/src/libjpeg-turbo.main/jquant1.c
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1 | | /* |
2 | | * jquant1.c |
3 | | * |
4 | | * This file was part of the Independent JPEG Group's software: |
5 | | * Copyright (C) 1991-1996, Thomas G. Lane. |
6 | | * libjpeg-turbo Modifications: |
7 | | * Copyright (C) 2009, 2015, 2022, D. R. Commander. |
8 | | * For conditions of distribution and use, see the accompanying README.ijg |
9 | | * file. |
10 | | * |
11 | | * This file contains 1-pass color quantization (color mapping) routines. |
12 | | * These routines provide mapping to a fixed color map using equally spaced |
13 | | * color values. Optional Floyd-Steinberg or ordered dithering is available. |
14 | | */ |
15 | | |
16 | | #define JPEG_INTERNALS |
17 | | #include "jinclude.h" |
18 | | #include "jpeglib.h" |
19 | | #include "jsamplecomp.h" |
20 | | |
21 | | #if defined(QUANT_1PASS_SUPPORTED) && \ |
22 | | (BITS_IN_JSAMPLE != 16 || defined(D_LOSSLESS_SUPPORTED)) |
23 | | |
24 | | |
25 | | /* |
26 | | * The main purpose of 1-pass quantization is to provide a fast, if not very |
27 | | * high quality, colormapped output capability. A 2-pass quantizer usually |
28 | | * gives better visual quality; however, for quantized grayscale output this |
29 | | * quantizer is perfectly adequate. Dithering is highly recommended with this |
30 | | * quantizer, though you can turn it off if you really want to. |
31 | | * |
32 | | * In 1-pass quantization the colormap must be chosen in advance of seeing the |
33 | | * image. We use a map consisting of all combinations of Ncolors[i] color |
34 | | * values for the i'th component. The Ncolors[] values are chosen so that |
35 | | * their product, the total number of colors, is no more than that requested. |
36 | | * (In most cases, the product will be somewhat less.) |
37 | | * |
38 | | * Since the colormap is orthogonal, the representative value for each color |
39 | | * component can be determined without considering the other components; |
40 | | * then these indexes can be combined into a colormap index by a standard |
41 | | * N-dimensional-array-subscript calculation. Most of the arithmetic involved |
42 | | * can be precalculated and stored in the lookup table colorindex[]. |
43 | | * colorindex[i][j] maps pixel value j in component i to the nearest |
44 | | * representative value (grid plane) for that component; this index is |
45 | | * multiplied by the array stride for component i, so that the |
46 | | * index of the colormap entry closest to a given pixel value is just |
47 | | * sum( colorindex[component-number][pixel-component-value] ) |
48 | | * Aside from being fast, this scheme allows for variable spacing between |
49 | | * representative values with no additional lookup cost. |
50 | | * |
51 | | * If gamma correction has been applied in color conversion, it might be wise |
52 | | * to adjust the color grid spacing so that the representative colors are |
53 | | * equidistant in linear space. At this writing, gamma correction is not |
54 | | * implemented by jdcolor, so nothing is done here. |
55 | | */ |
56 | | |
57 | | |
58 | | /* Declarations for ordered dithering. |
59 | | * |
60 | | * We use a standard 16x16 ordered dither array. The basic concept of ordered |
61 | | * dithering is described in many references, for instance Dale Schumacher's |
62 | | * chapter II.2 of Graphics Gems II (James Arvo, ed. Academic Press, 1991). |
63 | | * In place of Schumacher's comparisons against a "threshold" value, we add a |
64 | | * "dither" value to the input pixel and then round the result to the nearest |
65 | | * output value. The dither value is equivalent to (0.5 - threshold) times |
66 | | * the distance between output values. For ordered dithering, we assume that |
67 | | * the output colors are equally spaced; if not, results will probably be |
68 | | * worse, since the dither may be too much or too little at a given point. |
69 | | * |
70 | | * The normal calculation would be to form pixel value + dither, range-limit |
71 | | * this to 0.._MAXJSAMPLE, and then index into the colorindex table as usual. |
72 | | * We can skip the separate range-limiting step by extending the colorindex |
73 | | * table in both directions. |
74 | | */ |
75 | | |
76 | 0 | #define ODITHER_SIZE 16 /* dimension of dither matrix */ |
77 | | /* NB: if ODITHER_SIZE is not a power of 2, ODITHER_MASK uses will break */ |
78 | 0 | #define ODITHER_CELLS (ODITHER_SIZE * ODITHER_SIZE) /* # cells in matrix */ |
79 | 0 | #define ODITHER_MASK (ODITHER_SIZE - 1) /* mask for wrapping around |
80 | | counters */ |
81 | | |
82 | | typedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE]; |
83 | | typedef int (*ODITHER_MATRIX_PTR)[ODITHER_SIZE]; |
84 | | |
85 | | static const UINT8 base_dither_matrix[ODITHER_SIZE][ODITHER_SIZE] = { |
86 | | /* Bayer's order-4 dither array. Generated by the code given in |
