1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libjpeg/jquant1.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,861 @@
1.4 +/*
1.5 + * jquant1.c
1.6 + *
1.7 + * This file was part of the Independent JPEG Group's software:
1.8 + * Copyright (C) 1991-1996, Thomas G. Lane.
1.9 + * libjpeg-turbo Modifications:
1.10 + * Copyright (C) 2009, D. R. Commander
1.11 + * For conditions of distribution and use, see the accompanying README file.
1.12 + *
1.13 + * This file contains 1-pass color quantization (color mapping) routines.
1.14 + * These routines provide mapping to a fixed color map using equally spaced
1.15 + * color values. Optional Floyd-Steinberg or ordered dithering is available.
1.16 + */
1.17 +
1.18 +#define JPEG_INTERNALS
1.19 +#include "jinclude.h"
1.20 +#include "jpeglib.h"
1.21 +
1.22 +#ifdef QUANT_1PASS_SUPPORTED
1.23 +
1.24 +
1.25 +/*
1.26 + * The main purpose of 1-pass quantization is to provide a fast, if not very
1.27 + * high quality, colormapped output capability. A 2-pass quantizer usually
1.28 + * gives better visual quality; however, for quantized grayscale output this
1.29 + * quantizer is perfectly adequate. Dithering is highly recommended with this
1.30 + * quantizer, though you can turn it off if you really want to.
1.31 + *
1.32 + * In 1-pass quantization the colormap must be chosen in advance of seeing the
1.33 + * image. We use a map consisting of all combinations of Ncolors[i] color
1.34 + * values for the i'th component. The Ncolors[] values are chosen so that
1.35 + * their product, the total number of colors, is no more than that requested.
1.36 + * (In most cases, the product will be somewhat less.)
1.37 + *
1.38 + * Since the colormap is orthogonal, the representative value for each color
1.39 + * component can be determined without considering the other components;
1.40 + * then these indexes can be combined into a colormap index by a standard
1.41 + * N-dimensional-array-subscript calculation. Most of the arithmetic involved
1.42 + * can be precalculated and stored in the lookup table colorindex[].
1.43 + * colorindex[i][j] maps pixel value j in component i to the nearest
1.44 + * representative value (grid plane) for that component; this index is
1.45 + * multiplied by the array stride for component i, so that the
1.46 + * index of the colormap entry closest to a given pixel value is just
1.47 + * sum( colorindex[component-number][pixel-component-value] )
1.48 + * Aside from being fast, this scheme allows for variable spacing between
1.49 + * representative values with no additional lookup cost.
1.50 + *
1.51 + * If gamma correction has been applied in color conversion, it might be wise
1.52 + * to adjust the color grid spacing so that the representative colors are
1.53 + * equidistant in linear space. At this writing, gamma correction is not
1.54 + * implemented by jdcolor, so nothing is done here.
1.55 + */
1.56 +
1.57 +
1.58 +/* Declarations for ordered dithering.
1.59 + *
1.60 + * We use a standard 16x16 ordered dither array. The basic concept of ordered
1.61 + * dithering is described in many references, for instance Dale Schumacher's
1.62 + * chapter II.2 of Graphics Gems II (James Arvo, ed. Academic Press, 1991).
1.63 + * In place of Schumacher's comparisons against a "threshold" value, we add a
1.64 + * "dither" value to the input pixel and then round the result to the nearest
1.65 + * output value. The dither value is equivalent to (0.5 - threshold) times
1.66 + * the distance between output values. For ordered dithering, we assume that
1.67 + * the output colors are equally spaced; if not, results will probably be
1.68 + * worse, since the dither may be too much or too little at a given point.
1.69 + *
1.70 + * The normal calculation would be to form pixel value + dither, range-limit
1.71 + * this to 0..MAXJSAMPLE, and then index into the colorindex table as usual.
1.72 + * We can skip the separate range-limiting step by extending the colorindex
1.73 + * table in both directions.
1.74 + */
1.75 +
1.76 +#define ODITHER_SIZE 16 /* dimension of dither matrix */
1.77 +/* NB: if ODITHER_SIZE is not a power of 2, ODITHER_MASK uses will break */
1.78 +#define ODITHER_CELLS (ODITHER_SIZE*ODITHER_SIZE) /* # cells in matrix */
1.79 +#define ODITHER_MASK (ODITHER_SIZE-1) /* mask for wrapping around counters */
1.80 +
1.81 +typedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE];
1.82 +typedef int (*ODITHER_MATRIX_PTR)[ODITHER_SIZE];
1.83 +
1.84 +static const UINT8 base_dither_matrix[ODITHER_SIZE][ODITHER_SIZE] = {
1.85 + /* Bayer's order-4 dither array. Generated by the code given in
1.86 + * Stephen Hawley's article "Ordered Dithering" in Graphics Gems I.
1.87 + * The values in this array must range from 0 to ODITHER_CELLS-1.
