Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 1 | /* |
| 2 | * jquant1.c |
| 3 | * |
DRC | a73e870 | 2012-12-31 02:52:30 +0000 | [diff] [blame] | 4 | * This file was part of the Independent JPEG Group's software: |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 5 | * Copyright (C) 1991-1996, Thomas G. Lane. |
DRC | a6ef282 | 2013-09-28 03:23:49 +0000 | [diff] [blame] | 6 | * libjpeg-turbo Modifications: |
DRC | 8ece7fe | 2009-08-06 08:32:00 +0000 | [diff] [blame] | 7 | * Copyright (C) 2009, D. R. Commander |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 8 | * For conditions of distribution and use, see the accompanying README file. |
| 9 | * |
| 10 | * This file contains 1-pass color quantization (color mapping) routines. |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 11 | * These routines provide mapping to a fixed color map using equally spaced |
| 12 | * color values. Optional Floyd-Steinberg or ordered dithering is available. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 13 | */ |
| 14 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 15 | #define JPEG_INTERNALS |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 16 | #include "jinclude.h" |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 17 | #include "jpeglib.h" |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 18 | |
| 19 | #ifdef QUANT_1PASS_SUPPORTED |
| 20 | |
| 21 | |
| 22 | /* |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 23 | * The main purpose of 1-pass quantization is to provide a fast, if not very |
| 24 | * high quality, colormapped output capability. A 2-pass quantizer usually |
| 25 | * gives better visual quality; however, for quantized grayscale output this |
| 26 | * quantizer is perfectly adequate. Dithering is highly recommended with this |
| 27 | * quantizer, though you can turn it off if you really want to. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 28 | * |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 29 | * In 1-pass quantization the colormap must be chosen in advance of seeing the |
| 30 | * image. We use a map consisting of all combinations of Ncolors[i] color |
| 31 | * values for the i'th component. The Ncolors[] values are chosen so that |
| 32 | * their product, the total number of colors, is no more than that requested. |
| 33 | * (In most cases, the product will be somewhat less.) |
| 34 | * |
| 35 | * Since the colormap is orthogonal, the representative value for each color |
| 36 | * component can be determined without considering the other components; |
| 37 | * then these indexes can be combined into a colormap index by a standard |
| 38 | * N-dimensional-array-subscript calculation. Most of the arithmetic involved |
| 39 | * can be precalculated and stored in the lookup table colorindex[]. |
| 40 | * colorindex[i][j] maps pixel value j in component i to the nearest |
| 41 | * representative value (grid plane) for that component; this index is |
| 42 | * multiplied by the array stride for component i, so that the |
| 43 | * index of the colormap entry closest to a given pixel value is just |
| 44 | * sum( colorindex[component-number][pixel-component-value] ) |
| 45 | * Aside from being fast, this scheme allows for variable spacing between |
| 46 | * representative values with no additional lookup cost. |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 47 | * |
| 48 | * If gamma correction has been applied in color conversion, it might be wise |
| 49 | * to adjust the color grid spacing so that the representative colors are |
| 50 | * equidistant in linear space. At this writing, gamma correction is not |
| 51 | * implemented by jdcolor, so nothing is done here. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 52 | */ |
| 53 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 54 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 55 | /* Declarations for ordered dithering. |
| 56 | * |
Thomas G. Lane | 9ba2f5e | 1994-12-07 00:00:00 +0000 | [diff] [blame] | 57 | * We use a standard 16x16 ordered dither array. The basic concept of ordered |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 58 | * dithering is described in many references, for instance Dale Schumacher's |
| 59 | * chapter II.2 of Graphics Gems II (James Arvo, ed. Academic Press, 1991). |
| 60 | * In place of Schumacher's comparisons against a "threshold" value, we add a |
| 61 | * "dither" value to the input pixel and then round the result to the nearest |
| 62 | * output value. The dither value is equivalent to (0.5 - threshold) times |
| 63 | * the distance between output values. For ordered dithering, we assume that |
| 64 | * the output colors are equally spaced; if not, results will probably be |
| 65 | * worse, since the dither may be too much or too little at a given point. |
| 66 | * |
| 67 | * The normal calculation would be to form pixel value + dither, range-limit |
| 68 | * this to 0..MAXJSAMPLE, and then index into the colorindex table as usual. |
| 69 | * We can skip the separate range-limiting step by extending the colorindex |
| 70 | * table in both directions. |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 71 | */ |
| 72 | |
Thomas G. Lane | 9ba2f5e | 1994-12-07 00:00:00 +0000 | [diff] [blame] | 73 | #define ODITHER_SIZE 16 /* dimension of dither matrix */ |
| 74 | /* NB: if ODITHER_SIZE is not a power of 2, ODITHER_MASK uses will break */ |
| 75 | #define ODITHER_CELLS (ODITHER_SIZE*ODITHER_SIZE) /* # cells in matrix */ |
| 76 | #define ODITHER_MASK (ODITHER_SIZE-1) /* mask for wrapping around counters */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 77 | |
| 78 | typedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE]; |
Thomas G. Lane | 9ba2f5e | 1994-12-07 00:00:00 +0000 | [diff] [blame] | 79 | typedef int (*ODITHER_MATRIX_PTR)[ODITHER_SIZE]; |
| 80 | |
| 81 | static const UINT8 base_dither_matrix[ODITHER_SIZE][ODITHER_SIZE] = { |
Thomas G. Lane | a8b67c4 | 1995-03-15 00:00:00 +0000 | [diff] [blame] | 82 | /* Bayer's order-4 dither array. Generated by the code given in |
