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annotate libs/libjpeg/jquant1.c @ 17:aef7f51f6397

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author John Tsiombikas <nuclear@member.fsf.org>
date Wed, 10 Jun 2015 06:56:27 +0300
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nuclear@14 1 /*
nuclear@14 2 * jquant1.c
nuclear@14 3 *
nuclear@14 4 * Copyright (C) 1991-1996, Thomas G. Lane.
nuclear@14 5 * This file is part of the Independent JPEG Group's software.
nuclear@14 6 * For conditions of distribution and use, see the accompanying README file.
nuclear@14 7 *
nuclear@14 8 * This file contains 1-pass color quantization (color mapping) routines.
nuclear@14 9 * These routines provide mapping to a fixed color map using equally spaced
nuclear@14 10 * color values. Optional Floyd-Steinberg or ordered dithering is available.
nuclear@14 11 */
nuclear@14 12
nuclear@14 13 #define JPEG_INTERNALS
nuclear@14 14 #include "jinclude.h"
nuclear@14 15 #include "jpeglib.h"
nuclear@14 16
nuclear@14 17 #ifdef QUANT_1PASS_SUPPORTED
nuclear@14 18
nuclear@14 19
nuclear@14 20 /*
nuclear@14 21 * The main purpose of 1-pass quantization is to provide a fast, if not very
nuclear@14 22 * high quality, colormapped output capability. A 2-pass quantizer usually
nuclear@14 23 * gives better visual quality; however, for quantized grayscale output this
nuclear@14 24 * quantizer is perfectly adequate. Dithering is highly recommended with this
nuclear@14 25 * quantizer, though you can turn it off if you really want to.
nuclear@14 26 *
nuclear@14 27 * In 1-pass quantization the colormap must be chosen in advance of seeing the
nuclear@14 28 * image. We use a map consisting of all combinations of Ncolors[i] color
nuclear@14 29 * values for the i'th component. The Ncolors[] values are chosen so that
nuclear@14 30 * their product, the total number of colors, is no more than that requested.
nuclear@14 31 * (In most cases, the product will be somewhat less.)
nuclear@14 32 *
nuclear@14 33 * Since the colormap is orthogonal, the representative value for each color
nuclear@14 34 * component can be determined without considering the other components;
nuclear@14 35 * then these indexes can be combined into a colormap index by a standard
nuclear@14 36 * N-dimensional-array-subscript calculation. Most of the arithmetic involved
nuclear@14 37 * can be precalculated and stored in the lookup table colorindex[].
nuclear@14 38 * colorindex[i][j] maps pixel value j in component i to the nearest
nuclear@14 39 * representative value (grid plane) for that component; this index is
nuclear@14 40 * multiplied by the array stride for component i, so that the
nuclear@14 41 * index of the colormap entry closest to a given pixel value is just
nuclear@14 42 * sum( colorindex[component-number][pixel-component-value] )
nuclear@14 43 * Aside from being fast, this scheme allows for variable spacing between
nuclear@14 44 * representative values with no additional lookup cost.
nuclear@14 45 *
nuclear@14 46 * If gamma correction has been applied in color conversion, it might be wise
nuclear@14 47 * to adjust the color grid spacing so that the representative colors are
nuclear@14 48 * equidistant in linear space. At this writing, gamma correction is not
nuclear@14 49 * implemented by jdcolor, so nothing is done here.
nuclear@14 50 */
nuclear@14 51
nuclear@14 52
nuclear@14 53 /* Declarations for ordered dithering.
nuclear@14 54 *
nuclear@14 55 * We use a standard 16x16 ordered dither array. The basic concept of ordered
nuclear@14 56 * dithering is described in many references, for instance Dale Schumacher's
nuclear@14 57 * chapter II.2 of Graphics Gems II (James Arvo, ed. Academic Press, 1991).
nuclear@14 58 * In place of Schumacher's comparisons against a "threshold" value, we add a
nuclear@14 59 * "dither" value to the input pixel and then round the result to the nearest
nuclear@14 60 * output value. The dither value is equivalent to (0.5 - threshold) times
nuclear@14 61 * the distance between output values. For ordered dithering, we assume that
nuclear@14 62 * the output colors are equally spaced; if not, results will probably be
nuclear@14 63 * worse, since the dither may be too much or too little at a given point.
nuclear@14 64 *
nuclear@14 65 * The normal calculation would be to form pixel value + dither, range-limit
nuclear@14 66 * this to 0..MAXJSAMPLE, and then index into the colorindex table as usual.
nuclear@14 67 * We can skip the separate range-limiting step by extending the colorindex
nuclear@14 68 * table in both directions.
nuclear@14 69 */
nuclear@14 70
nuclear@14 71 #define ODITHER_SIZE 16 /* dimension of dither matrix */
nuclear@14 72 /* NB: if ODITHER_SIZE is not a power of 2, ODITHER_MASK uses will break */
nuclear@14 73 #define ODITHER_CELLS (ODITHER_SIZE*ODITHER_SIZE) /* # cells in matrix */
nuclear@14 74 #define ODITHER_MASK (ODITHER_SIZE-1) /* mask for wrapping around counters */
nuclear@14 75
nuclear@14 76 typedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE];
nuclear@14 77 typedef int (*ODITHER_MATRIX_PTR)[ODITHER_SIZE];
nuclear@14 78
nuclear@14 79 static const UINT8 base_dither_matrix[ODITHER_SIZE][ODITHER_SIZE] = {
nuclear@14 80 /* Bayer's order-4 dither array. Generated by the code given in
nuclear@14 81 * Stephen Hawley's article "Ordered Dithering" in Graphics Gems I.
nuclear@14 82 * The values in this array must range from 0 to ODITHER_CELLS-1.
