| OLD | NEW |
|---|
| (Empty) |
| 1 /* | |
| 2 * jquant1.c | |
| 3 * | |
| 4 * Copyright (C) 1991-1996, Thomas G. Lane. | |
| 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. | |
| 9 * These routines provide mapping to a fixed color map using equally spaced | |
| 10 * color values. Optional Floyd-Steinberg or ordered dithering is available. | |
| 11 */ | |
| 12 | |
| 13 #define JPEG_INTERNALS | |
| 14 #include "jinclude.h" | |
| 15 #include "jpeglib.h" | |
| 16 | |
| 17 #ifdef QUANT_1PASS_SUPPORTED | |
| 18 | |
| 19 | |
| 20 /* | |
| 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. | |
| 26 * | |
| 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. | |
| 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. | |
| 50 */ | |
| 51 | |
| 52 | |
| 53 /* Declarations for ordered dithering. | |
| 54 * | |
| 55 * We use a standard 16x16 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. | |
| 69 */ | |
| 70 | |
| 71 #define ODITHER_SIZE 16 /* dimension of dither matrix */ | |
| 72 /* NB: if ODITHER_SIZE is not a power of 2, ODITHER_MASK uses will break */ | |
| 73 #define ODITHER_CELLS (ODITHER_SIZE*ODITHER_SIZE) /* # cells in matrix */ | |
| 74 #define ODITHER_MASK (ODITHER_SIZE-1) /* mask for wrapping around counters */ | |
| 75 | |
| 76 typedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE]; | |
| 77 typedef int (*ODITHER_MATRIX_PTR)[ODITHER_SIZE]; | |
| 78 | |
| 79 static const UINT8 base_dither_matrix[ODITHER_SIZE][ODITHER_SIZE] = { | |
| 80 /* Bayer's order-4 dither array. Generated by the code given in | |
| 81 * Stephen Hawley's article "Ordered Dithering" in Graphics Gems I. | |
| 82 * The values in this array must range from 0 to ODITHER_CELLS-1. | |
| 83 */ | |
| 84 { 0,192, 48,240, 12,204, 60,252, 3,195, 51,243, 15,207, 63,255 }, | |
| 85 { 128, 64,176,112,140, 76,188,124,131, 67,179,115,143, 79,191,127 }, | |
| 86 { 32,224, 16,208, 44,236, 28,220, 35,227, 19,211, 47,239, 31,223 }, | |
| 87 { 160, 96,144, 80,172,108,156, 92,163, 99,147, 83,175,111,159, 95 }, | |
| 88 { 8,200, 56,248, 4,196, 52,244, 11,203, 59,251, 7,199, 55,247 }, | |
| 89 { 136, 72,184,120,132, 68,180,116,139, 75,187,123,135, 71,183,119 }, | |
| 90 { 40,232, 24,216, 36,228, 20,212, 43,235, 27,219, 39,231, 23,215 }, | |
| 91 { 168,104,152, 88,164,100,148, 84,171,107,155, 91,167,103,151, 87 }, | |
| 92 { 2,194, 50,242, 14,206, 62,254, 1,193, 49,241, 13,205, 61,253 }, | |
| 93 { 130, 66,178,114,142, 78,190,126,129, 65,177,113,141, 77,189,125 }, | |
| 94 { 34,226, 18,210, 46,238, 30,222, 33,225, 17,209, 45,237, 29,221 }, | |
| 95 { 162, 98,146, 82,174,110,158, 94,161, 97,145, 81,173,109,157, 93 }, | |
| 96 { 10,202, 58,250, 6,198, 54,246, 9,201, 57,249, 5,197, 53,245 }, | |
| 97 { 138, 74,186,122,134, 70,182,118,137, 73,185,121,133, 69,181,117 }, | |
| 98 { 42,234, 26,218, 38,230, 22,214, 41,233, 25,217, 37,229, 21,213 }, | |
| 99 { 170,106,154, 90,166,102,150, 86,169,105,153, 89,165,101,149, 85 } | |
| 100 }; | |
| 101 | |
| 102 | |
| 103 /* Declarations for Floyd-Steinberg dithering. | |
| 104 * | |
| 105 * Errors are accumulated into the array fserrors[], at a resolution of | |
| 106 * 1/16th of a pixel count. The error at a given pixel is propagated | |
| 107 * to its not-yet-processed neighbors using the standard F-S fractions, | |
| 108 * ... (here) 7/16 | |
| 109 * 3/16 5/16 1/16 | |
| 110 * We work left-to-right on even rows, right-to-left on odd rows. | |
| 111 * | |
| 112 * We can get away with a single array (holding one row's worth of errors) | |
| 113 * by using it to store the current row's errors at pixel columns not yet | |
| 114 * processed, but the next row's errors at columns already processed. We | |
| 115 * need only a few extra variables to hold the errors immediately around the | |
| 116 * current column. (If we are lucky, those variables are in registers, but | |
| 117 * even if not, they're probably cheaper to access than array elements are.) | |
| 118 * | |
| 119 * The fserrors[] array is indexed [component#][position]. | |
| 120 * We provide (#columns + 2) entries per component; the extra entry at each | |
| 121 * end saves us from special-casing the first and last pixels. | |
| 122 * | |
| 123 * Note: on a wide image, we might not have enough room in a PC's near data | |
| 124 * segment to hold the error array; so it is allocated with alloc_large. | |
| 125 */ | |
