1793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 2793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * jquant1.c 3793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 4793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Copyright (C) 1991-1996, Thomas G. Lane. 5793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Modified 2011 by Guido Vollbeding. 6793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * This file is part of the Independent JPEG Group's software. 7793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * For conditions of distribution and use, see the accompanying README file. 8793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 9793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * This file contains 1-pass color quantization (color mapping) routines. 10793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * These routines provide mapping to a fixed color map using equally spaced 11793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * color values. Optional Floyd-Steinberg or ordered dithering is available. 12793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 13793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 14793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#define JPEG_INTERNALS 15793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#include "jinclude.h" 16793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#include "jpeglib.h" 17793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 18793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#ifdef QUANT_1PASS_SUPPORTED 19793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 20793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 21793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 22793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * The main purpose of 1-pass quantization is to provide a fast, if not very 23793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * high quality, colormapped output capability. A 2-pass quantizer usually 24793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * gives better visual quality; however, for quantized grayscale output this 25793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * quantizer is perfectly adequate. Dithering is highly recommended with this 26793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * quantizer, though you can turn it off if you really want to. 27793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 28793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * In 1-pass quantization the colormap must be chosen in advance of seeing the 29793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * image. We use a map consisting of all combinations of Ncolors[i] color 30793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * values for the i'th component. The Ncolors[] values are chosen so that 31793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * their product, the total number of colors, is no more than that requested. 32793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * (In most cases, the product will be somewhat less.) 33793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 34793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Since the colormap is orthogonal, the representative value for each color 35793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * component can be determined without considering the other components; 36793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * then these indexes can be combined into a colormap index by a standard 37793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * N-dimensional-array-subscript calculation. Most of the arithmetic involved 38793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * can be precalculated and stored in the lookup table colorindex[]. 39793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * colorindex[i][j] maps pixel value j in component i to the nearest 40793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * representative value (grid plane) for that component; this index is 41793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * multiplied by the array stride for component i, so that the 42793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * index of the colormap entry closest to a given pixel value is just 43793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * sum( colorindex[component-number][pixel-component-value] ) 44793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Aside from being fast, this scheme allows for variable spacing between 45793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * representative values with no additional lookup cost. 46793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 47793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * If gamma correction has been applied in color conversion, it might be wise 48793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * to adjust the color grid spacing so that the representative colors are 49793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * equidistant in linear space. At this writing, gamma correction is not 50793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * implemented by jdcolor, so nothing is done here. 51793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 52793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 53793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 54793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* Declarations for ordered dithering. 55793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 56793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * We use a standard 16x16 ordered dither array. The basic concept of ordered 57793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * dithering is described in many references, for instance Dale Schumacher's 58793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * chapter II.2 of Graphics Gems II (James Arvo, ed. Academic Press, 1991). 59793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * In place of Schumacher's comparisons against a "threshold" value, we add a 60793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * "dither" value to the input pixel and then round the result to the nearest 61793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * output value. The dither value is equivalent to (0.5 - threshold) times 62793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * the distance between output values. For ordered dithering, we assume that 63793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * the output colors are equally spaced; if not, results will probably be 64793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * worse, since the dither may be too much or too little at a given point. 65793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 66793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * The normal calculation would be to form pixel value + dither, range-limit 67793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * this to 0..MAXJSAMPLE, and then index into the colorindex table as usual. 68793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * We can skip the separate range-limiting step by extending the colorindex 69793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * table in both directions. 70793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 71793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 72793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#define ODITHER_SIZE 16 /* dimension of dither matrix */ 73793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* NB: if ODITHER_SIZE is not a power of 2, ODITHER_MASK uses will break */ 74793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#define ODITHER_CELLS (ODITHER_SIZE*ODITHER_SIZE) /* # cells in matrix */ 75793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#define ODITHER_MASK (ODITHER_SIZE-1) /* mask for wrapping around counters */ 76793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 77793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslertypedef int ODITHER_MATRIX[ODITHER_SIZE][ODITHER_SIZE]; 78793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslertypedef int (*ODITHER_MATRIX_PTR)[ODITHER_SIZE]; 79793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 80793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslerstatic const UINT8 base_dither_matrix[ODITHER_SIZE][ODITHER_SIZE] = { 81793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Bayer's order-4 dither array. Generated by the code given in 82793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Stephen Hawley's article "Ordered Dithering" in Graphics Gems I. 83793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * The values in this array must range from 0 to ODITHER_CELLS-1. 