两个UIImage 叠加

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

{

    UIGraphicsBeginImageContext(image2.size);

    

    //Draw image2

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

    

    //Draw image1

    [image1 drawInRect:CGRectMake(20, 20, image1.size.width, image1.size.height)];

    

    UIImage *resultImage=UIGraphicsGetImageFromCurrentImageContext();

    

    UIGraphicsEndImageContext();

    

    return resultImage;

}