为什么masksToBounds = YES 会阻止CALayer 阴影? [英] Why masksToBounds = YES prevents CALayer shadow?

问题描述

使用以下代码段，我将向我的 UIView 添加阴影效果.这很好用.但是一旦我将视图的 ma​​sksToBounds 属性设置为 YES.不再渲染阴影效果.

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;

您对此有什么想法吗?

推荐答案

因为 shadow 是在 View 之外完成的效果，而将 maskToBounds 设置为 YES 将告诉 UIView 不要绘制任何超出其自身的东西.

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

如果您想要带阴影的圆角视图，我建议您使用 2 个视图:

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];

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