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 = 0.;
    float y1 = 0.;
    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*2;
    
    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, 0, self.size.height);
    CGContextScaleCTM(gc, 1, -1);
    CGContextDrawImage(gc, CGRectMake(0, 0, self.size.width, self.size.height), self.CGImage);
    
    
    
    UIImage *newimage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return newimage;
}