| 126 | |
| 127 #if BITS_IN_JSAMPLE == 8 | |
| 128 typedef INT16 FSERROR; /* 16 bits should be enough */ | |
| 129 typedef int LOCFSERROR; /* use 'int' for calculation temps */ | |
| 130 #else | |
| 131 typedef INT32 FSERROR; /* may need more than 16 bits */ | |
| 132 typedef INT32 LOCFSERROR; /* be sure calculation temps are big enough */ | |
| 133 #endif | |
| 134 | |
| 135 typedef FSERROR FAR *FSERRPTR; /* pointer to error array (in FAR storage!) */ | |
| 136 | |
| 137 | |
| 138 /* Private subobject */ | |
| 139 | |
| 140 #define MAX_Q_COMPS 4 /* max components I can handle */ | |
| 141 | |
| 142 typedef struct { | |
| 143 struct jpeg_color_quantizer pub; /* public fields */ | |
| 144 | |
| 145 /* Initially allocated colormap is saved here */ | |
| 146 JSAMPARRAY sv_colormap; /* The color map as a 2-D pixel array */ | |
| 147 int sv_actual; /* number of entries in use */ | |
| 148 | |
| 149 JSAMPARRAY colorindex; /* Precomputed mapping for speed */ | |
| 150 /* colorindex[i][j] = index of color closest to pixel value j in component i, | |
| 151 * premultiplied as described above. Since colormap indexes must fit into | |
| 152 * JSAMPLEs, the entries of this array will too. | |
| 153 */ | |
| 154 boolean is_padded; /* is the colorindex padded for odither? */ | |
| 155 | |
| 156 int Ncolors[MAX_Q_COMPS]; /* # of values alloced to each component */ | |
| 157 | |
| 158 /* Variables for ordered dithering */ | |
| 159 int row_index; /* cur row's vertical index in dither matrix */ | |
| 160 ODITHER_MATRIX_PTR odither[MAX_Q_COMPS]; /* one dither array per component */ | |
| 161 | |
| 162 /* Variables for Floyd-Steinberg dithering */ | |
| 163 FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */ | |
| 164 boolean on_odd_row; /* flag to remember which row we are on */ | |
| 165 } my_cquantizer; | |
| 166 | |
| 167 typedef my_cquantizer * my_cquantize_ptr; | |
| 168 | |
| 169 | |
| 170 /* | |
| 171 * Policy-making subroutines for create_colormap and create_colorindex. | |
| 172 * These routines determine the colormap to be used. The rest of the module | |
| 173 * only assumes that the colormap is orthogonal. | |
| 174 * | |
| 175 * * select_ncolors decides how to divvy up the available colors | |
| 176 * among the components. | |
| 177 * * output_value defines the set of representative values for a component. | |
| 178 * * largest_input_value defines the mapping from input values to | |
| 179 * representative values for a component. | |
| 180 * Note that the latter two routines may impose different policies for | |
| 181 * different components, though this is not currently done. | |
| 182 */ | |
| 183 | |
| 184 | |
| 185 LOCAL(int) | |
| 186 select_ncolors (j_decompress_ptr cinfo, int Ncolors[]) | |
| 187 /* Determine allocation of desired colors to components, */ | |
| 188 /* and fill in Ncolors[] array to indicate choice. */ | |
| 189 /* Return value is total number of colors (product of Ncolors[] values). */ | |
| 190 { | |
| 191 int nc = cinfo->out_color_components; /* number of color components */ | |
| 192 int max_colors = cinfo->desired_number_of_colors; | |
| 193 int total_colors, iroot, i, j; | |
| 194 boolean changed; | |
| 195 long temp; | |
| 196 static const int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE }; | |
| 197 | |
| 198 /* We can allocate at least the nc'th root of max_colors per component. */ | |
| 199 /* Compute floor(nc'th root of max_colors). */ | |
| 200 iroot = 1; | |
| 201 do { | |
| 202 iroot++; | |
| 203 temp = iroot; /* set temp = iroot ** nc */ | |
| 204 for (i = 1; i < nc; i++) | |
| 205 temp *= iroot; | |
| 206 } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */ | |
| 207 iroot--; /* now iroot = floor(root) */ | |
| 208 | |
| 209 /* Must have at least 2 color values per component */ | |
| 210 if (iroot < 2) | |
| 211 ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int) temp); | |
| 212 | |
| 213 /* Initialize to iroot color values for each component */ | |
| 214 total_colors = 1; | |
| 215 for (i = 0; i < nc; i++) { | |
| 216 Ncolors[i] = iroot; | |
| 217 total_colors *= iroot; | |
| 218 } | |
| 219 /* We may be able to increment the count for one or more components without | |
| 220 * exceeding max_colors, though we know not all can be incremented. | |
| 221 * Sometimes, the first component can be incremented more than once! | |
