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annotate libs/libjpeg/jquant1.c @ 33:33e9eedad390

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author John Tsiombikas <nuclear@mutantstargoat.com>
date Fri, 09 Sep 2011 00:03:37 +0300
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nuclear@26 1 /*
nuclear@26 2 * jquant1.c
nuclear@26 3 *
nuclear@26 4 * Copyright (C) 1991-1996, Thomas G. Lane.
nuclear@26 5 * This file is part of the Independent JPEG Group's software.
nuclear@26 6 * For conditions of distribution and use, see the accompanying README file.
nuclear@26 7 *
nuclear@26 8 * This file contains 1-pass color quantization (color mapping) routines.
nuclear@26 9 * These routines provide mapping to a fixed color map using equally spaced
nuclear@26 10 * color values. Optional Floyd-Steinberg or ordered dithering is available.
nuclear@26 11 */
nuclear@26 12
nuclear@26 13 #define JPEG_INTERNALS
nuclear@26 14 #include "jinclude.h"
nuclear@26 15 #include "jpeglib.h"
nuclear@26 16
nuclear@26 17 #ifdef QUANT_1PASS_SUPPORTED
nuclear@26 18
nuclear@26 19
nuclear@26 20 /*
nuclear@26 21 * The main purpose of 1-pass quantization is to provide a fast, if not very
nuclear@26 22 * high quality, colormapped output capability. A 2-pass quantizer usually
nuclear@26 23 * gives better visual quality; however, for quantized grayscale output this
nuclear@26 24 * quantizer is perfectly adequate. Dithering is highly recommended with this
nuclear@26 25 * quantizer, though you can turn it off if you really want to.
nuclear@26 26 *
nuclear@26 27 * In 1-pass quantization the colormap must be chosen in advance of seeing the
nuclear@26 28 * image. We use a map consisting of all combinations of Ncolors[i] color
nuclear@26 29 * values for the i'th component. The Ncolors[] values are chosen so that
nuclear@26 30 * their product, the total number of colors, is no more than that requested.
nuclear@26 31 * (In most cases, the product will be somewhat less.)
nuclear@26 32 *
nuclear@26 33 * Since the colormap is orthogonal, the representative value for each color
nuclear@26 34 * component can be determined without considering the other components;
nuclear@26 35 * then these indexes can be combined into a colormap index by a standard
nuclear@26 36 * N-dimensional-array-subscript calculation. Most of the arithmetic involved
nuclear@26 37 * can be precalculated and stored in the lookup table colorindex[].
nuclear@26 38 * colorindex[i][j] maps pixel value j in component i to the nearest
nuclear@26 39 * representative value (grid plane) for that component; this index is
nuclear@26 40 * multiplied by the array stride for component i, so that the
nuclear@26 41 * index of the colormap entry closest to a given pixel value is just
nuclear@26 42 * sum( colorindex[component-number][pixel-component-value] )
nuclear@26 43 * Aside from being fast, this scheme allows for variable spacing between
nuclear@26 44 * representative values with no additional lookup cost.
nuclear@26 45 *
nuclear@26 46 * If gamma correction has been applied in color conversion, it might be wise
nuclear@26 47 * to adjust the color grid spacing so that the representative colors are
nuclear@26 48 * equidistant in linear space. At this writing, gamma correction is not
nuclear@26 49 * implemented by jdcolor, so nothing is done here.
nuclear@26 50 */
nuclear@26 51
nuclear@26 52
nuclear@26 53 /* Declarations for ordered dithering.
nuclear@26 54 *
nuclear@26 55 * We use a standard 16x16 ordered dither array. The basic concept of ordered
nuclear@26 56 * dithering is described in many references, for instance Dale Schumacher's
nuclear@26 57 * chapter II.2 of Graphics Gems II (James Arvo, ed. Academic Press, 1991).
nuclear@26 58 * In place of Schumacher's comparisons against a "threshold" value, we add a
nuclear@26 59 * "dither" value to the input pixel and then round the result to the nearest
nuclear@26 60 * output value. The dither value is equivalent to (0.5 - threshold) times
nuclear@26 61 * the distance between output values. For ordered dithering, we assume that
nuclear@26 62 * the output colors are equally spaced; if not, results will probably be
nuclear@26 63 * worse, since the dither may be too much or too little at a given point.
nuclear@26 64 *
nuclear@26 65 * The normal calculation would be to form pixel value + dither, range-limit
nuclear@26 66 * this to 0..MAXJSAMPLE, and then index into the colorindex table as usual.
nuclear@26 67 * We can skip the separate range-limiting step by extending the colorindex
nuclear@26 68 * table in both directions.
nuclear@26 69 */
nuclear@26 70
nuclear@26 71 #define ODITHER_SIZE 16 /* dimension of dither matrix */
nuclear@26 72 /* NB: if ODITHER_SIZE is not a power of 2, ODITHER_MASK uses will break */
nuclear@26 73 #define ODITHER_CELLS (ODITHER_SIZE*ODITHER_SIZE) /* # cells in matrix */
nuclear@26 74 #define ODITHER_MASK (ODITHER_SIZE-1) /* mask for wrapping around counters */
nuclear@26 75
nuclear@26 76 typedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE];
nuclear@26 77 typedef int (*ODITHER_MATRIX_PTR)[ODITHER_SIZE];
nuclear@26 78
nuclear@26 79 static const UINT8 base_dither_matrix[ODITHER_SIZE][ODITHER_SIZE] = {
nuclear@26 80 /* Bayer's order-4 dither array. Generated by the code given in
nuclear@26 81 * Stephen Hawley's article "Ordered Dithering" in Graphics Gems I.
nuclear@26 82 * The values in this array must range from 0 to ODITHER_CELLS-1.