84793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 85793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 0,192, 48,240, 12,204, 60,252, 3,195, 51,243, 15,207, 63,255 }, 86793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 128, 64,176,112,140, 76,188,124,131, 67,179,115,143, 79,191,127 }, 87793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 32,224, 16,208, 44,236, 28,220, 35,227, 19,211, 47,239, 31,223 }, 88793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 160, 96,144, 80,172,108,156, 92,163, 99,147, 83,175,111,159, 95 }, 89793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 8,200, 56,248, 4,196, 52,244, 11,203, 59,251, 7,199, 55,247 }, 90793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 136, 72,184,120,132, 68,180,116,139, 75,187,123,135, 71,183,119 }, 91793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 40,232, 24,216, 36,228, 20,212, 43,235, 27,219, 39,231, 23,215 }, 92793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 168,104,152, 88,164,100,148, 84,171,107,155, 91,167,103,151, 87 }, 93793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 2,194, 50,242, 14,206, 62,254, 1,193, 49,241, 13,205, 61,253 }, 94793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 130, 66,178,114,142, 78,190,126,129, 65,177,113,141, 77,189,125 }, 95793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 34,226, 18,210, 46,238, 30,222, 33,225, 17,209, 45,237, 29,221 }, 96793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 162, 98,146, 82,174,110,158, 94,161, 97,145, 81,173,109,157, 93 }, 97793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 10,202, 58,250, 6,198, 54,246, 9,201, 57,249, 5,197, 53,245 }, 98793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 138, 74,186,122,134, 70,182,118,137, 73,185,121,133, 69,181,117 }, 99793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 42,234, 26,218, 38,230, 22,214, 41,233, 25,217, 37,229, 21,213 }, 100793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler { 170,106,154, 90,166,102,150, 86,169,105,153, 89,165,101,149, 85 } 101793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler}; 102793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 103793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 104793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* Declarations for Floyd-Steinberg dithering. 105793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 106793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Errors are accumulated into the array fserrors[], at a resolution of 107793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 1/16th of a pixel count. The error at a given pixel is propagated 108793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * to its not-yet-processed neighbors using the standard F-S fractions, 109793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * ... (here) 7/16 110793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 3/16 5/16 1/16 111793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * We work left-to-right on even rows, right-to-left on odd rows. 112793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 113793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * We can get away with a single array (holding one row's worth of errors) 114793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * by using it to store the current row's errors at pixel columns not yet 115793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * processed, but the next row's errors at columns already processed. We 116793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * need only a few extra variables to hold the errors immediately around the 117793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * current column. (If we are lucky, those variables are in registers, but 118793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * even if not, they're probably cheaper to access than array elements are.) 119793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 120793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * The fserrors[] array is indexed [component#][position]. 121793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * We provide (#columns + 2) entries per component; the extra entry at each 122793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * end saves us from special-casing the first and last pixels. 123793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 124793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Note: on a wide image, we might not have enough room in a PC's near data 125793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * segment to hold the error array; so it is allocated with alloc_large. 126793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 127793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 128793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#if BITS_IN_JSAMPLE == 8 129793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslertypedef INT16 FSERROR; /* 16 bits should be enough */ 130793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslertypedef int LOCFSERROR; /* use 'int' for calculation temps */ 131793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#else 132793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslertypedef INT32 FSERROR; /* may need more than 16 bits */ 133793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslertypedef INT32 LOCFSERROR; /* be sure calculation temps are big enough */ 134793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#endif 135793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 136793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslertypedef FSERROR FAR *FSERRPTR; /* pointer to error array (in FAR storage!) */ 137793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 138793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 139793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* Private subobject */ 140793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 141793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#define MAX_Q_COMPS 4 /* max components I can handle */ 142793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 143793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslertypedef struct { 144793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler struct jpeg_color_quantizer pub; /* public fields */ 145793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 146793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Initially allocated colormap is saved here */ 147793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPARRAY sv_colormap; /* The color map as a 2-D pixel array */ 148793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int sv_actual; /* number of entries in use */ 149793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 150793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPARRAY colorindex; /* Precomputed mapping for speed */ 151793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* colorindex[i][j] = index of color closest to pixel value j in component i, 152793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * premultiplied as described above. Since colormap indexes must fit into 153793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * JSAMPLEs, the entries of this array will too. 154793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 155793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler boolean is_padded; /* is the colorindex padded for odither? */ 156793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 157793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int Ncolors[MAX_Q_COMPS]; /* # of values alloced to each component */ 158793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 159793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Variables for ordered dithering */ 160793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int row_index; /* cur row's vertical index in dither matrix */ 161793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ODITHER_MATRIX_PTR odither[MAX_Q_COMPS]; /* one dither array per component */ 162793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 163793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Variables for Floyd-Steinberg dithering */ 164793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler FSERRPTR fserrors[MAX_Q_COMPS]; /* accumulated errors */ 165793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler boolean on_odd_row; /* flag to remember which row we are on */ 166793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} my_cquantizer; 167793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 168793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslertypedef my_cquantizer * my_cquantize_ptr; 169793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 170793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 171793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 172793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Policy-making subroutines for create_colormap and create_colorindex. 173793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * These routines determine the colormap to be used. The rest of the module 174793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * only assumes that the colormap is orthogonal. 175793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * 176793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * * select_ncolors decides how to divvy up the available colors 177793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * among the components. 178793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * * output_value defines the set of representative values for a component. 179793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * * largest_input_value defines the mapping from input values to 180793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * representative values for a component. 