nuclear@14 83 */
nuclear@14 84 { 0,192, 48,240, 12,204, 60,252, 3,195, 51,243, 15,207, 63,255 },
nuclear@14 85 { 128, 64,176,112,140, 76,188,124,131, 67,179,115,143, 79,191,127 },
nuclear@14 86 { 32,224, 16,208, 44,236, 28,220, 35,227, 19,211, 47,239, 31,223 },
nuclear@14 87 { 160, 96,144, 80,172,108,156, 92,163, 99,147, 83,175,111,159, 95 },
nuclear@14 88 { 8,200, 56,248, 4,196, 52,244, 11,203, 59,251, 7,199, 55,247 },
nuclear@14 89 { 136, 72,184,120,132, 68,180,116,139, 75,187,123,135, 71,183,119 },
nuclear@14 90 { 40,232, 24,216, 36,228, 20,212, 43,235, 27,219, 39,231, 23,215 },
nuclear@14 91 { 168,104,152, 88,164,100,148, 84,171,107,155, 91,167,103,151, 87 },
nuclear@14 92 { 2,194, 50,242, 14,206, 62,254, 1,193, 49,241, 13,205, 61,253 },
nuclear@14 93 { 130, 66,178,114,142, 78,190,126,129, 65,177,113,141, 77,189,125 },
nuclear@14 94 { 34,226, 18,210, 46,238, 30,222, 33,225, 17,209, 45,237, 29,221 },
nuclear@14 95 { 162, 98,146, 82,174,110,158, 94,161, 97,145, 81,173,109,157, 93 },
nuclear@14 96 { 10,202, 58,250, 6,198, 54,246, 9,201, 57,249, 5,197, 53,245 },
nuclear@14 97 { 138, 74,186,122,134, 70,182,118,137, 73,185,121,133, 69,181,117 },
nuclear@14 98 { 42,234, 26,218, 38,230, 22,214, 41,233, 25,217, 37,229, 21,213 },
nuclear@14 99 { 170,106,154, 90,166,102,150, 86,169,105,153, 89,165,101,149, 85 }
nuclear@14 100 };
nuclear@14 101
nuclear@14 102
nuclear@14 103 /* Declarations for Floyd-Steinberg dithering.
nuclear@14 104 *
nuclear@14 105 * Errors are accumulated into the array fserrors[], at a resolution of
nuclear@14 106 * 1/16th of a pixel count. The error at a given pixel is propagated
nuclear@14 107 * to its not-yet-processed neighbors using the standard F-S fractions,
nuclear@14 108 * ... (here) 7/16
nuclear@14 109 * 3/16 5/16 1/16
nuclear@14 110 * We work left-to-right on even rows, right-to-left on odd rows.
nuclear@14 111 *
nuclear@14 112 * We can get away with a single array (holding one row's worth of errors)
nuclear@14 113 * by using it to store the current row's errors at pixel columns not yet
nuclear@14 114 * processed, but the next row's errors at columns already processed. We
nuclear@14 115 * need only a few extra variables to hold the errors immediately around the
nuclear@14 116 * current column. (If we are lucky, those variables are in registers, but
nuclear@14 117 * even if not, they're probably cheaper to access than array elements are.)
nuclear@14 118 *
nuclear@14 119 * The fserrors[] array is indexed [component#][position].
nuclear@14 120 * We provide (#columns + 2) entries per component; the extra entry at each
nuclear@14 121 * end saves us from special-casing the first and last pixels.
nuclear@14 122 *
nuclear@14 123 * Note: on a wide image, we might not have enough room in a PC's near data
nuclear@14 124 * segment to hold the error array; so it is allocated with alloc_large.
nuclear@14 125 */
nuclear@14 126
nuclear@14 127 #if BITS_IN_JSAMPLE == 8
nuclear@14 128 typedef INT16 FSERROR; /* 16 bits should be enough */
nuclear@14 129 typedef int LOCFSERROR; /* use 'int' for calculation temps */
nuclear@14 130 #else
nuclear@14 131 typedef INT32 FSERROR; /* may need more than 16 bits */
nuclear@14 132 typedef INT32 LOCFSERROR; /* be sure calculation temps are big enough */
nuclear@14 133 #endif
nuclear@14 134
nuclear@14 135 typedef FSERROR FAR *FSERRPTR; /* pointer to error array (in FAR storage!) */
nuclear@14 136
nuclear@14 137
nuclear@14 138 /* Private subobject */
nuclear@14 139
nuclear@14 140 #define MAX_Q_COMPS 4 /* max components I can handle */
nuclear@14 141
nuclear@14 142 typedef struct {
nuclear@14 143 struct jpeg_color_quantizer pub; /* public fields */
nuclear@14 144
nuclear@14 145 /* Initially allocated colormap is saved here */
nuclear@14 146 JSAMPARRAY sv_colormap; /* The color map as a 2-D pixel array */
nuclear@14 147 int sv_actual; /* number of entries in use */
nuclear@14 148
nuclear@14 149 JSAMPARRAY colorindex; /* Precomputed mapping for speed */
nuclear@14 150 /* colorindex[i][j] = index of color closest to pixel value j in component i,
nuclear@14 151 * premultiplied as described above. Since colormap indexes must fit into
nuclear@14 152 * JSAMPLEs, the entries of this array will too.
nuclear@14 153 */
nuclear@14 154 boolean is_padded; /* is the colorindex padded for odither? */
nuclear@14 155
nuclear@14 156 int Ncolors[MAX_Q_COMPS]; /* # of values alloced to each component */
nuclear@14 157
nuclear@14 158 /* Variables for ordered dithering */
nuclear@14 159 int row_index; /* cur row's vertical index in dither matrix */
nuclear@14 160 ODITHER_MATRIX_PTR odither[MAX_Q_COMPS]; /* one dither array per component */
nuclear@14 161
nuclear@14 162 /* Variables for Floyd-Steinberg dithering */
nuclear@14 163 FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */
nuclear@14 164 boolean on_odd_row; /* flag to remember which row we are on */
nuclear@14 165 } my_cquantizer;
nuclear@14 166
nuclear@14 167 typedef my_cquantizer * my_cquantize_ptr;
nuclear@14 168
nuclear@14 169
nuclear@14 170 /*
nuclear@14 171 * Policy-making subroutines for create_colormap and create_colorindex.
nuclear@14 172 * These routines determine the colormap to be used. The rest of the module
nuclear@14 173 * only assumes that the colormap is orthogonal.
nuclear@14 174 *
nuclear@14 175 * * select_ncolors decides how to divvy up the available colors
nuclear@14 176 * among the components.