| 83 | * Stephen Hawley's article "Ordered Dithering" in Graphics Gems I. |
| 84 | * The values in this array must range from 0 to ODITHER_CELLS-1. |
| 85 | */ |
| 86 | { 0,192, 48,240, 12,204, 60,252, 3,195, 51,243, 15,207, 63,255 }, |
| 87 | { 128, 64,176,112,140, 76,188,124,131, 67,179,115,143, 79,191,127 }, |
| 88 | { 32,224, 16,208, 44,236, 28,220, 35,227, 19,211, 47,239, 31,223 }, |
| 89 | { 160, 96,144, 80,172,108,156, 92,163, 99,147, 83,175,111,159, 95 }, |
| 90 | { 8,200, 56,248, 4,196, 52,244, 11,203, 59,251, 7,199, 55,247 }, |
| 91 | { 136, 72,184,120,132, 68,180,116,139, 75,187,123,135, 71,183,119 }, |
| 92 | { 40,232, 24,216, 36,228, 20,212, 43,235, 27,219, 39,231, 23,215 }, |
| 93 | { 168,104,152, 88,164,100,148, 84,171,107,155, 91,167,103,151, 87 }, |
| 94 | { 2,194, 50,242, 14,206, 62,254, 1,193, 49,241, 13,205, 61,253 }, |
| 95 | { 130, 66,178,114,142, 78,190,126,129, 65,177,113,141, 77,189,125 }, |
| 96 | { 34,226, 18,210, 46,238, 30,222, 33,225, 17,209, 45,237, 29,221 }, |
| 97 | { 162, 98,146, 82,174,110,158, 94,161, 97,145, 81,173,109,157, 93 }, |
| 98 | { 10,202, 58,250, 6,198, 54,246, 9,201, 57,249, 5,197, 53,245 }, |
| 99 | { 138, 74,186,122,134, 70,182,118,137, 73,185,121,133, 69,181,117 }, |
| 100 | { 42,234, 26,218, 38,230, 22,214, 41,233, 25,217, 37,229, 21,213 }, |
| 101 | { 170,106,154, 90,166,102,150, 86,169,105,153, 89,165,101,149, 85 } |
Thomas G. Lane | 9ba2f5e | 1994-12-07 00:00:00 +0000 | [diff] [blame] | 102 | }; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 103 | |
| 104 | |
| 105 | /* Declarations for Floyd-Steinberg dithering. |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 106 | * |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 107 | * Errors are accumulated into the array fserrors[], at a resolution of |
| 108 | * 1/16th of a pixel count. The error at a given pixel is propagated |
| 109 | * to its not-yet-processed neighbors using the standard F-S fractions, |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 110 | * ... (here) 7/16 |
| 111 | * 3/16 5/16 1/16 |
| 112 | * We work left-to-right on even rows, right-to-left on odd rows. |
| 113 | * |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 114 | * We can get away with a single array (holding one row's worth of errors) |
| 115 | * by using it to store the current row's errors at pixel columns not yet |
| 116 | * processed, but the next row's errors at columns already processed. We |
| 117 | * need only a few extra variables to hold the errors immediately around the |
| 118 | * current column. (If we are lucky, those variables are in registers, but |
| 119 | * even if not, they're probably cheaper to access than array elements are.) |
| 120 | * |
| 121 | * The fserrors[] array is indexed [component#][position]. |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 122 | * We provide (#columns + 2) entries per component; the extra entry at each |
| 123 | * end saves us from special-casing the first and last pixels. |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 124 | * |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 125 | * Note: on a wide image, we might not have enough room in a PC's near data |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 126 | * segment to hold the error array; so it is allocated with alloc_large. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 127 | */ |
| 128 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 129 | #if BITS_IN_JSAMPLE == 8 |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 130 | typedef INT16 FSERROR; /* 16 bits should be enough */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 131 | typedef int LOCFSERROR; /* use 'int' for calculation temps */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 132 | #else |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 133 | typedef INT32 FSERROR; /* may need more than 16 bits */ |
| 134 | typedef INT32 LOCFSERROR; /* be sure calculation temps are big enough */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 135 | #endif |
| 136 | |
| 137 | typedef FSERROR FAR *FSERRPTR; /* pointer to error array (in FAR storage!) */ |
| 138 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 139 | |
| 140 | /* Private subobject */ |
| 141 | |
| 142 | #define MAX_Q_COMPS 4 /* max components I can handle */ |
| 143 | |
| 144 | typedef struct { |
| 145 | struct jpeg_color_quantizer pub; /* public fields */ |
| 146 | |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 147 | /* Initially allocated colormap is saved here */ |
| 148 | JSAMPARRAY sv_colormap; /* The color map as a 2-D pixel array */ |
| 149 | int sv_actual; /* number of entries in use */ |
| 150 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 151 | JSAMPARRAY colorindex; /* Precomputed mapping for speed */ |
| 152 | /* colorindex[i][j] = index of color closest to pixel value j in component i, |
| 153 | * premultiplied as described above. Since colormap indexes must fit into |
| 154 | * JSAMPLEs, the entries of this array will too. |
| 155 | */ |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 156 | boolean is_padded; /* is the colorindex padded for odither? */ |
| 157 | |
| 158 | int Ncolors[MAX_Q_COMPS]; /* # of values alloced to each component */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 159 | |
| 160 | /* Variables for ordered dithering */ |
| 161 | int row_index; /* cur row's vertical index in dither matrix */ |
Thomas G. Lane | 9ba2f5e | 1994-12-07 00:00:00 +0000 | [diff] [blame] | 162 | ODITHER_MATRIX_PTR odither[MAX_Q_COMPS]; /* one dither array per component */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 163 | |
| 164 | /* Variables for Floyd-Steinberg dithering */ |
| 165 | FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */ |
| 166 | boolean on_odd_row; /* flag to remember which row we are on */ |
| 167 | } my_cquantizer; |
| 168 | |
| 169 | typedef my_cquantizer * my_cquantize_ptr; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 170 | |
| 171 | |
