gd_transform.c

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#include "gd.h"
 
void gdImageFlipVertical(gdImagePtr im)
{
    register int x, y;
 
    if (im->trueColor) {
        for (y = 0; y < im->sy / 2; y++) {
            int *row_dst = im->tpixels[y];
            int *row_src = im->tpixels[im->sy - 1 - y];
            for (x = 0; x < im->sx; x++) {
                register int p;
                p = row_dst[x];
                row_dst[x] = im->tpixels[im->sy - 1 - y][x];
                row_src[x] = p;
            }
        }
    } else {
        unsigned char p;
        for (y = 0; y < im->sy / 2; y++) {
            for (x = 0; x < im->sx; x++) {
                p = im->pixels[y][x];
                im->pixels[y][x] =    im->pixels[im->sy - 1 - y][x];
                im->pixels[im->sy - 1 - y][x] = p;
            }
        }
    }
    return;
}
 
void gdImageFlipHorizontal(gdImagePtr im)
{
 
    int x, y;
 
    if (im->trueColor) {
        int *px1, *px2, tmp;
 
        for (y = 0; y < im->sy; y++) {
            px1 = im->tpixels[y];
            px2 = im->tpixels[y] + im->sx - 1;
            for (x = 0; x < (im->sx >> 1); x++) {
                tmp = *px1;
                *px1 = *px2;
                *px2 = tmp;
                px1++;
                px2--;
            }
        }
    } else {
        unsigned char *px1, *px2, tmp;
 
        for (y = 0; y < im->sy; y++) {
            px1 = im->pixels[y];
            px2 = im->pixels[y] + im->sx - 1;
            for (x = 0; x < (im->sx >> 1); x++) {
                tmp = *px1;
                *px1 = *px2;
                *px2 = tmp;
                px1++;
                px2--;
            }
        }
    }
}
 
void gdImageFlipBoth(gdImagePtr im)
{
    gdImageFlipVertical(im);
    gdImageFlipHorizontal(im);
}