nuclear@14 177 * * output_value defines the set of representative values for a component.
nuclear@14 178 * * largest_input_value defines the mapping from input values to
nuclear@14 179 * representative values for a component.
nuclear@14 180 * Note that the latter two routines may impose different policies for
nuclear@14 181 * different components, though this is not currently done.
nuclear@14 182 */
nuclear@14 183
nuclear@14 184
nuclear@14 185 LOCAL(int)
nuclear@14 186 select_ncolors (j_decompress_ptr cinfo, int Ncolors[])
nuclear@14 187 /* Determine allocation of desired colors to components, */
nuclear@14 188 /* and fill in Ncolors[] array to indicate choice. */
nuclear@14 189 /* Return value is total number of colors (product of Ncolors[] values). */
nuclear@14 190 {
nuclear@14 191 int nc = cinfo->out_color_components; /* number of color components */
nuclear@14 192 int max_colors = cinfo->desired_number_of_colors;
nuclear@14 193 int total_colors, iroot, i, j;
nuclear@14 194 boolean changed;
nuclear@14 195 long temp;
nuclear@14 196 static const int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE };
nuclear@14 197
nuclear@14 198 /* We can allocate at least the nc'th root of max_colors per component. */
nuclear@14 199 /* Compute floor(nc'th root of max_colors). */
nuclear@14 200 iroot = 1;
nuclear@14 201 do {
nuclear@14 202 iroot++;
nuclear@14 203 temp = iroot; /* set temp = iroot ** nc */
nuclear@14 204 for (i = 1; i < nc; i++)
nuclear@14 205 temp *= iroot;
nuclear@14 206 } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */
nuclear@14 207 iroot--; /* now iroot = floor(root) */
nuclear@14 208
nuclear@14 209 /* Must have at least 2 color values per component */
nuclear@14 210 if (iroot < 2)
nuclear@14 211 ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int) temp);
nuclear@14 212
nuclear@14 213 /* Initialize to iroot color values for each component */
nuclear@14 214 total_colors = 1;
nuclear@14 215 for (i = 0; i < nc; i++) {
nuclear@14 216 Ncolors[i] = iroot;
nuclear@14 217 total_colors *= iroot;
nuclear@14 218 }
nuclear@14 219 /* We may be able to increment the count for one or more components without
nuclear@14 220 * exceeding max_colors, though we know not all can be incremented.
nuclear@14 221 * Sometimes, the first component can be incremented more than once!
nuclear@14 222 * (Example: for 16 colors, we start at 2*2*2, go to 3*2*2, then 4*2*2.)
nuclear@14 223 * In RGB colorspace, try to increment G first, then R, then B.
nuclear@14 224 */
nuclear@14 225 do {
nuclear@14 226 changed = FALSE;
nuclear@14 227 for (i = 0; i < nc; i++) {
nuclear@14 228 j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i);
nuclear@14 229 /* calculate new total_colors if Ncolors[j] is incremented */
nuclear@14 230 temp = total_colors / Ncolors[j];
nuclear@14 231 temp *= Ncolors[j]+1; /* done in long arith to avoid oflo */
nuclear@14 232 if (temp > (long) max_colors)
nuclear@14 233 break; /* won't fit, done with this pass */
nuclear@14 234 Ncolors[j]++; /* OK, apply the increment */
nuclear@14 235 total_colors = (int) temp;
nuclear@14 236 changed = TRUE;
nuclear@14 237 }
nuclear@14 238 } while (changed);
nuclear@14 239
nuclear@14 240 return total_colors;
nuclear@14 241 }
nuclear@14 242
nuclear@14 243
nuclear@14 244 LOCAL(int)
nuclear@14 245 output_value (j_decompress_ptr cinfo, int ci, int j, int maxj)
nuclear@14 246 /* Return j'th output value, where j will range from 0 to maxj */
nuclear@14 247 /* The output values must fall in 0..MAXJSAMPLE in increasing order */
nuclear@14 248 {
nuclear@14 249 /* We always provide values 0 and MAXJSAMPLE for each component;
nuclear@14 250 * any additional values are equally spaced between these limits.
nuclear@14 251 * (Forcing the upper and lower values to the limits ensures that
nuclear@14 252 * dithering can't produce a color outside the selected gamut.)
nuclear@14 253 */
nuclear@14 254 return (int) (((INT32) j * MAXJSAMPLE + maxj/2) / maxj);
nuclear@14 255 }
nuclear@14 256
nuclear@14 257
nuclear@14 258 LOCAL(int)
nuclear@14 259 largest_input_value (j_decompress_ptr cinfo, int ci, int j, int maxj)
nuclear@14 260 /* Return largest input value that should map to j'th output value */
nuclear@14 261 /* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */
nuclear@14 262 {
nuclear@14 263 /* Breakpoints are halfway between values returned by output_value */
nuclear@14 264 return (int) (((INT32) (2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj));
nuclear@14 265 }
nuclear@14 266
nuclear@14 267
nuclear@14 268 /*
nuclear@14 269 * Create the colormap.
