轉(zhuǎn)載：https://www.cnblogs.com/mafeng/p/5672528.html
這三種方法中第三種最好，對內(nèi)存的消耗最少啊，而且渲染快速。
第一種方法:通過設(shè)置layer的屬性轉(zhuǎn)最簡單的一種,但是很影響性能,一般在正常的開發(fā)中使用很少.
UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];
//只需要設(shè)置layer層的兩個(gè)屬性
//設(shè)置圓角
imageView.layer.cornerRadius = imageView.frame.size.width / 2;//將多余的部分切掉imageView.layer.masksToBounds = YES;
[self.view addSubview:imageView];
第二種方法:使用貝塞爾曲線UIBezierPath和Core Graphics框架畫出一個(gè)圓角
UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];imageView.image = [UIImage imageNamed:@"1"];
//開始對imageView進(jìn)行畫圖
UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, NO, 1.0);
//使用貝塞爾曲線畫出一個(gè)圓形圖
[[UIBezierPath bezierPathWithRoundedRect:imageView.bounds cornerRadius:imageView.frame.size.width] addClip];
[imageView drawRect:imageView.bounds];
imageView.image = UIGraphicsGetImageFromCurrentImageContext();//結(jié)束畫圖
UIGraphicsEndImageContext();
[self.view addSubview:imageView];
第三種方法:使用CAShapeLayer和UIBezierPath設(shè)置圓角首先需要導(dǎo)入
#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];
//設(shè)置大小
maskLayer.frame = imageView.bounds;
//設(shè)置圖形樣子
maskLayer.path = maskPath.CGPath;
imageView.layer.mask = maskLayer;
[self.view addSubview:imageView];
}