| 222 * (Example: for 16 colors, we start at 2*2*2, go to 3*2*2, then 4*2*2.) | |
| 223 * In RGB colorspace, try to increment G first, then R, then B. | |
| 224 */ | |
| 225 do { | |
| 226 changed = FALSE; | |
| 227 for (i = 0; i < nc; i++) { | |
| 228 j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i); | |
| 229 /* calculate new total_colors if Ncolors[j] is incremented */ | |
| 230 temp = total_colors / Ncolors[j]; | |
| 231 temp *= Ncolors[j]+1; /* done in long arith to avoid oflo */ | |
| 232 if (temp > (long) max_colors) | |
| 233 break; /* won't fit, done with this pass */ | |
| 234 Ncolors[j]++; /* OK, apply the increment */ | |
| 235 total_colors = (int) temp; | |
| 236 changed = TRUE; | |
| 237 } | |
| 238 } while (changed); | |
| 239 | |
| 240 return total_colors; | |
| 241 } | |
| 242 | |
| 243 | |
| 244 LOCAL(int) | |
| 245 output_value (j_decompress_ptr cinfo, int ci, int j, int maxj) | |
| 246 /* Return j'th output value, where j will range from 0 to maxj */ | |
| 247 /* The output values must fall in 0..MAXJSAMPLE in increasing order */ | |
| 248 { | |
| 249 /* We always provide values 0 and MAXJSAMPLE for each component; | |
| 250 * any additional values are equally spaced between these limits. | |
| 251 * (Forcing the upper and lower values to the limits ensures that | |
| 252 * dithering can't produce a color outside the selected gamut.) | |
| 253 */ | |
| 254 return (int) (((INT32) j * MAXJSAMPLE + maxj/2) / maxj); | |
| 255 } | |
| 256 | |
| 257 | |
| 258 LOCAL(int) | |
| 259 largest_input_value (j_decompress_ptr cinfo, int ci, int j, int maxj) | |
| 260 /* Return largest input value that should map to j'th output value */ | |
| 261 /* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */ | |
| 262 { | |
| 263 /* Breakpoints are halfway between values returned by output_value */ | |
| 264 return (int) (((INT32) (2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj)); | |
| 265 } | |
| 266 | |
| 267 | |
| 268 /* | |
| 269 * Create the colormap. | |
| 270 */ | |
| 271 | |
| 272 LOCAL(void) | |
| 273 create_colormap (j_decompress_ptr cinfo) | |
| 274 { | |
| 275 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; | |
| 276 JSAMPARRAY colormap; /* Created colormap */ | |
| 277 int total_colors; /* Number of distinct output colors */ | |
| 278 int i,j,k, nci, blksize, blkdist, ptr, val; | |
| 279 | |
| 280 /* Select number of colors for each component */ | |
| 281 total_colors = select_ncolors(cinfo, cquantize->Ncolors); | |
| 282 | |
| 283 /* Report selected color counts */ | |
| 284 if (cinfo->out_color_components == 3) | |
| 285 TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS, | |
| 286 total_colors, cquantize->Ncolors[0], | |
| 287 cquantize->Ncolors[1], cquantize->Ncolors[2]); | |
| 288 else | |
| 289 TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors); | |
| 290 | |
| 291 /* Allocate and fill in the colormap. */ | |
| 292 /* The colors are ordered in the map in standard row-major order, */ | |
| 293 /* i.e. rightmost (highest-indexed) color changes most rapidly. */ | |
| 294 | |
| 295 colormap = (*cinfo->mem->alloc_sarray) | |
| 296 ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
| 297 (JDIMENSION) total_colors, (JDIMENSION) cinfo->out_color_components); | |
| 298 | |
| 299 /* blksize is number of adjacent repeated entries for a component */ | |
| 300 /* blkdist is distance between groups of identical entries for a component */ | |
| 301 blkdist = total_colors; | |
| 302 | |
| 303 for (i = 0; i < cinfo->out_color_components; i++) { | |
| 304 /* fill in colormap entries for i'th color component */ | |
| 305 nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ | |
| 306 blksize = blkdist / nci; | |
| 307 for (j = 0; j < nci; j++) { | |
| 308 /* Compute j'th output value (out of nci) for component */ | |
| 309 val = output_value(cinfo, i, j, nci-1); | |
| 310 /* Fill in all colormap entries that have this value of this component */ | |
| 311 for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) { | |
| 312 /* fill in blksize entries beginning at ptr */ | |
| 313 for (k = 0; k < blksize; k++) | |
| 314 colormap[i][ptr+k] = (JSAMPLE) val; | |
| 315 } | |
| 316 } | |
| 317 blkdist = blksize; /* blksize of this color is blkdist of next */ | |
| 318 } | |
| 319 | |
| 320 /* Save the colormap in private storage, | |