nuclear@14 270 */
nuclear@14 271
nuclear@14 272 LOCAL(void)
nuclear@14 273 create_colormap (j_decompress_ptr cinfo)
nuclear@14 274 {
nuclear@14 275 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@14 276 JSAMPARRAY colormap; /* Created colormap */
nuclear@14 277 int total_colors; /* Number of distinct output colors */
nuclear@14 278 int i,j,k, nci, blksize, blkdist, ptr, val;
nuclear@14 279
nuclear@14 280 /* Select number of colors for each component */
nuclear@14 281 total_colors = select_ncolors(cinfo, cquantize->Ncolors);
nuclear@14 282
nuclear@14 283 /* Report selected color counts */
nuclear@14 284 if (cinfo->out_color_components == 3)
nuclear@14 285 TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS,
nuclear@14 286 total_colors, cquantize->Ncolors[0],
nuclear@14 287 cquantize->Ncolors[1], cquantize->Ncolors[2]);
nuclear@14 288 else
nuclear@14 289 TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors);
nuclear@14 290
nuclear@14 291 /* Allocate and fill in the colormap. */
nuclear@14 292 /* The colors are ordered in the map in standard row-major order, */
nuclear@14 293 /* i.e. rightmost (highest-indexed) color changes most rapidly. */
nuclear@14 294
nuclear@14 295 colormap = (*cinfo->mem->alloc_sarray)
nuclear@14 296 ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@14 297 (JDIMENSION) total_colors, (JDIMENSION) cinfo->out_color_components);
nuclear@14 298
nuclear@14 299 /* blksize is number of adjacent repeated entries for a component */
nuclear@14 300 /* blkdist is distance between groups of identical entries for a component */
nuclear@14 301 blkdist = total_colors;
nuclear@14 302
nuclear@14 303 for (i = 0; i < cinfo->out_color_components; i++) {
nuclear@14 304 /* fill in colormap entries for i'th color component */
nuclear@14 305 nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
nuclear@14 306 blksize = blkdist / nci;
nuclear@14 307 for (j = 0; j < nci; j++) {
nuclear@14 308 /* Compute j'th output value (out of nci) for component */
nuclear@14 309 val = output_value(cinfo, i, j, nci-1);
nuclear@14 310 /* Fill in all colormap entries that have this value of this component */
nuclear@14 311 for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) {
nuclear@14 312 /* fill in blksize entries beginning at ptr */
nuclear@14 313 for (k = 0; k < blksize; k++)
nuclear@14 314 colormap[i][ptr+k] = (JSAMPLE) val;
nuclear@14 315 }
nuclear@14 316 }
nuclear@14 317 blkdist = blksize; /* blksize of this color is blkdist of next */
nuclear@14 318 }
nuclear@14 319
nuclear@14 320 /* Save the colormap in private storage,
nuclear@14 321 * where it will survive color quantization mode changes.
nuclear@14 322 */
nuclear@14 323 cquantize->sv_colormap = colormap;
nuclear@14 324 cquantize->sv_actual = total_colors;
nuclear@14 325 }
nuclear@14 326
nuclear@14 327
nuclear@14 328 /*
nuclear@14 329 * Create the color index table.
nuclear@14 330 */
nuclear@14 331
nuclear@14 332 LOCAL(void)
nuclear@14 333 create_colorindex (j_decompress_ptr cinfo)
nuclear@14 334 {
nuclear@14 335 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@14 336 JSAMPROW indexptr;
nuclear@14 337 int i,j,k, nci, blksize, val, pad;
nuclear@14 338
nuclear@14 339 /* For ordered dither, we pad the color index tables by MAXJSAMPLE in
nuclear@14 340 * each direction (input index values can be -MAXJSAMPLE .. 2*MAXJSAMPLE).
nuclear@14 341 * This is not necessary in the other dithering modes. However, we
nuclear@14 342 * flag whether it was done in case user changes dithering mode.
nuclear@14 343 */
nuclear@14 344 if (cinfo->dither_mode == JDITHER_ORDERED) {
nuclear@14 345 pad = MAXJSAMPLE*2;
nuclear@14 346 cquantize->is_padded = TRUE;
nuclear@14 347 } else {
nuclear@14 348 pad = 0;
nuclear@14 349 cquantize->is_padded = FALSE;
nuclear@14 350 }
nuclear@14 351
nuclear@14 352 cquantize->colorindex = (*cinfo->mem->alloc_sarray)
nuclear@14 353 ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@14 354 (JDIMENSION) (MAXJSAMPLE+1 + pad),
nuclear@14 355 (JDIMENSION) cinfo->out_color_components);
nuclear@14 356
nuclear@14 357 /* blksize is number of adjacent repeated entries for a component */
nuclear@14 358 blksize = cquantize->sv_actual;
nuclear@14 359
nuclear@14 360 for (i = 0; i < cinfo->out_color_components; i++) {
nuclear@14 361 /* fill in colorindex entries for i'th color component */
nuclear@14 362 nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
nuclear@14 363 blksize = blksize / nci;
nuclear@14 364
nuclear@14 365 /* adjust colorindex pointers to provide padding at negative indexes. */
nuclear@14 366 if (pad)
nuclear@14 367 cquantize->colorindex[i] += MAXJSAMPLE;
nuclear@14 368
nuclear@14 369 /* in loop, val = index of current output value, */
nuclear@14 370 /* and k = largest j that maps to current val */
nuclear@14 371 indexptr = cquantize->colorindex[i];
nuclear@14 372 val = 0;
nuclear@14 373 k = largest_input_value(cinfo, i, 0, nci-1);
nuclear@14 374 for (j = 0; j <= MAXJSAMPLE; j++) {
nuclear@14 375 while (j > k) /* advance val if past boundary */
nuclear@14 376 k = largest_input_value(cinfo, i, ++val, nci-1);
nuclear@14 377 /* premultiply so that no multiplication needed in main processing */
nuclear@14 378 indexptr[j] = (JSAMPLE) (val * blksize);
nuclear@14 379 }
nuclear@14 380 /* Pad at both ends if necessary */
nuclear@14 381 if (pad)
nuclear@14 382 for (j = 1; j <= MAXJSAMPLE; j++) {
nuclear@14 383 indexptr[-j] = indexptr[0];
nuclear@14 384 indexptr[MAXJSAMPLE+j] = indexptr[MAXJSAMPLE];
nuclear@14 385 }
nuclear@14 386 }
nuclear@14 387 }
nuclear@14 388
nuclear@14 389
nuclear@14 390 /*
nuclear@14 391 * Create an ordered-dither array for a component having ncolors
nuclear@14 392 * distinct output values.
nuclear@14 393 */
nuclear@14 394
nuclear@14 395 LOCAL(ODITHER_MATRIX_PTR)
nuclear@14 396 make_odither_array (j_decompress_ptr cinfo, int ncolors)
nuclear@14 397 {
nuclear@14 398 ODITHER_MATRIX_PTR odither;
nuclear@14 399 int j,k;
nuclear@14 400 INT32 num,den;
nuclear@14 401
nuclear@14 402 odither = (ODITHER_MATRIX_PTR)
nuclear@14 403 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@14 404 SIZEOF(ODITHER_MATRIX));
nuclear@14 405 /* The inter-value distance for this color is MAXJSAMPLE/(ncolors-1).