181793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Note that the latter two routines may impose different policies for 182793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * different components, though this is not currently done. 183793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 184793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 185793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 186793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerLOCAL(int) 187793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslerselect_ncolors (j_decompress_ptr cinfo, int Ncolors[]) 188793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* Determine allocation of desired colors to components, */ 189793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* and fill in Ncolors[] array to indicate choice. */ 190793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* Return value is total number of colors (product of Ncolors[] values). */ 191793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 192793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int nc = cinfo->out_color_components; /* number of color components */ 193793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int max_colors = cinfo->desired_number_of_colors; 194793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int total_colors, iroot, i, j; 195793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler boolean changed; 196793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler long temp; 197793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler static const int RGB_order[3] = { RGB_GREEN, RGB_RED, RGB_BLUE }; 198793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 199793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* We can allocate at least the nc'th root of max_colors per component. */ 200793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Compute floor(nc'th root of max_colors). */ 201793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler iroot = 1; 202793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler do { 203793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler iroot++; 204793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler temp = iroot; /* set temp = iroot ** nc */ 205793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (i = 1; i < nc; i++) 206793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler temp *= iroot; 207793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } while (temp <= (long) max_colors); /* repeat till iroot exceeds root */ 208793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler iroot--; /* now iroot = floor(root) */ 209793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 210793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Must have at least 2 color values per component */ 211793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (iroot < 2) 212793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ERREXIT1(cinfo, JERR_QUANT_FEW_COLORS, (int) temp); 213793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 214793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Initialize to iroot color values for each component */ 215793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler total_colors = 1; 216793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (i = 0; i < nc; i++) { 217793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler Ncolors[i] = iroot; 218793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler total_colors *= iroot; 219793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 220793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* We may be able to increment the count for one or more components without 221793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * exceeding max_colors, though we know not all can be incremented. 222793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Sometimes, the first component can be incremented more than once! 223793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * (Example: for 16 colors, we start at 2*2*2, go to 3*2*2, then 4*2*2.) 224793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * In RGB colorspace, try to increment G first, then R, then B. 225793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 226793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler do { 227793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler changed = FALSE; 228793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (i = 0; i < nc; i++) { 229793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler j = (cinfo->out_color_space == JCS_RGB ? RGB_order[i] : i); 230793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* calculate new total_colors if Ncolors[j] is incremented */ 231793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler temp = total_colors / Ncolors[j]; 232793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler temp *= Ncolors[j]+1; /* done in long arith to avoid oflo */ 233793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (temp > (long) max_colors) 234793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler break; /* won't fit, done with this pass */ 235793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler Ncolors[j]++; /* OK, apply the increment */ 236793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler total_colors = (int) temp; 237793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler changed = TRUE; 238793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 239793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } while (changed); 240793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 241793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler return total_colors; 242793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 243793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 244793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 245793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerLOCAL(int) 246793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presleroutput_value (j_decompress_ptr cinfo, int ci, int j, int maxj) 247793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* Return j'th output value, where j will range from 0 to maxj */ 248793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* The output values must fall in 0..MAXJSAMPLE in increasing order */ 249793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 250793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* We always provide values 0 and MAXJSAMPLE for each component; 251793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * any additional values are equally spaced between these limits. 252793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * (Forcing the upper and lower values to the limits ensures that 253793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * dithering can't produce a color outside the selected gamut.) 254793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 255793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler return (int) (((INT32) j * MAXJSAMPLE + maxj/2) / maxj); 256793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 257793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 258793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 259793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerLOCAL(int) 260793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslerlargest_input_value (j_decompress_ptr cinfo, int ci, int j, int maxj) 261793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* Return largest input value that should map to j'th output value */ 262793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* Must have largest(j=0) >= 0, and largest(j=maxj) >= MAXJSAMPLE */ 263793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 264793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Breakpoints are halfway between values returned by output_value */ 265793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler return (int) (((INT32) (2*j + 1) * MAXJSAMPLE + maxj) / (2*maxj)); 266793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 267793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 268793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 269793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 270793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Create the colormap. 271793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 272793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 273793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerLOCAL(void) 274793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslercreate_colormap (j_decompress_ptr cinfo) 275793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 276793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; 277793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPARRAY colormap; /* Created colormap */ 278793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int total_colors; /* Number of distinct output colors */ 279793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int i,j,k, nci, blksize, blkdist, ptr, val; 280793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 281793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Select number of colors for each component */ 282793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler total_colors = select_ncolors(cinfo, cquantize->Ncolors); 283793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 284793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Report selected color counts */ 285793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (cinfo->out_color_components == 3) 286793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler TRACEMS4(cinfo, 1, JTRC_QUANT_3_NCOLORS, 287793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler total_colors, cquantize->Ncolors[0], 288793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->Ncolors[1], cquantize->Ncolors[2]); 289793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler else 290793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler TRACEMS1(cinfo, 1, JTRC_QUANT_NCOLORS, total_colors); 291793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 292793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Allocate and fill in the colormap. */ 293793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* The colors are ordered in the map in standard row-major order, */ 294793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* i.e. rightmost (highest-indexed) color changes most rapidly. */ 295793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 296793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler colormap = (*cinfo->mem->alloc_sarray) 297793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ((j_common_ptr) cinfo, JPOOL_IMAGE, 298793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler (JDIMENSION) total_colors, (JDIMENSION) cinfo->out_color_components); 299793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 300793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* blksize is number of adjacent repeated entries for a component */ 301793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* blkdist is distance between groups of identical entries for a component */ 302793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler blkdist = total_colors; 303793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 304793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (i = 0; i < cinfo->out_color_components; i++) { 305793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* fill in colormap entries for i'th color component */ 306793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ 307793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler blksize = blkdist / nci; 308793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (j = 0; j < nci; j++) { 309793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Compute j'th output value (out of nci) for component */ 310793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler val = output_value(cinfo, i, j, nci-1); 311793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Fill in all colormap entries that have this value of this component */ 312793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (ptr = j * blksize; ptr < total_colors; ptr += blkdist) { 313793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* fill in blksize entries beginning at ptr */ 314793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (k = 0; k < blksize; k++) 315793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler colormap[i][ptr+k] = (JSAMPLE) val; 316793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 317793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 318793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler blkdist = blksize; /* blksize of this color is blkdist of next */ 319793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 320793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 321793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Save the colormap in private storage, 322793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * where it will survive color quantization mode changes. 323793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 324793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->sv_colormap = colormap; 325793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->sv_actual = total_colors; 326793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 327793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 328793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 329793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 330793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Create the color index table. 331793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 332793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 333793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerLOCAL(void) 334793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslercreate_colorindex (j_decompress_ptr cinfo) 335793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 336793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; 337793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPROW indexptr; 338793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int i,j,k, nci, blksize, val, pad; 339793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 340793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* For ordered dither, we pad the color index tables by MAXJSAMPLE in 341793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * each direction (input index values can be -MAXJSAMPLE .. 2*MAXJSAMPLE). 342793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * This is not necessary in the other dithering modes. However, we 343793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * flag whether it was done in case user changes dithering mode. 344793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 345793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (cinfo->dither_mode == JDITHER_ORDERED) { 346793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pad = MAXJSAMPLE*2; 347793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->is_padded = TRUE; 348793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } else { 349793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pad = 0; 350793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->is_padded = FALSE; 351793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 352793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 353793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->colorindex = (*cinfo->mem->alloc_sarray) 354793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ((j_common_ptr) cinfo, JPOOL_IMAGE, 355793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler (JDIMENSION) (MAXJSAMPLE+1 + pad), 356793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler (JDIMENSION) cinfo->out_color_components); 357793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 358793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* blksize is number of adjacent repeated entries for a component */ 359793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler blksize = cquantize->sv_actual; 360793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 361793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (i = 0; i < cinfo->out_color_components; i++) { 362793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* fill in colorindex entries for i'th color component */ 363793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ 364793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler blksize = blksize / nci; 365793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 366793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* adjust colorindex pointers to provide padding at negative indexes. */ 367793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (pad) 368793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->colorindex[i] += MAXJSAMPLE; 369793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 370793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* in loop, val = index of current output value, */ 371793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* and k = largest j that maps to current val */ 372793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler indexptr = cquantize->colorindex[i]; 373793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler val = 0; 374793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler k = largest_input_value(cinfo, i, 0, nci-1); 375793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (j = 0; j <= MAXJSAMPLE; j++) { 376793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler while (j > k) /* advance val if past boundary */ 377793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler k = largest_input_value(cinfo, i, ++val, nci-1); 378793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* premultiply so that no multiplication needed in main processing */ 379793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler indexptr[j] = (JSAMPLE) (val * blksize); 380793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 381793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Pad at both ends if necessary */ 382793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (pad) 383793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (j = 1; j <= MAXJSAMPLE; j++) { 384793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler indexptr[-j] = indexptr[0]; 385793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler indexptr[MAXJSAMPLE+j] = indexptr[MAXJSAMPLE]; 386793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 387793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 388793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 389793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 390793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 391793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 392793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Create an ordered-dither array for a component having ncolors 393793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * distinct output values. 394793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 395793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 396793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerLOCAL(ODITHER_MATRIX_PTR) 397793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslermake_odither_array (j_decompress_ptr cinfo, int ncolors) 398793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 399793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ODITHER_MATRIX_PTR odither; 400793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int j,k; 401793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler INT32 num,den; 402793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 403793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler odither = (ODITHER_MATRIX_PTR) 404793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 405793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler SIZEOF(ODITHER_MATRIX)); 406793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* The inter-value distance for this color is MAXJSAMPLE/(ncolors-1). 407793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Hence the dither value for the matrix cell with fill order f 408793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * (f=0..N-1) should be (N-1-2*f)/(2*N) * MAXJSAMPLE/(ncolors-1). 409793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * On 16-bit-int machine, be careful to avoid overflow. 