| 172 | /* |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 173 | * Policy-making subroutines for create_colormap and create_colorindex. |
| 174 | * These routines determine the colormap to be used. The rest of the module |
| 175 | * only assumes that the colormap is orthogonal. |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 176 | * |
| 177 | * * select_ncolors decides how to divvy up the available colors |
| 178 | * among the components. |
| 179 | * * output_value defines the set of representative values for a component. |
| 180 | * * largest_input_value defines the mapping from input values to |
| 181 | * representative values for a component. |
| 182 | * Note that the latter two routines may impose different policies for |
| 183 | * different components, though this is not currently done. |
| 184 | */ |
| 185 | |
| 186 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 187 | LOCAL(int) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 188 | select_ncolors (j_decompress_ptr cinfo, int Ncolors[]) |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 189 | /* Determine allocation of desired colors to components, */ |
| 190 | /* and fill in Ncolors[] array to indicate choice. */ |
| 191 | /* Return value is total number of colors (product of Ncolors[] values). */ |
| 192 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 193 | int nc = cinfo->out_color_components; /* number of color components */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 194 | int max_colors = cinfo->desired_number_of_colors; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 195 | int total_colors, iroot, i, j; |
Thomas G. Lane | a8b67c4 | 1995-03-15 00:00:00 +0000 | [diff] [blame] | 196 | boolean changed; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 197 | long temp; |
DRC | f25c071 | 2009-04-03 12:00:51 +0000 | [diff] [blame] | 198 | int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE }; |
| 199 | RGB_order[0] = rgb_green[cinfo->out_color_space]; |
| 200 | RGB_order[1] = rgb_red[cinfo->out_color_space]; |
| 201 | RGB_order[2] = rgb_blue[cinfo->out_color_space]; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 202 | |
| 203 | /* We can allocate at least the nc'th root of max_colors per component. */ |
| 204 | /* Compute floor(nc'th root of max_colors). */ |
| 205 | iroot = 1; |
| 206 | do { |
| 207 | iroot++; |
| 208 | temp = iroot; /* set temp = iroot ** nc */ |
| 209 | for (i = 1; i < nc; i++) |
| 210 | temp *= iroot; |
| 211 | } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */ |
| 212 | iroot--; /* now iroot = floor(root) */ |
| 213 | |
| 214 | /* Must have at least 2 color values per component */ |
| 215 | if (iroot < 2) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 216 | ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int) temp); |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 217 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 218 | /* Initialize to iroot color values for each component */ |
| 219 | total_colors = 1; |
| 220 | for (i = 0; i < nc; i++) { |
| 221 | Ncolors[i] = iroot; |
| 222 | total_colors *= iroot; |
| 223 | } |
| 224 | /* We may be able to increment the count for one or more components without |
| 225 | * exceeding max_colors, though we know not all can be incremented. |
Thomas G. Lane | a8b67c4 | 1995-03-15 00:00:00 +0000 | [diff] [blame] | 226 | * Sometimes, the first component can be incremented more than once! |
| 227 | * (Example: for 16 colors, we start at 2*2*2, go to 3*2*2, then 4*2*2.) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 228 | * In RGB colorspace, try to increment G first, then R, then B. |
| 229 | */ |
Thomas G. Lane | a8b67c4 | 1995-03-15 00:00:00 +0000 | [diff] [blame] | 230 | do { |
| 231 | changed = FALSE; |
| 232 | for (i = 0; i < nc; i++) { |
| 233 | j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i); |
| 234 | /* calculate new total_colors if Ncolors[j] is incremented */ |
| 235 | temp = total_colors / Ncolors[j]; |
| 236 | temp *= Ncolors[j]+1; /* done in long arith to avoid oflo */ |
| 237 | if (temp > (long) max_colors) |
| 238 | break; /* won't fit, done with this pass */ |
| 239 | Ncolors[j]++; /* OK, apply the increment */ |
| 240 | total_colors = (int) temp; |
| 241 | changed = TRUE; |
| 242 | } |
| 243 | } while (changed); |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 244 | |
| 245 | return total_colors; |
| 246 | } |
| 247 | |
| 248 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 249 | LOCAL(int) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 250 | output_value (j_decompress_ptr cinfo, int ci, int j, int maxj) |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 251 | /* Return j'th output value, where j will range from 0 to maxj */ |
| 252 | /* The output values must fall in 0..MAXJSAMPLE in increasing order */ |
| 253 | { |
| 254 | /* We always provide values 0 and MAXJSAMPLE for each component; |
| 255 | * any additional values are equally spaced between these limits. |
| 256 | * (Forcing the upper and lower values to the limits ensures that |
| 257 | * dithering can't produce a color outside the selected gamut.) |
| 258 | */ |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 259 | return (int) (((INT32) j * MAXJSAMPLE + maxj/2) / maxj); |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 260 | } |
| 261 | |
| 262 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 263 | LOCAL(int) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 264 | largest_input_value (j_decompress_ptr cinfo, int ci, int j, int maxj) |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 265 | /* Return largest input value that should map to j'th output value */ |
| 266 | /* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */ |
| 267 | { |
| 268 | /* Breakpoints are halfway between values returned by output_value */ |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 269 | return (int) (((INT32) (2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj)); |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 270 | } |
| 271 | |
| 272 | |
