方式一:设置layer相关的属性

最简单的一种,但是很影响性能。

情景一:使用代码设置

UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)]; //只需要设置layer层的两个属性 //设置圆角 imageView.layer.cornerRadius = imageView.frame.size.width / 2; //将多余的部分切掉 imageView.layer.masksToBounds = YES; [self.view addSubview:imageView]; 情景二:在xib中设置              1、利用KVC设置（Key Path）,下图                                   2、利用 IBInspectable设置,下图                                实现：项目中添加了一个UIView的分类,代码如下

//

//  UIView+BorderRadius.h

//  DaZhongChuXing

//

//  Created by fujunzhi on 2017/3/10.

//  Copyright © 2017年 tony. All rights reserved.

//

#import <UIKit/UIKit.h>

@interface UIView (BorderRadius)

//加上IBInspectable就可以可视化显示相关的属性哦

@property (nonatomic, strong) IBInspectable UIColor *borderColor;

@property (nonatomic, assign) IBInspectable CGFloat borderWidth;

@property (nonatomic, assign) IBInspectable CGFloat cornerRadius;

@end

//

//  UIView+BorderRadius.m

//  DaZhongChuXing

//

//  Created by fujunzhi on 2017/3/10.

//  Copyright © 2017年 tony. All rights reserved.

//

#import "UIView+BorderRadius.h"

@implementation UIView (BorderRadius)

- (void)setBorderColor:(UIColor *)borderColor {

   self.layer.borderColor = borderColor.CGColor;

}

- (UIColor *)borderColor {

   return [UIColor colorWithCGColor:self.layer.borderColor];

}

- (void)setBorderWidth:(CGFloat)borderWidth

{

   self.layer.borderWidth = borderWidth;

}

- (CGFloat)borderWidth

{

   return self.layer.borderWidth;

}

- (void)setCornerRadius:(CGFloat)cornerRadius

{

   self.layer.cornerRadius = cornerRadius;

   self.layer.masksToBounds = cornerRadius > 0;

}

- (CGFloat)cornerRadius

{

   return self.layer.cornerRadius;

}

@end

IB_DESIGNABLE／IBInspectable的使用

方式二:使用贝塞尔曲线UIBezierPath和Core Graphics框架画出一个圆角

UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)]; 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(); //结束画图 UIGraphicsEndImageContext(); [self.view addSubview:imageView];

第三种方法:使用CAShapeLayer和UIBezierPath设置圆角

首先需要导入<AVFoundation/AVFoundation.h>

#import "ViewController.h" @interface ViewController () @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)]; imageView.image = [UIImage imageNamed:@"1"]; UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:imageView.bounds byRoundingCorners:UIRectCornerAllCorners cornerRadii:imageView.bounds.size]; CAShapeLayer *maskLayer = [[CAShapeLayer alloc]init]; //设置大小 maskLayer.frame = imageView.bounds; //设置图形样子 maskLayer.path = maskPath.CGPath; imageView.layer.mask = maskLayer; [self.view addSubview:imageView]; } 推荐的文章：

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