Dropping a shadow

gistfile1.txt

- (void)animationDidStop:(CABasicAnimation *)anim finished:(BOOL)flag
{
	self.layer.shadowPath = (CGPathRef)anim.toValue;
}

- (void)updateShadowWithDuration:(NSTimeInterval)duration
{
	CALayer *layer = self.layer;
	
	if (_dropShadow)
	{
		layer.shadowColor = [UIColor blackColor].CGColor;
		layer.shadowOffset = CGSizeMake(0,0);
		layer.shadowOpacity = 0.9;
		layer.shadowRadius = 10;	 
		
		UIBezierPath *path = [UIBezierPath bezierPathWithRect:self.bounds];
		
		if (layer.shadowPath && duration>0)
		{
			NSLog(@"animate: %@", self);
			// need animation
			CABasicAnimation *theAnimation = [CABasicAnimation animationWithKeyPath:@"shadowPath"];
			theAnimation.duration = duration;
			theAnimation.fromValue = (id)layer.shadowPath;
			theAnimation.toValue = (id)path.CGPath;
			theAnimation.delegate = self;
			theAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
			theAnimation.removedOnCompletion = NO;
			
			[layer addAnimation:theAnimation forKey:@"shadowPath"];
		}
		else
		{
			layer.shadowPath = path.CGPath;
		}
	}
	else
	{
		// no shadow
		layer.shadowOpacity = 0;
		layer.shadowPath = NULL;
		return;
	}
}