nuclear@26 83 */
nuclear@26 84 { 0,192, 48,240, 12,204, 60,252, 3,195, 51,243, 15,207, 63,255 },
nuclear@26 85 { 128, 64,176,112,140, 76,188,124,131, 67,179,115,143, 79,191,127 },
nuclear@26 86 { 32,224, 16,208, 44,236, 28,220, 35,227, 19,211, 47,239, 31,223 },
nuclear@26 87 { 160, 96,144, 80,172,108,156, 92,163, 99,147, 83,175,111,159, 95 },
nuclear@26 88 { 8,200, 56,248, 4,196, 52,244, 11,203, 59,251, 7,199, 55,247 },
nuclear@26 89 { 136, 72,184,120,132, 68,180,116,139, 75,187,123,135, 71,183,119 },
nuclear@26 90 { 40,232, 24,216, 36,228, 20,212, 43,235, 27,219, 39,231, 23,215 },
nuclear@26 91 { 168,104,152, 88,164,100,148, 84,171,107,155, 91,167,103,151, 87 },
nuclear@26 92 { 2,194, 50,242, 14,206, 62,254, 1,193, 49,241, 13,205, 61,253 },
nuclear@26 93 { 130, 66,178,114,142, 78,190,126,129, 65,177,113,141, 77,189,125 },
nuclear@26 94 { 34,226, 18,210, 46,238, 30,222, 33,225, 17,209, 45,237, 29,221 },
nuclear@26 95 { 162, 98,146, 82,174,110,158, 94,161, 97,145, 81,173,109,157, 93 },
nuclear@26 96 { 10,202, 58,250, 6,198, 54,246, 9,201, 57,249, 5,197, 53,245 },
nuclear@26 97 { 138, 74,186,122,134, 70,182,118,137, 73,185,121,133, 69,181,117 },
nuclear@26 98 { 42,234, 26,218, 38,230, 22,214, 41,233, 25,217, 37,229, 21,213 },
nuclear@26 99 { 170,106,154, 90,166,102,150, 86,169,105,153, 89,165,101,149, 85 }
nuclear@26 100 };
nuclear@26 101
nuclear@26 102
nuclear@26 103 /* Declarations for Floyd-Steinberg dithering.
nuclear@26 104 *
nuclear@26 105 * Errors are accumulated into the array fserrors[], at a resolution of
nuclear@26 106 * 1/16th of a pixel count. The error at a given pixel is propagated
nuclear@26 107 * to its not-yet-processed neighbors using the standard F-S fractions,
nuclear@26 108 * ... (here) 7/16
nuclear@26 109 * 3/16 5/16 1/16
nuclear@26 110 * We work left-to-right on even rows, right-to-left on odd rows.
nuclear@26 111 *
nuclear@26 112 * We can get away with a single array (holding one row's worth of errors)
nuclear@26 113 * by using it to store the current row's errors at pixel columns not yet
nuclear@26 114 * processed, but the next row's errors at columns already processed. We
nuclear@26 115 * need only a few extra variables to hold the errors immediately around the
nuclear@26 116 * current column. (If we are lucky, those variables are in registers, but
nuclear@26 117 * even if not, they're probably cheaper to access than array elements are.)
nuclear@26 118 *
nuclear@26 119 * The fserrors[] array is indexed [component#][position].
nuclear@26 120 * We provide (#columns + 2) entries per component; the extra entry at each
nuclear@26 121 * end saves us from special-casing the first and last pixels.
nuclear@26 122 *
nuclear@26 123 * Note: on a wide image, we might not have enough room in a PC's near data
nuclear@26 124 * segment to hold the error array; so it is allocated with alloc_large.
nuclear@26 125 */
nuclear@26 126
nuclear@26 127 #if BITS_IN_JSAMPLE == 8
nuclear@26 128 typedef INT16 FSERROR; /* 16 bits should be enough */
nuclear@26 129 typedef int LOCFSERROR; /* use 'int' for calculation temps */
nuclear@26 130 #else
nuclear@26 131 typedef INT32 FSERROR; /* may need more than 16 bits */
nuclear@26 132 typedef INT32 LOCFSERROR; /* be sure calculation temps are big enough */
nuclear@26 133 #endif
nuclear@26 134
nuclear@26 135 typedef FSERROR FAR *FSERRPTR; /* pointer to error array (in FAR storage!) */
nuclear@26 136
nuclear@26 137
nuclear@26 138 /* Private subobject */
nuclear@26 139
nuclear@26 140 #define MAX_Q_COMPS 4 /* max components I can handle */
nuclear@26 141
nuclear@26 142 typedef struct {
nuclear@26 143 struct jpeg_color_quantizer pub; /* public fields */
nuclear@26 144
nuclear@26 145 /* Initially allocated colormap is saved here */
nuclear@26 146 JSAMPARRAY sv_colormap; /* The color map as a 2-D pixel array */
nuclear@26 147 int sv_actual; /* number of entries in use */
nuclear@26 148
nuclear@26 149 JSAMPARRAY colorindex; /* Precomputed mapping for speed */
nuclear@26 150 /* colorindex[i][j] = index of color closest to pixel value j in component i,
nuclear@26 151 * premultiplied as described above. Since colormap indexes must fit into
nuclear@26 152 * JSAMPLEs, the entries of this array will too.
nuclear@26 153 */
nuclear@26 154 boolean is_padded; /* is the colorindex padded for odither? */
nuclear@26 155
nuclear@26 156 int Ncolors[MAX_Q_COMPS]; /* # of values alloced to each component */
nuclear@26 157
nuclear@26 158 /* Variables for ordered dithering */
nuclear@26 159 int row_index; /* cur row's vertical index in dither matrix */
nuclear@26 160 ODITHER_MATRIX_PTR odither[MAX_Q_COMPS]; /* one dither array per component */
nuclear@26 161
nuclear@26 162 /* Variables for Floyd-Steinberg dithering */
nuclear@26 163 FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */
nuclear@26 164 boolean on_odd_row; /* flag to remember which row we are on */
nuclear@26 165 } my_cquantizer;
nuclear@26 166
nuclear@26 167 typedef my_cquantizer * my_cquantize_ptr;
nuclear@26 168
nuclear@26 169
nuclear@26 170 /*
nuclear@26 171 * Policy-making subroutines for create_colormap and create_colorindex.
nuclear@26 172 * These routines determine the colormap to be used. The rest of the module
nuclear@26 173 * only assumes that the colormap is orthogonal.
nuclear@26 174 *
nuclear@26 175 * * select_ncolors decides how to divvy up the available colors
nuclear@26 176 * among the components.
