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/*

 * 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.

 */

/*

 * Copyright (c) 1995 Erik Corry

 * 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 ERIK CORRY 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 ERIK CORRY HAS BEEN ADVISED

 * OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * ERIK CORRY 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 ERIK CORRY HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,

 * UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 */

/*

 * Portions of this software Copyright (c) 1995 Brown University.

 * 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 BROWN UNIVERSITY 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 BROWN

 * UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * BROWN UNIVERSITY 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 BROWN UNIVERSITY HAS NO OBLIGATION TO PROVIDE MAINTENANCE,

 * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 */

#include "video.h"

#include "dither.h"

#include "proto.h"

#include <math.h>

/*

   Changes to make the code reentrant:

     None

   Additional changes:

     do not define INTERPOLATE, add #ifdef INTERPOLATE

   -lsh@cs.brown.edu (Loring Holden)

 */

/* #define INTERPOLATE */

/*

 * Erik Corry's multi-byte dither routines.

 *

 * The basic idea is that the Init generates all the necessary tables.

 * The tables incorporate the information about the layout of pixels

 * in the XImage, so that it should be able to cope with 15-bit, 16-bit

 * 24-bit (non-packed) and 32-bit (10-11 bits per color!) screens.

 * At present it cannot cope with 24-bit packed mode, since this involves

 * getting down to byte level again. It is assumed that the bits for each

 * color are contiguous in the longword.

 *

 * Writing to memory is done in shorts or ints. (Unfortunately, short is not

 * very fast on Alpha, so there is room for improvement here). There is no

 * dither time check for overflow - instead the tables have slack at

 * each end. This is likely to be faster than an 'if' test as many modern

 * architectures are really bad at ifs. Potentially, each '&&' causes a

 * pipeline flush!

 *

 * There is no shifting and fixed point arithmetic, as I really doubt you

 * can see the difference, and it costs. This may be just my bias, since I

 * heard that Intel is really bad at shifting.

 */

/*

 * How many 1 bits are there in the longword.

 * Low performance, do not call often.

 */

static int

number_of_bits_set(a)

unsigned long a;

{

    if(!a) return 0;

    if(a & 1) return 1 + number_of_bits_set(a >> 1);

    return(number_of_bits_set(a >> 1));

}

/*

 * Shift the 0s in the least significant end out of the longword.

 * Low performance, do not call often.

 */

static unsigned long

shifted_down(a)

unsigned long a;

{

    if(!a) return 0;

    if(a & 1) return a;

    return a >> 1;

}

/*

 * How many 0 bits are there at most significant end of longword.

 * Low performance, do not call often.

 */

static int

free_bits_at_top(a)

unsigned long a;

{

      /* assume char is 8 bits */

    if(!a) return sizeof(unsigned long) * 8;

        /* assume twos complement */

    if(((long)a) < 0l) return 0;

    return 1 + free_bits_at_top ( a << 1);

}

/*

 * How many 0 bits are there at least significant end of longword.

 * Low performance, do not call often.

 */

static int

free_bits_at_bottom(a)

unsigned long a;

{

      /* assume char is 8 bits */

    if(!a) return sizeof(unsigned long) * 8;

    if(((long)a) & 1l) return 0;

    return 1 + free_bits_at_bottom ( a >> 1);

}

static int *L_tab=NULL, *Cr_r_tab=NULL, *Cr_g_tab=NULL, *Cb_g_tab=NULL,

           *Cb_b_tab=NULL;

/*

 * We define tables that convert a color value between -256 and 512

 * into the R, G and B parts of the pixel. The normal range is 0-255.

 */

static long *r_2_pix=NULL;

static long *g_2_pix=NULL;

static long *b_2_pix=NULL;

static long *r_2_pix_alloc=NULL;

static long *g_2_pix_alloc=NULL;

static long *b_2_pix_alloc=NULL;

/*

 *--------------------------------------------------------------

 *

 * InitColor16Dither --

 *

 *      To get rid of the multiply and other conversions in color

 *      dither, we use a lookup table.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      The lookup tables are initialized.