| 321 * where it will survive color quantization mode changes. | |
| 322 */ | |
| 323 cquantize->sv_colormap = colormap; | |
| 324 cquantize->sv_actual = total_colors; | |
| 325 } | |
| 326 | |
| 327 | |
| 328 /* | |
| 329 * Create the color index table. | |
| 330 */ | |
| 331 | |
| 332 LOCAL(void) | |
| 333 create_colorindex (j_decompress_ptr cinfo) | |
| 334 { | |
| 335 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; | |
| 336 JSAMPROW indexptr; | |
| 337 int i,j,k, nci, blksize, val, pad; | |
| 338 | |
| 339 /* For ordered dither, we pad the color index tables by MAXJSAMPLE in | |
| 340 * each direction (input index values can be -MAXJSAMPLE .. 2*MAXJSAMPLE). | |
| 341 * This is not necessary in the other dithering modes. However, we | |
| 342 * flag whether it was done in case user changes dithering mode. | |
| 343 */ | |
| 344 if (cinfo->dither_mode == JDITHER_ORDERED) { | |
| 345 pad = MAXJSAMPLE*2; | |
| 346 cquantize->is_padded = TRUE; | |
| 347 } else { | |
| 348 pad = 0; | |
| 349 cquantize->is_padded = FALSE; | |
| 350 } | |
| 351 | |
| 352 cquantize->colorindex = (*cinfo->mem->alloc_sarray) | |
| 353 ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
| 354 (JDIMENSION) (MAXJSAMPLE+1 + pad), | |
| 355 (JDIMENSION) cinfo->out_color_components); | |
| 356 | |
| 357 /* blksize is number of adjacent repeated entries for a component */ | |
| 358 blksize = cquantize->sv_actual; | |
| 359 | |
| 360 for (i = 0; i < cinfo->out_color_components; i++) { | |
| 361 /* fill in colorindex entries for i'th color component */ | |
| 362 nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ | |
| 363 blksize = blksize / nci; | |
| 364 | |
| 365 /* adjust colorindex pointers to provide padding at negative indexes. */ | |
| 366 if (pad) | |
| 367 cquantize->colorindex[i] += MAXJSAMPLE; | |
| 368 | |
| 369 /* in loop, val = index of current output value, */ | |
| 370 /* and k = largest j that maps to current val */ | |
| 371 indexptr = cquantize->colorindex[i]; | |
| 372 val = 0; | |
| 373 k = largest_input_value(cinfo, i, 0, nci-1); | |
| 374 for (j = 0; j <= MAXJSAMPLE; j++) { | |
| 375 while (j > k) /* advance val if past boundary */ | |
| 376 k = largest_input_value(cinfo, i, ++val, nci-1); | |
| 377 /* premultiply so that no multiplication needed in main processing */ | |
| 378 indexptr[j] = (JSAMPLE) (val * blksize); | |
| 379 } | |
| 380 /* Pad at both ends if necessary */ | |
| 381 if (pad) | |
| 382 for (j = 1; j <= MAXJSAMPLE; j++) { | |
| 383 indexptr[-j] = indexptr[0]; | |
| 384 indexptr[MAXJSAMPLE+j] = indexptr[MAXJSAMPLE]; | |
| 385 } | |
| 386 } | |
| 387 } | |
| 388 | |
| 389 | |
| 390 /* | |
| 391 * Create an ordered-dither array for a component having ncolors | |
| 392 * distinct output values. | |
| 393 */ | |
| 394 | |
| 395 LOCAL(ODITHER_MATRIX_PTR) | |
| 396 make_odither_array (j_decompress_ptr cinfo, int ncolors) | |
| 397 { | |
| 398 ODITHER_MATRIX_PTR odither; | |
| 399 int j,k; | |
| 400 INT32 num,den; | |
| 401 | |
| 402 odither = (ODITHER_MATRIX_PTR) | |
| 403 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
| 404 SIZEOF(ODITHER_MATRIX)); | |
| 405 /* The inter-value distance for this color is MAXJSAMPLE/(ncolors-1). | |
| 406 * Hence the dither value for the matrix cell with fill order f | |
| 407 * (f=0..N-1) should be (N-1-2*f)/(2*N) * MAXJSAMPLE/(ncolors-1). | |
| 408 * On 16-bit-int machine, be careful to avoid overflow. | |
| 409 */ | |
| 410 den = 2 * ODITHER_CELLS * ((INT32) (ncolors - 1)); | |
| 411 for (j = 0; j < ODITHER_SIZE; j++) { | |
| 412 for (k = 0; k < ODITHER_SIZE; k++) { | |
| 413 num = ((INT32) (ODITHER_CELLS-1 - 2*((int)base_dither_matrix[j][k]))) | |
| 414 * MAXJSAMPLE; | |
| 415 /* Ensure round towards zero despite C's lack of consistency | |
| 416 * about rounding negative values in integer division... | |
| 417 */ | |
| 418 odither[j][k] = (int) (num<0 ? -((-num)/den) : num/den); | |
| 419 } | |
| 420 } | |
| 421 return odither; | |
| 422 } | |
| 423 | |
| 424 | |
| 425 /* | |
| 426 * Create the ordered-dither tables. | |
| 427 * Components having the same number of representative colors may | |
| 428 * share a dither table. | |
| 429 */ | |
| 430 | |
| 431 LOCAL(void) | |
| 432 create_odither_tables (j_decompress_ptr cinfo) | |
| 433 { | |
| 434 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; | |
| 435 ODITHER_MATRIX_PTR odither; | |