nuclear@26 177 * * output_value defines the set of representative values for a component.
nuclear@26 178 * * largest_input_value defines the mapping from input values to
nuclear@26 179 * representative values for a component.
nuclear@26 180 * Note that the latter two routines may impose different policies for
nuclear@26 181 * different components, though this is not currently done.
nuclear@26 182 */
nuclear@26 183
nuclear@26 184
nuclear@26 185 LOCAL(int)
nuclear@26 186 select_ncolors (j_decompress_ptr cinfo, int Ncolors[])
nuclear@26 187 /* Determine allocation of desired colors to components, */
nuclear@26 188 /* and fill in Ncolors[] array to indicate choice. */
nuclear@26 189 /* Return value is total number of colors (product of Ncolors[] values). */
nuclear@26 190 {
nuclear@26 191 int nc = cinfo->out_color_components; /* number of color components */
nuclear@26 192 int max_colors = cinfo->desired_number_of_colors;
nuclear@26 193 int total_colors, iroot, i, j;
nuclear@26 194 boolean changed;
nuclear@26 195 long temp;
nuclear@26 196 static const int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE };
nuclear@26 197
nuclear@26 198 /* We can allocate at least the nc'th root of max_colors per component. */
nuclear@26 199 /* Compute floor(nc'th root of max_colors). */
nuclear@26 200 iroot = 1;
nuclear@26 201 do {
nuclear@26 202 iroot++;
nuclear@26 203 temp = iroot; /* set temp = iroot ** nc */
nuclear@26 204 for (i = 1; i < nc; i++)
nuclear@26 205 temp *= iroot;
nuclear@26 206 } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */
nuclear@26 207 iroot--; /* now iroot = floor(root) */
nuclear@26 208
nuclear@26 209 /* Must have at least 2 color values per component */
nuclear@26 210 if (iroot < 2)
nuclear@26 211 ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int) temp);
nuclear@26 212
nuclear@26 213 /* Initialize to iroot color values for each component */
nuclear@26 214 total_colors = 1;
nuclear@26 215 for (i = 0; i < nc; i++) {
nuclear@26 216 Ncolors[i] = iroot;
nuclear@26 217 total_colors *= iroot;
nuclear@26 218 }
nuclear@26 219 /* We may be able to increment the count for one or more components without
nuclear@26 220 * exceeding max_colors, though we know not all can be incremented.
nuclear@26 221 * Sometimes, the first component can be incremented more than once!
nuclear@26 222 * (Example: for 16 colors, we start at 2*2*2, go to 3*2*2, then 4*2*2.)
nuclear@26 223 * In RGB colorspace, try to increment G first, then R, then B.
nuclear@26 224 */
nuclear@26 225 do {
nuclear@26 226 changed = FALSE;
nuclear@26 227 for (i = 0; i < nc; i++) {
nuclear@26 228 j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i);
nuclear@26 229 /* calculate new total_colors if Ncolors[j] is incremented */
nuclear@26 230 temp = total_colors / Ncolors[j];
nuclear@26 231 temp *= Ncolors[j]+1; /* done in long arith to avoid oflo */
nuclear@26 232 if (temp > (long) max_colors)
nuclear@26 233 break; /* won't fit, done with this pass */
nuclear@26 234 Ncolors[j]++; /* OK, apply the increment */
nuclear@26 235 total_colors = (int) temp;
nuclear@26 236 changed = TRUE;
nuclear@26 237 }
nuclear@26 238 } while (changed);
nuclear@26 239
nuclear@26 240 return total_colors;
nuclear@26 241 }
nuclear@26 242
nuclear@26 243
nuclear@26 244 LOCAL(int)
nuclear@26 245 output_value (j_decompress_ptr cinfo, int ci, int j, int maxj)
nuclear@26 246 /* Return j'th output value, where j will range from 0 to maxj */
nuclear@26 247 /* The output values must fall in 0..MAXJSAMPLE in increasing order */
nuclear@26 248 {
nuclear@26 249 /* We always provide values 0 and MAXJSAMPLE for each component;
nuclear@26 250 * any additional values are equally spaced between these limits.
nuclear@26 251 * (Forcing the upper and lower values to the limits ensures that
nuclear@26 252 * dithering can't produce a color outside the selected gamut.)
nuclear@26 253 */
nuclear@26 254 return (int) (((INT32) j * MAXJSAMPLE + maxj/2) / maxj);
nuclear@26 255 }
nuclear@26 256
nuclear@26 257
nuclear@26 258 LOCAL(int)
nuclear@26 259 largest_input_value (j_decompress_ptr cinfo, int ci, int j, int maxj)
nuclear@26 260 /* Return largest input value that should map to j'th output value */
nuclear@26 261 /* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */
nuclear@26 262 {
nuclear@26 263 /* Breakpoints are halfway between values returned by output_value */
nuclear@26 264 return (int) (((INT32) (2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj));
nuclear@26 265 }
nuclear@26 266
nuclear@26 267
nuclear@26 268 /*
nuclear@26 269 * Create the colormap.
