if(x < 0 || y < 0) return 0;
PutPixel32(ximage, x, y, pixel)    register XImage *ximage;    int x;    int y;    unsigned long pixel;{    unsigned char *addr;    addr = &((unsigned char *)ximage->data) [ZINDEX32(x, y, ximage)];    *((unsigned long *)addr) = pixel;    return 1;}