| 436 int i, j, nci; | |
| 437 | |
| 438 for (i = 0; i < cinfo->out_color_components; i++) { | |
| 439 nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ | |
| 440 odither = NULL; /* search for matching prior component */ | |
| 441 for (j = 0; j < i; j++) { | |
| 442 if (nci == cquantize->Ncolors[j]) { | |
| 443 odither = cquantize->odither[j]; | |
| 444 break; | |
| 445 } | |
| 446 } | |
| 447 if (odither == NULL) /* need a new table? */ | |
| 448 odither = make_odither_array(cinfo, nci); | |
| 449 cquantize->odither[i] = odither; | |
| 450 } | |
| 451 } | |
| 452 | |
| 453 | |
| 454 /* | |
| 455 * Map some rows of pixels to the output colormapped representation. | |
| 456 */ | |
| 457 | |
| 458 METHODDEF(void) | |
| 459 color_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf, | |
| 460 JSAMPARRAY output_buf, int num_rows) | |
| 461 /* General case, no dithering */ | |
| 462 { | |
| 463 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; | |
| 464 JSAMPARRAY colorindex = cquantize->colorindex; | |
| 465 register int pixcode, ci; | |
| 466 register JSAMPROW ptrin, ptrout; | |
| 467 int row; | |
| 468 JDIMENSION col; | |
| 469 JDIMENSION width = cinfo->output_width; | |
| 470 register int nc = cinfo->out_color_components; | |
| 471 | |
| 472 for (row = 0; row < num_rows; row++) { | |
| 473 ptrin = input_buf[row]; | |
| 474 ptrout = output_buf[row]; | |
| 475 for (col = width; col > 0; col--) { | |
| 476 pixcode = 0; | |
| 477 for (ci = 0; ci < nc; ci++) { | |
| 478 pixcode += GETJSAMPLE(colorindex[ci][GETJSAMPLE(*ptrin++)]); | |
| 479 } | |
| 480 *ptrout++ = (JSAMPLE) pixcode; | |
| 481 } | |
| 482 } | |
| 483 } | |
| 484 | |
| 485 | |
| 486 METHODDEF(void) | |
| 487 color_quantize3 (j_decompress_ptr cinfo, JSAMPARRAY input_buf, | |
| 488 JSAMPARRAY output_buf, int num_rows) | |
| 489 /* Fast path for out_color_components==3, no dithering */ | |
| 490 { | |
| 491 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; | |
| 492 register int pixcode; | |
| 493 register JSAMPROW ptrin, ptrout; | |
| 494 JSAMPROW colorindex0 = cquantize->colorindex[0]; | |
| 495 JSAMPROW colorindex1 = cquantize->colorindex[1]; | |
| 496 JSAMPROW colorindex2 = cquantize->colorindex[2]; | |
| 497 int row; | |
| 498 JDIMENSION col; | |
| 499 JDIMENSION width = cinfo->output_width; | |
| 500 | |
| 501 for (row = 0; row < num_rows; row++) { | |
| 502 ptrin = input_buf[row]; | |
| 503 ptrout = output_buf[row]; | |
| 504 for (col = width; col > 0; col--) { | |
| 505 pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*ptrin++)]); | |
| 506 pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*ptrin++)]); | |
| 507 pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*ptrin++)]); | |
| 508 *ptrout++ = (JSAMPLE) pixcode; | |
| 509 } | |
| 510 } | |
| 511 } | |
| 512 | |
| 513 | |
| 514 METHODDEF(void) | |
| 515 quantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, | |
| 516 JSAMPARRAY output_buf, int num_rows) | |
| 517 /* General case, with ordered dithering */ | |
| 518 { | |
| 519 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; | |
| 520 register JSAMPROW input_ptr; | |
| 521 register JSAMPROW output_ptr; | |
| 522 JSAMPROW colorindex_ci; | |
| 523 int * dither; /* points to active row of dither matrix */ | |
| 524 int row_index, col_index; /* current indexes into dither matrix */ | |
| 525 int nc = cinfo->out_color_components; | |
| 526 int ci; | |
| 527 int row; | |
| 528 JDIMENSION col; | |
| 529 JDIMENSION width = cinfo->output_width; | |
| 530 | |
| 531 for (row = 0; row < num_rows; row++) { | |
| 532 /* Initialize output values to 0 so can process components separately */ | |
| 533 jzero_far((void FAR *) output_buf[row], | |
| 534 (size_t) (width * SIZEOF(JSAMPLE))); | |
| 535 row_index = cquantize->row_index; | |
| 536 for (ci = 0; ci < nc; ci++) { | |
| 537 input_ptr = input_buf[row] + ci; | |
| 538 output_ptr = output_buf[row]; | |
| 539 colorindex_ci = cquantize->colorindex[ci]; | |
| 540 dither = cquantize->odither[ci][row_index]; | |
| 541 col_index = 0; | |
| 542 | |
| 543 for (col = width; col > 0; col--) { | |
| 544 /* Form pixel value + dither, range-limit to 0..MAXJSAMPLE, | |
| 545 * select output value, accumulate into output code for this pixel. | |
| 546 * Range-limiting need not be done explicitly, as we have extended | |
