ios - 在 Objective-C 中屏蔽视图

Question

在ActionScript 3中，我们可以像这样对可视对象应用蒙版：

SomeVisualObject.mask = maskShapeObject; 

如何在Objective-C中获得类似的结果？假设我有两个UIImageView对象，我想要这样的东西：

imageView1.mask = imageView2;

我如何使用一个UIImageView来掩盖或剪辑另一个的形状？

Answer 1

CALayer *maskLayer = [CALayer layer];
 UIImage *maskImage = [UIImage imageNamed:@"maskImage.png"];
maskLayer.contents = (id)maskImage.CGImage;
maskLayer.bounds = (CGRect){CGPointZero, maskImage.size};

UIImageView *imageViewToMask = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 1024, 768)];
imageViewToMask.image = [UIImage imageNamed:@"image2.png"];
imageViewToMask.layer.mask = maskLayer;