410793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 411793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler den = 2 * ODITHER_CELLS * ((INT32) (ncolors - 1)); 412793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (j = 0; j < ODITHER_SIZE; j++) { 413793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (k = 0; k < ODITHER_SIZE; k++) { 414793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler num = ((INT32) (ODITHER_CELLS-1 - 2*((int)base_dither_matrix[j][k]))) 415793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * MAXJSAMPLE; 416793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Ensure round towards zero despite C's lack of consistency 417793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * about rounding negative values in integer division... 418793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 419793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler odither[j][k] = (int) (num<0 ? -((-num)/den) : num/den); 420793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 421793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 422793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler return odither; 423793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 424793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 425793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 426793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 427793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Create the ordered-dither tables. 428793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Components having the same number of representative colors may 429793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * share a dither table. 430793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 431793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 432793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerLOCAL(void) 433793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslercreate_odither_tables (j_decompress_ptr cinfo) 434793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 435793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; 436793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ODITHER_MATRIX_PTR odither; 437793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int i, j, nci; 438793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 439793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (i = 0; i < cinfo->out_color_components; i++) { 440793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler nci = cquantize->Ncolors[i]; /* # of distinct values for this color */ 441793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler odither = NULL; /* search for matching prior component */ 442793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (j = 0; j < i; j++) { 443793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (nci == cquantize->Ncolors[j]) { 444793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler odither = cquantize->odither[j]; 445793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler break; 446793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 447793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 448793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (odither == NULL) /* need a new table? */ 449793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler odither = make_odither_array(cinfo, nci); 450793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->odither[i] = odither; 451793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 452793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 453793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 454793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 455793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 456793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Map some rows of pixels to the output colormapped representation. 457793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 458793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 459793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerMETHODDEF(void) 460793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslercolor_quantize (j_decompress_ptr cinfo, JSAMPARRAY input_buf, 461793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPARRAY output_buf, int num_rows) 462793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* General case, no dithering */ 463793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 464793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; 465793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPARRAY colorindex = cquantize->colorindex; 466793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register int pixcode, ci; 467793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register JSAMPROW ptrin, ptrout; 468793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int row; 469793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JDIMENSION col; 470793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JDIMENSION width = cinfo->output_width; 471793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register int nc = cinfo->out_color_components; 472793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 473793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (row = 0; row < num_rows; row++) { 474793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ptrin = input_buf[row]; 475793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ptrout = output_buf[row]; 476793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (col = width; col > 0; col--) { 477793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pixcode = 0; 478793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (ci = 0; ci < nc; ci++) { 479793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pixcode += GETJSAMPLE(colorindex[ci][GETJSAMPLE(*ptrin++)]); 480793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 481793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler *ptrout++ = (JSAMPLE) pixcode; 482793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 483793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 484793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 485793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 486793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 487793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerMETHODDEF(void) 488793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslercolor_quantize3 (j_decompress_ptr cinfo, JSAMPARRAY input_buf, 489793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPARRAY output_buf, int num_rows) 490793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* Fast path for out_color_components==3, no dithering */ 491793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 492793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; 493793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register int pixcode; 494793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register JSAMPROW ptrin, ptrout; 495793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPROW colorindex0 = cquantize->colorindex[0]; 496793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPROW colorindex1 = cquantize->colorindex[1]; 497793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPROW colorindex2 = cquantize->colorindex[2]; 498793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int row; 499793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JDIMENSION col; 500793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JDIMENSION width = cinfo->output_width; 501793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 502793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (row = 0; row < num_rows; row++) { 503793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ptrin = input_buf[row]; 504793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ptrout = output_buf[row]; 505793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (col = width; col > 0; col--) { 506793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*ptrin++)]); 507793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*ptrin++)]); 508793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*ptrin++)]); 509793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler *ptrout++ = (JSAMPLE) pixcode; 510793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 511793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 512793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 513793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 514793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 515793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerMETHODDEF(void) 516793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslerquantize_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, 517793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPARRAY output_buf, int num_rows) 518793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* General case, with ordered dithering */ 519793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 520793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; 521793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register JSAMPROW input_ptr; 522793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register JSAMPROW output_ptr; 523793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPROW colorindex_ci; 524793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int * dither; /* points to active row of dither matrix */ 525793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int row_index, col_index; /* current indexes into dither matrix */ 526793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int nc = cinfo->out_color_components; 527793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int ci; 528793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int row; 529793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JDIMENSION col; 530793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JDIMENSION