如何制作任何视图的圆形

问题描述

我只想将视图的形状从Square更改为Round。当我尝试使用cornerRadious时，它只是在拐角处。因为我想将整个视图视为圆形。

I just want to change the shape of view from Square to Round. As i try with cornerRadious, But it just round the corner only. As I want to make whole view as a round shape.

推荐答案

UIView始终是矩形的。但是，您可以使用蒙版使其看起来圆形（或任何形状）。为此，请创建一个黑色圆圈的UIImage（在透明背景中）。现在获取该UIImage的CGImage并将其作为CALayer的内容。最后，将CALayer设置为视图图层的掩码。

A UIView is always rectangular. However, you can make it look round (or any shape at all, actually) with a mask. To do so, make a UIImage which is a black circle (in a transparent background). Now take the CGImage of that UIImage and make it the contents of a CALayer. Finally, set that CALayer as the mask of the layer of your view.

让我们假设您的视图是100 x 100.然后（未测试，但应该非常正确）：

Let us suppose that your view is 100 x 100. Then (not tested, but should be pretty much right):

UIGraphicsBeginImageContextWithOptions(CGSizeMake(100,100), NO, 0);
CGContextRef c = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(c, [UIColor blackColor].CGColor);
CGContextFillEllipseInRect(c, CGRectMake(0,0,100,100));
UIImage* maskim = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

CALayer* mask = [CALayer new];
mask.frame = CGRectMake(0,0,100,100);
mask.contents = (id)maskim.CGImage;

view.layer.mask = mask;

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