| 547 * the colorindex table to produce the right answers for out-of-range | |
| 548 * inputs. The maximum dither is +- MAXJSAMPLE; this sets the | |
| 549 * required amount of padding. | |
| 550 */ | |
| 551 *output_ptr += colorindex_ci[GETJSAMPLE(*input_ptr)+dither[col_index]]; | |
| 552 input_ptr += nc; | |
| 553 output_ptr++; | |
| 554 col_index = (col_index + 1) & ODITHER_MASK; | |
| 555 } | |
| 556 } | |
| 557 /* Advance row index for next row */ | |
| 558 row_index = (row_index + 1) & ODITHER_MASK; | |
| 559 cquantize->row_index = row_index; | |
| 560 } | |
| 561 } | |
| 562 | |
| 563 | |
| 564 METHODDEF(void) | |
| 565 quantize3_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, | |
| 566 JSAMPARRAY output_buf, int num_rows) | |
| 567 /* Fast path for out_color_components==3, with ordered dithering */ | |
| 568 { | |
| 569 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; | |
| 570 register int pixcode; | |
| 571 register JSAMPROW input_ptr; | |
| 572 register JSAMPROW output_ptr; | |
| 573 JSAMPROW colorindex0 = cquantize->colorindex[0]; | |
| 574 JSAMPROW colorindex1 = cquantize->colorindex[1]; | |
| 575 JSAMPROW colorindex2 = cquantize->colorindex[2]; | |
| 576 int * dither0; /* points to active row of dither matrix */ | |
| 577 int * dither1; | |
| 578 int * dither2; | |
| 579 int row_index, col_index; /* current indexes into dither matrix */ | |
| 580 int row; | |
| 581 JDIMENSION col; | |
| 582 JDIMENSION width = cinfo->output_width; | |
| 583 | |
| 584 for (row = 0; row < num_rows; row++) { | |
| 585 row_index = cquantize->row_index; | |
| 586 input_ptr = input_buf[row]; | |
| 587 output_ptr = output_buf[row]; | |
| 588 dither0 = cquantize->odither[0][row_index]; | |
| 589 dither1 = cquantize->odither[1][row_index]; | |
| 590 dither2 = cquantize->odither[2][row_index]; | |
| 591 col_index = 0; | |
| 592 | |
| 593 for (col = width; col > 0; col--) { | |
| 594 pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*input_ptr++) + | |
| 595 dither0[col_index]]); | |
| 596 pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*input_ptr++) + | |
| 597 dither1[col_index]]); | |
| 598 pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*input_ptr++) + | |
| 599 dither2[col_index]]); | |
| 600 *output_ptr++ = (JSAMPLE) pixcode; | |
| 601 col_index = (col_index + 1) & ODITHER_MASK; | |
| 602 } | |
| 603 row_index = (row_index + 1) & ODITHER_MASK; | |
| 604 cquantize->row_index = row_index; | |
| 605 } | |
| 606 } | |
| 607 | |
| 608 | |
| 609 METHODDEF(void) | |
| 610 quantize_fs_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, | |
| 611 JSAMPARRAY output_buf, int num_rows) | |
| 612 /* General case, with Floyd-Steinberg dithering */ | |
| 613 { | |
| 614 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; | |
| 615 register LOCFSERROR cur; /* current error or pixel value */ | |
| 616 LOCFSERROR belowerr; /* error for pixel below cur */ | |
| 617 LOCFSERROR bpreverr; /* error for below/prev col */ | |
| 618 LOCFSERROR bnexterr; /* error for below/next col */ | |
| 619 LOCFSERROR delta; | |
| 620 register FSERRPTR errorptr; /* => fserrors[] at column before current */ | |
| 621 register JSAMPROW input_ptr; | |
| 622 register JSAMPROW output_ptr; | |
| 623 JSAMPROW colorindex_ci; | |
| 624 JSAMPROW colormap_ci; | |
| 625 int pixcode; | |
| 626 int nc = cinfo->out_color_components; | |
| 627 int dir; /* 1 for left-to-right, -1 for right-to-left */ | |
| 628 int dirnc; /* dir * nc */ | |
| 629 int ci; | |
| 630 int row; | |
| 631 JDIMENSION col; | |
| 632 JDIMENSION width = cinfo->output_width; | |
| 633 JSAMPLE *range_limit = cinfo->sample_range_limit; | |
| 634 SHIFT_TEMPS | |
| 635 | |
| 636 for (row = 0; row < num_rows; row++) { | |
| 637 /* Initialize output values to 0 so can process components separately */ | |
| 638 jzero_far((void FAR *) output_buf[row], | |
| 639 (size_t) (width * SIZEOF(JSAMPLE))); | |
| 640 for (ci = 0; ci < nc; ci++) { | |
| 641 input_ptr = input_buf[row] + ci; | |
| 642 output_ptr = output_buf[row]; | |
| 643 if (cquantize->on_odd_row) { | |
| 644 /* work right to left in this row */ | |
| 645 input_ptr += (width-1) * nc; /* so point to rightmost pixel */ | |
| 646 output_ptr += width-1; | |
| 647 dir = -1; | |
| 648 dirnc = -nc; | |
| 649 errorptr = cquantize->fserrors[ci] + (width+1); /* => entry after last c
olumn */ | |
| 650 } else { | |