87 | | * Stephen Hawley's article "Ordered Dithering" in Graphics Gems I. |
88 | | * The values in this array must range from 0 to ODITHER_CELLS-1. |
89 | | */ |
90 | | { 0,192, 48,240, 12,204, 60,252, 3,195, 51,243, 15,207, 63,255 }, |
91 | | { 128, 64,176,112,140, 76,188,124,131, 67,179,115,143, 79,191,127 }, |
92 | | { 32,224, 16,208, 44,236, 28,220, 35,227, 19,211, 47,239, 31,223 }, |
93 | | { 160, 96,144, 80,172,108,156, 92,163, 99,147, 83,175,111,159, 95 }, |
94 | | { 8,200, 56,248, 4,196, 52,244, 11,203, 59,251, 7,199, 55,247 }, |
95 | | { 136, 72,184,120,132, 68,180,116,139, 75,187,123,135, 71,183,119 }, |
96 | | { 40,232, 24,216, 36,228, 20,212, 43,235, 27,219, 39,231, 23,215 }, |
97 | | { 168,104,152, 88,164,100,148, 84,171,107,155, 91,167,103,151, 87 }, |
98 | | { 2,194, 50,242, 14,206, 62,254, 1,193, 49,241, 13,205, 61,253 }, |
99 | | { 130, 66,178,114,142, 78,190,126,129, 65,177,113,141, 77,189,125 }, |
100 | | { 34,226, 18,210, 46,238, 30,222, 33,225, 17,209, 45,237, 29,221 }, |
101 | | { 162, 98,146, 82,174,110,158, 94,161, 97,145, 81,173,109,157, 93 }, |
102 | | { 10,202, 58,250, 6,198, 54,246, 9,201, 57,249, 5,197, 53,245 }, |
103 | | { 138, 74,186,122,134, 70,182,118,137, 73,185,121,133, 69,181,117 }, |
104 | | { 42,234, 26,218, 38,230, 22,214, 41,233, 25,217, 37,229, 21,213 }, |
105 | | { 170,106,154, 90,166,102,150, 86,169,105,153, 89,165,101,149, 85 } |
106 | | }; |
107 | | |
108 | | |
109 | | /* Declarations for Floyd-Steinberg dithering. |
110 | | * |
111 | | * Errors are accumulated into the array fserrors[], at a resolution of |
112 | | * 1/16th of a pixel count. The error at a given pixel is propagated |
113 | | * to its not-yet-processed neighbors using the standard F-S fractions, |
114 | | * ... (here) 7/16 |
115 | | * 3/16 5/16 1/16 |
116 | | * We work left-to-right on even rows, right-to-left on odd rows. |
117 | | * |
118 | | * We can get away with a single array (holding one row's worth of errors) |
119 | | * by using it to store the current row's errors at pixel columns not yet |
120 | | * processed, but the next row's errors at columns already processed. We |
121 | | * need only a few extra variables to hold the errors immediately around the |
122 | | * current column. (If we are lucky, those variables are in registers, but |
123 | | * even if not, they're probably cheaper to access than array elements are.) |
124 | | * |
125 | | * The fserrors[] array is indexed [component#][position]. |
126 | | * We provide (#columns + 2) entries per component; the extra entry at each |
127 | | * end saves us from special-casing the first and last pixels. |
128 | | */ |
129 | | |
130 | | #if BITS_IN_JSAMPLE == 8 |
131 | | typedef INT16 FSERROR; /* 16 bits should be enough */ |
132 | | typedef int LOCFSERROR; /* use 'int' for calculation temps */ |
133 | | #else |
134 | | typedef JLONG FSERROR; /* may need more than 16 bits */ |
135 | | typedef JLONG LOCFSERROR; /* be sure calculation temps are big enough */ |
136 | | #endif |
137 | | |
138 | | typedef FSERROR *FSERRPTR; /* pointer to error array */ |
139 | | |
140 | | |
141 | | /* Private subobject */ |
142 | | |
143 | 0 | #define MAX_Q_COMPS 4 /* max components I can handle */ |
144 | | |
145 | | typedef struct { |
146 | | struct jpeg_color_quantizer pub; /* public fields */ |
147 | | |
148 | | /* Initially allocated colormap is saved here */ |
149 | | _JSAMPARRAY sv_colormap; /* The color map as a 2-D pixel array */ |
150 | | int sv_actual; /* number of entries in use */ |
151 | | |
152 | | _JSAMPARRAY colorindex; /* Precomputed mapping for speed */ |
153 | | /* colorindex[i][j] = index of color closest to pixel value j in component i, |
154 | | * premultiplied as described above. Since colormap indexes must fit into |
155 | | * _JSAMPLEs, the entries of this array will too. |
156 | | */ |
157 | | boolean is_padded; /* is the colorindex padded for odither? */ |
158 | | |
159 | | int Ncolors[MAX_Q_COMPS]; /* # of values allocated to each component */ |
160 | | |
161 | | /* Variables for ordered dithering */ |
162 | | int row_index; /* cur row's vertical index in dither matrix */ |
163 | | ODITHER_MATRIX_PTR odither[MAX_Q_COMPS]; /* one dither array per component */ |
164 | | |
165 | | /* Variables for Floyd-Steinberg dithering */ |
166 | | FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */ |
167 | | boolean on_odd_row; /* flag to remember which row we are on */ |
168 | | } my_cquantizer; |
169 | | |
170 | | typedef my_cquantizer *my_cquantize_ptr; |
171 | | |
172 | | |
173 | | /* |
174 | | * Policy-making subroutines for create_colormap and create_colorindex. |
175 | | * These routines determine the colormap to be used. The rest of the module |
176 | | * only assumes that the colormap is orthogonal. |
177 | | * |
178 | | * * select_ncolors decides how to divvy up the available colors |
179 | | * among the components. |