1.88 + */
1.89 + { 0,192, 48,240, 12,204, 60,252, 3,195, 51,243, 15,207, 63,255 },
1.90 + { 128, 64,176,112,140, 76,188,124,131, 67,179,115,143, 79,191,127 },
1.91 + { 32,224, 16,208, 44,236, 28,220, 35,227, 19,211, 47,239, 31,223 },
1.92 + { 160, 96,144, 80,172,108,156, 92,163, 99,147, 83,175,111,159, 95 },
1.93 + { 8,200, 56,248, 4,196, 52,244, 11,203, 59,251, 7,199, 55,247 },
1.94 + { 136, 72,184,120,132, 68,180,116,139, 75,187,123,135, 71,183,119 },
1.95 + { 40,232, 24,216, 36,228, 20,212, 43,235, 27,219, 39,231, 23,215 },
1.96 + { 168,104,152, 88,164,100,148, 84,171,107,155, 91,167,103,151, 87 },
1.97 + { 2,194, 50,242, 14,206, 62,254, 1,193, 49,241, 13,205, 61,253 },
1.98 + { 130, 66,178,114,142, 78,190,126,129, 65,177,113,141, 77,189,125 },
1.99 + { 34,226, 18,210, 46,238, 30,222, 33,225, 17,209, 45,237, 29,221 },
1.100 + { 162, 98,146, 82,174,110,158, 94,161, 97,145, 81,173,109,157, 93 },
1.101 + { 10,202, 58,250, 6,198, 54,246, 9,201, 57,249, 5,197, 53,245 },
1.102 + { 138, 74,186,122,134, 70,182,118,137, 73,185,121,133, 69,181,117 },
1.103 + { 42,234, 26,218, 38,230, 22,214, 41,233, 25,217, 37,229, 21,213 },
1.104 + { 170,106,154, 90,166,102,150, 86,169,105,153, 89,165,101,149, 85 }
1.105 +};
1.106 +
1.107 +
1.108 +/* Declarations for Floyd-Steinberg dithering.
1.109 + *
1.110 + * Errors are accumulated into the array fserrors[], at a resolution of
1.111 + * 1/16th of a pixel count. The error at a given pixel is propagated
1.112 + * to its not-yet-processed neighbors using the standard F-S fractions,
1.113 + * ... (here) 7/16
1.114 + * 3/16 5/16 1/16
1.115 + * We work left-to-right on even rows, right-to-left on odd rows.
1.116 + *
1.117 + * We can get away with a single array (holding one row's worth of errors)
1.118 + * by using it to store the current row's errors at pixel columns not yet
1.119 + * processed, but the next row's errors at columns already processed. We
1.120 + * need only a few extra variables to hold the errors immediately around the
1.121 + * current column. (If we are lucky, those variables are in registers, but
1.122 + * even if not, they're probably cheaper to access than array elements are.)
1.123 + *
1.124 + * The fserrors[] array is indexed [component#][position].
1.125 + * We provide (#columns + 2) entries per component; the extra entry at each
1.126 + * end saves us from special-casing the first and last pixels.
1.127 + *
1.128 + * Note: on a wide image, we might not have enough room in a PC's near data
1.129 + * segment to hold the error array; so it is allocated with alloc_large.
1.130 + */
1.131 +
1.132 +#if BITS_IN_JSAMPLE == 8
1.133 +typedef INT16 FSERROR; /* 16 bits should be enough */
1.134 +typedef int LOCFSERROR; /* use 'int' for calculation temps */
1.135 +#else
1.136 +typedef INT32 FSERROR; /* may need more than 16 bits */
1.137 +typedef INT32 LOCFSERROR; /* be sure calculation temps are big enough */
1.138 +#endif
1.139 +
1.140 +typedef FSERROR FAR *FSERRPTR; /* pointer to error array (in FAR storage!) */
1.141 +
1.142 +
1.143 +/* Private subobject */
1.144 +
1.145 +#define MAX_Q_COMPS 4 /* max components I can handle */
1.146 +
1.147 +typedef struct {
1.148 + struct jpeg_color_quantizer pub; /* public fields */
1.149 +
1.150 + /* Initially allocated colormap is saved here */
1.151 + JSAMPARRAY sv_colormap; /* The color map as a 2-D pixel array */
1.152 + int sv_actual; /* number of entries in use */
1.153 +
1.154 + JSAMPARRAY colorindex; /* Precomputed mapping for speed */
1.155 + /* colorindex[i][j] = index of color closest to pixel value j in component i,
1.156 + * premultiplied as described above. Since colormap indexes must fit into
1.157 + * JSAMPLEs, the entries of this array will too.
1.158 + */
1.159 + boolean is_padded; /* is the colorindex padded for odither? */
1.160 +
1.161 + int Ncolors[MAX_Q_COMPS]; /* # of values alloced to each component */
1.162 +
1.163 + /* Variables for ordered dithering */
1.164 + int row_index; /* cur row's vertical index in dither matrix */
1.165 + ODITHER_MATRIX_PTR odither[MAX_Q_COMPS]; /* one dither array per component */
1.166 +
1.167 + /* Variables for Floyd-Steinberg dithering */
1.168 + FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */
1.169 + boolean on_odd_row; /* flag to remember which row we are on */
1.170 +} my_cquantizer;
1.171 +
1.172 +typedef my_cquantizer * my_cquantize_ptr;
1.173 +
1.174 +
1.175 +/*
1.176 + * Policy-making subroutines for create_colormap and create_colorindex.