nuclear@26 270 */
nuclear@26 271
nuclear@26 272 LOCAL(void)
nuclear@26 273 create_colormap (j_decompress_ptr cinfo)
nuclear@26 274 {
nuclear@26 275 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@26 276 JSAMPARRAY colormap; /* Created colormap */
nuclear@26 277 int total_colors; /* Number of distinct output colors */
nuclear@26 278 int i,j,k, nci, blksize, blkdist, ptr, val;
nuclear@26 279
nuclear@26 280 /* Select number of colors for each component */
nuclear@26 281 total_colors = select_ncolors(cinfo, cquantize->Ncolors);
nuclear@26 282
nuclear@26 283 /* Report selected color counts */
nuclear@26 284 if (cinfo->out_color_components == 3)
nuclear@26 285 TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS,
nuclear@26 286 total_colors, cquantize->Ncolors[0],
nuclear@26 287 cquantize->Ncolors[1], cquantize->Ncolors[2]);
nuclear@26 288 else
nuclear@26 289 TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors);
nuclear@26 290
nuclear@26 291 /* Allocate and fill in the colormap. */
nuclear@26 292 /* The colors are ordered in the map in standard row-major order, */
nuclear@26 293 /* i.e. rightmost (highest-indexed) color changes most rapidly. */
nuclear@26 294
nuclear@26 295 colormap = (*cinfo->mem->alloc_sarray)
nuclear@26 296 ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26 297 (JDIMENSION) total_colors, (JDIMENSION) cinfo->out_color_components);
nuclear@26 298
nuclear@26 299 /* blksize is number of adjacent repeated entries for a component */
nuclear@26 300 /* blkdist is distance between groups of identical entries for a component */
nuclear@26 301 blkdist = total_colors;
nuclear@26 302
nuclear@26 303 for (i = 0; i < cinfo->out_color_components; i++) {
nuclear@26 304 /* fill in colormap entries for i'th color component */
nuclear@26 305 nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
nuclear@26 306 blksize = blkdist / nci;
nuclear@26 307 for (j = 0; j < nci; j++) {
nuclear@26 308 /* Compute j'th output value (out of nci) for component */
nuclear@26 309 val = output_value(cinfo, i, j, nci-1);
nuclear@26 310 /* Fill in all colormap entries that have this value of this component */
nuclear@26 311 for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) {
nuclear@26 312 /* fill in blksize entries beginning at ptr */
nuclear@26 313 for (k = 0; k < blksize; k++)
nuclear@26 314 colormap[i][ptr+k] = (JSAMPLE) val;
nuclear@26 315 }
nuclear@26 316 }
nuclear@26 317 blkdist = blksize; /* blksize of this color is blkdist of next */
nuclear@26 318 }
nuclear@26 319
nuclear@26 320 /* Save the colormap in private storage,
nuclear@26 321 * where it will survive color quantization mode changes.
nuclear@26 322 */
nuclear@26 323 cquantize->sv_colormap = colormap;
nuclear@26 324 cquantize->sv_actual = total_colors;
nuclear@26 325 }
nuclear@26 326
nuclear@26 327
nuclear@26 328 /*
nuclear@26 329 * Create the color index table.
nuclear@26 330 */
nuclear@26 331
nuclear@26 332 LOCAL(void)
nuclear@26 333 create_colorindex (j_decompress_ptr cinfo)
nuclear@26 334 {
nuclear@26 335 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@26 336 JSAMPROW indexptr;
nuclear@26 337 int i,j,k, nci, blksize, val, pad;
nuclear@26 338
nuclear@26 339 /* For ordered dither, we pad the color index tables by MAXJSAMPLE in
nuclear@26 340 * each direction (input index values can be -MAXJSAMPLE .. 2*MAXJSAMPLE).
nuclear@26 341 * This is not necessary in the other dithering modes. However, we
nuclear@26 342 * flag whether it was done in case user changes dithering mode.
nuclear@26 343 */
nuclear@26 344 if (cinfo->dither_mode == JDITHER_ORDERED) {
nuclear@26 345 pad = MAXJSAMPLE*2;
nuclear@26 346 cquantize->is_padded = TRUE;
nuclear@26 347 } else {
nuclear@26 348 pad = 0;
nuclear@26 349 cquantize->is_padded = FALSE;
nuclear@26 350 }
nuclear@26 351
nuclear@26 352 cquantize->colorindex = (*cinfo->mem->alloc_sarray)
nuclear@26 353 ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26 354 (JDIMENSION) (MAXJSAMPLE+1 + pad),
nuclear@26 355 (JDIMENSION) cinfo->out_color_components);
nuclear@26 356
nuclear@26 357 /* blksize is number of adjacent repeated entries for a component */
nuclear@26 358 blksize = cquantize->sv_actual;
nuclear@26 359
nuclear@26 360 for (i = 0; i < cinfo->out_color_components; i++) {
nuclear@26 361 /* fill in colorindex entries for i'th color component */
nuclear@26 362 nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
nuclear@26 363 blksize = blksize / nci;
nuclear@26 364
nuclear@26 365 /* adjust colorindex pointers to provide padding at negative indexes. */
nuclear@26 366 if (pad)
nuclear@26 367 cquantize->colorindex[i] += MAXJSAMPLE;
nuclear@26 368
nuclear@26 369 /* in loop, val = index of current output value, */
nuclear@26 370 /* and k = largest j that maps to current val */
nuclear@26 371 indexptr = cquantize->colorindex[i];
nuclear@26 372 val = 0;
nuclear@26 373 k = largest_input_value(cinfo, i, 0, nci-1);
nuclear@26 374 for (j = 0; j <= MAXJSAMPLE; j++) {
nuclear@26 375 while (j > k) /* advance val if past boundary */
nuclear@26 376 k = largest_input_value(cinfo, i, ++val, nci-1);
nuclear@26 377 /* premultiply so that no multiplication needed in main processing */
nuclear@26 378 indexptr[j] = (JSAMPLE) (val * blksize);
nuclear@26 379 }
nuclear@26 380 /* Pad at both ends if necessary */
nuclear@26 381 if (pad)
nuclear@26 382 for (j = 1; j <= MAXJSAMPLE; j++) {
nuclear@26 383 indexptr[-j] = indexptr[0];
nuclear@26 384 indexptr[MAXJSAMPLE+j] = indexptr[MAXJSAMPLE];
nuclear@26 385 }
nuclear@26 386 }
nuclear@26 387 }
nuclear@26 388
nuclear@26 389
nuclear@26 390 /*
nuclear@26 391 * Create an ordered-dither array for a component having ncolors
nuclear@26 392 * distinct output values.
nuclear@26 393 */
nuclear@26 394
nuclear@26 395 LOCAL(ODITHER_MATRIX_PTR)
nuclear@26 396 make_odither_array (j_decompress_ptr cinfo, int ncolors)
nuclear@26 397 {
nuclear@26 398 ODITHER_MATRIX_PTR odither;
nuclear@26 399 int j,k;
nuclear@26 400 INT32 num,den;
nuclear@26 401
nuclear@26 402 odither = (ODITHER_MATRIX_PTR)
nuclear@26 403 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26 404 SIZEOF(ODITHER_MATRIX));
nuclear@26 405 /* The inter-value distance for this color is MAXJSAMPLE/(ncolors-1).
