图片裁剪

图片裁剪代码：

-(UIImage*)getSubImage:(UIImage*)image rect:(CGRect)rect

{

CGRect newrect = CGRectMake(0, 0, rect.size.width*2, rect.size.height*2);

CGImageRef subImageRef = CGImageCreateWithImageInRect(image.CGImage, newrect);

UIGraphicsBeginImageContext(rect.size);

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextDrawImage(context, newrect, subImageRef);

UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];

CGImageRelease(subImageRef);//手动释放

UIGraphicsEndImageContext();

return smallImage;

}