1.177 + * These routines determine the colormap to be used. The rest of the module
1.178 + * only assumes that the colormap is orthogonal.
1.179 + *
1.180 + * * select_ncolors decides how to divvy up the available colors
1.181 + * among the components.
1.182 + * * output_value defines the set of representative values for a component.
1.183 + * * largest_input_value defines the mapping from input values to
1.184 + * representative values for a component.
1.185 + * Note that the latter two routines may impose different policies for
1.186 + * different components, though this is not currently done.
1.187 + */
1.188 +
1.189 +
1.190 +LOCAL(int)
1.191 +select_ncolors (j_decompress_ptr cinfo, int Ncolors[])
1.192 +/* Determine allocation of desired colors to components, */
1.193 +/* and fill in Ncolors[] array to indicate choice. */
1.194 +/* Return value is total number of colors (product of Ncolors[] values). */
1.195 +{
1.196 + int nc = cinfo->out_color_components; /* number of color components */
1.197 + int max_colors = cinfo->desired_number_of_colors;
1.198 + int total_colors, iroot, i, j;
1.199 + boolean changed;
1.200 + long temp;
1.201 + int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE };
1.202 + RGB_order[0] = rgb_green[cinfo->out_color_space];
1.203 + RGB_order[1] = rgb_red[cinfo->out_color_space];
1.204 + RGB_order[2] = rgb_blue[cinfo->out_color_space];
1.205 +
1.206 + /* We can allocate at least the nc'th root of max_colors per component. */
1.207 + /* Compute floor(nc'th root of max_colors). */
1.208 + iroot = 1;
1.209 + do {
1.210 + iroot++;
1.211 + temp = iroot; /* set temp = iroot ** nc */
1.212 + for (i = 1; i < nc; i++)
1.213 + temp *= iroot;
1.214 + } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */
1.215 + iroot--; /* now iroot = floor(root) */
1.216 +
1.217 + /* Must have at least 2 color values per component */
1.218 + if (iroot < 2)
1.219 + ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int) temp);
1.220 +
1.221 + /* Initialize to iroot color values for each component */
1.222 + total_colors = 1;
1.223 + for (i = 0; i < nc; i++) {
1.224 + Ncolors[i] = iroot;
1.225 + total_colors *= iroot;
1.226 + }
1.227 + /* We may be able to increment the count for one or more components without
1.228 + * exceeding max_colors, though we know not all can be incremented.
1.229 + * Sometimes, the first component can be incremented more than once!
1.230 + * (Example: for 16 colors, we start at 2*2*2, go to 3*2*2, then 4*2*2.)
1.231 + * In RGB colorspace, try to increment G first, then R, then B.
1.232 + */
1.233 + do {
1.234 + changed = FALSE;
1.235 + for (i = 0; i < nc; i++) {
1.236 + j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i);
1.237 + /* calculate new total_colors if Ncolors[j] is incremented */
1.238 + temp = total_colors / Ncolors[j];
1.239 + temp *= Ncolors[j]+1; /* done in long arith to avoid oflo */
1.240 + if (temp > (long) max_colors)
1.241 + break; /* won't fit, done with this pass */
1.242 + Ncolors[j]++; /* OK, apply the increment */
1.243 + total_colors = (int) temp;
1.244 + changed = TRUE;
1.245 + }
1.246 + } while (changed);
1.247 +
1.248 + return total_colors;
1.249 +}
1.250 +
1.251 +
1.252 +LOCAL(int)
1.253 +output_value (j_decompress_ptr cinfo, int ci, int j, int maxj)
1.254 +/* Return j'th output value, where j will range from 0 to maxj */
1.255 +/* The output values must fall in 0..MAXJSAMPLE in increasing order */
1.256 +{
1.257 + /* We always provide values 0 and MAXJSAMPLE for each component;
1.258 + * any additional values are equally spaced between these limits.
1.259 + * (Forcing the upper and lower values to the limits ensures that
1.260 + * dithering can't produce a color outside the selected gamut.)
1.261 + */
1.262 + return (int) (((INT32) j * MAXJSAMPLE + maxj/2) / maxj);
1.263 +}
1.264 +
1.265 +
1.266 +LOCAL(int)
1.267 +largest_input_value (j_decompress_ptr cinfo, int ci, int j, int maxj)
1.268 +/* Return largest input value that should map to j'th output value */
1.269 +/* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */
1.270 +{
1.271 + /* Breakpoints are halfway between values returned by output_value */
1.272 + return (int) (((INT32) (2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj));
1.273 +}
1.274 +
1.275 +
1.276 +/*
1.277 + * Create the colormap.