180 | | * * output_value defines the set of representative values for a component. |
181 | | * * largest_input_value defines the mapping from input values to |
182 | | * representative values for a component. |
183 | | * Note that the latter two routines may impose different policies for |
184 | | * different components, though this is not currently done. |
185 | | */ |
186 | | |
187 | | |
188 | | LOCAL(int) |
189 | | select_ncolors(j_decompress_ptr cinfo, int Ncolors[]) |
190 | | /* Determine allocation of desired colors to components, */ |
191 | | /* and fill in Ncolors[] array to indicate choice. */ |
192 | | /* Return value is total number of colors (product of Ncolors[] values). */ |
193 | 0 | { |
194 | 0 | int nc = cinfo->out_color_components; /* number of color components */ |
195 | 0 | int max_colors = cinfo->desired_number_of_colors; |
196 | 0 | int total_colors, iroot, i, j; |
197 | 0 | boolean changed; |
198 | 0 | long temp; |
199 | 0 | int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE }; |
200 | 0 | RGB_order[0] = rgb_green[cinfo->out_color_space]; |
201 | 0 | RGB_order[1] = rgb_red[cinfo->out_color_space]; |
202 | 0 | RGB_order[2] = rgb_blue[cinfo->out_color_space]; |
203 | | |
204 | | /* We can allocate at least the nc'th root of max_colors per component. */ |
205 | | /* Compute floor(nc'th root of max_colors). */ |
206 | 0 | iroot = 1; |
207 | 0 | do { |
208 | 0 | iroot++; |
209 | 0 | temp = iroot; /* set temp = iroot ** nc */ |
210 | 0 | for (i = 1; i < nc; i++) |
211 | 0 | temp *= iroot; |
212 | 0 | } while (temp <= (long)max_colors); /* repeat till iroot exceeds root */ |
213 | 0 | iroot--; /* now iroot = floor(root) */ |
214 | | |
215 | | /* Must have at least 2 color values per component */ |
216 | 0 | if (iroot < 2) |
217 | 0 | ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int)temp); |
218 | | |
219 | | /* Initialize to iroot color values for each component */ |
220 | 0 | total_colors = 1; |
221 | 0 | for (i = 0; i < nc; i++) { |
222 | 0 | Ncolors[i] = iroot; |
223 | 0 | total_colors *= iroot; |
224 | 0 | } |
225 | | /* We may be able to increment the count for one or more components without |
226 | | * exceeding max_colors, though we know not all can be incremented. |
227 | | * Sometimes, the first component can be incremented more than once! |
228 | | * (Example: for 16 colors, we start at 2*2*2, go to 3*2*2, then 4*2*2.) |
229 | | * In RGB colorspace, try to increment G first, then R, then B. |
230 | | */ |
231 | 0 | do { |
232 | 0 | changed = FALSE; |
233 | 0 | for (i = 0; i < nc; i++) { |
234 | 0 | j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i); |
235 | | /* calculate new total_colors if Ncolors[j] is incremented */ |
236 | 0 | temp = total_colors / Ncolors[j]; |
237 | 0 | temp *= Ncolors[j] + 1; /* done in long arith to avoid oflo */ |
238 | 0 | if (temp > (long)max_colors) |
239 | 0 | break; /* won't fit, done with this pass */ |
240 | 0 | Ncolors[j]++; /* OK, apply the increment */ |
241 | 0 | total_colors = (int)temp; |
242 | 0 | changed = TRUE; |
243 | 0 | } |
244 | 0 | } while (changed); |
245 | |
|
246 | 0 | return total_colors; |
247 | 0 | } |
248 | | |
249 | | |
250 | | LOCAL(int) |
251 | | output_value(j_decompress_ptr cinfo, int ci, int j, int maxj) |
252 | | /* Return j'th output value, where j will range from 0 to maxj */ |
253 | | /* The output values must fall in 0.._MAXJSAMPLE in increasing order */ |
254 | 0 | { |
255 | | /* We always provide values 0 and _MAXJSAMPLE for each component; |
256 | | * any additional values are equally spaced between these limits. |
257 | | * (Forcing the upper and lower values to the limits ensures that |
258 | | * dithering can't produce a color outside the selected gamut.) |
259 | | */ |
260 | 0 | return (int)(((JLONG)j * _MAXJSAMPLE + maxj / 2) / maxj); |
261 | 0 | } |
262 | | |
263 | | |
264 | | LOCAL(int) |
265 | | largest_input_value(j_decompress_ptr cinfo, int ci, int j, int maxj) |
266 | | /* Return largest input value that should map to j'th output value */ |
267 | | /* Must have largest(j=0) >= 0, and largest(j=maxj) >= _MAXJSAMPLE */ |
268 | 0 | { |
269 | | /* Breakpoints are halfway between values returned by output_value */ |
270 | 0 | return (int)(((JLONG)(2 * j + 1) * _MAXJSAMPLE + maxj) / (2 * maxj)); |
271 | 0 | } |
272 | | |
273 | | |
274 | | /* |
275 | | * Create the colormap. |
276 | | */ |
277 | | |
278 | | LOCAL(void) |
279 | | create_colormap(j_decompress_ptr cinfo) |
280 | 0 | { |
281 | 0 | my_cquantize_ptr cquantize = (my_cquantize_ptr)cinfo->cquantize; |
282 | 0 | _JSAMPARRAY colormap; /* Created colormap */ |
283 | 0 | int total_colors; /* Number of distinct output colors */ |
284 | 0 | int i, j, k, nci, blksize, blkdist, ptr, val; |
285 | | |
286 | | /* Select number of colors for each component */ |
287 | 0 | total_colors = select_ncolors(cinfo, cquantize->Ncolors); |
