Flipping Coordinates

gistfile1.m

CGPoint CGPointFlipped(CGPoint point, CGRect bounds) {
    return CGPointMake(point.x, CGRectGetMaxY(bounds)-point.y);
}

CGRect CGRectFlipped(CGRect rect, CGRect bounds) {
    return CGRectMake(CGRectGetMinX(rect),
                      CGRectGetMaxY(bounds)-CGRectGetMaxY(rect),
                      CGRectGetWidth(rect),
                      CGRectGetHeight(rect));
}