nuclear@26 406 * Hence the dither value for the matrix cell with fill order f
nuclear@26 407 * (f=0..N-1) should be (N-1-2*f)/(2*N) * MAXJSAMPLE/(ncolors-1).
nuclear@26 408 * On 16-bit-int machine, be careful to avoid overflow.
nuclear@26 409 */
nuclear@26 410 den = 2 * ODITHER_CELLS * ((INT32) (ncolors - 1));
nuclear@26 411 for (j = 0; j < ODITHER_SIZE; j++) {
nuclear@26 412 for (k = 0; k < ODITHER_SIZE; k++) {
nuclear@26 413 num = ((INT32) (ODITHER_CELLS-1 - 2*((int)base_dither_matrix[j][k])))
nuclear@26 414 * MAXJSAMPLE;
nuclear@26 415 /* Ensure round towards zero despite C's lack of consistency
nuclear@26 416 * about rounding negative values in integer division...
nuclear@26 417 */
nuclear@26 418 odither[j][k] = (int) (num<0 ? -((-num)/den) : num/den);
nuclear@26 419 }
nuclear@26 420 }
nuclear@26 421 return odither;
nuclear@26 422 }
nuclear@26 423
nuclear@26 424
nuclear@26 425 /*
nuclear@26 426 * Create the ordered-dither tables.
nuclear@26 427 * Components having the same number of representative colors may
nuclear@26 428 * share a dither table.
nuclear@26 429 */
nuclear@26 430
nuclear@26 431 LOCAL(void)
nuclear@26 432 create_odither_tables (j_decompress_ptr cinfo)
nuclear@26 433 {
nuclear@26 434 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@26 435 ODITHER_MATRIX_PTR odither;
nuclear@26 436 int i, j, nci;
nuclear@26 437
nuclear@26 438 for (i = 0; i < cinfo->out_color_components; i++) {
nuclear@26 439 nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
nuclear@26 440 odither = NULL; /* search for matching prior component */
nuclear@26 441 for (j = 0; j < i; j++) {
nuclear@26 442 if (nci == cquantize->Ncolors[j]) {
nuclear@26 443 odither = cquantize->odither[j];
nuclear@26 444 break;
nuclear@26 445 }
nuclear@26 446 }
nuclear@26 447 if (odither == NULL) /* need a new table? */
nuclear@26 448 odither = make_odither_array(cinfo, nci);
nuclear@26 449 cquantize->odither[i] = odither;
nuclear@26 450 }
nuclear@26 451 }
nuclear@26 452
nuclear@26 453
nuclear@26 454 /*
nuclear@26 455 * Map some rows of pixels to the output colormapped representation.
nuclear@26 456 */
nuclear@26 457
nuclear@26 458 METHODDEF(void)
nuclear@26 459 color_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@26 460 JSAMPARRAY output_buf, int num_rows)
nuclear@26 461 /* General case, no dithering */
nuclear@26 462 {
nuclear@26 463 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@26 464 JSAMPARRAY colorindex = cquantize->colorindex;
nuclear@26 465 register int pixcode, ci;
nuclear@26 466 register JSAMPROW ptrin, ptrout;
nuclear@26 467 int row;
nuclear@26 468 JDIMENSION col;
nuclear@26 469 JDIMENSION width = cinfo->output_width;
nuclear@26 470 register int nc = cinfo->out_color_components;
nuclear@26 471
nuclear@26 472 for (row = 0; row < num_rows; row++) {
nuclear@26 473 ptrin = input_buf[row];
nuclear@26 474 ptrout = output_buf[row];
nuclear@26 475 for (col = width; col > 0; col--) {
nuclear@26 476 pixcode = 0;
nuclear@26 477 for (ci = 0; ci < nc; ci++) {
nuclear@26 478 pixcode += GETJSAMPLE(colorindex[ci][GETJSAMPLE(*ptrin++)]);
nuclear@26 479 }
nuclear@26 480 *ptrout++ = (JSAMPLE) pixcode;
nuclear@26 481 }
nuclear@26 482 }
nuclear@26 483 }
nuclear@26 484
nuclear@26 485
nuclear@26 486 METHODDEF(void)
nuclear@26 487 color_quantize3 (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@26 488 JSAMPARRAY output_buf, int num_rows)
nuclear@26 489 /* Fast path for out_color_components==3, no dithering */
nuclear@26 490 {
nuclear@26 491 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@26 492 register int pixcode;
nuclear@26 493 register JSAMPROW ptrin, ptrout;
nuclear@26 494 JSAMPROW colorindex0 = cquantize->colorindex[0];
nuclear@26 495 JSAMPROW colorindex1 = cquantize->colorindex[1];
nuclear@26 496 JSAMPROW colorindex2 = cquantize->colorindex[2];
nuclear@26 497 int row;
nuclear@26 498 JDIMENSION col;
nuclear@26 499 JDIMENSION width = cinfo->output_width;
nuclear@26 500
nuclear@26 501 for (row = 0; row < num_rows; row++) {
nuclear@26 502 ptrin = input_buf[row];
nuclear@26 503 ptrout = output_buf[row];
nuclear@26 504 for (col = width; col > 0; col--) {
nuclear@26 505 pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*ptrin++)]);
nuclear@26 506 pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*ptrin++)]);
nuclear@26 507 pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*ptrin++)]);
nuclear@26 508 *ptrout++ = (JSAMPLE) pixcode;
nuclear@26 509 }
nuclear@26 510 }
nuclear@26 511 }
nuclear@26 512
nuclear@26 513
nuclear@26 514 METHODDEF(void)
nuclear@26 515 quantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@26 516 JSAMPARRAY output_buf, int num_rows)
nuclear@26 517 /* General case, with ordered dithering */
nuclear@26 518 {
nuclear@26 519 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@26 520 register JSAMPROW input_ptr;
nuclear@26 521 register JSAMPROW output_ptr;
nuclear@26 522 JSAMPROW colorindex_ci;
nuclear@26 523 int * dither; /* points to active row of dither matrix */
nuclear@26 524 int row_index, col_index; /* current indexes into dither matrix */
nuclear@26 525 int nc = cinfo->out_color_components;
nuclear@26 526 int ci;
nuclear@26 527 int row;
nuclear@26 528 JDIMENSION col;
nuclear@26 529 JDIMENSION width = cinfo->output_width;
nuclear@26 530
nuclear@26 531 for (row = 0; row < num_rows; row++) {
nuclear@26 532 /* Initialize output values to 0 so can process components separately */
nuclear@26 533 jzero_far((void FAR *) output_buf[row],
nuclear@26 534 (size_t) (width * SIZEOF(JSAMPLE)));
nuclear@26 535 row_index = cquantize->row_index;
nuclear@26 536 for (ci = 0; ci < nc; ci++) {
nuclear@26 537 input_ptr = input_buf[row] + ci;
nuclear@26 538 output_ptr = output_buf[row];
nuclear@26 539 colorindex_ci = cquantize->colorindex[ci];
nuclear@26 540 dither = cquantize->odither[ci][row_index];
nuclear@26 541 col_index = 0;
nuclear@26 542
nuclear@26 543 for (col = width; col > 0; col--) {
nuclear@26 544 /* Form pixel value + dither, range-limit to 0..MAXJSAMPLE,
nuclear@26 545 * select output value, accumulate into output code for this pixel.