288 | | |
289 | | /* Report selected color counts */ |
290 | 0 | if (cinfo->out_color_components == 3) |
291 | 0 | TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS, total_colors, |
292 | 0 | cquantize->Ncolors[0], cquantize->Ncolors[1], |
293 | 0 | cquantize->Ncolors[2]); |
294 | 0 | else |
295 | 0 | TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors); |
296 | | |
297 | | /* Allocate and fill in the colormap. */ |
298 | | /* The colors are ordered in the map in standard row-major order, */ |
299 | | /* i.e. rightmost (highest-indexed) color changes most rapidly. */ |
300 | |
|
301 | 0 | colormap = (_JSAMPARRAY)(*cinfo->mem->alloc_sarray) |
302 | 0 | ((j_common_ptr)cinfo, JPOOL_IMAGE, |
303 | 0 | (JDIMENSION)total_colors, (JDIMENSION)cinfo->out_color_components); |
304 | | |
305 | | /* blksize is number of adjacent repeated entries for a component */ |
306 | | /* blkdist is distance between groups of identical entries for a component */ |
307 | 0 | blkdist = total_colors; |
308 | |
|
309 | 0 | for (i = 0; i < cinfo->out_color_components; i++) { |
310 | | /* fill in colormap entries for i'th color component */ |
311 | 0 | nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ |
312 | 0 | blksize = blkdist / nci; |
313 | 0 | for (j = 0; j < nci; j++) { |
314 | | /* Compute j'th output value (out of nci) for component */ |
315 | 0 | val = output_value(cinfo, i, j, nci - 1); |
316 | | /* Fill in all colormap entries that have this value of this component */ |
317 | 0 | for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) { |
318 | | /* fill in blksize entries beginning at ptr */ |
319 | 0 | for (k = 0; k < blksize; k++) |
320 | 0 | colormap[i][ptr + k] = (_JSAMPLE)val; |
321 | 0 | } |
322 | 0 | } |
323 | 0 | blkdist = blksize; /* blksize of this color is blkdist of next */ |
324 | 0 | } |
325 | | |
326 | | /* Save the colormap in private storage, |
327 | | * where it will survive color quantization mode changes. |
328 | | */ |
329 | 0 | cquantize->sv_colormap = colormap; |
330 | 0 | cquantize->sv_actual = total_colors; |
331 | 0 | } |
332 | | |
333 | | |
334 | | /* |
335 | | * Create the color index table. |
336 | | */ |
337 | | |
338 | | LOCAL(void) |
339 | | create_colorindex(j_decompress_ptr cinfo) |
340 | 0 | { |
341 | 0 | my_cquantize_ptr cquantize = (my_cquantize_ptr)cinfo->cquantize; |
342 | 0 | _JSAMPROW indexptr; |
343 | 0 | int i, j, k, nci, blksize, val, pad; |
344 | | |
345 | | /* For ordered dither, we pad the color index tables by _MAXJSAMPLE in |
346 | | * each direction (input index values can be -_MAXJSAMPLE .. 2*_MAXJSAMPLE). |
347 | | * This is not necessary in the other dithering modes. However, we |
348 | | * flag whether it was done in case user changes dithering mode. |
349 | | */ |
350 | 0 | if (cinfo->dither_mode == JDITHER_ORDERED) { |
351 | 0 | pad = _MAXJSAMPLE * 2; |
352 | 0 | cquantize->is_padded = TRUE; |
353 | 0 | } else { |
354 | 0 | pad = 0; |
355 | 0 | cquantize->is_padded = FALSE; |
356 | 0 | } |
357 | |
|
358 | 0 | cquantize->colorindex = (_JSAMPARRAY)(*cinfo->mem->alloc_sarray) |
359 | 0 | ((j_common_ptr)cinfo, JPOOL_IMAGE, |
360 | 0 | (JDIMENSION)(_MAXJSAMPLE + 1 + pad), |
361 | 0 | (JDIMENSION)cinfo->out_color_components); |
362 | | |
363 | | /* blksize is number of adjacent repeated entries for a component */ |
364 | 0 | blksize = cquantize->sv_actual; |
365 | |
|
366 | 0 | for (i = 0; i < cinfo->out_color_components; i++) { |
367 | | /* fill in colorindex entries for i'th color component */ |
368 | 0 | nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ |
369 | 0 | blksize = blksize / nci; |
370 | | |
371 | | /* adjust colorindex pointers to provide padding at negative indexes. */ |
372 | 0 | if (pad) |
373 | 0 | cquantize->colorindex[i] += _MAXJSAMPLE; |
374 | | |
375 | | /* in loop, val = index of current output value, */ |
376 | | /* and k = largest j that maps to current val */ |
377 | 0 | indexptr = cquantize->colorindex[i]; |
378 | 0 | val = 0; |
379 | 0 | k = largest_input_value(cinfo, i, 0, nci - 1); |
380 | 0 | for (j = 0; j <= _MAXJSAMPLE; j++) { |
381 | 0 | while (j > k) /* advance val if past boundary */ |
382 | 0 | k = largest_input_value(cinfo, i, ++val, nci - 1); |
383 | | /* premultiply so that no multiplication needed in main processing */ |
384 | 0 | indexptr[j] = (_JSAMPLE)(val * blksize); |
385 | 0 | } |
386 | | /* Pad at both ends if necessary */ |
387 | 0 | if (pad) |
388 | 0 | for (j = 1; j <= _MAXJSAMPLE; j++) { |
389 | 0 | indexptr[-j] = indexptr[0]; |
390 | 0 | indexptr[_MAXJSAMPLE + j] = indexptr[_MAXJSAMPLE]; |
391 | 0 | } |
392 | 0 | } |
393 | 0 | } |
394 | | |
395 | | |
396 | | /* |
397 | | * Create an ordered-dither array for a component having ncolors |
398 | | * distinct output values. |
399 | | */ |
400 | | |
401 | | LOCAL(ODITHER_MATRIX_PTR) |
402 | | make_odither_array(j_decompress_ptr cinfo, int ncolors) |
