/* * ordered.c -- * *     This file contains C code to implement an ordered dither. * *//* * Copyright (c) 1995 The Regents of the University of California. * All rights reserved. *  * Permission to use, copy, modify, and distribute this software and its * documentation for any purpose, without fee, and without written agreement is * hereby granted, provided that the above copyright notice and the following * two paragraphs appear in all copies of this software. *  * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. *  * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. */#include "video.h"#include "proto.h"#include "dither.h"#define DITH_SIZE 16/* Structures used to implement hybrid ordered dither/floyd-steinberg   dither algorithm.*/static unsigned char *l_darrays[DITH_SIZE];static unsigned char *cr_darrays[DITH_SIZE];static unsigned char *cb_darrays[DITH_SIZE];/* *-------------------------------------------------------------- * *  InitOrderedDither-- * *	Structures intialized for ordered dithering.  * * Results: *	None. * * Side effects: *      None. * *-------------------------------------------------------------- */voidInitOrderedDither(){  int i, j, k, err_range, threshval;  unsigned char *lmark, *cmark;  for (i=0; i<DITH_SIZE; i++) {    lmark = l_darrays[i] = (unsigned char *) malloc(256);    for (j=0; j<lum_values[0]; j++) {      *lmark++ = 0;    }    for (j=0; j<(LUM_RANGE-1); j++) {      err_range = lum_values[j+1] - lum_values[j];      threshval = ((i * err_range) / DITH_SIZE)+lum_values[j];      for (k=lum_values[j]; k<lum_values[j+1]; k++) {        if (k > threshval) {          *lmark++ = ((j+1) * (CR_RANGE * CB_RANGE));        }        else {          *lmark++ = (j * (CR_RANGE * CB_RANGE));        }      }    }    for (j=lum_values[LUM_RANGE-1]; j<256; j++) {      *lmark++ = (LUM_RANGE-1)*(CR_RANGE * CB_RANGE);    }  }  for (i=0; i<DITH_SIZE; i++) {    cmark = cr_darrays[i] = (unsigned char *) malloc(256);    for (j=0; j<cr_values[0]; j++) {      *cmark++ = 0;    }    for (j=0; j<(CR_RANGE-1); j++) {      err_range = cr_values[j+1] - cr_values[j];      threshval = ((i * err_range) / DITH_SIZE)+cr_values[j];      for (k=cr_values[j]; k<cr_values[j+1]; k++) {        if (k > threshval) {          *cmark++ = ((j+1) * CB_RANGE);        }        else {          *cmark++ = (j * CB_RANGE);        }      }    }    for (j=cr_values[CR_RANGE-1]; j<256; j++) {      *cmark++ = (CR_RANGE-1)*(CB_RANGE);    }  }  for (i=0; i<DITH_SIZE; i++) {    cmark = cb_darrays[i] = (unsigned char *) malloc(256);    for (j=0; j<cb_values[0]; j++) {      *cmark++ = 0;    }    for (j=0; j<(CB_RANGE-1); j++) {      err_range = cb_values[j+1] - cb_values[j];      threshval = ((i * err_range) / DITH_SIZE)+cb_values[j];      for (k=cb_values[j]; k<cb_values[j+1]; k++) {        if (k > threshval) {          *cmark++ = j+1;        }        else {          *cmark++ = j;        }      }    }    for (j=cb_values[CB_RANGE-1]; j<256; j++) {      *cmark++ = CB_RANGE-1;    }  }}/* *-------------------------------------------------------------- * * OrderedDitherImage -- * *	Dithers an image using an ordered dither. *	Assumptions made: *	  1) The color space is allocated y:cr:cb = 8:4:4 *	  2) The spatial resolution of y:cr:cb is 4:1:1 *      The channels are dithered based on the standard *      ordered dither pattern for a 4x4 area.  * * Results: *	None. * * Side effects: *	None. * *-------------------------------------------------------------- */voidOrderedDitherImage (lum, cr, cb, out, h, w)    unsigned char *lum;    unsigned char *cr;    unsigned char *cb;    unsigned char *out;    int w, h;{  unsigned char *l, *r, *b, *o1, *o2;  unsigned char *l2;  unsigned char L, R, B;  int i, j;  l = lum;  l2 = lum+w;  r = cr;  b = cb;  o1 = out;  o2 = out+w;  for (i=0; i<h; i+=4) {    for (j=0; j<w; j+=8) {      R = r[0]; B = b[0];      L = l[0];      o1[0] = pixel[(l_darrays[0][L] + cr_darrays[0][R] + cb_darrays[0][B])];      L = l[1];      o1[1] = pixel[(l_darrays[8][L] + cr_darrays[8][R] + cb_darrays[8][B])];      L = l2[0];      o2[0] = pixel[(l_darrays[12][L] + cr_darrays[12][R] + cb_darrays[12][B])];      L = l2[1];      o2[1] = pixel[(l_darrays[4][L] + cr_darrays[4][R] + cb_darrays[4][B])];      R = r[1]; B = b[1];      L = l[2];      o1[2] = pixel[(l_darrays[2][L] + cr_darrays[2][R] + cb_darrays[2][B])];      L = l[3];      o1[3] = pixel[(l_darrays[10][L] + cr_darrays[10][R] + cb_darrays[10][B])];      L = l2[2];      o2[2] = pixel[(l_darrays[14][L] + cr_darrays[14][R] + cb_darrays[14][B])];      L = l2[3];      o2[3] = pixel[(l_darrays[6][L] + cr_darrays[6][R] + cb_darrays[6][B])];      R = r[2]; B = b[2];      L = l[4];      o1[4] = pixel[(l_darrays[0][L] + cr_darrays[0][R] + cb_darrays[0][B])];      L = l[5];      o1[5] = pixel[(l_darrays[8][L] + cr_darrays[8][R] + cb_darrays[8][B])];      L = l2[4];      o2[4] = pixel[(l_darrays[12][L] + cr_darrays[12][R] + cb_darrays[12][B])];      L = l2[5];      o2[5] = pixel[(l_darrays[4][L] + cr_darrays[4][R] + cb_darrays[4][B])];      R = r[3]; B = b[3];      L = l[6];      o1[6] = pixel[(l_darrays[2][L] + cr_darrays[2][R] + cb_darrays[2][B])];      L = l[7];      o1[7] = pixel[(l_darrays[10][L] + cr_darrays[10][R] + cb_darrays[10][B])];      L = l2[6];      o2[6] = pixel[(l_darrays[14][L] + cr_darrays[14][R] + cb_darrays[14][B])];      L = l2[7];      o2[7] = pixel[(l_darrays[6][L] + cr_darrays[6][R] + cb_darrays[6][B])];      l += 8;      l2 += 8;      r += 4;      b += 4;      o1 += 8;      o2 += 8;    }    l += w; 	l2 += w;    o1 += w; 	o2 += w;    for (j=0; j<w; j+=8) {      R = r[0]; B = b[0];      L = l[0];      o1[0] = pixel[(l_darrays[3][L] + cr_darrays[3][R] + cb_darrays[3][B])];      L = l[1];      o1[1] = pixel[(l_darrays[11][L] + cr_darrays[11][R] + cb_darrays[11][B])];      L = l2[0];      o2[0] = pixel[(l_darrays[15][L] + cr_darrays[15][R] + cb_darrays[15][B])];      L = l2[1];      o2[1] = pixel[(l_darrays[7][L] + cr_darrays[7][R] + cb_darrays[7][B])];      R = r[1]; B = b[1];      L = l[2];      o1[2] = pixel[(l_darrays[1][L] + cr_darrays[1][R] + cb_darrays[1][B])];      L = l[3];      o1[3] = pixel[(l_darrays[9][L] + cr_darrays[9][R] + cb_darrays[9][B])];      L = l2[2];      o2[2] = pixel[(l_darrays[13][L] + cr_darrays[13][R] + cb_darrays[13][B])];      L = l2[3];      o2[3] = pixel[(l_darrays[5][L] + cr_darrays[5][R] + cb_darrays[5][B])];      R = r[2]; B = b[2];      L = l[4];      o1[4] = pixel[(l_darrays[3][L] + cr_darrays[3][R] + cb_darrays[3][B])];      L = l[5];      o1[5] = pixel[(l_darrays[11][L] + cr_darrays[11][R] + cb_darrays[11][B])];      L = l2[4];      o2[4] = pixel[(l_darrays[15][L] + cr_darrays[15][R] + cb_darrays[15][B])];      L = l2[5];      o2[5] = pixel[(l_darrays[7][L] + cr_darrays[7][R] + cb_darrays[7][B])];      R = r[3]; B = b[3];      L = l[6];      o1[6] = pixel[(l_darrays[1][L] + cr_darrays[1][R] + cb_darrays[1][B])];      L = l[7];      o1[7] = pixel[(l_darrays[9][L] + cr_darrays[9][R] + cb_darrays[9][B])];      L = l2[6];      o2[6] = pixel[(l_darrays[13][L] + cr_darrays[13][R] + cb_darrays[13][B])];      L = l2[7];      o2[7] = pixel[(l_darrays[5][L] + cr_darrays[5][R] + cb_darrays[5][B])];      l += 8;      l2 += 8;      r += 4;      b += 4;      o1 += 8;      o2 += 8;    }    l += w; 	l2 += w;    o1 += w; 	o2 += w;  }}