root/ext/gd/libgd/gd_transform.c

DEFINITIONS

1. gdImageFlipVertical
2. gdImageFlipHorizontal
3. gdImageFlipBoth

#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);
}