403 | 0 | { |
404 | 0 | ODITHER_MATRIX_PTR odither; |
405 | 0 | int j, k; |
406 | 0 | JLONG num, den; |
407 | |
|
408 | 0 | odither = (ODITHER_MATRIX_PTR) |
409 | 0 | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
410 | 0 | sizeof(ODITHER_MATRIX)); |
411 | | /* The inter-value distance for this color is _MAXJSAMPLE/(ncolors-1). |
412 | | * Hence the dither value for the matrix cell with fill order f |
413 | | * (f=0..N-1) should be (N-1-2*f)/(2*N) * _MAXJSAMPLE/(ncolors-1). |
414 | | * On 16-bit-int machine, be careful to avoid overflow. |
415 | | */ |
416 | 0 | den = 2 * ODITHER_CELLS * ((JLONG)(ncolors - 1)); |
417 | 0 | for (j = 0; j < ODITHER_SIZE; j++) { |
418 | 0 | for (k = 0; k < ODITHER_SIZE; k++) { |
419 | 0 | num = ((JLONG)(ODITHER_CELLS - 1 - |
420 | 0 | 2 * ((int)base_dither_matrix[j][k]))) * _MAXJSAMPLE; |
421 | | /* Ensure round towards zero despite C's lack of consistency |
422 | | * about rounding negative values in integer division... |
423 | | */ |
424 | 0 | odither[j][k] = (int)(num < 0 ? -((-num) / den) : num / den); |
425 | 0 | } |
426 | 0 | } |
427 | 0 | return odither; |
428 | 0 | } |
429 | | |
430 | | |
431 | | /* |
432 | | * Create the ordered-dither tables. |
433 | | * Components having the same number of representative colors may |
434 | | * share a dither table. |
435 | | */ |
436 | | |
437 | | LOCAL(void) |
438 | | create_odither_tables(j_decompress_ptr cinfo) |
439 | 0 | { |
440 | 0 | my_cquantize_ptr cquantize = (my_cquantize_ptr)cinfo->cquantize; |
441 | 0 | ODITHER_MATRIX_PTR odither; |
442 | 0 | int i, j, nci; |
443 | |
|
444 | 0 | for (i = 0; i < cinfo->out_color_components; i++) { |
445 | 0 | nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ |
446 | 0 | odither = NULL; /* search for matching prior component */ |
447 | 0 | for (j = 0; j < i; j++) { |
448 | 0 | if (nci == cquantize->Ncolors[j]) { |
449 | 0 | odither = cquantize->odither[j]; |
450 | 0 | break; |
451 | 0 | } |
452 | 0 | } |
453 | 0 | if (odither == NULL) /* need a new table? */ |
454 | 0 | odither = make_odither_array(cinfo, nci); |
455 | 0 | cquantize->odither[i] = odither; |
456 | 0 | } |
457 | 0 | } |
458 | | |
459 | | |
460 | | /* |
461 | | * Map some rows of pixels to the output colormapped representation. |
462 | | */ |
463 | | |
464 | | METHODDEF(void) |
465 | | color_quantize(j_decompress_ptr cinfo, _JSAMPARRAY input_buf, |
466 | | _JSAMPARRAY output_buf, int num_rows) |
467 | | /* General case, no dithering */ |
468 | 0 | { |
469 | 0 | my_cquantize_ptr cquantize = (my_cquantize_ptr)cinfo->cquantize; |
470 | 0 | _JSAMPARRAY colorindex = cquantize->colorindex; |
471 | 0 | register int pixcode, ci; |
472 | 0 | register _JSAMPROW ptrin, ptrout; |
473 | 0 | int row; |
474 | 0 | JDIMENSION col; |
475 | 0 | JDIMENSION width = cinfo->output_width; |
476 | 0 | register int nc = cinfo->out_color_components; |
477 | |
|
478 | 0 | for (row = 0; row < num_rows; row++) { |
479 | 0 | ptrin = input_buf[row]; |
480 | 0 | ptrout = output_buf[row]; |
481 | 0 | for (col = width; col > 0; col--) { |
482 | 0 | pixcode = 0; |
483 | 0 | for (ci = 0; ci < nc; ci++) { |
484 | 0 | pixcode += colorindex[ci][*ptrin++]; |
485 | 0 | } |
486 | 0 | *ptrout++ = (_JSAMPLE)pixcode; |
487 | 0 | } |
488 | 0 | } |
489 | 0 | } |
490 | | |
491 | | |
492 | | METHODDEF(void) |
493 | | color_quantize3(j_decompress_ptr cinfo, _JSAMPARRAY input_buf, |
494 | | _JSAMPARRAY output_buf, int num_rows) |
495 | | /* Fast path for out_color_components==3, no dithering */ |
496 | 0 | { |
497 | 0 | my_cquantize_ptr cquantize = (my_cquantize_ptr)cinfo->cquantize; |
498 | 0 | register int pixcode; |
499 | 0 | register _JSAMPROW ptrin, ptrout; |
500 | 0 | _JSAMPROW colorindex0 = cquantize->colorindex[0]; |
501 | 0 | _JSAMPROW colorindex1 = cquantize->colorindex[1]; |
502 | 0 | _JSAMPROW colorindex2 = cquantize->colorindex[2]; |
503 | 0 | int row; |
504 | 0 | JDIMENSION col; |
505 | 0 | JDIMENSION width = cinfo->output_width; |
506 | |
|
507 | 0 | for (row = 0; row < num_rows; row++) { |
508 | 0 | ptrin = input_buf[row]; |
509 | 0 | ptrout = output_buf[row]; |
510 | 0 | for (col = width; col > 0; col--) { |
511 | 0 | pixcode = colorindex0[*ptrin++]; |
512 | 0 | pixcode += colorindex1[*ptrin++]; |
513 | 0 | pixcode += colorindex2[*ptrin++]; |
514 | 0 | *ptrout++ = (_JSAMPLE)pixcode; |
515 | 0 | } |
516 | 0 | } |
517 | 0 | } |
518 | | |
519 | | |
520 | | METHODDEF(void) |
521 | | quantize_ord_dither(j_decompress_ptr cinfo, _JSAMPARRAY input_buf, |
522 | | _JSAMPARRAY output_buf, int num_rows) |
523 | | /* General case, with ordered dithering */ |
524 | 0 | { |
525 | 0 | my_cquantize_ptr cquantize = (my_cquantize_ptr)cinfo->cquantize; |
526 | 0 | register _JSAMPROW input_ptr; |
527 | 0 | register _JSAMPROW output_ptr; |
528 | 0 | _JSAMPROW colorindex_ci; |
529 | 0 | int *dither; /* points to active row of dither matrix */ |
