iOS的UIIMAGE圖片合成

 - (UIImage *)addImage:(UIImage *)image1 toImage:(UIImage *)image2 {

    UIGraphicsBeginImageContext(image1.size);

    [image1 drawInRect:CGRectMake(0, 0, image1.size.width, image1.size.height)];

    [image2 drawInRect:CGRectMake(0, 0, image2.size.width, image2.size.height)];

    UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return resultingImage;

}