width = cinfo->output_width; 531793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 532793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (row = 0; row < num_rows; row++) { 533793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Initialize output values to 0 so can process components separately */ 534793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler FMEMZERO((void FAR *) output_buf[row], 535793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler (size_t) (width * SIZEOF(JSAMPLE))); 536793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler row_index = cquantize->row_index; 537793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (ci = 0; ci < nc; ci++) { 538793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler input_ptr = input_buf[row] + ci; 539793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler output_ptr = output_buf[row]; 540793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler colorindex_ci = cquantize->colorindex[ci]; 541793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dither = cquantize->odither[ci][row_index]; 542793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler col_index = 0; 543793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 544793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (col = width; col > 0; col--) { 545793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Form pixel value + dither, range-limit to 0..MAXJSAMPLE, 546793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * select output value, accumulate into output code for this pixel. 547793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Range-limiting need not be done explicitly, as we have extended 548793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * the colorindex table to produce the right answers for out-of-range 549793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * inputs. The maximum dither is +- MAXJSAMPLE; this sets the 550793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * required amount of padding. 551793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 552793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler *output_ptr += colorindex_ci[GETJSAMPLE(*input_ptr)+dither[col_index]]; 553793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler input_ptr += nc; 554793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler output_ptr++; 555793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler col_index = (col_index + 1) & ODITHER_MASK; 556793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 557793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 558793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Advance row index for next row */ 559793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler row_index = (row_index + 1) & ODITHER_MASK; 560793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->row_index = row_index; 561793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 562793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 563793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 564793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 565793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerMETHODDEF(void) 566793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslerquantize3_ord_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, 567793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPARRAY output_buf, int num_rows) 568793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* Fast path for out_color_components==3, with ordered dithering */ 569793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 570793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; 571793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register int pixcode; 572793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register JSAMPROW input_ptr; 573793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register JSAMPROW output_ptr; 574793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPROW colorindex0 = cquantize->colorindex[0]; 575793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPROW colorindex1 = cquantize->colorindex[1]; 576793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPROW colorindex2 = cquantize->colorindex[2]; 577793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int * dither0; /* points to active row of dither matrix */ 578793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int * dither1; 579793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int * dither2; 580793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int row_index, col_index; /* current indexes into dither matrix */ 581793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int row; 582793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JDIMENSION col; 583793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JDIMENSION width = cinfo->output_width; 584793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 585793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (row = 0; row < num_rows; row++) { 586793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler row_index = cquantize->row_index; 587793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler input_ptr = input_buf[row]; 588793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler output_ptr = output_buf[row]; 589793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dither0 = cquantize->odither[0][row_index]; 590793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dither1 = cquantize->odither[1][row_index]; 591793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dither2 = cquantize->odither[2][row_index]; 592793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler col_index = 0; 593793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 594793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (col = width; col > 0; col--) { 595793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pixcode = GETJSAMPLE(colorindex0[GETJSAMPLE(*input_ptr++) + 596793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dither0[col_index]]); 597793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pixcode += GETJSAMPLE(colorindex1[GETJSAMPLE(*input_ptr++) + 598793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dither1[col_index]]); 599793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pixcode += GETJSAMPLE(colorindex2[GETJSAMPLE(*input_ptr++) + 600793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dither2[col_index]]); 601793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler *output_ptr++ = (JSAMPLE) pixcode; 602793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler col_index = (col_index + 1) & ODITHER_MASK; 603793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 604793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler row_index = (row_index + 1) & ODITHER_MASK; 605793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->row_index = row_index; 606793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 607793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 608793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 609793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 610793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerMETHODDEF(void) 611793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslerquantize_fs_dither (j_decompress_ptr cinfo, JSAMPARRAY input_buf, 612793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPARRAY output_buf, int num_rows) 613793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* General case, with Floyd-Steinberg dithering */ 614793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 615793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; 616793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register LOCFSERROR cur; /* current error or pixel value */ 617793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler LOCFSERROR belowerr; /* error for pixel below cur */ 618793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler LOCFSERROR bpreverr; /* error for below/prev col */ 619793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler LOCFSERROR bnexterr; /* error for below/next col */ 620793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler LOCFSERROR delta; 621793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register FSERRPTR errorptr; /* => fserrors[] at column before current */ 622793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register JSAMPROW input_ptr; 623793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler register JSAMPROW output_ptr; 624793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPROW colorindex_ci; 625793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPROW colormap_ci; 626793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int pixcode; 627793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int nc = cinfo->out_color_components; 628793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int dir; /* 1 for left-to-right, -1 for right-to-left */ 629793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int dirnc; /* dir * nc */ 630793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int ci; 631793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int row; 632793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JDIMENSION col; 633793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JDIMENSION width = cinfo->output_width; 634793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler JSAMPLE *range_limit = cinfo->sample_range_limit; 635793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler SHIFT_TEMPS 636793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 637793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (row = 0; row < num_rows; row++) { 638793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Initialize output values to 0 so can process