530 | 0 | int row_index, col_index; /* current indexes into dither matrix */ |
531 | 0 | int nc = cinfo->out_color_components; |
532 | 0 | int ci; |
533 | 0 | int row; |
534 | 0 | JDIMENSION col; |
535 | 0 | JDIMENSION width = cinfo->output_width; |
536 | |
|
537 | 0 | for (row = 0; row < num_rows; row++) { |
538 | | /* Initialize output values to 0 so can process components separately */ |
539 | 0 | jzero_far((void *)output_buf[row], (size_t)(width * sizeof(_JSAMPLE))); |
540 | 0 | row_index = cquantize->row_index; |
541 | 0 | for (ci = 0; ci < nc; ci++) { |
542 | 0 | input_ptr = input_buf[row] + ci; |
543 | 0 | output_ptr = output_buf[row]; |
544 | 0 | colorindex_ci = cquantize->colorindex[ci]; |
545 | 0 | dither = cquantize->odither[ci][row_index]; |
546 | 0 | col_index = 0; |
547 | |
|
548 | 0 | for (col = width; col > 0; col--) { |
549 | | /* Form pixel value + dither, range-limit to 0.._MAXJSAMPLE, |
550 | | * select output value, accumulate into output code for this pixel. |
551 | | * Range-limiting need not be done explicitly, as we have extended |
552 | | * the colorindex table to produce the right answers for out-of-range |
553 | | * inputs. The maximum dither is +- _MAXJSAMPLE; this sets the |
554 | | * required amount of padding. |
555 | | */ |
556 | 0 | *output_ptr += |
557 | 0 | colorindex_ci[*input_ptr + dither[col_index]]; |
558 | 0 | input_ptr += nc; |
559 | 0 | output_ptr++; |
560 | 0 | col_index = (col_index + 1) & ODITHER_MASK; |
561 | 0 | } |
562 | 0 | } |
563 | | /* Advance row index for next row */ |
564 | 0 | row_index = (row_index + 1) & ODITHER_MASK; |
565 | 0 | cquantize->row_index = row_index; |
566 | 0 | } |
567 | 0 | } |
568 | | |
569 | | |
570 | | METHODDEF(void) |
571 | | quantize3_ord_dither(j_decompress_ptr cinfo, _JSAMPARRAY input_buf, |
572 | | _JSAMPARRAY output_buf, int num_rows) |
573 | | /* Fast path for out_color_components==3, with ordered dithering */ |
574 | 0 | { |
575 | 0 | my_cquantize_ptr cquantize = (my_cquantize_ptr)cinfo->cquantize; |
576 | 0 | register int pixcode; |
577 | 0 | register _JSAMPROW input_ptr; |
578 | 0 | register _JSAMPROW output_ptr; |
579 | 0 | _JSAMPROW colorindex0 = cquantize->colorindex[0]; |
580 | 0 | _JSAMPROW colorindex1 = cquantize->colorindex[1]; |
581 | 0 | _JSAMPROW colorindex2 = cquantize->colorindex[2]; |
582 | 0 | int *dither0; /* points to active row of dither matrix */ |
583 | 0 | int *dither1; |
584 | 0 | int *dither2; |
585 | 0 | int row_index, col_index; /* current indexes into dither matrix */ |
586 | 0 | int row; |
587 | 0 | JDIMENSION col; |
588 | 0 | JDIMENSION width = cinfo->output_width; |
589 | |
|
590 | 0 | for (row = 0; row < num_rows; row++) { |
591 | 0 | row_index = cquantize->row_index; |
592 | 0 | input_ptr = input_buf[row]; |
593 | 0 | output_ptr = output_buf[row]; |
594 | 0 | dither0 = cquantize->odither[0][row_index]; |
595 | 0 | dither1 = cquantize->odither[1][row_index]; |
596 | 0 | dither2 = cquantize->odither[2][row_index]; |
597 | 0 | col_index = 0; |
598 | |
|
599 | 0 | for (col = width; col > 0; col--) { |
600 | 0 | pixcode = colorindex0[(*input_ptr++) + dither0[col_index]]; |
601 | 0 | pixcode += colorindex1[(*input_ptr++) + dither1[col_index]]; |
602 | 0 | pixcode += colorindex2[(*input_ptr++) + dither2[col_index]]; |
603 | 0 | *output_ptr++ = (_JSAMPLE)pixcode; |
604 | 0 | col_index = (col_index + 1) & ODITHER_MASK; |
605 | 0 | } |
606 | 0 | row_index = (row_index + 1) & ODITHER_MASK; |
607 | 0 | cquantize->row_index = row_index; |
608 | 0 | } |
609 | 0 | } |
610 | | |
611 | | |
612 | | METHODDEF(void) |
613 | | quantize_fs_dither(j_decompress_ptr cinfo, _JSAMPARRAY input_buf, |
614 | | _JSAMPARRAY output_buf, int num_rows) |
615 | | /* General case, with Floyd-Steinberg dithering */ |
616 | 0 | { |
617 | 0 | my_cquantize_ptr cquantize = (my_cquantize_ptr)cinfo->cquantize; |
618 | 0 | register LOCFSERROR cur; /* current error or pixel value */ |
619 | 0 | LOCFSERROR belowerr; /* error for pixel below cur */ |
620 | 0 | LOCFSERROR bpreverr; /* error for below/prev col */ |
621 | 0 | LOCFSERROR bnexterr; /* error for below/next col */ |
622 | 0 | LOCFSERROR delta; |
623 | 0 | register FSERRPTR errorptr; /* => fserrors[] at column before current */ |
624 | 0 | register _JSAMPROW input_ptr; |
625 | 0 | register _JSAMPROW output_ptr; |
626 | 0 | _JSAMPROW colorindex_ci; |
627 | 0 | _JSAMPROW colormap_ci; |
628 | 0 | int pixcode; |
629 | 0 | int nc = cinfo->out_color_components; |
630 | 0 | int dir; /* 1 for left-to-right, -1 for right-to-left */ |
631 | 0 | int dirnc; /* dir * nc */ |
632 | 0 | int ci; |
633 | 0 | int row; |
634 | 0 | JDIMENSION col; |
635 | 0 | JDIMENSION width = cinfo->output_width; |
636 | 0 | _JSAMPLE *range_limit = (_JSAMPLE *)cinfo->sample_range_limit; |
637 | 0 | SHIFT_TEMPS |
638 | |
|
639 | 0 | for (row = 0; row < num_rows; row++) { |