nuclear@14 406 * Hence the dither value for the matrix cell with fill order f
nuclear@14 407 * (f=0..N-1) should be (N-1-2*f)/(2*N) * MAXJSAMPLE/(ncolors-1).
nuclear@14 408 * On 16-bit-int machine, be careful to avoid overflow.
nuclear@14 409 */
nuclear@14 410 den = 2 * ODITHER_CELLS * ((INT32) (ncolors - 1));
nuclear@14 411 for (j = 0; j < ODITHER_SIZE; j++) {
nuclear@14 412 for (k = 0; k < ODITHER_SIZE; k++) {
nuclear@14 413 num = ((INT32) (ODITHER_CELLS-1 - 2*((int)base_dither_matrix[j][k])))
nuclear@14 414 * MAXJSAMPLE;
nuclear@14 415 /* Ensure round towards zero despite C's lack of consistency
nuclear@14 416 * about rounding negative values in integer division...
nuclear@14 417 */
nuclear@14 418 odither[j][k] = (int) (num<0 ? -((-num)/den) : num/den);
nuclear@14 419 }
nuclear@14 420 }
nuclear@14 421 return odither;
nuclear@14 422 }
nuclear@14 423
nuclear@14 424
nuclear@14 425 /*
nuclear@14 426 * Create the ordered-dither tables.
nuclear@14 427 * Components having the same number of representative colors may
nuclear@14 428 * share a dither table.
nuclear@14 429 */
nuclear@14 430
nuclear@14 431 LOCAL(void)
nuclear@14 432 create_odither_tables (j_decompress_ptr cinfo)
nuclear@14 433 {
nuclear@14 434 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@14 435 ODITHER_MATRIX_PTR odither;
nuclear@14 436 int i, j, nci;
nuclear@14 437
nuclear@14 438 for (i = 0; i < cinfo->out_color_components; i++) {
nuclear@14 439 nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
nuclear@14 440 odither = NULL; /* search for matching prior component */
nuclear@14 441 for (j = 0; j < i; j++) {
nuclear@14 442 if (nci == cquantize->Ncolors[j]) {
nuclear@14 443 odither = cquantize->odither[j];
nuclear@14 444 break;
nuclear@14 445 }
nuclear@14 446 }
nuclear@14 447 if (odither == NULL) /* need a new table? */
nuclear@14 448 odither = make_odither_array(cinfo, nci);
nuclear@14 449 cquantize->odither[i] = odither;
nuclear@14 450 }
nuclear@14 451 }
nuclear@14 452
nuclear@14 453
nuclear@14 454 /*
nuclear@14 455 * Map some rows of pixels to the output colormapped representation.
nuclear@14 456 */
nuclear@14 457
nuclear@14 458 METHODDEF(void)
nuclear@14 459 color_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@14 460 JSAMPARRAY output_buf, int num_rows)
nuclear@14 461 /* General case, no dithering */
nuclear@14 462 {
nuclear@14 463 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@14 464 JSAMPARRAY colorindex = cquantize->colorindex;
nuclear@14 465 register int pixcode, ci;
nuclear@14 466 register JSAMPROW ptrin, ptrout;
nuclear@14 467 int row;
nuclear@14 468 JDIMENSION col;
nuclear@14 469 JDIMENSION width = cinfo->output_width;
nuclear@14 470 register int nc = cinfo->out_color_components;
nuclear@14 471
nuclear@14 472 for (row = 0; row < num_rows; row++) {
nuclear@14 473 ptrin = input_buf[row];
nuclear@14 474 ptrout = output_buf[row];
nuclear@14 475 for (col = width; col > 0; col--) {
nuclear@14 476 pixcode = 0;
nuclear@14 477 for (ci = 0; ci < nc; ci++) {
nuclear@14 478 pixcode += GETJSAMPLE(colorindex[ci][GETJSAMPLE(*ptrin++)]);
nuclear@14 479 }
nuclear@14 480 *ptrout++ = (JSAMPLE) pixcode;
nuclear@14 481 }
nuclear@14 482 }
nuclear@14 483 }
nuclear@14 484
nuclear@14 485
nuclear@14 486 METHODDEF(void)
nuclear@14 487 color_quantize3 (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@14 488 JSAMPARRAY output_buf, int num_rows)
nuclear@14 489 /* Fast path for out_color_components==3, no dithering */
nuclear@14 490 {
nuclear@14 491 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@14 492 register int pixcode;
nuclear@14 493 register JSAMPROW ptrin, ptrout;
nuclear@14 494 JSAMPROW colorindex0 = cquantize->colorindex[0];
nuclear@14 495 JSAMPROW colorindex1 = cquantize->colorindex[1];
nuclear@14 496 JSAMPROW colorindex2 = cquantize->colorindex[2];
nuclear@14 497 int row;
nuclear@14 498 JDIMENSION col;
nuclear@14 499 JDIMENSION width = cinfo->output_width;
nuclear@14 500
nuclear@14 501 for (row = 0; row < num_rows; row++) {
nuclear@14 502 ptrin = input_buf[row];
nuclear@14 503 ptrout = output_buf[row];
nuclear@14 504 for (col = width; col > 0; col--) {
nuclear@14 505 pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*ptrin++)]);
nuclear@14 506 pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*ptrin++)]);
nuclear@14 507 pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*ptrin++)]);
nuclear@14 508 *ptrout++ = (JSAMPLE) pixcode;
nuclear@14 509 }
nuclear@14 510 }
nuclear@14 511 }
nuclear@14 512
nuclear@14 513
nuclear@14 514 METHODDEF(void)
nuclear@14 515 quantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@14 516 JSAMPARRAY output_buf, int num_rows)
nuclear@14 517 /* General case, with ordered dithering */
nuclear@14 518 {
nuclear@14 519 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@14 520 register JSAMPROW input_ptr;
nuclear@14 521 register JSAMPROW output_ptr;
nuclear@14 522 JSAMPROW colorindex_ci;
nuclear@14 523 int * dither; /* points to active row of dither matrix */
nuclear@14 524 int row_index, col_index; /* current indexes into dither matrix */
nuclear@14 525 int nc = cinfo->out_color_components;
nuclear@14 526 int ci;
nuclear@14 527 int row;
nuclear@14 528 JDIMENSION col;
nuclear@14 529 JDIMENSION width = cinfo->output_width;
nuclear@14 530
nuclear@14 531 for (row = 0; row < num_rows; row++) {
nuclear@14 532 /* Initialize output values to 0 so can process components separately */
nuclear@14 533 jzero_far((void FAR *) output_buf[row],
nuclear@14 534 (size_t) (width * SIZEOF(JSAMPLE)));
nuclear@14 535 row_index = cquantize->row_index;
nuclear@14 536 for (ci = 0; ci < nc; ci++) {
nuclear@14 537 input_ptr = input_buf[row] + ci;
nuclear@14 538 output_ptr = output_buf[row];
nuclear@14 539 colorindex_ci = cquantize->colorindex[ci];
nuclear@14 540 dither = cquantize->odither[ci][row_index];
nuclear@14 541 col_index = 0;
nuclear@14 542
nuclear@14 543 for (col = width; col > 0; col--) {
nuclear@14 544 /* Form pixel value + dither, range-limit to 0..MAXJSAMPLE,
nuclear@14 545 * select output value, accumulate into output code for this pixel.
