ios UIImage 圆形图片剪切方案

@interface UIImage (Resize)

//按形状切割图像
- (UIImage*)cutImageWithRadius:(int)radius;

@end

//图片剪切
- (UIImage*)cutImageWithRadius:(int)radius
{
    UIGraphicsBeginImageContext(self.size);
    CGContextRef gc = UIGraphicsGetCurrentContext();

    float x1 = .;
    float y1 = .;
    float x2 = x1+self.size.width;
    float y2 = y1;
    float x3 = x2;
    float y3 = y1+self.size.height;
    float x4 = x1;
    float y4 = y3;
    radius = radius*;

    CGContextMoveToPoint(gc, x1, y1+radius);
    CGContextAddArcToPoint(gc, x1, y1, x1+radius, y1, radius);
    CGContextAddArcToPoint(gc, x2, y2, x2, y2+radius, radius);
    CGContextAddArcToPoint(gc, x3, y3, x3-radius, y3, radius);
    CGContextAddArcToPoint(gc, x4, y4, x4, y4-radius, radius);

    CGContextClosePath(gc);
    CGContextClip(gc);

    CGContextTranslateCTM(gc, , self.size.height);
    CGContextScaleCTM(gc, , -);
    CGContextDrawImage(gc, CGRectMake(, , self.size.width, self.size.height), self.CGImage);

    UIImage *newimage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return newimage;
}