 *

 *--------------------------------------------------------------

 */

void

InitColorDither(thirty2)

int thirty2;

{

    /*

     * misuse of the wpixel array for the pixel masks. Note that this

     * implies that the window is created before this routine is called

     */

    unsigned long red_mask = wpixel[0];

    unsigned long green_mask = wpixel[1];

    unsigned long blue_mask = wpixel[2];

    int L, CR, CB, i;

    if (L_tab==NULL)

       L_tab = (int *)malloc(256*sizeof(int));

    if (Cr_r_tab==NULL)

       Cr_r_tab = (int *)malloc(256*sizeof(int));

    if (Cr_g_tab==NULL)

       Cr_g_tab = (int *)malloc(256*sizeof(int));

    if (Cb_g_tab==NULL)

       Cb_g_tab = (int *)malloc(256*sizeof(int));

    if (Cb_b_tab==NULL)

       Cb_b_tab = (int *)malloc(256*sizeof(int));

    if (r_2_pix_alloc==NULL)

       r_2_pix_alloc = (long *)malloc(768*sizeof(long));

    if (g_2_pix_alloc==NULL)

       g_2_pix_alloc = (long *)malloc(768*sizeof(long));

    if (b_2_pix_alloc==NULL)

       b_2_pix_alloc = (long *)malloc(768*sizeof(long));

    if (L_tab == NULL ||

        Cr_r_tab == NULL ||

        Cr_g_tab == NULL ||

        Cb_g_tab == NULL ||

        Cb_b_tab == NULL ||

        r_2_pix_alloc == NULL ||

        g_2_pix_alloc == NULL ||

        b_2_pix_alloc == NULL) {

      fprintf(stderr, "Could not get enough memory in InitColorDither\n");

      exit(1);

    }

    for (i=0; i<256; i++) {

      L_tab[i] = i;

      if (gammaCorrectFlag) {

        L_tab[i] = GAMMA_CORRECTION(i);

      }

      CB = CR = i;

      if (chromaCorrectFlag) {

        CB -= 128;

        CB = CHROMA_CORRECTION128(CB);

        CR -= 128;

        CR = CHROMA_CORRECTION128(CR);

      } else {

        CB -= 128; CR -= 128;

      }

/* was

      Cr_r_tab[i] =  1.596 * CR;

      Cr_g_tab[i] = -0.813 * CR;

      Cb_g_tab[i] = -0.391 * CB;  

      Cb_b_tab[i] =  2.018 * CB;

  but they were just messed up.

  Then was (_Video Deymstified_):

      Cr_r_tab[i] =  1.366 * CR;

      Cr_g_tab[i] = -0.700 * CR;

      Cb_g_tab[i] = -0.334 * CB;  

      Cb_b_tab[i] =  1.732 * CB;

  but really should be:

   (from ITU-R BT.470-2 System B, G and SMPTE 170M )

*/

      Cr_r_tab[i] =  (0.419/0.299) * CR;

      Cr_g_tab[i] = -(0.299/0.419) * CR;

      Cb_g_tab[i] = -(0.114/0.331) * CB;

      Cb_b_tab[i] =  (0.587/0.331) * CB;

/*

  though you could argue for:

    SMPTE 240M

      Cr_r_tab[i] =  (0.445/0.212) * CR;

      Cr_g_tab[i] = -(0.212/0.445) * CR;

      Cb_g_tab[i] = -(0.087/0.384) * CB;

      Cb_b_tab[i] =  (0.701/0.384) * CB;

    FCC

      Cr_r_tab[i] =  (0.421/0.30) * CR;

      Cr_g_tab[i] = -(0.30/0.421) * CR;

      Cb_g_tab[i] = -(0.11/0.331) * CB;

      Cb_b_tab[i] =  (0.59/0.331) * CB;

    ITU-R BT.709

      Cr_r_tab[i] =  (0.454/0.2125) * CR;

      Cr_g_tab[i] = -(0.2125/0.454) * CR;

      Cb_g_tab[i] = -(0.0721/0.386) * CB;

      Cb_b_tab[i] =  (0.7154/0.386) * CB;

*/

    }

    /*

     * Set up entries 0-255 in rgb-to-pixel value tables.