1.278 + */
1.279 +
1.280 +LOCAL(void)
1.281 +create_colormap (j_decompress_ptr cinfo)
1.282 +{
1.283 + my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
1.284 + JSAMPARRAY colormap; /* Created colormap */
1.285 + int total_colors; /* Number of distinct output colors */
1.286 + int i,j,k, nci, blksize, blkdist, ptr, val;
1.287 +
1.288 + /* Select number of colors for each component */
1.289 + total_colors = select_ncolors(cinfo, cquantize->Ncolors);
1.290 +
1.291 + /* Report selected color counts */
1.292 + if (cinfo->out_color_components == 3)
1.293 + TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS,
1.294 + total_colors, cquantize->Ncolors[0],
1.295 + cquantize->Ncolors[1], cquantize->Ncolors[2]);
1.296 + else
1.297 + TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors);
1.298 +
1.299 + /* Allocate and fill in the colormap. */
1.300 + /* The colors are ordered in the map in standard row-major order, */
1.301 + /* i.e. rightmost (highest-indexed) color changes most rapidly. */
1.302 +
1.303 + colormap = (*cinfo->mem->alloc_sarray)
1.304 + ((j_common_ptr) cinfo, JPOOL_IMAGE,
1.305 + (JDIMENSION) total_colors, (JDIMENSION) cinfo->out_color_components);
1.306 +
1.307 + /* blksize is number of adjacent repeated entries for a component */
1.308 + /* blkdist is distance between groups of identical entries for a component */
1.309 + blkdist = total_colors;
1.310 +
1.311 + for (i = 0; i < cinfo->out_color_components; i++) {
1.312 + /* fill in colormap entries for i'th color component */
1.313 + nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
1.314 + blksize = blkdist / nci;
1.315 + for (j = 0; j < nci; j++) {
1.316 + /* Compute j'th output value (out of nci) for component */
1.317 + val = output_value(cinfo, i, j, nci-1);
1.318 + /* Fill in all colormap entries that have this value of this component */
1.319 + for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) {
1.320 + /* fill in blksize entries beginning at ptr */
1.321 + for (k = 0; k < blksize; k++)
1.322 + colormap[i][ptr+k] = (JSAMPLE) val;
1.323 + }
1.324 + }
1.325 + blkdist = blksize; /* blksize of this color is blkdist of next */
1.326 + }
1.327 +
1.328 + /* Save the colormap in private storage,
1.329 + * where it will survive color quantization mode changes.
1.330 + */
1.331 + cquantize->sv_colormap = colormap;
1.332 + cquantize->sv_actual = total_colors;
1.333 +}
1.334 +
1.335 +
1.336 +/*
1.337 + * Create the color index table.
1.338 + */
1.339 +
1.340 +LOCAL(void)
1.341 +create_colorindex (j_decompress_ptr cinfo)
1.342 +{
1.343 + my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
1.344 + JSAMPROW indexptr;
1.345 + int i,j,k, nci, blksize, val, pad;
1.346 +
1.347 + /* For ordered dither, we pad the color index tables by MAXJSAMPLE in
1.348 + * each direction (input index values can be -MAXJSAMPLE .. 2*MAXJSAMPLE).
1.349 + * This is not necessary in the other dithering modes. However, we
1.350 + * flag whether it was done in case user changes dithering mode.
1.351 + */
1.352 + if (cinfo->dither_mode == JDITHER_ORDERED) {
1.353 + pad = MAXJSAMPLE*2;
1.354 + cquantize->is_padded = TRUE;
1.355 + } else {
1.356 + pad = 0;
1.357 + cquantize->is_padded = FALSE;
1.358 + }
1.359 +
1.360 + cquantize->colorindex = (*cinfo->mem->alloc_sarray)
1.361 + ((j_common_ptr) cinfo, JPOOL_IMAGE,
1.362 + (JDIMENSION) (MAXJSAMPLE+1 + pad),
1.363 + (JDIMENSION) cinfo->out_color_components);
1.364 +
1.365 + /* blksize is number of adjacent repeated entries for a component */
1.366 + blksize = cquantize->sv_actual;
1.367 +
1.368 + for (i = 0; i < cinfo->out_color_components; i++) {
1.369 + /* fill in colorindex entries for i'th color component */
1.370 + nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
1.371 + blksize = blksize / nci;
1.372 +
1.373 + /* adjust colorindex pointers to provide padding at negative indexes. */
1.374 + if (pad)
1.375 + cquantize->colorindex[i] += MAXJSAMPLE;
1.376 +
1.377 + /* in loop, val = index of current output value, */
1.378 + /* and k = largest j that maps to current val */
1.379 + indexptr = cquantize->colorindex[i];
1.380 + val = 0;
1.381 + k = largest_input_value(cinfo, i, 0, nci-1);
1.382 + for (j = 0; j <= MAXJSAMPLE; j++) {
1.383 + while (j > k) /* advance val if past boundary */
1.384 + k = largest_input_value(cinfo, i, ++val, nci-1);
1.385 + /* premultiply so that no multiplication needed in main processing */
1.386 + indexptr[j] = (JSAMPLE) (val * blksize);
1.387 + }
1.388 + /* Pad at both ends if necessary */
1.389 + if (pad)
1.390 + for (j = 1; j <= MAXJSAMPLE; j++) {
1.391 + indexptr[-j] = indexptr[0];
1.392 + indexptr[MAXJSAMPLE+j] = indexptr[MAXJSAMPLE];
1.393 + }
1.394 + }
1.395 +}
1.396 +
1.397 +
1.398 +/*
1.399 + * Create an ordered-dither array for a component having ncolors
1.400 + * distinct output values.
