/*
 * Read a pixel from an X drawable.
 */
static unsigned long read_pixel( Display *dpy, Drawable d, int x, int y )
{
   XImage *pixel;
   unsigned long p;

   pixel = XGetImage( dpy, d, x, y, 1, 1, AllPlanes, ZPixmap );
   if (pixel) {
      p = XGetPixel( pixel, 0, 0 );
      XDestroyImage( pixel );
   }
   else {
      p = 0;
   }

   return p;
}