nuclear@14 546 * Range-limiting need not be done explicitly, as we have extended
nuclear@14 547 * the colorindex table to produce the right answers for out-of-range
nuclear@14 548 * inputs. The maximum dither is +- MAXJSAMPLE; this sets the
nuclear@14 549 * required amount of padding.
nuclear@14 550 */
nuclear@14 551 *output_ptr += colorindex_ci[GETJSAMPLE(*input_ptr)+dither[col_index]];
nuclear@14 552 input_ptr += nc;
nuclear@14 553 output_ptr++;
nuclear@14 554 col_index = (col_index + 1) & ODITHER_MASK;
nuclear@14 555 }
nuclear@14 556 }
nuclear@14 557 /* Advance row index for next row */
nuclear@14 558 row_index = (row_index + 1) & ODITHER_MASK;
nuclear@14 559 cquantize->row_index = row_index;
nuclear@14 560 }
nuclear@14 561 }
nuclear@14 562
nuclear@14 563
nuclear@14 564 METHODDEF(void)
nuclear@14 565 quantize3_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@14 566 JSAMPARRAY output_buf, int num_rows)
nuclear@14 567 /* Fast path for out_color_components==3, with ordered dithering */
nuclear@14 568 {
nuclear@14 569 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@14 570 register int pixcode;
nuclear@14 571 register JSAMPROW input_ptr;
nuclear@14 572 register JSAMPROW output_ptr;
nuclear@14 573 JSAMPROW colorindex0 = cquantize->colorindex[0];
nuclear@14 574 JSAMPROW colorindex1 = cquantize->colorindex[1];
nuclear@14 575 JSAMPROW colorindex2 = cquantize->colorindex[2];
nuclear@14 576 int * dither0; /* points to active row of dither matrix */
nuclear@14 577 int * dither1;
nuclear@14 578 int * dither2;
nuclear@14 579 int row_index, col_index; /* current indexes into dither matrix */
nuclear@14 580 int row;
nuclear@14 581 JDIMENSION col;
nuclear@14 582 JDIMENSION width = cinfo->output_width;
nuclear@14 583
nuclear@14 584 for (row = 0; row < num_rows; row++) {
nuclear@14 585 row_index = cquantize->row_index;
nuclear@14 586 input_ptr = input_buf[row];
nuclear@14 587 output_ptr = output_buf[row];
nuclear@14 588 dither0 = cquantize->odither[0][row_index];
nuclear@14 589 dither1 = cquantize->odither[1][row_index];
nuclear@14 590 dither2 = cquantize->odither[2][row_index];
nuclear@14 591 col_index = 0;
nuclear@14 592
nuclear@14 593 for (col = width; col > 0; col--) {
nuclear@14 594 pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*input_ptr++) +
nuclear@14 595 dither0[col_index]]);
nuclear@14 596 pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*input_ptr++) +
nuclear@14 597 dither1[col_index]]);
nuclear@14 598 pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*input_ptr++) +
nuclear@14 599 dither2[col_index]]);
nuclear@14 600 *output_ptr++ = (JSAMPLE) pixcode;
nuclear@14 601 col_index = (col_index + 1) & ODITHER_MASK;
nuclear@14 602 }
nuclear@14 603 row_index = (row_index + 1) & ODITHER_MASK;
nuclear@14 604 cquantize->row_index = row_index;
nuclear@14 605 }
nuclear@14 606 }
nuclear@14 607
nuclear@14 608
nuclear@14 609 METHODDEF(void)
nuclear@14 610 quantize_fs_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@14 611 JSAMPARRAY output_buf, int num_rows)
nuclear@14 612 /* General case, with Floyd-Steinberg dithering */
nuclear@14 613 {
nuclear@14 614 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@14 615 register LOCFSERROR cur; /* current error or pixel value */
nuclear@14 616 LOCFSERROR belowerr; /* error for pixel below cur */
nuclear@14 617 LOCFSERROR bpreverr; /* error for below/prev col */
nuclear@14 618 LOCFSERROR bnexterr; /* error for below/next col */
nuclear@14 619 LOCFSERROR delta;
nuclear@14 620 register FSERRPTR errorptr; /* => fserrors[] at column before current */
nuclear@14 621 register JSAMPROW input_ptr;
nuclear@14 622 register JSAMPROW output_ptr;
nuclear@14 623 JSAMPROW colorindex_ci;
nuclear@14 624 JSAMPROW colormap_ci;
nuclear@14 625 int pixcode;
nuclear@14 626 int nc = cinfo->out_color_components;
nuclear@14 627 int dir; /* 1 for left-to-right, -1 for right-to-left */
nuclear@14 628 int dirnc; /* dir * nc */
nuclear@14 629 int ci;
nuclear@14 630 int row;
nuclear@14 631 JDIMENSION col;
nuclear@14 632 JDIMENSION width = cinfo->output_width;
nuclear@14 633 JSAMPLE *range_limit = cinfo->sample_range_limit;
nuclear@14 634 SHIFT_TEMPS
nuclear@14 635
nuclear@14 636 for (row = 0; row < num_rows; row++) {
nuclear@14 637 /* Initialize output values to 0 so can process components separately */
nuclear@14 638 jzero_far((void FAR *) output_buf[row],
nuclear@14 639 (size_t) (width * SIZEOF(JSAMPLE)));
nuclear@14 640 for (ci = 0; ci < nc; ci++) {
nuclear@14 641 input_ptr = input_buf[row] + ci;
nuclear@14 642 output_ptr = output_buf[row];
nuclear@14 643 if (cquantize->on_odd_row) {
nuclear@14 644 /* work right to left in this row */