| 273 | /* |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 274 | * Create the colormap. |
| 275 | */ |
| 276 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 277 | LOCAL(void) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 278 | create_colormap (j_decompress_ptr cinfo) |
| 279 | { |
| 280 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
| 281 | JSAMPARRAY colormap; /* Created colormap */ |
| 282 | int total_colors; /* Number of distinct output colors */ |
| 283 | int i,j,k, nci, blksize, blkdist, ptr, val; |
| 284 | |
| 285 | /* Select number of colors for each component */ |
| 286 | total_colors = select_ncolors(cinfo, cquantize->Ncolors); |
| 287 | |
| 288 | /* Report selected color counts */ |
| 289 | if (cinfo->out_color_components == 3) |
| 290 | TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS, |
| 291 | total_colors, cquantize->Ncolors[0], |
| 292 | cquantize->Ncolors[1], cquantize->Ncolors[2]); |
| 293 | else |
| 294 | TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors); |
| 295 | |
| 296 | /* Allocate and fill in the colormap. */ |
| 297 | /* The colors are ordered in the map in standard row-major order, */ |
| 298 | /* i.e. rightmost (highest-indexed) color changes most rapidly. */ |
| 299 | |
| 300 | colormap = (*cinfo->mem->alloc_sarray) |
| 301 | ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 302 | (JDIMENSION) total_colors, (JDIMENSION) cinfo->out_color_components); |
| 303 | |
| 304 | /* blksize is number of adjacent repeated entries for a component */ |
| 305 | /* blkdist is distance between groups of identical entries for a component */ |
| 306 | blkdist = total_colors; |
| 307 | |
| 308 | for (i = 0; i < cinfo->out_color_components; i++) { |
| 309 | /* fill in colormap entries for i'th color component */ |
| 310 | nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ |
| 311 | blksize = blkdist / nci; |
| 312 | for (j = 0; j < nci; j++) { |
| 313 | /* Compute j'th output value (out of nci) for component */ |
| 314 | val = output_value(cinfo, i, j, nci-1); |
| 315 | /* Fill in all colormap entries that have this value of this component */ |
| 316 | for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) { |
| 317 | /* fill in blksize entries beginning at ptr */ |
| 318 | for (k = 0; k < blksize; k++) |
| 319 | colormap[i][ptr+k] = (JSAMPLE) val; |
| 320 | } |
| 321 | } |
| 322 | blkdist = blksize; /* blksize of this color is blkdist of next */ |
| 323 | } |
| 324 | |
| 325 | /* Save the colormap in private storage, |
| 326 | * where it will survive color quantization mode changes. |
| 327 | */ |
| 328 | cquantize->sv_colormap = colormap; |
| 329 | cquantize->sv_actual = total_colors; |
| 330 | } |
| 331 | |
| 332 | |
| 333 | /* |
| 334 | * Create the color index table. |
| 335 | */ |
| 336 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 337 | LOCAL(void) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 338 | create_colorindex (j_decompress_ptr cinfo) |
| 339 | { |
| 340 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
| 341 | JSAMPROW indexptr; |
| 342 | int i,j,k, nci, blksize, val, pad; |
| 343 | |
| 344 | /* For ordered dither, we pad the color index tables by MAXJSAMPLE in |
| 345 | * each direction (input index values can be -MAXJSAMPLE .. 2*MAXJSAMPLE). |
| 346 | * This is not necessary in the other dithering modes. However, we |
| 347 | * flag whether it was done in case user changes dithering mode. |
| 348 | */ |
| 349 | if (cinfo->dither_mode == JDITHER_ORDERED) { |
| 350 | pad = MAXJSAMPLE*2; |
| 351 | cquantize->is_padded = TRUE; |
| 352 | } else { |
| 353 | pad = 0; |
| 354 | cquantize->is_padded = FALSE; |
| 355 | } |
| 356 | |
| 357 | cquantize->colorindex = (*cinfo->mem->alloc_sarray) |
| 358 | ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 359 | (JDIMENSION) (MAXJSAMPLE+1 + pad), |
| 360 | (JDIMENSION) cinfo->out_color_components); |
| 361 | |
| 362 | /* blksize is number of adjacent repeated entries for a component */ |
| 363 | blksize = cquantize->sv_actual; |
| 364 | |
| 365 | for (i = 0; i < cinfo->out_color_components; i++) { |
| 366 | /* fill in colorindex entries for i'th color component */ |
| 367 | nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ |
| 368 | blksize = blksize / nci; |
| 369 | |
| 370 | /* adjust colorindex pointers to provide padding at negative indexes. */ |
| 371 | if (pad) |
| 372 | cquantize->colorindex[i] += MAXJSAMPLE; |
| 373 | |
| 374 | /* in loop, val = index of current output value, */ |
| 375 | /* and k = largest j that maps to current val */ |
| 376 | indexptr = cquantize->colorindex[i]; |
| 377 | val = 0; |
| 378 | k = largest_input_value(cinfo, i, 0, nci-1); |
| 379 | for (j = 0; j <= MAXJSAMPLE; j++) { |
| 380 | while (j > k) /* advance val if past boundary */ |
| 381 | k = largest_input_value(cinfo, i, ++val, nci-1); |
| 382 | /* premultiply so that no multiplication needed in main processing */ |
| 383 | indexptr[j] = (JSAMPLE) (val * blksize); |
| 384 | } |
| 385 | /* Pad at both ends if necessary */ |
| 386 | if (pad) |
| 387 | for (j = 1; j <= MAXJSAMPLE; j++) { |
| 388 | indexptr[-j] = indexptr[0]; |
| 389 | indexptr[MAXJSAMPLE+j] = indexptr[MAXJSAMPLE]; |
| 390 | } |
| 391 | } |
| 392 | } |
| 393 | |
| 394 | |
| 395 | /* |
Thomas G. Lane | 9ba2f5e | 1994-12-07 00:00:00 +0000 | [diff] [blame] | 396 | * Create an ordered-dither array for a component having ncolors |
| 397 | * distinct output values. |
| 398 | */ |
| 399 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 400 | LOCAL(ODITHER_MATRIX_PTR) |
Thomas G. Lane | 9ba2f5e | 1994-12-07 00:00:00 +0000 | [diff] [blame] | 401 | make_odither_array (j_decompress_ptr cinfo, int ncolors) |
| 402 | { |
| 403 | ODITHER_MATRIX_PTR odither; |
| 404 | int j,k; |
| 405 | INT32 num,den; |
| 406 | |
| 407 | odither = (ODITHER_MATRIX_PTR) |
| 408 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 409 | SIZEOF(ODITHER_MATRIX)); |
| 410 | /* The inter-value distance for this color is MAXJSAMPLE/(ncolors-1). |
| 411 | * Hence the dither value for the matrix cell with fill order f |