1.401 + */
1.402 +
1.403 +LOCAL(ODITHER_MATRIX_PTR)
1.404 +make_odither_array (j_decompress_ptr cinfo, int ncolors)
1.405 +{
1.406 + ODITHER_MATRIX_PTR odither;
1.407 + int j,k;
1.408 + INT32 num,den;
1.409 +
1.410 + odither = (ODITHER_MATRIX_PTR)
1.411 + (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
1.412 + SIZEOF(ODITHER_MATRIX));
1.413 + /* The inter-value distance for this color is MAXJSAMPLE/(ncolors-1).
1.414 + * Hence the dither value for the matrix cell with fill order f
1.415 + * (f=0..N-1) should be (N-1-2*f)/(2*N) * MAXJSAMPLE/(ncolors-1).
1.416 + * On 16-bit-int machine, be careful to avoid overflow.
1.417 + */
1.418 + den = 2 * ODITHER_CELLS * ((INT32) (ncolors - 1));
1.419 + for (j = 0; j < ODITHER_SIZE; j++) {
1.420 + for (k = 0; k < ODITHER_SIZE; k++) {
1.421 + num = ((INT32) (ODITHER_CELLS-1 - 2*((int)base_dither_matrix[j][k])))
1.422 + * MAXJSAMPLE;
1.423 + /* Ensure round towards zero despite C's lack of consistency
1.424 + * about rounding negative values in integer division...
1.425 + */
1.426 + odither[j][k] = (int) (num<0 ? -((-num)/den) : num/den);
1.427 + }
1.428 + }
1.429 + return odither;
1.430 +}
1.431 +
1.432 +
1.433 +/*
1.434 + * Create the ordered-dither tables.
1.435 + * Components having the same number of representative colors may
1.436 + * share a dither table.
1.437 + */
1.438 +
1.439 +LOCAL(void)
1.440 +create_odither_tables (j_decompress_ptr cinfo)
1.441 +{
1.442 + my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
1.443 + ODITHER_MATRIX_PTR odither;
1.444 + int i, j, nci;
1.445 +
1.446 + for (i = 0; i < cinfo->out_color_components; i++) {
1.447 + nci = cquantize->Ncolors[i]; /* # of distinct values for this color */
1.448 + odither = NULL; /* search for matching prior component */
1.449 + for (j = 0; j < i; j++) {
1.450 + if (nci == cquantize->Ncolors[j]) {
1.451 + odither = cquantize->odither[j];
1.452 + break;
1.453 + }
1.454 + }
1.455 + if (odither == NULL) /* need a new table? */
1.456 + odither = make_odither_array(cinfo, nci);
1.457 + cquantize->odither[i] = odither;
1.458 + }
1.459 +}
1.460 +
1.461 +
1.462 +/*
1.463 + * Map some rows of pixels to the output colormapped representation.
1.464 + */
1.465 +
1.466 +METHODDEF(void)
1.467 +color_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
1.468 + JSAMPARRAY output_buf, int num_rows)
1.469 +/* General case, no dithering */
1.470 +{
1.471 + my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
1.472 + JSAMPARRAY colorindex = cquantize->colorindex;
1.473 + register int pixcode, ci;
1.474 + register JSAMPROW ptrin, ptrout;
1.475 + int row;
1.476 + JDIMENSION col;
1.477 + JDIMENSION width = cinfo->output_width;
1.478 + register int nc = cinfo->out_color_components;
1.479 +
1.480 + for (row = 0; row < num_rows; row++) {
1.481 + ptrin = input_buf[row];
1.482 + ptrout = output_buf[row];
1.483 + for (col = width; col > 0; col--) {
1.484 + pixcode = 0;
1.485 + for (ci = 0; ci < nc; ci++) {
1.486 + pixcode += GETJSAMPLE(colorindex[ci][GETJSAMPLE(*ptrin++)]);
1.487 + }
1.488 + *ptrout++ = (JSAMPLE) pixcode;
1.489 + }
1.490 + }
1.491 +}
1.492 +
1.493 +
1.494 +METHODDEF(void)
1.495 +color_quantize3 (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
1.496 + JSAMPARRAY output_buf, int num_rows)
1.497 +/* Fast path for out_color_components==3, no dithering */
1.498 +{
1.499 + my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
1.500 + register int pixcode;
1.501 + register JSAMPROW ptrin, ptrout;
1.502 + JSAMPROW colorindex0 = cquantize->colorindex[0];
1.503 + JSAMPROW colorindex1 = cquantize->colorindex[1];
1.504 + JSAMPROW colorindex2 = cquantize->colorindex[2];
1.505 + int row;
1.506 + JDIMENSION col;
1.507 + JDIMENSION width = cinfo->output_width;
1.508 +
1.509 + for (row = 0; row < num_rows; row++) {
1.510 + ptrin = input_buf[row];
1.511 + ptrout = output_buf[row];
1.512 + for (col = width; col > 0; col--) {
1.513 + pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*ptrin++)]);
1.514 + pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*ptrin++)]);
1.515 + pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*ptrin++)]);
1.516 + *ptrout++ = (JSAMPLE) pixcode;
1.517 + }
1.518 + }
1.519 +}
1.520 +
1.521 +
1.522 +METHODDEF(void)
1.523 +quantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
1.524 + JSAMPARRAY output_buf, int num_rows)
1.525 +/* General case, with ordered dithering */
1.526 +{
1.527 + my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
1.528 + register JSAMPROW input_ptr;
1.529 + register JSAMPROW output_ptr;
1.530 + JSAMPROW colorindex_ci;
1.531 + int * dither; /* points to active row of dither matrix */
1.532 + int row_index, col_index; /* current indexes into dither matrix */
1.533 + int nc = cinfo->out_color_components;
1.534 + int ci;
1.535 + int row;
1.536 + JDIMENSION col;
1.537 + JDIMENSION width = cinfo->output_width;
1.538 +
1.539 + for (row = 0; row < num_rows; row++) {
1.540 + /* Initialize output values to 0 so can process components separately */
1.541 + jzero_far((void FAR *) output_buf[row],
1.542 + (size_t) (width * SIZEOF(JSAMPLE)));
1.543 + row_index = cquantize->row_index;
1.544 + for (ci = 0; ci < nc; ci++) {
1.545 + input_ptr = input_buf[row] + ci;
1.546 + output_ptr = output_buf[row];
1.547 + colorindex_ci = cquantize->colorindex[ci];
1.548 + dither = cquantize->odither[ci][row_index];
1.549 + col_index = 0;
1.550 +
1.551 + for (col = width; col > 0; col--) {
1.552 + /* Form pixel value + dither, range-limit to 0..MAXJSAMPLE,
1.553 + * select output value, accumulate into output code for this pixel.