nuclear@14 645 input_ptr += (width-1) * nc; /* so point to rightmost pixel */
nuclear@14 646 output_ptr += width-1;
nuclear@14 647 dir = -1;
nuclear@14 648 dirnc = -nc;
nuclear@14 649 errorptr = cquantize->fserrors[ci] + (width+1); /* => entry after last column */
nuclear@14 650 } else {
nuclear@14 651 /* work left to right in this row */
nuclear@14 652 dir = 1;
nuclear@14 653 dirnc = nc;
nuclear@14 654 errorptr = cquantize->fserrors[ci]; /* => entry before first column */
nuclear@14 655 }
nuclear@14 656 colorindex_ci = cquantize->colorindex[ci];
nuclear@14 657 colormap_ci = cquantize->sv_colormap[ci];
nuclear@14 658 /* Preset error values: no error propagated to first pixel from left */
nuclear@14 659 cur = 0;
nuclear@14 660 /* and no error propagated to row below yet */
nuclear@14 661 belowerr = bpreverr = 0;
nuclear@14 662
nuclear@14 663 for (col = width; col > 0; col--) {
nuclear@14 664 /* cur holds the error propagated from the previous pixel on the
nuclear@14 665 * current line. Add the error propagated from the previous line
nuclear@14 666 * to form the complete error correction term for this pixel, and
nuclear@14 667 * round the error term (which is expressed * 16) to an integer.
nuclear@14 668 * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct
nuclear@14 669 * for either sign of the error value.
nuclear@14 670 * Note: errorptr points to *previous* column's array entry.
nuclear@14 671 */
nuclear@14 672 cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4);
nuclear@14 673 /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE.
nuclear@14 674 * The maximum error is +- MAXJSAMPLE; this sets the required size
nuclear@14 675 * of the range_limit array.
nuclear@14 676 */
nuclear@14 677 cur += GETJSAMPLE(*input_ptr);
nuclear@14 678 cur = GETJSAMPLE(range_limit[cur]);
nuclear@14 679 /* Select output value, accumulate into output code for this pixel */
nuclear@14 680 pixcode = GETJSAMPLE(colorindex_ci[cur]);
nuclear@14 681 *output_ptr += (JSAMPLE) pixcode;
nuclear@14 682 /* Compute actual representation error at this pixel */
nuclear@14 683 /* Note: we can do this even though we don't have the final */
nuclear@14 684 /* pixel code, because the colormap is orthogonal. */
nuclear@14 685 cur -= GETJSAMPLE(colormap_ci[pixcode]);
nuclear@14 686 /* Compute error fractions to be propagated to adjacent pixels.
nuclear@14 687 * Add these into the running sums, and simultaneously shift the
nuclear@14 688 * next-line error sums left by 1 column.
nuclear@14 689 */
nuclear@14 690 bnexterr = cur;
nuclear@14 691 delta = cur * 2;
nuclear@14 692 cur += delta; /* form error * 3 */
nuclear@14 693 errorptr[0] = (FSERROR) (bpreverr + cur);
nuclear@14 694 cur += delta; /* form error * 5 */
nuclear@14 695 bpreverr = belowerr + cur;
nuclear@14 696 belowerr = bnexterr;
nuclear@14 697 cur += delta; /* form error * 7 */
nuclear@14 698 /* At this point cur contains the 7/16 error value to be propagated
nuclear@14 699 * to the next pixel on the current line, and all the errors for the
nuclear@14 700 * next line have been shifted over. We are therefore ready to move on.
nuclear@14 701 */
nuclear@14 702 input_ptr += dirnc; /* advance input ptr to next column */
nuclear@14 703 output_ptr += dir; /* advance output ptr to next column */
nuclear@14 704 errorptr += dir; /* advance errorptr to current column */
nuclear@14 705 }
nuclear@14 706 /* Post-loop cleanup: we must unload the final error value into the
nuclear@14 707 * final fserrors[] entry. Note we need not unload belowerr because
nuclear@14 708 * it is for the dummy column before or after the actual array.
nuclear@14 709 */
nuclear@14 710 errorptr[0] = (FSERROR) bpreverr; /* unload prev err into array */
nuclear@14 711 }
nuclear@14 712 cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE);
nuclear@14 713 }
nuclear@14 714 }
nuclear@14 715
nuclear@14 716
nuclear@14 717 /*
nuclear@14 718 * Allocate workspace for Floyd-Steinberg errors.
nuclear@14 719 */
nuclear@14 720
nuclear@14 721 LOCAL(void)
nuclear@14 722 alloc_fs_workspace (j_decompress_ptr cinfo)
nuclear@14 723 {
nuclear@14 724 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@14 725 size_t arraysize;
nuclear@14 726 int i;
nuclear@14 727
nuclear@14 728 arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));
nuclear@14 729 for (i = 0; i < cinfo->out_color_components; i++) {
nuclear@14 730 cquantize->fserrors[i] = (FSERRPTR)
nuclear@14 731 (*cinfo->mem->alloc_large)((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize);
nuclear@14 732 }
nuclear@14 733 }
nuclear@14 734
nuclear@14 735
nuclear@14 736 /*
nuclear@14 737 * Initialize for one-pass color quantization.