     */

    for (i = 0; i < 256; i++) {

      r_2_pix_alloc[i + 256] = i >> (8 - number_of_bits_set(red_mask));

      r_2_pix_alloc[i + 256] <<= free_bits_at_bottom(red_mask);

      g_2_pix_alloc[i + 256] = i >> (8 - number_of_bits_set(green_mask));

      g_2_pix_alloc[i + 256] <<= free_bits_at_bottom(green_mask);

      b_2_pix_alloc[i + 256] = i >> (8 - number_of_bits_set(blue_mask));

      b_2_pix_alloc[i + 256] <<= free_bits_at_bottom(blue_mask);

      /*

       * If we have 16-bit output depth, then we double the value

       * in the top word. This means that we can write out both

       * pixels in the pixel doubling mode with one op. It is

       * harmless in the normal case as storing a 32-bit value

       * through a short pointer will lose the top bits anyway.

       * A similar optimisation for Alpha for 64 bit has been

       * prepared for, but is not yet implemented.

       */

      if(!thirty2) {

        r_2_pix_alloc[i + 256] |= (r_2_pix_alloc[i + 256]) << 16;

        g_2_pix_alloc[i + 256] |= (g_2_pix_alloc[i + 256]) << 16;

        b_2_pix_alloc[i + 256] |= (b_2_pix_alloc[i + 256]) << 16;

      }

#ifdef SIXTYFOUR_BIT

      if(thirty2) {

        r_2_pix_alloc[i + 256] |= (r_2_pix_alloc[i + 256]) << 32;

        g_2_pix_alloc[i + 256] |= (g_2_pix_alloc[i + 256]) << 32;

        b_2_pix_alloc[i + 256] |= (b_2_pix_alloc[i + 256]) << 32;

      }

#endif

    }

    /*

     * Spread out the values we have to the rest of the array so that

     * we do not need to check for overflow.

     */

    for (i = 0; i < 256; i++) {

      r_2_pix_alloc[i] = r_2_pix_alloc[256];

      r_2_pix_alloc[i+ 512] = r_2_pix_alloc[511];

      g_2_pix_alloc[i] = g_2_pix_alloc[256];

      g_2_pix_alloc[i+ 512] = g_2_pix_alloc[511];

      b_2_pix_alloc[i] = b_2_pix_alloc[256];

      b_2_pix_alloc[i+ 512] = b_2_pix_alloc[511];

    }

    r_2_pix = r_2_pix_alloc + 256;

    g_2_pix = g_2_pix_alloc + 256;

    b_2_pix = b_2_pix_alloc + 256;

}

/*

 *--------------------------------------------------------------

 *

 * Color16DitherImage --

 *

 *      Converts image into 16 bit color.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      None.

 *

 *--------------------------------------------------------------

 */

void

Color16DitherImage(lum, cr, cb, out, rows, cols)

  unsigned char *lum;

  unsigned char *cr;

  unsigned char *cb;

  unsigned char *out;

  int cols, rows;

{

    int L, CR, CB;

    unsigned short *row1, *row2;

    unsigned char *lum2;

    int x, y;

    unsigned int r, b, g;

    int cr_r;

    int cr_g;

    int cb_g;

    int cb_b;

    int cols_2 = cols/2;

    row1 = (unsigned short *)out;

    row2 = row1 + cols_2 + cols_2;

    lum2 = lum + cols_2 + cols_2;

    for (y=0; y<rows; y+=2) {

        for (x=0; x<cols_2; x++) {

            int R, G, B;

            CR = *cr++;

            CB = *cb++;

            cr_r = Cr_r_tab[CR];

            cr_g = Cr_g_tab[CR];

            cb_g = Cb_g_tab[CB];

            cb_b = Cb_b_tab[CB];

            L = L_tab[(int) *lum++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            *row1++ = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

#ifdef INTERPOLATE

            if(x != cols_2 - 1) {

              CR = (CR + *cr) >> 1;

              CB = (CB + *cb) >> 1;

              cr_r = Cr_r_tab[CR];

              cr_g = Cr_g_tab[CR];

              cb_g = Cb_g_tab[CB];

              cb_b = Cb_b_tab[CB];

            }

#endif

            L = L_tab[(int) *lum++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            *row1++ = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

            /*

             * Now, do second row.