1.554 + * Range-limiting need not be done explicitly, as we have extended
1.555 + * the colorindex table to produce the right answers for out-of-range
1.556 + * inputs. The maximum dither is +- MAXJSAMPLE; this sets the
1.557 + * required amount of padding.
1.558 + */
1.559 + *output_ptr += colorindex_ci[GETJSAMPLE(*input_ptr)+dither[col_index]];
1.560 + input_ptr += nc;
1.561 + output_ptr++;
1.562 + col_index = (col_index + 1) & ODITHER_MASK;
1.563 + }
1.564 + }
1.565 + /* Advance row index for next row */
1.566 + row_index = (row_index + 1) & ODITHER_MASK;
1.567 + cquantize->row_index = row_index;
1.568 + }
1.569 +}
1.570 +
1.571 +
1.572 +METHODDEF(void)
1.573 +quantize3_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
1.574 + JSAMPARRAY output_buf, int num_rows)
1.575 +/* Fast path for out_color_components==3, with ordered dithering */
1.576 +{
1.577 + my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
1.578 + register int pixcode;
1.579 + register JSAMPROW input_ptr;
1.580 + register JSAMPROW output_ptr;
1.581 + JSAMPROW colorindex0 = cquantize->colorindex[0];
1.582 + JSAMPROW colorindex1 = cquantize->colorindex[1];
1.583 + JSAMPROW colorindex2 = cquantize->colorindex[2];
1.584 + int * dither0; /* points to active row of dither matrix */
1.585 + int * dither1;
1.586 + int * dither2;
1.587 + int row_index, col_index; /* current indexes into dither matrix */
1.588 + int row;
1.589 + JDIMENSION col;
1.590 + JDIMENSION width = cinfo->output_width;
1.591 +
1.592 + for (row = 0; row < num_rows; row++) {
1.593 + row_index = cquantize->row_index;
1.594 + input_ptr = input_buf[row];
1.595 + output_ptr = output_buf[row];
1.596 + dither0 = cquantize->odither[0][row_index];
1.597 + dither1 = cquantize->odither[1][row_index];
1.598 + dither2 = cquantize->odither[2][row_index];
1.599 + col_index = 0;
1.600 +
1.601 + for (col = width; col > 0; col--) {
1.602 + pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*input_ptr++) +
1.603 + dither0[col_index]]);
1.604 + pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*input_ptr++) +
1.605 + dither1[col_index]]);
1.606 + pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*input_ptr++) +
1.607 + dither2[col_index]]);
1.608 + *output_ptr++ = (JSAMPLE) pixcode;
1.609 + col_index = (col_index + 1) & ODITHER_MASK;
1.610 + }
1.611 + row_index = (row_index + 1) & ODITHER_MASK;
1.612 + cquantize->row_index = row_index;
1.613 + }
1.614 +}
1.615 +
1.616 +
1.617 +METHODDEF(void)
1.618 +quantize_fs_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
1.619 + JSAMPARRAY output_buf, int num_rows)
1.620 +/* General case, with Floyd-Steinberg dithering */
1.621 +{
1.622 + my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
1.623 + register LOCFSERROR cur; /* current error or pixel value */
1.624 + LOCFSERROR belowerr; /* error for pixel below cur */
1.625 + LOCFSERROR bpreverr; /* error for below/prev col */
1.626 + LOCFSERROR bnexterr; /* error for below/next col */
1.627 + LOCFSERROR delta;
1.628 + register FSERRPTR errorptr; /* => fserrors[] at column before current */
1.629 + register JSAMPROW input_ptr;
1.630 + register JSAMPROW output_ptr;
1.631 + JSAMPROW colorindex_ci;
1.632 + JSAMPROW colormap_ci;
1.633 + int pixcode;
1.634 + int nc = cinfo->out_color_components;
1.635 + int dir; /* 1 for left-to-right, -1 for right-to-left */
1.636 + int dirnc; /* dir * nc */
1.637 + int ci;
1.638 + int row;
1.639 + JDIMENSION col;
1.640 + JDIMENSION width = cinfo->output_width;
1.641 + JSAMPLE *range_limit = cinfo->sample_range_limit;
1.642 + SHIFT_TEMPS
1.643 +
1.644 + for (row = 0; row < num_rows; row++) {
1.645 + /* Initialize output values to 0 so can process components separately */
1.646 + jzero_far((void FAR *) output_buf[row],
1.647 + (size_t) (width * SIZEOF(JSAMPLE)));
1.648 + for (ci = 0; ci < nc; ci++) {
1.649 + input_ptr = input_buf[row] + ci;
1.650 + output_ptr = output_buf[row];
1.651 + if (cquantize->on_odd_row) {
1.652 + /* work right to left in this row */