components separately */ 639793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler FMEMZERO((void FAR *) output_buf[row], 640793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler (size_t) (width * SIZEOF(JSAMPLE))); 641793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (ci = 0; ci < nc; ci++) { 642793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler input_ptr = input_buf[row] + ci; 643793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler output_ptr = output_buf[row]; 644793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (cquantize->on_odd_row) { 645793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* work right to left in this row */ 646793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler input_ptr += (width-1) * nc; /* so point to rightmost pixel */ 647793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler output_ptr += width-1; 648793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dir = -1; 649793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dirnc = -nc; 650793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler errorptr = cquantize->fserrors[ci] + (width+1); /* => entry after last column */ 651793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } else { 652793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* work left to right in this row */ 653793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dir = 1; 654793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler dirnc = nc; 655793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler errorptr = cquantize->fserrors[ci]; /* => entry before first column */ 656793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 657793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler colorindex_ci = cquantize->colorindex[ci]; 658793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler colormap_ci = cquantize->sv_colormap[ci]; 659793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Preset error values: no error propagated to first pixel from left */ 660793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cur = 0; 661793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* and no error propagated to row below yet */ 662793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler belowerr = bpreverr = 0; 663793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 664793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (col = width; col > 0; col--) { 665793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* cur holds the error propagated from the previous pixel on the 666793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * current line. Add the error propagated from the previous line 667793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * to form the complete error correction term for this pixel, and 668793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * round the error term (which is expressed * 16) to an integer. 669793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * RIGHT_SHIFT rounds towards minus infinity, so adding 8 is correct 670793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * for either sign of the error value. 671793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Note: errorptr points to *previous* column's array entry. 672793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 673793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cur = RIGHT_SHIFT(cur + errorptr[dir] + 8, 4); 674793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Form pixel value + error, and range-limit to 0..MAXJSAMPLE. 675793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * The maximum error is +- MAXJSAMPLE; this sets the required size 676793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * of the range_limit array. 677793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 678793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cur += GETJSAMPLE(*input_ptr); 679793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cur = GETJSAMPLE(range_limit[cur]); 680793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Select output value, accumulate into output code for this pixel */ 681793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler pixcode = GETJSAMPLE(colorindex_ci[cur]); 682793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler *output_ptr += (JSAMPLE) pixcode; 683793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Compute actual representation error at this pixel */ 684793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Note: we can do this even though we don't have the final */ 685793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* pixel code, because the colormap is orthogonal. */ 686793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cur -= GETJSAMPLE(colormap_ci[pixcode]); 687793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Compute error fractions to be propagated to adjacent pixels. 688793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Add these into the running sums, and simultaneously shift the 689793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * next-line error sums left by 1 column. 690793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 691793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler bnexterr = cur; 692793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler delta = cur * 2; 693793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cur += delta; /* form error * 3 */ 694793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler errorptr[0] = (FSERROR) (bpreverr + cur); 695793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cur += delta; /* form error * 5 */ 696793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler bpreverr = belowerr + cur; 697793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler belowerr = bnexterr; 698793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cur += delta; /* form error * 7 */ 699793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* At this point cur contains the 7/16 error value to be propagated 700793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * to the next pixel on the current line, and all the errors for the 701793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * next line have been shifted over. We are therefore ready to move on. 702793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 703793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler input_ptr += dirnc; /* advance input ptr to next column */ 704793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler output_ptr += dir; /* advance output ptr to next column */ 705793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler errorptr += dir; /* advance errorptr to current column */ 706793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 707793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Post-loop cleanup: we must unload the final error value into the 708793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * final fserrors[] entry. Note we need not unload belowerr because 709793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * it is for the dummy column before or after the actual array. 710793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 711793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler errorptr[0] = (FSERROR) bpreverr; /* unload prev err into array */ 712793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 713793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->on_odd_row = (cquantize->on_odd_row ? FALSE : TRUE); 714793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 715793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 716793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 717793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 718793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 719793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Allocate workspace for Floyd-Steinberg errors. 720793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 721793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 722793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerLOCAL(void) 723793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presleralloc_fs_workspace (j_decompress_ptr cinfo) 724793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 725793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; 726793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler size_t arraysize; 727793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int i; 728793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 729793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR)); 730793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (i = 0; i < cinfo->out_color_components; i++) { 731793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->fserrors[i] = (FSERRPTR) 732793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler (*cinfo->mem->alloc_large)((j_common_ptr) cinfo, JPOOL_IMAGE, arraysize); 733793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 734793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 735793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 736793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 737793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 738793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Initialize for one-pass color quantization. 