nuclear@26 546 * Range-limiting need not be done explicitly, as we have extended
nuclear@26 547 * the colorindex table to produce the right answers for out-of-range
nuclear@26 548 * inputs. The maximum dither is +- MAXJSAMPLE; this sets the
nuclear@26 549 * required amount of padding.
nuclear@26 550 */
nuclear@26 551 *output_ptr += colorindex_ci[GETJSAMPLE(*input_ptr)+dither[col_index]];
nuclear@26 552 input_ptr += nc;
nuclear@26 553 output_ptr++;
nuclear@26 554 col_index = (col_index + 1) & ODITHER_MASK;
nuclear@26 555 }
nuclear@26 556 }
nuclear@26 557 /* Advance row index for next row */
nuclear@26 558 row_index = (row_index + 1) & ODITHER_MASK;
nuclear@26 559 cquantize->row_index = row_index;
nuclear@26 560 }
nuclear@26 561 }
nuclear@26 562
nuclear@26 563
nuclear@26 564 METHODDEF(void)
nuclear@26 565 quantize3_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@26 566 JSAMPARRAY output_buf, int num_rows)
nuclear@26 567 /* Fast path for out_color_components==3, with ordered dithering */
nuclear@26 568 {
nuclear@26 569 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@26 570 register int pixcode;
nuclear@26 571 register JSAMPROW input_ptr;
nuclear@26 572 register JSAMPROW output_ptr;
nuclear@26 573 JSAMPROW colorindex0 = cquantize->colorindex[0];
nuclear@26 574 JSAMPROW colorindex1 = cquantize->colorindex[1];
nuclear@26 575 JSAMPROW colorindex2 = cquantize->colorindex[2];
nuclear@26 576 int * dither0; /* points to active row of dither matrix */
nuclear@26 577 int * dither1;
nuclear@26 578 int * dither2;
nuclear@26 579 int row_index, col_index; /* current indexes into dither matrix */
nuclear@26 580 int row;
nuclear@26 581 JDIMENSION col;
nuclear@26 582 JDIMENSION width = cinfo->output_width;
nuclear@26 583
nuclear@26 584 for (row = 0; row < num_rows; row++) {
nuclear@26 585 row_index = cquantize->row_index;
nuclear@26 586 input_ptr = input_buf[row];
nuclear@26 587 output_ptr = output_buf[row];
nuclear@26 588 dither0 = cquantize->odither[0][row_index];
nuclear@26 589 dither1 = cquantize->odither[1][row_index];
nuclear@26 590 dither2 = cquantize->odither[2][row_index];
nuclear@26 591 col_index = 0;
nuclear@26 592
nuclear@26 593 for (col = width; col > 0; col--) {
nuclear@26 594 pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*input_ptr++) +
nuclear@26 595 dither0[col_index]]);
nuclear@26 596 pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*input_ptr++) +
nuclear@26 597 dither1[col_index]]);
nuclear@26 598 pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*input_ptr++) +
nuclear@26 599 dither2[col_index]]);
nuclear@26 600 *output_ptr++ = (JSAMPLE) pixcode;
nuclear@26 601 col_index = (col_index + 1) & ODITHER_MASK;
nuclear@26 602 }
nuclear@26 603 row_index = (row_index + 1) & ODITHER_MASK;
nuclear@26 604 cquantize->row_index = row_index;
nuclear@26 605 }
nuclear@26 606 }
nuclear@26 607
nuclear@26 608
nuclear@26 609 METHODDEF(void)
nuclear@26 610 quantize_fs_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@26 611 JSAMPARRAY output_buf, int num_rows)
nuclear@26 612 /* General case, with Floyd-Steinberg dithering */
nuclear@26 613 {
nuclear@26 614 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@26 615 register LOCFSERROR cur; /* current error or pixel value */
nuclear@26 616 LOCFSERROR belowerr; /* error for pixel below cur */
nuclear@26 617 LOCFSERROR bpreverr; /* error for below/prev col */
nuclear@26 618 LOCFSERROR bnexterr; /* error for below/next col */
nuclear@26 619 LOCFSERROR delta;
nuclear@26 620 register FSERRPTR errorptr; /* => fserrors[] at column before current */
nuclear@26 621 register JSAMPROW input_ptr;
nuclear@26 622 register JSAMPROW output_ptr;
nuclear@26 623 JSAMPROW colorindex_ci;
nuclear@26 624 JSAMPROW colormap_ci;
nuclear@26 625 int pixcode;
nuclear@26 626 int nc = cinfo->out_color_components;
nuclear@26 627 int dir; /* 1 for left-to-right, -1 for right-to-left */
nuclear@26 628 int dirnc; /* dir * nc */
nuclear@26 629 int ci;
nuclear@26 630 int row;
nuclear@26 631 JDIMENSION col;
nuclear@26 632 JDIMENSION width = cinfo->output_width;
nuclear@26 633 JSAMPLE *range_limit = cinfo->sample_range_limit;
nuclear@26 634 SHIFT_TEMPS
nuclear@26 635
nuclear@26 636 for (row = 0; row < num_rows; row++) {
nuclear@26 637 /* Initialize output values to 0 so can process components separately */
nuclear@26 638 jzero_far((void FAR *) output_buf[row],
nuclear@26 639 (size_t) (width * SIZEOF(JSAMPLE)));
nuclear@26 640 for (ci = 0; ci < nc; ci++) {
nuclear@26 641 input_ptr = input_buf[row] + ci;
nuclear@26 642 output_ptr = output_buf[row];
nuclear@26 643 if (cquantize->on_odd_row) {
nuclear@26 644 /* work right to left in this row */
