为什么maskToBounds = 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，我正在为我的UIView添加阴影效果。哪个效果很好。但只要我将视图的 masksToBounds 属性设置为 YES 。投影效果不再呈现。

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

因为阴影是在视图之外完成的效果，并且maskToBounds设置为YES将告诉UIView不要绘制任何超出其自身的内容。

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.

如果你想要带有阴影的roundedCorner视图我建议你用2个视图来做：

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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