640 | | /* Initialize output values to 0 so can process components separately */ |
641 | 0 | jzero_far((void *)output_buf[row], (size_t)(width * sizeof(_JSAMPLE))); |
642 | 0 | for (ci = 0; ci < nc; ci++) { |
643 | 0 | input_ptr = input_buf[row] + ci; |
644 | 0 | output_ptr = output_buf[row]; |
645 | 0 | if (cquantize->on_odd_row) { |
646 | | /* work right to left in this row */ |
647 | 0 | input_ptr += (width - 1) * nc; /* so point to rightmost pixel */ |
648 | 0 | output_ptr += width - 1; |
649 | 0 | dir = -1; |
650 | 0 | dirnc = -nc; |
651 | 0 | errorptr = cquantize->fserrors[ci] + (width + 1); /* => entry after last column */ |
652 | 0 | } else { |
653 | | /* work left to right in this row */ |
654 | 0 | dir = 1; |
655 | 0 | dirnc = nc; |
656 | 0 | errorptr = cquantize->fserrors[ci]; /* => entry before first column */ |
657 | 0 | } |
658 | 0 | colorindex_ci = cquantize->colorindex[ci]; |
659 | 0 | colormap_ci = cquantize->sv_colormap[ci]; |
660 | | /* Preset error values: no error propagated to first pixel from left */ |
661 | 0 | cur = 0; |
662 | | /* and no error propagated to row below yet */ |
663 | 0 | belowerr = bpreverr = 0; |
664 | |
|
665 | 0 | for (col = width; col > 0; col--) { |
666 | | /* cur holds the error propagated from the previous pixel on the |
667 | | * current line. Add the error propagated from the previous line |
668 | | * to form the complete error correction term for this pixel, and |
669 | | * round the error term (which is expressed * 16) to an integer. |
670 | | * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct |
671 | | * for either sign of the error value. |
672 | | * Note: errorptr points to *previous* column's array entry. |
673 | | */ |
674 | 0 | cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4); |
675 | | /* Form pixel value + error, and range-limit to 0.._MAXJSAMPLE. |
676 | | * The maximum error is +- _MAXJSAMPLE; this sets the required size |
677 | | * of the range_limit array. |
678 | | */ |
679 | 0 | cur += *input_ptr; |
680 | 0 | cur = range_limit[cur]; |
681 | | /* Select output value, accumulate into output code for this pixel */ |
682 | 0 | pixcode = colorindex_ci[cur]; |
683 | 0 | *output_ptr += (_JSAMPLE)pixcode; |
684 | | /* Compute actual representation error at this pixel */ |
685 | | /* Note: we can do this even though we don't have the final */ |
686 | | /* pixel code, because the colormap is orthogonal. */ |
687 | 0 | cur -= colormap_ci[pixcode]; |
688 | | /* Compute error fractions to be propagated to adjacent pixels. |
689 | | * Add these into the running sums, and simultaneously shift the |
690 | | * next-line error sums left by 1 column. |
691 | | */ |
692 | 0 | bnexterr = cur; |
693 | 0 | delta = cur * 2; |
694 | 0 | cur += delta; /* form error * 3 */ |
695 | 0 | errorptr[0] = (FSERROR)(bpreverr + cur); |
696 | 0 | cur += delta; /* form error * 5 */ |
697 | 0 | bpreverr = belowerr + cur; |
698 | 0 | belowerr = bnexterr; |
699 | 0 | cur += delta; /* form error * 7 */ |
700 | | /* At this point cur contains the 7/16 error value to be propagated |
701 | | * to the next pixel on the current line, and all the errors for the |
702 | | * next line have been shifted over. We are therefore ready to move on. |
703 | | */ |
704 | 0 | input_ptr += dirnc; /* advance input ptr to next column */ |
705 | 0 | output_ptr += dir; /* advance output ptr to next column */ |
706 | 0 | errorptr += dir; /* advance errorptr to current column */ |
707 | 0 | } |
708 | | /* Post-loop cleanup: we must unload the final error value into the |
709 | | * final fserrors[] entry. Note we need not unload belowerr because |
710 | | * it is for the dummy column before or after the actual array. |
711 | | */ |
712 | 0 | errorptr[0] = (FSERROR)bpreverr; /* unload prev err into array */ |
713 | 0 | } |
714 | 0 | cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE); |
715 | 0 | } |
716 | 0 | } |
717 | | |
718 | | |
719 | | /* |
720 | | * Allocate workspace for Floyd-Steinberg errors. |
721 | | */ |
722 | | |
723 | | LOCAL(void) |
724 | | alloc_fs_workspace(j_decompress_ptr cinfo) |
725 | 0 | { |
726 | 0 | my_cquantize_ptr cquantize = (my_cquantize_ptr)cinfo->cquantize; |
727 | 0 | size_t arraysize; |
728 | 0 | int i; |
729 | |
|
730 | 0 | arraysize = (size_t)((cinfo->output_width + 2) * sizeof(FSERROR)); |
731 | 0 | for (i = 0; i < cinfo->out_color_components; i++) { |
732 | 0 | cquantize->fserrors[i] = (FSERRPTR) |
733 | 0 | (*cinfo->mem->alloc_large) ((j_common_ptr)cinfo, JPOOL_IMAGE, arraysize); |
734 | 0 | } |
735 | 0 | } |
736 | | |
737 | | |
738 | | /* |
739 | | * Initialize for one-pass color quantization. |
740 | | */ |
741 | | |
742 | | METHODDEF(void) |
743 | | start_pass_1_quant(j_decompress_ptr cinfo, boolean is_pre_scan) |
744 | 0 | { |
745 | 0 | my_cquantize_ptr cquantize = (my_cquantize_ptr)cinfo->cquantize; |
746 | 0 | size_t arraysize; |
747 | 0 | int i; |
748 | | |
