ios 将两张图片写为一张图片

- (UIImage *)addImage:(UIImage *)image1 toImage:(UIImage *)image2 {    UIGraphicsBeginImageContext(image1.size);        // Draw image1    [image1 drawInRect:CGRectMake(0, 0, image1.size.width, image1.size.height)];        // Draw image2    [image2 drawInRect:CGRectMake(0, 0, image2.size.width, image2.size.height)];        UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();        UIGraphicsEndImageContext();        return resultingImage;}