| 412 | * (f=0..N-1) should be (N-1-2*f)/(2*N) * MAXJSAMPLE/(ncolors-1). |
| 413 | * On 16-bit-int machine, be careful to avoid overflow. |
| 414 | */ |
| 415 | den = 2 * ODITHER_CELLS * ((INT32) (ncolors - 1)); |
| 416 | for (j = 0; j < ODITHER_SIZE; j++) { |
| 417 | for (k = 0; k < ODITHER_SIZE; k++) { |
| 418 | num = ((INT32) (ODITHER_CELLS-1 - 2*((int)base_dither_matrix[j][k]))) |
| 419 | * MAXJSAMPLE; |
| 420 | /* Ensure round towards zero despite C's lack of consistency |
| 421 | * about rounding negative values in integer division... |
| 422 | */ |
| 423 | odither[j][k] = (int) (num<0 ? -((-num)/den) : num/den); |
| 424 | } |
| 425 | } |
| 426 | return odither; |
| 427 | } |
| 428 | |
| 429 | |
| 430 | /* |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 431 | * Create the ordered-dither tables. |
| 432 | * Components having the same number of representative colors may |
| 433 | * share a dither table. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 434 | */ |
| 435 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 436 | LOCAL(void) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 437 | create_odither_tables (j_decompress_ptr cinfo) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 438 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 439 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
Thomas G. Lane | 9ba2f5e | 1994-12-07 00:00:00 +0000 | [diff] [blame] | 440 | ODITHER_MATRIX_PTR odither; |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 441 | int i, j, nci; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 442 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 443 | for (i = 0; i < cinfo->out_color_components; i++) { |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 444 | nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ |
| 445 | odither = NULL; /* search for matching prior component */ |
| 446 | for (j = 0; j < i; j++) { |
| 447 | if (nci == cquantize->Ncolors[j]) { |
| 448 | odither = cquantize->odither[j]; |
| 449 | break; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 450 | } |
| 451 | } |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 452 | if (odither == NULL) /* need a new table? */ |
| 453 | odither = make_odither_array(cinfo, nci); |
| 454 | cquantize->odither[i] = odither; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 455 | } |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 456 | } |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 457 | |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 458 | |
| 459 | /* |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 460 | * Map some rows of pixels to the output colormapped representation. |
| 461 | */ |
| 462 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 463 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 464 | color_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf, |
| 465 | JSAMPARRAY output_buf, int num_rows) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 466 | /* General case, no dithering */ |
| 467 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 468 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
| 469 | JSAMPARRAY colorindex = cquantize->colorindex; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 470 | register int pixcode, ci; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 471 | register JSAMPROW ptrin, ptrout; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 472 | int row; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 473 | JDIMENSION col; |
| 474 | JDIMENSION width = cinfo->output_width; |
| 475 | register int nc = cinfo->out_color_components; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 476 | |
| 477 | for (row = 0; row < num_rows; row++) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 478 | ptrin = input_buf[row]; |
| 479 | ptrout = output_buf[row]; |
| 480 | for (col = width; col > 0; col--) { |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 481 | pixcode = 0; |
| 482 | for (ci = 0; ci < nc; ci++) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 483 | pixcode += GETJSAMPLE(colorindex[ci][GETJSAMPLE(*ptrin++)]); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 484 | } |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 485 | *ptrout++ = (JSAMPLE) pixcode; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 486 | } |
| 487 | } |
| 488 | } |
| 489 | |
| 490 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 491 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 492 | color_quantize3 (j_decompress_ptr cinfo, JSAMPARRAY input_buf, |
| 493 | JSAMPARRAY output_buf, int num_rows) |
| 494 | /* Fast path for out_color_components==3, no dithering */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 495 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 496 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 497 | register int pixcode; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 498 | register JSAMPROW ptrin, ptrout; |
| 499 | JSAMPROW colorindex0 = cquantize->colorindex[0]; |
| 500 | JSAMPROW colorindex1 = cquantize->colorindex[1]; |
| 501 | JSAMPROW colorindex2 = cquantize->colorindex[2]; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 502 | int row; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 503 | JDIMENSION col; |
| 504 | JDIMENSION width = cinfo->output_width; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 505 | |
| 506 | for (row = 0; row < num_rows; row++) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 507 | ptrin = input_buf[row]; |
| 508 | ptrout = output_buf[row]; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 509 | for (col = width; col > 0; col--) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 510 | pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*ptrin++)]); |
| 511 | pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*ptrin++)]); |
| 512 | pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*ptrin++)]); |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 513 | *ptrout++ = (JSAMPLE) pixcode; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 514 | } |
