root/gd/libgd/gd_color.c

DEFINITIONS

1. gdImageColorMatch

#if HAVE_GD_BUNDLED
# include "gd.h"
# include "gdhelpers.h"
#else
# include <gd.h>
# include "libgd/gdhelpers.h"
#endif

#include "gd_intern.h"
#include "php.h"

/* bring the palette colors in im2 to be closer to im1
 *
 */
int gdImageColorMatch (gdImagePtr im1, gdImagePtr im2)
{
        unsigned long *buf; /* stores our calculations */
        unsigned long *bp; /* buf ptr */
        int color, rgb;
        int x,y;
        int count;

        if( !im1->trueColor ) {
                return -1; /* im1 must be True Color */
        }
        if( im2->trueColor ) {
                return -2; /* im2 must be indexed */
        }
        if( (im1->sx != im2->sx) || (im1->sy != im2->sy) ) {
                return -3; /* the images are meant to be the same dimensions */
        }
        if (im2->colorsTotal<1) {
                return -4; /* At least 1 color must be allocated */
        }

        buf = (unsigned long *)safe_emalloc(sizeof(unsigned long), 5 * im2->colorsTotal, 0);
        memset( buf, 0, sizeof(unsigned long) * 5 * im2->colorsTotal );

        for (x=0; x<im1->sx; x++) {
                for( y=0; y<im1->sy; y++ ) {
                        color = im2->pixels[y][x];
                        rgb = im1->tpixels[y][x];
                        bp = buf + (color * 5);
                        (*(bp++))++;
                        *(bp++) += gdTrueColorGetRed(rgb);
                        *(bp++) += gdTrueColorGetGreen(rgb);
                        *(bp++) += gdTrueColorGetBlue(rgb);
                        *(bp++) += gdTrueColorGetAlpha(rgb);
                }
        }
        bp = buf;
        for (color=0; color<im2->colorsTotal; color++) {
                count = *(bp++);
                if( count > 0 ) {
                        im2->red[color]         = *(bp++) / count;
                        im2->green[color]       = *(bp++) / count;
                        im2->blue[color]        = *(bp++) / count;
                        im2->alpha[color]       = *(bp++) / count;
                } else {
                        bp += 4;
                }
        }
        gdFree(buf);
        return 0;
}