CAShapeLayer 裁剪图像

Question

我正在尝试使用带有此代码的 CAShapeLayer 裁剪图像

    CALayer* contentLayer = [CALayer layer];
    CAShapeLayer* mask = [CAShapeLayer layer];

    CGMutablePathRef path = CGPathCreateMutable();

    CGPathMoveToPoint(path, NULL, 10, 10);
    CGPathAddLineToPoint(path, NULL, 10, 80);
    CGPathAddLineToPoint(path, NULL, 80, 80);
    CGPathAddLineToPoint(path, NULL, 80, 10);
    mask.path = path;

    [contentLayer setContents:(id)[[UIImage imageNamed:@"image.png"] CGImage]];
    [contentLayer setMask:mask];          

    [[self layer]addSublayer:contentLayer];

执行此操作后，我只能看到空视图；

Answer 1

你从不设置contentLayer 的frame，所以它默认为CGRectZero，这使得它的内容不可见。将框架设置为图像的大小，您应该会看到它。