方法一：
self.cycleImv= [[UIImageView alloc]initWithFrame:CGRectMake(100, 100, 50, 50)];
[self.view addSubview:self.cycleImv];
// 为图片切圆
self.cycleImv.layer.masksToBounds = YES;
self.cycleImv.layer.cornerRadius = self.cycleImv.frame.size.width / 2.0;
// 为图片添加边框,根据需要设置边框
self.cycleImv.layer.borderWidth = 2.0;//边框的宽度
self.cycleImv.layer.borderColor = [UIColor redColor].CGColor;//边框的颜色
方法二：
- (void)drawRect:(CGRect)rect
{
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:self.cycleImv.bounds byRoundingCorners:UIRectCornerAllCorners cornerRadii:self.cycleImv.bounds.size];
CAShapeLayer *maskLayer = [[CAShapeLayer alloc]init];
//设置大小
maskLayer.frame = self.cycleImv.bounds;
//设置图形样子
maskLayer.path = maskPath.CGPath;
self.cycleImv.layer.mask = maskLayer;
}
方法三：
将网络图片裁剪为圆形，首先建立一个UIImage分类UIImage+Extension，一个UIImageView分类UIImageView+CircularImv。
UIImage+Extension.h文件
#import@interface UIImage (Extension)
- (UIImage *)circleImage;
@end
UIImage+Extension.m文件
#import "UIImage+Extension.h"
@implementation UIImage (Extension)
- (UIImage *)circleImage
{
// 开始图形上下文，NO代表透明
UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0);
// 获得图形上下文
CGContextRef ctx = UIGraphicsGetCurrentContext();
// 设置一个范围
CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
// 根据一个rect创建一个椭圆
CGContextAddEllipseInRect(ctx, rect);
// 裁剪
CGContextClip(ctx);
// 将原照片画到图形上下文
[self drawInRect:rect];
// 从上下文上获取剪裁后的照片
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
// 关闭上下文
UIGraphicsEndImageContext();
return newImage;
}
@end
使用了SDWebImage加载网络图片，所以加上UIImageView+WebCache.h头文件。
UIImageView+CircularImv.h文件
#import@interface UIImageView (CircularImv)
- (void)setCircularImvURL:(NSString *)imageUrl holderImageName:(NSString *)imageName;
@end
UIImageView+CircularImv.m文件
#import "UIImageView+CircularImv.h"
#import "UIImageView+WebCache.h"
#import "UIImage+Extension.h"
@implementation UIImageView (CircularImv)
- (void)setCircularImvURL:(NSString *)imageUrl holderImageName:(NSString *)imageName
{
//占位图片，当URL上下载的图片为空，就显示该图片
UIImage *placeholder = [[UIImage imageNamed:imageName] circleImage];
[self sd_setImageWithURL:[NSURL URLWithString:imageUrl] placeholderImage:placeholder completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {
//当图片下载完会来到这个block，执行以下代码
self.image = image ? [image circleImage] : placeholder;
}];
}
@end