1.653 + input_ptr += (width-1) * nc; /* so point to rightmost pixel */
1.654 + output_ptr += width-1;
1.655 + dir = -1;
1.656 + dirnc = -nc;
1.657 + errorptr = cquantize->fserrors[ci] + (width+1); /* => entry after last column */
1.658 + } else {
1.659 + /* work left to right in this row */
1.660 + dir = 1;
1.661 + dirnc = nc;
1.662 + errorptr = cquantize->fserrors[ci]; /* => entry before first column */
1.663 + }
1.664 + colorindex_ci = cquantize->colorindex[ci];
1.665 + colormap_ci = cquantize->sv_colormap[ci];
1.666 + /* Preset error values: no error propagated to first pixel from left */
1.667 + cur = 0;
1.668 + /* and no error propagated to row below yet */
1.669 + belowerr = bpreverr = 0;
1.670 +
1.671 + for (col = width; col > 0; col--) {
1.672 + /* cur holds the error propagated from the previous pixel on the
1.673 + * current line. Add the error propagated from the previous line
1.674 + * to form the complete error correction term for this pixel, and
1.675 + * round the error term (which is expressed * 16) to an integer.
1.676 + * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct
1.677 + * for either sign of the error value.
1.678 + * Note: errorptr points to *previous* column's array entry.
1.679 + */
1.680 + cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4);
1.681 + /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE.
1.682 + * The maximum error is +- MAXJSAMPLE; this sets the required size
1.683 + * of the range_limit array.
1.684 + */
1.685 + cur += GETJSAMPLE(*input_ptr);
1.686 + cur = GETJSAMPLE(range_limit[cur]);
1.687 + /* Select output value, accumulate into output code for this pixel */
1.688 + pixcode = GETJSAMPLE(colorindex_ci[cur]);
1.689 + *output_ptr += (JSAMPLE) pixcode;
1.690 + /* Compute actual representation error at this pixel */
1.691 + /* Note: we can do this even though we don't have the final */
1.692 + /* pixel code, because the colormap is orthogonal. */
1.693 + cur -= GETJSAMPLE(colormap_ci[pixcode]);
1.694 + /* Compute error fractions to be propagated to adjacent pixels.
1.695 + * Add these into the running sums, and simultaneously shift the
1.696 + * next-line error sums left by 1 column.
1.697 + */
1.698 + bnexterr = cur;
1.699 + delta = cur * 2;
1.700 + cur += delta; /* form error * 3 */
1.701 + errorptr[0] = (FSERROR) (bpreverr + cur);
1.702 + cur += delta; /* form error * 5 */
1.703 + bpreverr = belowerr + cur;
1.704 + belowerr = bnexterr;
1.705 + cur += delta; /* form error * 7 */
1.706 + /* At this point cur contains the 7/16 error value to be propagated
1.707 + * to the next pixel on the current line, and all the errors for the
1.708 + * next line have been shifted over. We are therefore ready to move on.
1.709 + */
1.710 + input_ptr += dirnc; /* advance input ptr to next column */
1.711 + output_ptr += dir; /* advance output ptr to next column */
1.712 + errorptr += dir; /* advance errorptr to current column */
1.713 + }
1.714 + /* Post-loop cleanup: we must unload the final error value into the
1.715 + * final fserrors[] entry. Note we need not unload belowerr because
1.716 + * it is for the dummy column before or after the actual array.
1.717 + */
1.718 + errorptr[0] = (FSERROR) bpreverr; /* unload prev err into array */
1.719 + }
1.720 + cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE);
1.721 + }
1.722 +}
1.723 +
1.724 +
1.725 +/*
1.726 + * Allocate workspace for Floyd-Steinberg errors.
1.727 + */
1.728 +
1.729 +LOCAL(void)
1.730 +alloc_fs_workspace (j_decompress_ptr cinfo)
1.731 +{
1.732 + my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
1.733 + size_t arraysize;
1.734 + int i;
1.735 +
1.736 + arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));
1.737 + for (i = 0; i < cinfo->out_color_components; i++) {
1.738 + cquantize->fserrors[i] = (FSERRPTR)
1.739 + (*cinfo->mem->alloc_large)((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize);
1.740 + }
1.741 +}
1.742 +
1.743 +
1.744 +/*
1.745 + * Initialize for one-pass color quantization.