739793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 740793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 741793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerMETHODDEF(void) 742793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslerstart_pass_1_quant (j_decompress_ptr cinfo, boolean is_pre_scan) 743793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 744793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize = (my_cquantize_ptr) cinfo->cquantize; 745793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler size_t arraysize; 746793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler int i; 747793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 748793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Install my colormap. */ 749793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cinfo->colormap = cquantize->sv_colormap; 750793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cinfo->actual_number_of_colors = cquantize->sv_actual; 751793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 752793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Initialize for desired dithering mode. */ 753793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler switch (cinfo->dither_mode) { 754793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler case JDITHER_NONE: 755793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (cinfo->out_color_components == 3) 756793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->pub.color_quantize = color_quantize3; 757793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler else 758793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->pub.color_quantize = color_quantize; 759793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler break; 760793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler case JDITHER_ORDERED: 761793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (cinfo->out_color_components == 3) 762793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->pub.color_quantize = quantize3_ord_dither; 763793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler else 764793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->pub.color_quantize = quantize_ord_dither; 765793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->row_index = 0; /* initialize state for ordered dither */ 766793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* If user changed to ordered dither from another mode, 767793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * we must recreate the color index table with padding. 768793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * This will cost extra space, but probably isn't very likely. 769793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 770793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (! cquantize->is_padded) 771793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler create_colorindex(cinfo); 772793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Create ordered-dither tables if we didn't already. */ 773793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (cquantize->odither[0] == NULL) 774793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler create_odither_tables(cinfo); 775793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler break; 776793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler case JDITHER_FS: 777793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->pub.color_quantize = quantize_fs_dither; 778793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->on_odd_row = FALSE; /* initialize state for F-S dither */ 779793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Allocate Floyd-Steinberg workspace if didn't already. */ 780793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (cquantize->fserrors[0] == NULL) 781793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler alloc_fs_workspace(cinfo); 782793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Initialize the propagated errors to zero. */ 783793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler arraysize = (size_t) ((cinfo->output_width + 2) * SIZEOF(FSERROR)); 784793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler for (i = 0; i < cinfo->out_color_components; i++) 785793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler FMEMZERO((void FAR *) cquantize->fserrors[i], arraysize); 786793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler break; 787793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler default: 788793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ERREXIT(cinfo, JERR_NOT_COMPILED); 789793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler break; 790793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler } 791793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 792793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 793793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 794793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 795793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Finish up at the end of the pass. 796793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 797793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 798793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerMETHODDEF(void) 799793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslerfinish_pass_1_quant (j_decompress_ptr cinfo) 800793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 801793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* no work in 1-pass case */ 802793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 803793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 804793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 805793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 806793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Switch to a new external colormap between output passes. 807793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Shouldn't get to this module! 808793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 809793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 810793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerMETHODDEF(void) 811793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslernew_color_map_1_quant (j_decompress_ptr cinfo) 812793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 813793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ERREXIT(cinfo, JERR_MODE_CHANGE); 814793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 815793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 816793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 817793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler/* 818793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * Module initialization routine for 1-pass color quantization. 819793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 820793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 821793ee12c6df9cad3806238d32528c49a3ff9331dNoah PreslerGLOBAL(void) 822793ee12c6df9cad3806238d32528c49a3ff9331dNoah Preslerjinit_1pass_quantizer (j_decompress_ptr cinfo) 823793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler{ 824793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler my_cquantize_ptr cquantize; 825793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 826793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize = (my_cquantize_ptr) 827793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 828793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler SIZEOF(my_cquantizer)); 829793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cinfo->cquantize = (struct jpeg_color_quantizer *) cquantize; 830793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->pub.start_pass = start_pass_1_quant; 831793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->pub.finish_pass = finish_pass_1_quant; 832793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->pub.new_color_map = new_color_map_1_quant; 833793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->fserrors[0] = NULL; /* Flag FS workspace not allocated */ 834793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler cquantize->odither[0] = NULL; /* Also flag odither arrays not allocated */ 835793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 836793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Make sure my internal arrays won't overflow */ 837793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (cinfo->out_color_components > MAX_Q_COMPS) 838793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ERREXIT1(cinfo, JERR_QUANT_COMPONENTS, MAX_Q_COMPS); 839793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Make sure colormap indexes can be represented by JSAMPLEs */ 840793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (cinfo->desired_number_of_colors > (MAXJSAMPLE+1)) 841793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, MAXJSAMPLE+1); 842793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 843793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Create the colormap and color index table. */ 844793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler create_colormap(cinfo); 845793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler create_colorindex(cinfo); 846793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 847793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler /* Allocate Floyd-Steinberg workspace now if requested. 848793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * We do this now since it is FAR storage and may affect the memory 849793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * manager's space calculations. If the user changes to FS dither 850793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * mode in a later pass, we will allocate the space then, and will 851793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler * possibly overrun the max_memory_to_use setting. 852793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler */ 853793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler if (cinfo->dither_mode == JDITHER_FS) 854793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler alloc_fs_workspace(cinfo); 855793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler} 856793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler 857793ee12c6df9cad3806238d32528c49a3ff9331dNoah Presler#endif /* QUANT_1PASS_SUPPORTED */ 858