| 515 | } |
| 516 | } |
| 517 | |
| 518 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 519 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 520 | quantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, |
| 521 | JSAMPARRAY output_buf, int num_rows) |
| 522 | /* General case, with ordered dithering */ |
| 523 | { |
| 524 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
| 525 | register JSAMPROW input_ptr; |
| 526 | register JSAMPROW output_ptr; |
| 527 | JSAMPROW colorindex_ci; |
| 528 | int * dither; /* points to active row of dither matrix */ |
| 529 | int row_index, col_index; /* current indexes into dither matrix */ |
| 530 | int nc = cinfo->out_color_components; |
| 531 | int ci; |
| 532 | int row; |
| 533 | JDIMENSION col; |
| 534 | JDIMENSION width = cinfo->output_width; |
| 535 | |
| 536 | for (row = 0; row < num_rows; row++) { |
| 537 | /* Initialize output values to 0 so can process components separately */ |
| 538 | jzero_far((void FAR *) output_buf[row], |
| 539 | (size_t) (width * SIZEOF(JSAMPLE))); |
| 540 | row_index = cquantize->row_index; |
| 541 | for (ci = 0; ci < nc; ci++) { |
| 542 | input_ptr = input_buf[row] + ci; |
| 543 | output_ptr = output_buf[row]; |
| 544 | colorindex_ci = cquantize->colorindex[ci]; |
| 545 | dither = cquantize->odither[ci][row_index]; |
| 546 | col_index = 0; |
| 547 | |
| 548 | 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 | *output_ptr += colorindex_ci[GETJSAMPLE(*input_ptr)+dither[col_index]]; |
| 557 | input_ptr += nc; |
| 558 | output_ptr++; |
| 559 | col_index = (col_index + 1) & ODITHER_MASK; |
| 560 | } |
| 561 | } |
| 562 | /* Advance row index for next row */ |
| 563 | row_index = (row_index + 1) & ODITHER_MASK; |
| 564 | cquantize->row_index = row_index; |
| 565 | } |
| 566 | } |
| 567 | |
| 568 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 569 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 570 | quantize3_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, |
| 571 | JSAMPARRAY output_buf, int num_rows) |
| 572 | /* Fast path for out_color_components==3, with ordered dithering */ |
| 573 | { |
| 574 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
| 575 | register int pixcode; |
| 576 | register JSAMPROW input_ptr; |
| 577 | register JSAMPROW output_ptr; |
| 578 | JSAMPROW colorindex0 = cquantize->colorindex[0]; |
| 579 | JSAMPROW colorindex1 = cquantize->colorindex[1]; |
| 580 | JSAMPROW colorindex2 = cquantize->colorindex[2]; |
| 581 | int * dither0; /* points to active row of dither matrix */ |
| 582 | int * dither1; |
| 583 | int * dither2; |
| 584 | int row_index, col_index; /* current indexes into dither matrix */ |
| 585 | int row; |
| 586 | JDIMENSION col; |
| 587 | JDIMENSION width = cinfo->output_width; |
| 588 | |
| 589 | for (row = 0; row < num_rows; row++) { |
| 590 | row_index = cquantize->row_index; |
| 591 | input_ptr = input_buf[row]; |
| 592 | output_ptr = output_buf[row]; |
| 593 | dither0 = cquantize->odither[0][row_index]; |
| 594 | dither1 = cquantize->odither[1][row_index]; |
| 595 | dither2 = cquantize->odither[2][row_index]; |
| 596 | col_index = 0; |
| 597 | |
| 598 | for (col = width; col > 0; col--) { |
| 599 | pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*input_ptr++) + |
| 600 | dither0[col_index]]); |
| 601 | pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*input_ptr++) + |
| 602 | dither1[col_index]]); |
| 603 | pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*input_ptr++) + |
| 604 | dither2[col_index]]); |
| 605 | *output_ptr++ = (JSAMPLE) pixcode; |
| 606 | col_index = (col_index + 1) & ODITHER_MASK; |
| 607 | } |
| 608 | row_index = (row_index + 1) & ODITHER_MASK; |
| 609 | cquantize->row_index = row_index; |
| 610 | } |
| 611 | } |
| 612 | |
| 613 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 614 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 615 | quantize_fs_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, |
| 616 | JSAMPARRAY output_buf, int num_rows) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 617 | /* General case, with Floyd-Steinberg dithering */ |
| 618 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 619 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 620 | register LOCFSERROR cur; /* current error or pixel value */ |
| 621 | LOCFSERROR belowerr; /* error for pixel below cur */ |
| 622 | LOCFSERROR bpreverr; /* error for below/prev col */ |
| 623 | LOCFSERROR bnexterr; /* error for below/next col */ |
| 624 | LOCFSERROR delta; |
| 625 | register FSERRPTR errorptr; /* => fserrors[] at column before current */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 626 | register JSAMPROW input_ptr; |
| 627 | register JSAMPROW output_ptr; |
| 628 | JSAMPROW colorindex_ci; |
| 629 | JSAMPROW colormap_ci; |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 630 | int pixcode; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 631 | int nc = cinfo->out_color_components; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 632 | int dir; /* 1 for left-to-right, -1 for right-to-left */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 633 | int dirnc; /* dir * nc */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 634 | int ci; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 635 | int row; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 636 | JDIMENSION col; |
| 637 | JDIMENSION width = cinfo->output_width; |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 638 | JSAMPLE *range_limit = cinfo->sample_range_limit; |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 639 | SHIFT_TEMPS |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 640 | |
| 641 | for (row = 0; row < num_rows; row++) { |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 642 | /* Initialize output values to 0 so can process components separately */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 643 | jzero_far((void FAR *) output_buf[row], |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 644 | (size_t) (width * SIZEOF(JSAMPLE))); |