nuclear@26 645 input_ptr += (width-1) * nc; /* so point to rightmost pixel */
nuclear@26 646 output_ptr += width-1;
nuclear@26 647 dir = -1;
nuclear@26 648 dirnc = -nc;
nuclear@26 649 errorptr = cquantize->fserrors[ci] + (width+1); /* => entry after last column */
nuclear@26 650 } else {
nuclear@26 651 /* work left to right in this row */
nuclear@26 652 dir = 1;
nuclear@26 653 dirnc = nc;
nuclear@26 654 errorptr = cquantize->fserrors[ci]; /* => entry before first column */
nuclear@26 655 }
nuclear@26 656 colorindex_ci = cquantize->colorindex[ci];
nuclear@26 657 colormap_ci = cquantize->sv_colormap[ci];
nuclear@26 658 /* Preset error values: no error propagated to first pixel from left */
nuclear@26 659 cur = 0;
nuclear@26 660 /* and no error propagated to row below yet */
nuclear@26 661 belowerr = bpreverr = 0;
nuclear@26 662
nuclear@26 663 for (col = width; col > 0; col--) {
nuclear@26 664 /* cur holds the error propagated from the previous pixel on the
nuclear@26 665 * current line. Add the error propagated from the previous line
nuclear@26 666 * to form the complete error correction term for this pixel, and
nuclear@26 667 * round the error term (which is expressed * 16) to an integer.
nuclear@26 668 * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct
nuclear@26 669 * for either sign of the error value.
nuclear@26 670 * Note: errorptr points to *previous* column's array entry.
nuclear@26 671 */
nuclear@26 672 cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4);
nuclear@26 673 /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE.
nuclear@26 674 * The maximum error is +- MAXJSAMPLE; this sets the required size
nuclear@26 675 * of the range_limit array.
nuclear@26 676 */
nuclear@26 677 cur += GETJSAMPLE(*input_ptr);
nuclear@26 678 cur = GETJSAMPLE(range_limit[cur]);
nuclear@26 679 /* Select output value, accumulate into output code for this pixel */
nuclear@26 680 pixcode = GETJSAMPLE(colorindex_ci[cur]);
nuclear@26 681 *output_ptr += (JSAMPLE) pixcode;
nuclear@26 682 /* Compute actual representation error at this pixel */
nuclear@26 683 /* Note: we can do this even though we don't have the final */
nuclear@26 684 /* pixel code, because the colormap is orthogonal. */
nuclear@26 685 cur -= GETJSAMPLE(colormap_ci[pixcode]);
nuclear@26 686 /* Compute error fractions to be propagated to adjacent pixels.
nuclear@26 687 * Add these into the running sums, and simultaneously shift the
nuclear@26 688 * next-line error sums left by 1 column.
nuclear@26 689 */
nuclear@26 690 bnexterr = cur;
nuclear@26 691 delta = cur * 2;
nuclear@26 692 cur += delta; /* form error * 3 */
nuclear@26 693 errorptr[0] = (FSERROR) (bpreverr + cur);
nuclear@26 694 cur += delta; /* form error * 5 */
nuclear@26 695 bpreverr = belowerr + cur;
nuclear@26 696 belowerr = bnexterr;
nuclear@26 697 cur += delta; /* form error * 7 */
nuclear@26 698 /* At this point cur contains the 7/16 error value to be propagated
nuclear@26 699 * to the next pixel on the current line, and all the errors for the
nuclear@26 700 * next line have been shifted over. We are therefore ready to move on.
nuclear@26 701 */
nuclear@26 702 input_ptr += dirnc; /* advance input ptr to next column */
nuclear@26 703 output_ptr += dir; /* advance output ptr to next column */
nuclear@26 704 errorptr += dir; /* advance errorptr to current column */
nuclear@26 705 }
nuclear@26 706 /* Post-loop cleanup: we must unload the final error value into the
nuclear@26 707 * final fserrors[] entry. Note we need not unload belowerr because
nuclear@26 708 * it is for the dummy column before or after the actual array.
nuclear@26 709 */
nuclear@26 710 errorptr[0] = (FSERROR) bpreverr; /* unload prev err into array */
nuclear@26 711 }
nuclear@26 712 cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE);
nuclear@26 713 }
nuclear@26 714 }
nuclear@26 715
nuclear@26 716
nuclear@26 717 /*
nuclear@26 718 * Allocate workspace for Floyd-Steinberg errors.
nuclear@26 719 */
nuclear@26 720
nuclear@26 721 LOCAL(void)
nuclear@26 722 alloc_fs_workspace (j_decompress_ptr cinfo)
nuclear@26 723 {
nuclear@26 724 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@26 725 size_t arraysize;
nuclear@26 726 int i;
nuclear@26 727
nuclear@26 728 arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));
nuclear@26 729 for (i = 0; i < cinfo->out_color_components; i++) {
nuclear@26 730 cquantize->fserrors[i] = (FSERRPTR)
nuclear@26 731 (*cinfo->mem->alloc_large)((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize);
nuclear@26 732 }
nuclear@26 733 }
nuclear@26 734
nuclear@26 735
nuclear@26 736 /*
nuclear@26 737 * Initialize for one-pass color quantization.