| 651 /* work left to right in this row */ | |
| 652 dir = 1; | |
| 653 dirnc = nc; | |
| 654 errorptr = cquantize->fserrors[ci]; /* => entry before first column */ | |
| 655 } | |
| 656 colorindex_ci = cquantize->colorindex[ci]; | |
| 657 colormap_ci = cquantize->sv_colormap[ci]; | |
| 658 /* Preset error values: no error propagated to first pixel from left */ | |
| 659 cur = 0; | |
| 660 /* and no error propagated to row below yet */ | |
| 661 belowerr = bpreverr = 0; | |
| 662 | |
| 663 for (col = width; col > 0; col--) { | |
| 664 /* cur holds the error propagated from the previous pixel on the | |
| 665 * current line. Add the error propagated from the previous line | |
| 666 * to form the complete error correction term for this pixel, and | |
| 667 * round the error term (which is expressed * 16) to an integer. | |
| 668 * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct | |
| 669 * for either sign of the error value. | |
| 670 * Note: errorptr points to *previous* column's array entry. | |
| 671 */ | |
| 672 cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4); | |
| 673 /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE. | |
| 674 * The maximum error is +- MAXJSAMPLE; this sets the required size | |
| 675 * of the range_limit array. | |
| 676 */ | |
| 677 cur += GETJSAMPLE(*input_ptr); | |
| 678 cur = GETJSAMPLE(range_limit[cur]); | |
| 679 /* Select output value, accumulate into output code for this pixel */ | |
| 680 pixcode = GETJSAMPLE(colorindex_ci[cur]); | |
| 681 *output_ptr += (JSAMPLE) pixcode; | |
| 682 /* Compute actual representation error at this pixel */ | |
| 683 /* Note: we can do this even though we don't have the final */ | |
| 684 /* pixel code, because the colormap is orthogonal. */ | |
| 685 cur -= GETJSAMPLE(colormap_ci[pixcode]); | |
| 686 /* Compute error fractions to be propagated to adjacent pixels. | |
| 687 * Add these into the running sums, and simultaneously shift the | |
| 688 * next-line error sums left by 1 column. | |
| 689 */ | |
| 690 bnexterr = cur; | |
| 691 delta = cur * 2; | |
| 692 cur += delta; /* form error * 3 */ | |
| 693 errorptr[0] = (FSERROR) (bpreverr + cur); | |
| 694 cur += delta; /* form error * 5 */ | |
| 695 bpreverr = belowerr + cur; | |
| 696 belowerr = bnexterr; | |
| 697 cur += delta; /* form error * 7 */ | |
| 698 /* At this point cur contains the 7/16 error value to be propagated | |
| 699 * to the next pixel on the current line, and all the errors for the | |
| 700 * next line have been shifted over. We are therefore ready to move on. | |
| 701 */ | |
| 702 input_ptr += dirnc; /* advance input ptr to next column */ | |
| 703 output_ptr += dir; /* advance output ptr to next column */ | |
| 704 errorptr += dir; /* advance errorptr to current column */ | |
| 705 } | |
| 706 /* Post-loop cleanup: we must unload the final error value into the | |
| 707 * final fserrors[] entry. Note we need not unload belowerr because | |
| 708 * it is for the dummy column before or after the actual array. | |
| 709 */ | |
| 710 errorptr[0] = (FSERROR) bpreverr; /* unload prev err into array */ | |
| 711 } | |
| 712 cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE); | |
| 713 } | |
| 714 } | |
| 715 | |
| 716 | |
| 717 /* | |
| 718 * Allocate workspace for Floyd-Steinberg errors. | |
| 719 */ | |
| 720 | |
| 721 LOCAL(void) | |
| 722 alloc_fs_workspace (j_decompress_ptr cinfo) | |
| 723 { | |
| 724 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; | |
| 725 size_t arraysize; | |
| 726 int i; | |
| 727 | |
| 728 arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR)); | |
| 729 for (i = 0; i < cinfo->out_color_components; i++) { | |
| 730 cquantize->fserrors[i] = (FSERRPTR) | |
| 731 (*cinfo->mem->alloc_large)((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize); | |
| 732 } | |
| 733 } | |
| 734 | |
| 735 | |
| 736 /* | |
| 737 * Initialize for one-pass color quantization. | |
| 738 */ | |
| 739 | |
| 740 METHODDEF(void) | |
| 741 start_pass_1_quant (j_decompress_ptr cinfo, boolean is_pre_scan) | |
| 742 { | |
| 743 my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; | |
| 744 size_t arraysize; | |
| 745 int i; | |
| 746 | |
| 747 /* Install my colormap. */ | |
| 748 cinfo->colormap = cquantize->sv_colormap; | |
| 749 cinfo->actual_number_of_colors = cquantize->sv_actual; | |
| 750 | |