| 645 | for (ci = 0; ci < nc; ci++) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 646 | input_ptr = input_buf[row] + ci; |
| 647 | output_ptr = output_buf[row]; |
| 648 | if (cquantize->on_odd_row) { |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 649 | /* work right to left in this row */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 650 | input_ptr += (width-1) * nc; /* so point to rightmost pixel */ |
| 651 | output_ptr += width-1; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 652 | dir = -1; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 653 | dirnc = -nc; |
| 654 | errorptr = cquantize->fserrors[ci] + (width+1); /* => entry after last column */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 655 | } else { |
| 656 | /* work left to right in this row */ |
| 657 | dir = 1; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 658 | dirnc = nc; |
| 659 | errorptr = cquantize->fserrors[ci]; /* => entry before first column */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 660 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 661 | colorindex_ci = cquantize->colorindex[ci]; |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 662 | colormap_ci = cquantize->sv_colormap[ci]; |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 663 | /* Preset error values: no error propagated to first pixel from left */ |
| 664 | cur = 0; |
| 665 | /* and no error propagated to row below yet */ |
| 666 | belowerr = bpreverr = 0; |
| 667 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 668 | for (col = width; col > 0; col--) { |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 669 | /* cur holds the error propagated from the previous pixel on the |
| 670 | * current line. Add the error propagated from the previous line |
| 671 | * to form the complete error correction term for this pixel, and |
| 672 | * round the error term (which is expressed * 16) to an integer. |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 673 | * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct |
| 674 | * for either sign of the error value. |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 675 | * Note: errorptr points to *previous* column's array entry. |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 676 | */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 677 | cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4); |
| 678 | /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE. |
| 679 | * The maximum error is +- MAXJSAMPLE; this sets the required size |
| 680 | * of the range_limit array. |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 681 | */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 682 | cur += GETJSAMPLE(*input_ptr); |
| 683 | cur = GETJSAMPLE(range_limit[cur]); |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 684 | /* Select output value, accumulate into output code for this pixel */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 685 | pixcode = GETJSAMPLE(colorindex_ci[cur]); |
| 686 | *output_ptr += (JSAMPLE) pixcode; |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 687 | /* Compute actual representation error at this pixel */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 688 | /* Note: we can do this even though we don't have the final */ |
| 689 | /* pixel code, because the colormap is orthogonal. */ |
| 690 | cur -= GETJSAMPLE(colormap_ci[pixcode]); |
| 691 | /* Compute error fractions to be propagated to adjacent pixels. |
| 692 | * Add these into the running sums, and simultaneously shift the |
| 693 | * next-line error sums left by 1 column. |
| 694 | */ |
| 695 | bnexterr = cur; |
| 696 | delta = cur * 2; |
| 697 | cur += delta; /* form error * 3 */ |
| 698 | errorptr[0] = (FSERROR) (bpreverr + cur); |
| 699 | cur += delta; /* form error * 5 */ |
| 700 | bpreverr = belowerr + cur; |
| 701 | belowerr = bnexterr; |
| 702 | cur += delta; /* form error * 7 */ |
| 703 | /* At this point cur contains the 7/16 error value to be propagated |
| 704 | * to the next pixel on the current line, and all the errors for the |
| 705 | * next line have been shifted over. We are therefore ready to move on. |
| 706 | */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 707 | input_ptr += dirnc; /* advance input ptr to next column */ |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 708 | output_ptr += dir; /* advance output ptr to next column */ |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 709 | errorptr += dir; /* advance errorptr to current column */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 710 | } |
Thomas G. Lane | cc7150e | 1993-02-18 00:00:00 +0000 | [diff] [blame] | 711 | /* Post-loop cleanup: we must unload the final error value into the |
| 712 | * final fserrors[] entry. Note we need not unload belowerr because |
| 713 | * it is for the dummy column before or after the actual array. |
| 714 | */ |
| 715 | errorptr[0] = (FSERROR) bpreverr; /* unload prev err into array */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 716 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 717 | cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 718 | } |
| 719 | } |
| 720 | |
| 721 | |
| 722 | /* |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 723 | * Allocate workspace for Floyd-Steinberg errors. |
| 724 | */ |
| 725 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 726 | LOCAL(void) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 727 | alloc_fs_workspace (j_decompress_ptr cinfo) |
| 728 | { |
| 729 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
| 730 | size_t arraysize; |
| 731 | int i; |
| 732 | |
| 733 | arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR)); |
| 734 | for (i = 0; i < cinfo->out_color_components; i++) { |
| 735 | cquantize->fserrors[i] = (FSERRPTR) |
| 736 | (*cinfo->mem->alloc_large)((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize); |
| 737 | } |
| 738 | } |
| 739 | |
| 740 | |