nuclear@26 738 */
nuclear@26 739
nuclear@26 740 METHODDEF(void)
nuclear@26 741 start_pass_1_quant (j_decompress_ptr cinfo, boolean is_pre_scan)
nuclear@26 742 {
nuclear@26 743 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
nuclear@26 744 size_t arraysize;
nuclear@26 745 int i;
nuclear@26 746
nuclear@26 747 /* Install my colormap. */
nuclear@26 748 cinfo->colormap = cquantize->sv_colormap;
nuclear@26 749 cinfo->actual_number_of_colors = cquantize->sv_actual;
nuclear@26 750
nuclear@26 751 /* Initialize for desired dithering mode. */
nuclear@26 752 switch (cinfo->dither_mode) {
nuclear@26 753 case JDITHER_NONE:
nuclear@26 754 if (cinfo->out_color_components == 3)
nuclear@26 755 cquantize->pub.color_quantize = color_quantize3;
nuclear@26 756 else
nuclear@26 757 cquantize->pub.color_quantize = color_quantize;
nuclear@26 758 break;
nuclear@26 759 case JDITHER_ORDERED:
nuclear@26 760 if (cinfo->out_color_components == 3)
nuclear@26 761 cquantize->pub.color_quantize = quantize3_ord_dither;
nuclear@26 762 else
nuclear@26 763 cquantize->pub.color_quantize = quantize_ord_dither;
nuclear@26 764 cquantize->row_index = 0; /* initialize state for ordered dither */
nuclear@26 765 /* If user changed to ordered dither from another mode,
nuclear@26 766 * we must recreate the color index table with padding.
nuclear@26 767 * This will cost extra space, but probably isn't very likely.
nuclear@26 768 */
nuclear@26 769 if (! cquantize->is_padded)
nuclear@26 770 create_colorindex(cinfo);
nuclear@26 771 /* Create ordered-dither tables if we didn't already. */
nuclear@26 772 if (cquantize->odither[0] == NULL)
nuclear@26 773 create_odither_tables(cinfo);
nuclear@26 774 break;
nuclear@26 775 case JDITHER_FS:
nuclear@26 776 cquantize->pub.color_quantize = quantize_fs_dither;
nuclear@26 777 cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */
nuclear@26 778 /* Allocate Floyd-Steinberg workspace if didn't already. */
nuclear@26 779 if (cquantize->fserrors[0] == NULL)
nuclear@26 780 alloc_fs_workspace(cinfo);
nuclear@26 781 /* Initialize the propagated errors to zero. */
nuclear@26 782 arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));
nuclear@26 783 for (i = 0; i < cinfo->out_color_components; i++)
nuclear@26 784 jzero_far((void FAR *) cquantize->fserrors[i], arraysize);
nuclear@26 785 break;
nuclear@26 786 default:
nuclear@26 787 ERREXIT(cinfo, JERR_NOT_COMPILED);
nuclear@26 788 break;
nuclear@26 789 }
nuclear@26 790 }
nuclear@26 791
nuclear@26 792
nuclear@26 793 /*
nuclear@26 794 * Finish up at the end of the pass.
nuclear@26 795 */
nuclear@26 796
nuclear@26 797 METHODDEF(void)
nuclear@26 798 finish_pass_1_quant (j_decompress_ptr cinfo)
nuclear@26 799 {
nuclear@26 800 /* no work in 1-pass case */
nuclear@26 801 }
nuclear@26 802
nuclear@26 803
nuclear@26 804 /*
nuclear@26 805 * Switch to a new external colormap between output passes.
nuclear@26 806 * Shouldn't get to this module!
nuclear@26 807 */
nuclear@26 808
nuclear@26 809 METHODDEF(void)
nuclear@26 810 new_color_map_1_quant (j_decompress_ptr cinfo)
nuclear@26 811 {
nuclear@26 812 ERREXIT(cinfo, JERR_MODE_CHANGE);
nuclear@26 813 }
nuclear@26 814
nuclear@26 815
nuclear@26 816 /*
nuclear@26 817 * Module initialization routine for 1-pass color quantization.
nuclear@26 818 */
nuclear@26 819
nuclear@26 820 GLOBAL(void)
nuclear@26 821 jinit_1pass_quantizer (j_decompress_ptr cinfo)
nuclear@26 822 {
nuclear@26 823 my_cquantize_ptr cquantize;
nuclear@26 824
nuclear@26 825 cquantize = (my_cquantize_ptr)
nuclear@26 826 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26 827 SIZEOF(my_cquantizer));
nuclear@26 828 cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize;
nuclear@26 829 cquantize->pub.start_pass = start_pass_1_quant;
nuclear@26 830 cquantize->pub.finish_pass = finish_pass_1_quant;
nuclear@26 831 cquantize->pub.new_color_map = new_color_map_1_quant;
nuclear@26 832 cquantize->fserrors[0] = NULL; /* Flag FS workspace not allocated */
nuclear@26 833 cquantize->odither[0] = NULL; /* Also flag odither arrays not allocated */
nuclear@26 834
nuclear@26 835 /* Make sure my internal arrays won't overflow */
nuclear@26 836 if (cinfo->out_color_components > MAX_Q_COMPS)
nuclear@26 837 ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS);
nuclear@26 838 /* Make sure colormap indexes can be represented by JSAMPLEs */
nuclear@26 839 if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1))
nuclear@26 840 ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXJSAMPLE+1);
nuclear@26 841
nuclear@26 842 /* Create the colormap and color index table. */
nuclear@26 843 create_colormap(cinfo);
nuclear@26 844 create_colorindex(cinfo);
nuclear@26 845
nuclear@26 846 /* Allocate Floyd-Steinberg workspace now if requested.
nuclear@26 847 * We do this now since it is FAR storage and may affect the memory
nuclear@26 848 * manager's space calculations. If the user changes to FS dither
nuclear@26 849 * mode in a later pass, we will allocate the space then, and will
nuclear@26 850 * possibly overrun the max_memory_to_use setting.
nuclear@26 851 */
nuclear@26 852 if (cinfo->dither_mode == JDITHER_FS)
nuclear@26 853 alloc_fs_workspace(cinfo);
nuclear@26 854 }
nuclear@26 855
nuclear@26 856 #endif /* QUANT_1PASS_SUPPORTED */