| 751 /* Initialize for desired dithering mode. */ | |
| 752 switch (cinfo->dither_mode) { | |
| 753 case JDITHER_NONE: | |
| 754 if (cinfo->out_color_components == 3) | |
| 755 cquantize->pub.color_quantize = color_quantize3; | |
| 756 else | |
| 757 cquantize->pub.color_quantize = color_quantize; | |
| 758 break; | |
| 759 case JDITHER_ORDERED: | |
| 760 if (cinfo->out_color_components == 3) | |
| 761 cquantize->pub.color_quantize = quantize3_ord_dither; | |
| 762 else | |
| 763 cquantize->pub.color_quantize = quantize_ord_dither; | |
| 764 cquantize->row_index = 0; /* initialize state for ordered dither */ | |
| 765 /* If user changed to ordered dither from another mode, | |
| 766 * we must recreate the color index table with padding. | |
| 767 * This will cost extra space, but probably isn't very likely. | |
| 768 */ | |
| 769 if (! cquantize->is_padded) | |
| 770 create_colorindex(cinfo); | |
| 771 /* Create ordered-dither tables if we didn't already. */ | |
| 772 if (cquantize->odither[0] == NULL) | |
| 773 create_odither_tables(cinfo); | |
| 774 break; | |
| 775 case JDITHER_FS: | |
| 776 cquantize->pub.color_quantize = quantize_fs_dither; | |
| 777 cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */ | |
| 778 /* Allocate Floyd-Steinberg workspace if didn't already. */ | |
| 779 if (cquantize->fserrors[0] == NULL) | |
| 780 alloc_fs_workspace(cinfo); | |
| 781 /* Initialize the propagated errors to zero. */ | |
| 782 arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR)); | |
| 783 for (i = 0; i < cinfo->out_color_components; i++) | |
| 784 jzero_far((void FAR *) cquantize->fserrors[i], arraysize); | |
| 785 break; | |
| 786 default: | |
| 787 ERREXIT(cinfo, JERR_NOT_COMPILED); | |
| 788 break; | |
| 789 } | |
| 790 } | |
| 791 | |
| 792 | |
| 793 /* | |
| 794 * Finish up at the end of the pass. | |
| 795 */ | |
| 796 | |
| 797 METHODDEF(void) | |
| 798 finish_pass_1_quant (j_decompress_ptr cinfo) | |
| 799 { | |
| 800 /* no work in 1-pass case */ | |
| 801 } | |
| 802 | |
| 803 | |
| 804 /* | |
| 805 * Switch to a new external colormap between output passes. | |
| 806 * Shouldn't get to this module! | |
| 807 */ | |
| 808 | |
| 809 METHODDEF(void) | |
| 810 new_color_map_1_quant (j_decompress_ptr cinfo) | |
| 811 { | |
| 812 ERREXIT(cinfo, JERR_MODE_CHANGE); | |
| 813 } | |
| 814 | |
| 815 | |
| 816 /* | |
| 817 * Module initialization routine for 1-pass color quantization. | |
| 818 */ | |
| 819 | |
| 820 GLOBAL(void) | |
| 821 jinit_1pass_quantizer (j_decompress_ptr cinfo) | |
| 822 { | |
| 823 my_cquantize_ptr cquantize; | |
| 824 | |
| 825 cquantize = (my_cquantize_ptr) | |
| 826 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
| 827 SIZEOF(my_cquantizer)); | |
| 828 cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize; | |
| 829 cquantize->pub.start_pass = start_pass_1_quant; | |
| 830 cquantize->pub.finish_pass = finish_pass_1_quant; | |
| 831 cquantize->pub.new_color_map = new_color_map_1_quant; | |
| 832 cquantize->fserrors[0] = NULL; /* Flag FS workspace not allocated */ | |
| 833 cquantize->odither[0] = NULL; /* Also flag odither arrays not allocated */ | |
| 834 | |
| 835 /* Make sure my internal arrays won't overflow */ | |
| 836 if (cinfo->out_color_components > MAX_Q_COMPS) | |
| 837 ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS); | |
| 838 /* Make sure colormap indexes can be represented by JSAMPLEs */ | |
| 839 if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1)) | |
| 840 ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXJSAMPLE+1); | |
| 841 | |
| 842 /* Create the colormap and color index table. */ | |
| 843 create_colormap(cinfo); | |
| 844 create_colorindex(cinfo); | |
| 845 | |
| 846 /* Allocate Floyd-Steinberg workspace now if requested. | |
| 847 * We do this now since it is FAR storage and may affect the memory | |
| 848 * manager's space calculations. If the user changes to FS dither | |
| 849 * mode in a later pass, we will allocate the space then, and will | |
| 850 * possibly overrun the max_memory_to_use setting. | |
| 851 */ | |
| 852 if (cinfo->dither_mode == JDITHER_FS) | |
| 853 alloc_fs_workspace(cinfo); | |
| 854 } | |
| 855 | |
| 856 #endif /* QUANT_1PASS_SUPPORTED */ | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 1705523002:
Remove libjpeg and libjpeg_turbo. (Closed)
Base URL: https://github.com/domokit/mojo.git@master