| 741 | /* |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 742 | * Initialize for one-pass color quantization. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 743 | */ |
| 744 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 745 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 746 | start_pass_1_quant (j_decompress_ptr cinfo, boolean is_pre_scan) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 747 | { |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 748 | my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 749 | size_t arraysize; |
| 750 | int i; |
| 751 | |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 752 | /* Install my colormap. */ |
| 753 | cinfo->colormap = cquantize->sv_colormap; |
| 754 | cinfo->actual_number_of_colors = cquantize->sv_actual; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 755 | |
| 756 | /* Initialize for desired dithering mode. */ |
| 757 | switch (cinfo->dither_mode) { |
| 758 | case JDITHER_NONE: |
| 759 | if (cinfo->out_color_components == 3) |
| 760 | cquantize->pub.color_quantize = color_quantize3; |
| 761 | else |
| 762 | cquantize->pub.color_quantize = color_quantize; |
| 763 | break; |
| 764 | case JDITHER_ORDERED: |
| 765 | if (cinfo->out_color_components == 3) |
| 766 | cquantize->pub.color_quantize = quantize3_ord_dither; |
| 767 | else |
| 768 | cquantize->pub.color_quantize = quantize_ord_dither; |
| 769 | cquantize->row_index = 0; /* initialize state for ordered dither */ |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 770 | /* If user changed to ordered dither from another mode, |
| 771 | * we must recreate the color index table with padding. |
| 772 | * This will cost extra space, but probably isn't very likely. |
| 773 | */ |
| 774 | if (! cquantize->is_padded) |
| 775 | create_colorindex(cinfo); |
| 776 | /* Create ordered-dither tables if we didn't already. */ |
| 777 | if (cquantize->odither[0] == NULL) |
| 778 | create_odither_tables(cinfo); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 779 | break; |
| 780 | case JDITHER_FS: |
| 781 | cquantize->pub.color_quantize = quantize_fs_dither; |
| 782 | cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */ |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 783 | /* Allocate Floyd-Steinberg workspace if didn't already. */ |
| 784 | if (cquantize->fserrors[0] == NULL) |
| 785 | alloc_fs_workspace(cinfo); |
| 786 | /* Initialize the propagated errors to zero. */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 787 | arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR)); |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 788 | for (i = 0; i < cinfo->out_color_components; i++) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 789 | jzero_far((void FAR *) cquantize->fserrors[i], arraysize); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 790 | break; |
| 791 | default: |
| 792 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
| 793 | break; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 794 | } |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 795 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 796 | |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 797 | |
| 798 | /* |
| 799 | * Finish up at the end of the pass. |
| 800 | */ |
| 801 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 802 | METHODDEF(void) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 803 | finish_pass_1_quant (j_decompress_ptr cinfo) |
| 804 | { |
| 805 | /* no work in 1-pass case */ |
| 806 | } |
| 807 | |
| 808 | |
| 809 | /* |
| 810 | * Switch to a new external colormap between output passes. |
| 811 | * Shouldn't get to this module! |
| 812 | */ |
| 813 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 814 | METHODDEF(void) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 815 | new_color_map_1_quant (j_decompress_ptr cinfo) |
| 816 | { |
| 817 | ERREXIT(cinfo, JERR_MODE_CHANGE); |
| 818 | } |
| 819 | |
| 820 | |
| 821 | /* |
| 822 | * Module initialization routine for 1-pass color quantization. |
| 823 | */ |
| 824 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 825 | GLOBAL(void) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 826 | jinit_1pass_quantizer (j_decompress_ptr cinfo) |
| 827 | { |
| 828 | my_cquantize_ptr cquantize; |
| 829 | |
| 830 | cquantize = (my_cquantize_ptr) |
| 831 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 832 | SIZEOF(my_cquantizer)); |
| 833 | cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize; |
| 834 | cquantize->pub.start_pass = start_pass_1_quant; |
| 835 | cquantize->pub.finish_pass = finish_pass_1_quant; |
| 836 | cquantize->pub.new_color_map = new_color_map_1_quant; |
| 837 | cquantize->fserrors[0] = NULL; /* Flag FS workspace not allocated */ |
| 838 | cquantize->odither[0] = NULL; /* Also flag odither arrays not allocated */ |
| 839 | |
| 840 | /* Make sure my internal arrays won't overflow */ |
| 841 | if (cinfo->out_color_components > MAX_Q_COMPS) |
| 842 | ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS); |
| 843 | /* Make sure colormap indexes can be represented by JSAMPLEs */ |
| 844 | if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1)) |
| 845 | ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXJSAMPLE+1); |
| 846 | |
| 847 | /* Create the colormap and color index table. */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 848 | create_colormap(cinfo); |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 849 | create_colorindex(cinfo); |
| 850 | |
| 851 | /* Allocate Floyd-Steinberg workspace now if requested. |
| 852 | * We do this now since it is FAR storage and may affect the memory |
| 853 | * manager's space calculations. If the user changes to FS dither |
| 854 | * mode in a later pass, we will allocate the space then, and will |
| 855 | * possibly overrun the max_memory_to_use setting. |
| 856 | */ |
| 857 | if (cinfo->dither_mode == JDITHER_FS) |
| 858 | alloc_fs_workspace(cinfo); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 859 | } |
| 860 | |
| 861 | #endif /* QUANT_1PASS_SUPPORTED */ |