             */

#ifdef INTERPOLATE

            if(y != rows - 2) {

              CR = (CR + *(cr + cols_2 - 1)) >> 1;

              CB = (CB + *(cb + cols_2 - 1)) >> 1;

              cr_r = Cr_r_tab[CR];

              cr_g = Cr_g_tab[CR];

              cb_g = Cb_g_tab[CB];

              cb_b = Cb_b_tab[CB];

            }

#endif

            L = L_tab[(int) *lum2++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            *row2++ = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

            L = L_tab[(int) *lum2++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            *row2++ = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

        }

        /*

         * These values are at the start of the next line, (due

         * to the ++'s above),but they need to be at the start

         * of the line after that.

         */

        lum += cols_2 + cols_2;

        lum2 += cols_2 + cols_2;

        row1 += cols_2 + cols_2;

        row2 += cols_2 + cols_2;

    }

}

/*

 *--------------------------------------------------------------

 *

 * Color32DitherImage --

 *

 *      Converts image into 32 bit color (or 24-bit non-packed).

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      None.

 *

 *--------------------------------------------------------------

 */

/*

 * This is a copysoft version of the function above with ints instead

 * of shorts to cause a 4-byte pixel size

 */

void

Color32DitherImage(lum, cr, cb, out, rows, cols)

  unsigned char *lum;

  unsigned char *cr;

  unsigned char *cb;

  unsigned char *out;

  int cols, rows;

{

    int L, CR, CB;

    unsigned int *row1, *row2;

    unsigned char *lum2;

    int x, y;

    unsigned int r, b, g;

    int cr_r;

    int cr_g;

    int cb_g;

    int cb_b;

    int cols_2 = cols / 2;

    row1 = (unsigned int *)out;

    row2 = row1 + cols_2 + cols_2;

    lum2 = lum + cols_2 + cols_2;

    for (y=0; y<rows; y+=2) {

        for (x=0; x<cols_2; x++) {

            int R, G, B;

            CR = *cr++;

            CB = *cb++;

            cr_r = Cr_r_tab[CR];

            cr_g = Cr_g_tab[CR];

            cb_g = Cb_g_tab[CB];

            cb_b = Cb_b_tab[CB];

            L = L_tab[(int) *lum++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            *row1++ = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

#ifdef INTERPOLATE

            if(x != cols_2 - 1) {

              CR = (CR + *cr) >> 1;

              CB = (CB + *cb) >> 1;

              cr_r = Cr_r_tab[CR];

              cr_g = Cr_g_tab[CR];

              cb_g = Cb_g_tab[CB];

              cb_b = Cb_b_tab[CB];

            }

#endif

            L = L_tab[(int) *lum++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            *row1++ = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

            /*

             * Now, do second row.

             */

#ifdef INTERPOLATE

            if(y != rows - 2) {

              CR = (CR + *(cr + cols_2 - 1)) >> 1;

              CB = (CB + *(cb + cols_2 - 1)) >> 1;

              cr_r = Cr_r_tab[CR];

              cr_g = Cr_g_tab[CR];

              cb_g = Cb_g_tab[CB];

              cb_b = Cb_b_tab[CB];

            }

#endif

            L = L_tab [(int) *lum2++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            *row2++ = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

            L = L_tab [(int) *lum2++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            *row2++ = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

        }

        lum += cols_2 + cols_2;

        lum2 += cols_2 + cols_2;

        row1 += cols_2 + cols_2;

        row2 += cols_2 + cols_2;

    }

}

/*

 * Erik Corry's pixel doubling routines for 15/16/24/32 bit screens.

 */

/*

 *--------------------------------------------------------------

 *

 * Twox2Color16DitherImage --

 *

 *      Converts image into 16 bit color at double size.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      None.

 *

 *--------------------------------------------------------------

 */

/*

 * In this function I make use of a nasty trick. The tables have the lower

 * 16 bits replicated in the upper 16. This means I can write ints and get

 * the horisontal doubling for free (almost).

