ios UIImage切圆形透明的正确方式

一下方法写在自定义的ImageView中.

// 创建一个图片上下文

UIGraphicsBeginImageContext(self.size);

// 指定半径

CGFloat radius = 50;

UIBezierPath *path =[UIBezierPath bezierPathWithRect:self.bounds];

UIBezierPath *circlePath = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(self.centerX - radius, self.centerY - radius, 2.0*radius, 2.0*radius) cornerRadius:radius];

[path appendPath:circlePath];

[path setUsesEvenOddFillRule:YES];

[path addClip]; // 裁剪

// 绘制图片到图片上下文中

[self.image drawInRect:self.bounds];

self.image = UIGraphicsGetImageFromCurrentImageContext();

//关闭图片上下文

UIGraphicsEndImageContext();