Transition a CGRect to another CGRect by the (CGFloat) ratio provided.

TransitionRect.m

+ (CGFloat)transitionFloat:(CGFloat)float1 toFloat:(CGFloat)float2 byRatio:(CGFloat)ratio
{
    return ( ratio * (float2 - float1) );
}

+ (CGRect)transitionRect:(CGRect)rect1 toRect:(CGRect)rect2 byRatio:(CGFloat)ratio
{
    if (CGRectIsNull(rect1) || CGRectIsNull(rect2)) {
        return CGRectZero;
    }
    
    return CGRectMake(
      rect1.origin.x + [self transitionFloat:rect1.origin.x toFloat:rect2.origin.x byRatio:ratio],
      rect1.origin.y + [self transitionFloat:rect1.origin.y toFloat:rect2.origin.y byRatio:ratio],
      rect1.size.width + [self transitionFloat:rect1.size.width toFloat:rect2.size.width byRatio:ratio],
      rect1.size.height + [self transitionFloat:rect1.size.height toFloat:rect2.size.height byRatio:ratio]);
}