; |
| 551 | if (cquantize->on_odd_row) { |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 552 | /* work right to left in this row */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 553 | input_ptr += (width-1) * nc; /* so point to rightmost pixel */ |
| 554 | output_ptr += width-1; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 555 | dir = -1; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 556 | dirnc = -nc; |
| 557 | errorptr = cquantize->fserrors[ci] + (width+1); /* => entry after last column */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 558 | } else { |
| 559 | /* work left to right in this row */ |
| 560 | dir = 1; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 561 | dirnc = nc; |
| 562 | errorptr = cquantize->fserrors[ci]; /* => entry before first column */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 563 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 564 | colorindex_ci = cquantize->colorindex[ci]; |
| 565 | colormap_ci = cinfo->colormap[ci]; |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 566 | /* Preset error values: no error propagated to first pixel from left */ |
| 567 | cur = 0; |
| 568 | /* and no error propagated to row below yet */ |
| 569 | belowerr = bpreverr = 0; |
| 570 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 571 | for (col = width; col > 0; col--) { |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 572 | /* cur holds the error propagated from the previous pixel on the |
| 573 | * current line. Add the error propagated from the previous line |
| 574 | * to form the complete error correction term for this pixel, and |
| 575 | * round the error term (which is expressed * 16) to an integer. |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 576 | * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct |
| 577 | * for either sign of the error value. |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 578 | * Note: errorptr points to *previous* column's array entry. |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 579 | */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 580 | cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4); |
| 581 | /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE. |
| 582 | * The maximum error is +- MAXJSAMPLE; this sets the required size |
| 583 | * of the range_limit array. |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 584 | */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 585 | cur += GETJSAMPLE(*input_ptr); |
| 586 | cur = GETJSAMPLE(range_limit[cur]); |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 587 | /* Select output value, accumulate into output code for this pixel */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 588 | pixcode = GETJSAMPLE(colorindex_ci[cur]); |
| 589 | *output_ptr += (JSAMPLE) pixcode; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 590 | /* Compute actual representation error at this pixel */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 591 | /* Note: we can do this even though we don't have the final */ |
| 592 | /* pixel code, because the colormap is orthogonal. */ |
| 593 | cur -= GETJSAMPLE(colormap_ci[pixcode]); |
| 594 | /* Compute error fractions to be propagated to adjacent pixels. |
| 595 | * Add these into the running sums, and simultaneously shift the |
| 596 | * next-line error sums left by 1 column. |
| 597 | */ |
| 598 | bnexterr = cur; |
| 599 | delta = cur * 2; |
| 600 | cur += delta; /* form error * 3 */ |
| 601 | errorptr[0] = (FSERROR) (bpreverr + cur); |
| 602 | cur += delta; /* form error * 5 */ |
| 603 | bpreverr = belowerr + cur; |
| 604 | belowerr = bnexterr; |
| 605 | cur += delta; /* form error * 7 */ |
| 606 | /* At this point cur contains the 7/16 error value to be propagated |
| 607 | * to the next pixel on the current line, and all the errors for the |
| 608 | * next line have been shifted over. We are therefore ready to move on. |
| 609 | */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 610 | input_ptr += dirnc; /* advance input ptr to next column */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 611 | output_ptr += dir; /* advance output ptr to next column */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 612 | errorptr += dir; /* advance errorptr to current column */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 613 | } |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 614 | /* Post-loop cleanup: we must unload the final error value into the |
| 615 | * final fserrors[] entry. Note we need not unload belowerr because |
| 616 | * it is for the dummy column before or after the actual array. |
| 617 | */ |
| 618 | errorptr[0] = (FSERROR) bpreverr; /* unload prev err into array */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 619 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 620 | cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 621 | } |
| 622 | } |
| 623 | |
| 624 | |
| 625 | /* |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 626 | * Initialize for one-pass color quantization. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 627 | */ |
| 628 | |
| 629 | METHODDEF void |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 630 | start_pass_1_quant (j_decompress_ptr cinfo, boolean is_pre_scan) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 631 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 632 | /* no work in 1-pass case */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 633 | } |
| 634 | |
| 635 | |
| 636 | /* |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 637 | * Finish up at the end of the pass. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 638 | */ |
| 639 | |
| 640 | METHODDEF void |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 641 | finish_pass_1_quant (j_decompress_ptr cinfo) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 642 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 643 | /* no work in 1-pass case */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 644 | } |
| 645 | |
| 646 | |
| 647 | /* |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 648 | * Module initialization routine for 1-pass color quantization. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 649 | */ |
| 650 | |
| 651 | GLOBAL void |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 652 | jinit_1pass_quantizer (j_decompress_ptr cinfo) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 653 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 654 | my_cquantize_ptr cquantize; |
| 655 | size_t arraysize; |
| 656 | int i; |
| 657 | |
| 658 | cquantize = (my_cquantize_ptr) |
| 659 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 660 | SIZEOF(my_cquantizer)); |
| 661 | cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize; |
| 662 | cquantize->pub.start_pass = start_pass_1_quant; |
| 663 | cquantize->pub.finish_pass = finish_pass_1_quant; |
| 664 | |
| 665 | /* Make sure my internal arrays won't overflow */ |
| 666 | if (cinfo->out_color_components > MAX_Q_COMPS) |
| 667 | ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS); |
| 668 | /* Make sure colormap indexes can be represented by JSAMPLEs */ |
| 669 | if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1)) |
| 670 | ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXJSAMPLE+1); |
| 671 | |
| 672 | /* Initialize for desired dithering mode. */ |
| 673 | switch (cinfo->dither_mode) { |
| 674 | case JDITHER_NONE: |
| 675 | if (cinfo->out_color_components == 3) |
| 676 | cquantize->pub.color_quantize = color_quantize3; |
| 677 | else |
| 678 | cquantize->pub.color_quantize = color_quantize; |
| 679 | break; |
| 680 | case JDITHER_ORDERED: |
| 681 | if (cinfo->out_color_components == 3) |
| 682 | cquantize->pub.color_quantize = quantize3_ord_dither; |
| 683 | else |
| 684 | cquantize->pub.color_quantize = quantize_ord_dither; |
| 685 | cquantize->row_index = 0; /* initialize state for ordered dither */ |
| 686 | break; |
| 687 | case JDITHER_FS: |
| 688 | cquantize->pub.color_quantize = quantize_fs_dither; |
| 689 | cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */ |
| 690 | /* Allocate Floyd-Steinberg workspace if necessary. */ |
| 691 | /* We do this now since it is FAR storage and may affect the memory */ |
| 692 | /* manager's space calculations. */ |
| 693 | arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR)); |
| 694 | for (i = 0; i < cinfo->out_color_components; i++) { |
| 695 | cquantize->fserrors[i] = (FSERRPTR) (*cinfo->mem->alloc_large) |
| 696 | ((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize); |
| 697 | /* Initialize the propagated errors to zero. */ |
| 698 | jzero_far((void FAR *) cquantize->fserrors[i], arraysize); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 699 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 700 | break; |
| 701 | default: |
| 702 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
| 703 | break; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 704 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame^] | 705 | |
| 706 | /* Create the colormap. */ |
| 707 | create_colormap(cinfo); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 708 | } |
| 709 | |
| 710 | #endif /* QUANT_1PASS_SUPPORTED */ |