nuclear@14 738 */
nuclear@14 739
nuclear@14 740 METHODDEF(void)
nuclear@14 741 start_pass_1_quant (j_decompress_ptr cinfo, boolean is_pre_scan)
nuclear@14 742 {
nuclear@14 743 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@14 744 size_t arraysize;
nuclear@14 745 int i;
nuclear@14 746
nuclear@14 747 /* Install my colormap. */
nuclear@14 748 cinfo->colormap = cquantize->sv_colormap;
nuclear@14 749 cinfo->actual_number_of_colors = cquantize->sv_actual;
nuclear@14 750
nuclear@14 751 /* Initialize for desired dithering mode. */
nuclear@14 752 switch (cinfo->dither_mode) {
nuclear@14 753 case JDITHER_NONE:
nuclear@14 754 if (cinfo->out_color_components == 3)
nuclear@14 755 cquantize->pub.color_quantize = color_quantize3;
nuclear@14 756 else
nuclear@14 757 cquantize->pub.color_quantize = color_quantize;
nuclear@14 758 break;
nuclear@14 759 case JDITHER_ORDERED:
nuclear@14 760 if (cinfo->out_color_components == 3)
nuclear@14 761 cquantize->pub.color_quantize = quantize3_ord_dither;
nuclear@14 762 else
nuclear@14 763 cquantize->pub.color_quantize = quantize_ord_dither;
nuclear@14 764 cquantize->row_index = 0; /* initialize state for ordered dither */
nuclear@14 765 /* If user changed to ordered dither from another mode,
nuclear@14 766 * we must recreate the color index table with padding.
nuclear@14 767 * This will cost extra space, but probably isn't very likely.
nuclear@14 768 */
nuclear@14 769 if (! cquantize->is_padded)
nuclear@14 770 create_colorindex(cinfo);
nuclear@14 771 /* Create ordered-dither tables if we didn't already. */
nuclear@14 772 if (cquantize->odither[0] == NULL)
nuclear@14 773 create_odither_tables(cinfo);
nuclear@14 774 break;
nuclear@14 775 case JDITHER_FS:
nuclear@14 776 cquantize->pub.color_quantize = quantize_fs_dither;
nuclear@14 777 cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */
nuclear@14 778 /* Allocate Floyd-Steinberg workspace if didn't already. */
nuclear@14 779 if (cquantize->fserrors[0] == NULL)
nuclear@14 780 alloc_fs_workspace(cinfo);
nuclear@14 781 /* Initialize the propagated errors to zero. */
nuclear@14 782 arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));
nuclear@14 783 for (i = 0; i < cinfo->out_color_components; i++)
nuclear@14 784 jzero_far((void FAR *) cquantize->fserrors[i], arraysize);
nuclear@14 785 break;
nuclear@14 786 default:
nuclear@14 787 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@14 788 break;
nuclear@14 789 }
nuclear@14 790 }
nuclear@14 791
nuclear@14 792
nuclear@14 793 /*
nuclear@14 794 * Finish up at the end of the pass.
nuclear@14 795 */
nuclear@14 796
nuclear@14 797 METHODDEF(void)
nuclear@14 798 finish_pass_1_quant (j_decompress_ptr cinfo)
nuclear@14 799 {
nuclear@14 800 /* no work in 1-pass case */
nuclear@14 801 }
nuclear@14 802
nuclear@14 803
nuclear@14 804 /*
nuclear@14 805 * Switch to a new external colormap between output passes.
nuclear@14 806 * Shouldn't get to this module!
nuclear@14 807 */
nuclear@14 808
nuclear@14 809 METHODDEF(void)
nuclear@14 810 new_color_map_1_quant (j_decompress_ptr cinfo)
nuclear@14 811 {
nuclear@14 812 ERREXIT(cinfo, JERR_MODE_CHANGE);
nuclear@14 813 }
nuclear@14 814
nuclear@14 815
nuclear@14 816 /*
nuclear@14 817 * Module initialization routine for 1-pass color quantization.
nuclear@14 818 */
nuclear@14 819
nuclear@14 820 GLOBAL(void)
nuclear@14 821 jinit_1pass_quantizer (j_decompress_ptr cinfo)
nuclear@14 822 {
nuclear@14 823 my_cquantize_ptr cquantize;
nuclear@14 824
nuclear@14 825 cquantize = (my_cquantize_ptr)
nuclear@14 826 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@14 827 SIZEOF(my_cquantizer));
nuclear@14 828 cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize;
nuclear@14 829 cquantize->pub.start_pass = start_pass_1_quant;
nuclear@14 830 cquantize->pub.finish_pass = finish_pass_1_quant;
nuclear@14 831 cquantize->pub.new_color_map = new_color_map_1_quant;
nuclear@14 832 cquantize->fserrors[0] = NULL; /* Flag FS workspace not allocated */
nuclear@14 833 cquantize->odither[0] = NULL; /* Also flag odither arrays not allocated */
nuclear@14 834
nuclear@14 835 /* Make sure my internal arrays won't overflow */
nuclear@14 836 if (cinfo->out_color_components > MAX_Q_COMPS)
nuclear@14 837 ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS);
nuclear@14 838 /* Make sure colormap indexes can be represented by JSAMPLEs */
nuclear@14 839 if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1))
nuclear@14 840 ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXJSAMPLE+1);
nuclear@14 841
nuclear@14 842 /* Create the colormap and color index table. */
nuclear@14 843 create_colormap(cinfo);
nuclear@14 844 create_colorindex(cinfo);
nuclear@14 845
nuclear@14 846 /* Allocate Floyd-Steinberg workspace now if requested.
nuclear@14 847 * We do this now since it is FAR storage and may affect the memory
nuclear@14 848 * manager's space calculations. If the user changes to FS dither
nuclear@14 849 * mode in a later pass, we will allocate the space then, and will
nuclear@14 850 * possibly overrun the max_memory_to_use setting.
nuclear@14 851 */
nuclear@14 852 if (cinfo->dither_mode == JDITHER_FS)
nuclear@14 853 alloc_fs_workspace(cinfo);
nuclear@14 854 }
nuclear@14 855
nuclear@14 856 #endif /* QUANT_1PASS_SUPPORTED */