1.746 + */
1.747 +
1.748 +METHODDEF(void)
1.749 +start_pass_1_quant (j_decompress_ptr cinfo, boolean is_pre_scan)
1.750 +{
1.751 + my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize;
1.752 + size_t arraysize;
1.753 + int i;
1.754 +
1.755 + /* Install my colormap. */
1.756 + cinfo->colormap = cquantize->sv_colormap;
1.757 + cinfo->actual_number_of_colors = cquantize->sv_actual;
1.758 +
1.759 + /* Initialize for desired dithering mode. */
1.760 + switch (cinfo->dither_mode) {
1.761 + case JDITHER_NONE:
1.762 + if (cinfo->out_color_components == 3)
1.763 + cquantize->pub.color_quantize = color_quantize3;
1.764 + else
1.765 + cquantize->pub.color_quantize = color_quantize;
1.766 + break;
1.767 + case JDITHER_ORDERED:
1.768 + if (cinfo->out_color_components == 3)
1.769 + cquantize->pub.color_quantize = quantize3_ord_dither;
1.770 + else
1.771 + cquantize->pub.color_quantize = quantize_ord_dither;
1.772 + cquantize->row_index = 0; /* initialize state for ordered dither */
1.773 + /* If user changed to ordered dither from another mode,
1.774 + * we must recreate the color index table with padding.
1.775 + * This will cost extra space, but probably isn't very likely.
1.776 + */
1.777 + if (! cquantize->is_padded)
1.778 + create_colorindex(cinfo);
1.779 + /* Create ordered-dither tables if we didn't already. */
1.780 + if (cquantize->odither[0] == NULL)
1.781 + create_odither_tables(cinfo);
1.782 + break;
1.783 + case JDITHER_FS:
1.784 + cquantize->pub.color_quantize = quantize_fs_dither;
1.785 + cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */
1.786 + /* Allocate Floyd-Steinberg workspace if didn't already. */
1.787 + if (cquantize->fserrors[0] == NULL)
1.788 + alloc_fs_workspace(cinfo);
1.789 + /* Initialize the propagated errors to zero. */
1.790 + arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR));
1.791 + for (i = 0; i < cinfo->out_color_components; i++)
1.792 + jzero_far((void FAR *) cquantize->fserrors[i], arraysize);
1.793 + break;
1.794 + default:
1.795 + ERREXIT(cinfo, JERR_NOT_COMPILED);
1.796 + break;
1.797 + }
1.798 +}
1.799 +
1.800 +
1.801 +/*
1.802 + * Finish up at the end of the pass.
1.803 + */
1.804 +
1.805 +METHODDEF(void)
1.806 +finish_pass_1_quant (j_decompress_ptr cinfo)
1.807 +{
1.808 + /* no work in 1-pass case */
1.809 +}
1.810 +
1.811 +
1.812 +/*
1.813 + * Switch to a new external colormap between output passes.
1.814 + * Shouldn't get to this module!
1.815 + */
1.816 +
1.817 +METHODDEF(void)
1.818 +new_color_map_1_quant (j_decompress_ptr cinfo)
1.819 +{
1.820 + ERREXIT(cinfo, JERR_MODE_CHANGE);
1.821 +}
1.822 +
1.823 +
1.824 +/*
1.825 + * Module initialization routine for 1-pass color quantization.
1.826 + */
1.827 +
1.828 +GLOBAL(void)
1.829 +jinit_1pass_quantizer (j_decompress_ptr cinfo)
1.830 +{
1.831 + my_cquantize_ptr cquantize;
1.832 +
1.833 + cquantize = (my_cquantize_ptr)
1.834 + (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
1.835 + SIZEOF(my_cquantizer));
1.836 + cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize;
1.837 + cquantize->pub.start_pass = start_pass_1_quant;
1.838 + cquantize->pub.finish_pass = finish_pass_1_quant;
1.839 + cquantize->pub.new_color_map = new_color_map_1_quant;
1.840 + cquantize->fserrors[0] = NULL; /* Flag FS workspace not allocated */
1.841 + cquantize->odither[0] = NULL; /* Also flag odither arrays not allocated */
1.842 +
1.843 + /* Make sure my internal arrays won't overflow */
1.844 + if (cinfo->out_color_components > MAX_Q_COMPS)
1.845 + ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS);
1.846 + /* Make sure colormap indexes can be represented by JSAMPLEs */
1.847 + if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1))
1.848 + ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXJSAMPLE+1);
1.849 +
1.850 + /* Create the colormap and color index table. */
1.851 + create_colormap(cinfo);
1.852 + create_colorindex(cinfo);
1.853 +
1.854 + /* Allocate Floyd-Steinberg workspace now if requested.
1.855 + * We do this now since it is FAR storage and may affect the memory
1.856 + * manager's space calculations. If the user changes to FS dither
1.857 + * mode in a later pass, we will allocate the space then, and will
1.858 + * possibly overrun the max_memory_to_use setting.
1.859 + */
1.860 + if (cinfo->dither_mode == JDITHER_FS)
1.861 + alloc_fs_workspace(cinfo);
1.862 +}
1.863 +
1.864 +#endif /* QUANT_1PASS_SUPPORTED */