749 | | /* Install my colormap. */ |
750 | 0 | cinfo->colormap = (JSAMPARRAY)cquantize->sv_colormap; |
751 | 0 | cinfo->actual_number_of_colors = cquantize->sv_actual; |
752 | | |
753 | | /* Initialize for desired dithering mode. */ |
754 | 0 | switch (cinfo->dither_mode) { |
755 | 0 | case JDITHER_NONE: |
756 | 0 | if (cinfo->out_color_components == 3) |
757 | 0 | cquantize->pub._color_quantize = color_quantize3; |
758 | 0 | else |
759 | 0 | cquantize->pub._color_quantize = color_quantize; |
760 | 0 | break; |
761 | 0 | case JDITHER_ORDERED: |
762 | 0 | if (cinfo->out_color_components == 3) |
763 | 0 | cquantize->pub._color_quantize = quantize3_ord_dither; |
764 | 0 | else |
765 | 0 | cquantize->pub._color_quantize = quantize_ord_dither; |
766 | 0 | cquantize->row_index = 0; /* initialize state for ordered dither */ |
767 | | /* If user changed to ordered dither from another mode, |
768 | | * we must recreate the color index table with padding. |
769 | | * This will cost extra space, but probably isn't very likely. |
770 | | */ |
771 | 0 | if (!cquantize->is_padded) |
772 | 0 | create_colorindex(cinfo); |
773 | | /* Create ordered-dither tables if we didn't already. */ |
774 | 0 | if (cquantize->odither[0] == NULL) |
775 | 0 | create_odither_tables(cinfo); |
776 | 0 | break; |
777 | 0 | case JDITHER_FS: |
778 | 0 | cquantize->pub._color_quantize = quantize_fs_dither; |
779 | 0 | cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */ |
780 | | /* Allocate Floyd-Steinberg workspace if didn't already. */ |
781 | 0 | if (cquantize->fserrors[0] == NULL) |
782 | 0 | alloc_fs_workspace(cinfo); |
783 | | /* Initialize the propagated errors to zero. */ |
784 | 0 | arraysize = (size_t)((cinfo->output_width + 2) * sizeof(FSERROR)); |
785 | 0 | for (i = 0; i < cinfo->out_color_components; i++) |
786 | 0 | jzero_far((void *)cquantize->fserrors[i], arraysize); |
787 | 0 | break; |
788 | 0 | default: |
789 | 0 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
790 | 0 | break; |
791 | 0 | } |
792 | 0 | } |
793 | | |
794 | | |
795 | | /* |
796 | | * Finish up at the end of the pass. |
797 | | */ |
798 | | |
799 | | METHODDEF(void) |
800 | | finish_pass_1_quant(j_decompress_ptr cinfo) |
801 | 0 | { |
802 | | /* no work in 1-pass case */ |
803 | 0 | } |
804 | | |
805 | | |
806 | | /* |
807 | | * Switch to a new external colormap between output passes. |
808 | | * Shouldn't get to this module! |
809 | | */ |
810 | | |
811 | | METHODDEF(void) |
812 | | new_color_map_1_quant(j_decompress_ptr cinfo) |
813 | 0 | { |
814 | 0 | ERREXIT(cinfo, JERR_MODE_CHANGE); |
815 | 0 | } |
816 | | |
817 | | |
818 | | /* |
819 | | * Module initialization routine for 1-pass color quantization. |
820 | | */ |
821 | | |
822 | | GLOBAL(void) |
823 | | _jinit_1pass_quantizer(j_decompress_ptr cinfo) |
824 | 0 | { |
825 | 0 | my_cquantize_ptr cquantize; |
826 | |
|
827 | 0 | if (cinfo->data_precision != BITS_IN_JSAMPLE) |
828 | 0 | ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); |
829 | |
|
830 | 0 | cquantize = (my_cquantize_ptr) |
831 | 0 | (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE, |
832 | 0 | sizeof(my_cquantizer)); |
833 | 0 | cinfo->cquantize = (struct jpeg_color_quantizer *)cquantize; |
834 | 0 | cquantize->pub.start_pass = start_pass_1_quant; |
835 | 0 | cquantize->pub.finish_pass = finish_pass_1_quant; |
836 | 0 | cquantize->pub.new_color_map = new_color_map_1_quant; |
837 | 0 | cquantize->fserrors[0] = NULL; /* Flag FS workspace not allocated */ |
838 | 0 | cquantize->odither[0] = NULL; /* Also flag odither arrays not allocated */ |
839 | | |
840 | | /* Make sure my internal arrays won't overflow */ |
841 | 0 | if (cinfo->out_color_components > MAX_Q_COMPS) |
842 | 0 | ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS); |
843 | | /* Make sure colormap indexes can be represented by _JSAMPLEs */ |
844 | 0 | if (cinfo->desired_number_of_colors > (_MAXJSAMPLE + 1)) |
845 | 0 | ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, _MAXJSAMPLE + 1); |
846 | | |
847 | | /* Create the colormap and color index table. */ |
848 | 0 | create_colormap(cinfo); |
849 | 0 | create_colorindex(cinfo); |
850 | | |
851 | | /* Allocate Floyd-Steinberg workspace now if requested. |
852 | | * We do this now since it may affect the memory manager's space |
853 | | * calculations. If the user changes to FS dither mode in a later pass, we |
854 | | * will allocate the space then, and will possibly overrun the |
855 | | * max_memory_to_use setting. |
856 | | */ |
857 | 0 | if (cinfo->dither_mode == JDITHER_FS) |
858 | 0 | alloc_fs_workspace(cinfo); |
859 | 0 | } Unexecuted instantiation: j12init_1pass_quantizer Unexecuted instantiation: j16init_1pass_quantizer Unexecuted instantiation: jinit_1pass_quantizer |
860 | | |
861 | | #endif /* defined(QUANT_1PASS_SUPPORTED) && |
862 | | (BITS_IN_JSAMPLE != 16 || defined(D_LOSSLESS_SUPPORTED)) */ |