Adding a mask with CALayers

Question

I seem to be having difficulties adding a mask via CALayers. I\'m simply trying to mask a UIImageView. Here\'s my code:

 CALayer *maskLayer = [CALayer layer];
 U         


        

Answer 1

Try

maskLayer.contents = (id)mask.CGImage;

Yes, the cast sucks, but it's necessary.

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I think you'll also need to say

maskLayer.bounds = (CGRect){CGPointZero, mask.size};

Answer 2

try this:

CALayer *maskLayer = [CALayer layer];
UIImage *mask = [UIImage imageNamed:@"mask.png"];
maskLayer.contents = (id)mask.CGImage;
//  maskLayer.contentsGravity = kCAGravityCenter;
maskLayer.frame = CGRectMake(0.0, 0.0,1024,768);

UIImageView *viewToMask = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 1024, 768)];
viewToMask.image = [UIImage imageNamed:@"picture.png"];
viewToMask.layer.mask = maskLayer;
[self.view addSubview:viewToMask];

you also need to set mask frame