Why masksToBounds = YES prevents CALayer shadow?

Question

With the following snippet, I'm adding a drop shadow effect to one my UIView. Which works pretty well. But as soon as I set the view's masksToBounds property to YES. The drop shadow effect isn't rendered any more.

self.myView.layer.shadowColor = [[UIColor blackColor] CGColor];
self.myView.layer.shadowOpacity = 1.0;
self.myView.layer.shadowRadius = 10.0;
self.myView.layer.shadowOffset = CGSizeMake(0.0f, 0.0f);
self.myView.layer.cornerRadius = 5.0;
self.myView.layer.masksToBounds = YES; // <-- This is causing the Drop shadow to not be rendered
UIBezierPath *path = [UIBezierPath bezierPathWithCurvedShadowForRect:self.myView.bounds];
self.myView.layer.shadowPath = path.CGPath;
self.myView.layer.shouldRasterize = YES;

Do you have any ideas on this?

Answer 1

Because shadow is an effect done outside the View, and that masksToBounds set to YES will tell the UIView not to draw everything that is outside itself.

If you want a roundedCorner view with shadow I suggest you do it with 2 views...

UIView view1 = [[UIView alloc] init];
UIView view2 = [[UIView alloc] init];

view1.layer.cornerRadius = 5.0;
view1.layer.masksToBounds = YES;
view2.layer.cornerRadius = 5.0;
view2.layer.shadowColor = [[UIColor blackColor] CGColor];
view2.layer.shadowOpacity = 1.0;
view2.layer.shadowRadius = 10.0;
view2.layer.shadowOffset = CGSizeMake(0.0f, 0.0f);
[view2 addSubview:view1];
[view1 release];