iOS 切割图片

- (UIImage *)CutImageWithImage:(UIImage *)image withRect:(CGRect)rect
{
    //使用CGImageCreateWithImageInRect方法切割图片，第一个参数为CGImage类型，第二个参数为要切割的CGRect
    CGImageRef cutImage = CGImageCreateWithImageInRect(image.CGImage, rect);
    //将切割出得图片转换为UIImage
    UIImage *resultImage = [UIImage imageWithCGImage:cutImage];
    return resultImage;
}