iOS视图切割圆角

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iOS切圆角的方式有三种

 1. 通过设置layer的属性

最简单的一种,但是很影响性能,一般在正常的开发中使用很少.

self.button.layer.cornerRadius = 30;
self.button.layer.masksToBounds = YES;

 2.使用贝塞尔曲线UIBezierPath和Core Graphics 使用不多 貌似只能使用ImageView 这个不太懂

UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];

    imageView.center = self.view.center;

    imageView.image = [UIImage imageNamed:@"1"];

    //开始对imageView进行画图

    UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, NO, [UIScreen mainScreen].scale);

    //使用贝塞尔曲线画出一个圆形图

    [[UIBezierPath bezierPathWithRoundedRect:imageView.bounds cornerRadius:imageView.frame.size.width] addClip];

    [imageView drawRect:imageView.bounds];

    imageView.image = UIGraphicsGetImageFromCurrentImageContext();

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    [self.button setImage:image forState:UIControlStateNormal];

    //结束画图

    UIGraphicsEndImageContext();

    [self.view addSubview:imageView];

3.使用CAShapeLayer和UIBezierPath设置圆角

// 只切一个角

//    UIBezierPath *maskPAth = [UIBezierPath bezierPathWithRoundedRect:self.button.bounds byRoundingCorners:UIRectCornerTopLeft cornerRadii:self.button.bounds.size];

   // 只切两个角

//    UIBezierPath *maskPAth = [UIBezierPath bezierPathWithRoundedRect:self.button.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerTopRight cornerRadii:CGSizeMake(10, 10)];

    // 注意 当size是整个大小时 切角是对角线会切成圆  size不是整个视图大小不会成圆角 有人说必须导入<AVFoundation/AVFoundation.h>  我是没有发现 如果不行可以导入试试

//    UIBezierPath *maskPAth = [UIBezierPath bezierPathWithRoundedRect:self.button.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerBottomRight cornerRadii:self.button.bounds.size];

   //     UIBezierPath *maskPAth = [UIBezierPath bezierPathWithRoundedRect:self.button.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerBottomRight cornerRadii:CGSizeMake(10, 10)];

    // 三个角

//    UIBezierPath *maskPAth = [UIBezierPath bezierPathWithRoundedRect:self.button.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerBottomRight | UIRectCornerTopRight cornerRadii:CGSizeMake(30, 30)];

    // 四个角

//    UIBezierPath *maskPAth = [UIBezierPath bezierPathWithRoundedRect:self.button.bounds byRoundingCorners:UIRectCornerAllCorners cornerRadii:self.button.bounds.size];

//    UIBezierPath *maskPAth = [UIBezierPath bezierPathWithRoundedRect:self.button.bounds cornerRadius:10];

//    CAShapeLayer *caShapeLayer = [CAShapeLayer layer];

//    caShapeLayer.path = maskPAth.CGPath;

//    self.button.layer.mask = caShapeLayer;

 这三种方法中第三种最好，对内存的消耗最少啊，而且渲染快速。

注意：这三种方法都是显示的是圆角，并不是真实切除角，在debug view hierarchy上可以看出大小不变 显示改变