 */

void

Twox2Color16DitherImage(lum, cr, cb, out, rows, cols)

  unsigned char *lum;

  unsigned char *cr;

  unsigned char *cb;

  unsigned char *out;

  int cols, rows;

{

    int L, CR, CB;

    unsigned int *row1 = (unsigned int *)out;

    unsigned int *row2 = row1 + cols;

    unsigned int *row3 = row2 + cols;

    unsigned int *row4 = row3 + cols;

    unsigned char *lum2;

    int x, y;

    unsigned int r, b, g;

    int cr_r;

    int cr_g;

    int cb_g;

    int cb_b;

    int cols_2 = cols/2;

    lum2 = lum + cols_2 + cols_2;

    for (y=0; y<rows; y+=2) {

        for (x=0; x<cols_2; x++) {

            int R, G, B;

            int t;

            CR = *cr++;

            CB = *cb++;

            cr_r = Cr_r_tab[CR];

            cr_g = Cr_g_tab[CR];

            cb_g = Cb_g_tab[CB];

            cb_b = Cb_b_tab[CB];

            L = L_tab[(int) *lum++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            t = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

            row1[0] = t;

            row1++;

            row2[0] = t;

            row2++;

#ifdef INTERPOLATE

            if(x != cols_2 - 1) {

              CR = (CR + *cr) >> 1;

              CB = (CB + *cb) >> 1;

              cr_r = Cr_r_tab[CR];

              cr_g = Cr_g_tab[CR];

              cb_g = Cb_g_tab[CB];

              cb_b = Cb_b_tab[CB];

            }

#endif

            L = L_tab[(int) *lum++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            t = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

            row1[0] = t;

            row1++;

            row2[0] = t;

            row2++;

            /*

             * Now, do second row.

             */

#ifdef INTERPOLATE

            if(y != rows - 2) {

              CR = (CR + *(cr + cols_2 - 1)) >> 1;

              CB = (CB + *(cb + cols_2 - 1)) >> 1;

              cr_r = Cr_r_tab[CR];

              cr_g = Cr_g_tab[CR];

              cb_g = Cb_g_tab[CB];

              cb_b = Cb_b_tab[CB];

            }

#endif

            L = L_tab[(int) *lum2++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            t = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

            row3[0] = t;

            row3++;

            row4[0] = t;

            row4++;

            L = L_tab[(int) *lum2++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;

            t = (r_2_pix[R] | g_2_pix[G] | b_2_pix[B]);

            row3[0] = t;

            row3++;

            row4[0] = t;

            row4++;

        }

        lum += cols_2 + cols_2;

        lum2 += cols_2 + cols_2;

        row1 += 6 * cols_2;

        row3 += 6 * cols_2;

        row2 += 6 * cols_2;

        row4 += 6 * cols_2;

    }

}

/*

 *--------------------------------------------------------------

 *

 * Twox2Color32 --

 *

 *      Converts image into 24/32 bit color.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      None.

 *

 *--------------------------------------------------------------

 */

#ifdef SIXTYFOUR_BIT

#define ONE_TWO 1

#else

#define ONE_TWO 2

#endif

void

Twox2Color32DitherImage(lum, cr, cb, out, rows, cols)

  unsigned char *lum;

  unsigned char *cr;

  unsigned char *cb;

  unsigned char *out;

  int cols, rows;

{

    int L, CR, CB;

    unsigned long *row1 = (unsigned long *)out;

    unsigned long *row2 = row1 + cols * ONE_TWO;

    unsigned long *row3 = row2 + cols * ONE_TWO;

    unsigned long *row4 = row3 + cols * ONE_TWO;

    unsigned char *lum2;

    int x, y;

    unsigned int r, b, g;

    int cr_r;

    int cr_g;

    int cb_g;

    int cb_b;

    int cols_2 = cols/2;

    lum2 = lum + cols_2 + cols_2;

    for (y=0; y<rows; y+=2) {

        for (x=0; x<cols_2; x++) {

            int R, G, B;

            long t;

            CR = *cr++;

            CB = *cb++;

            cr_r = Cr_r_tab[CR];

            cr_g = Cr_g_tab[CR];

            cb_g = Cb_g_tab[CB];

            cb_b = Cb_b_tab[CB];

            L = L_tab[ (int) *lum++];

            R = L + cr_r;

            G = L + cr_g + cb_g;

            B = L + cb_b;