图片合成截屏

-(UIImage *)saveImage:(UIView *)view {
    CGRect mainRect = [[UIScreen mainScreen] bounds];
   
    UIGraphicsBeginImageContext(CGSizeMake(320, 200));
    CGContextRef context = UIGraphicsGetCurrentContext();
    //    [[UIColor blackColor] set];
   
    CGContextFillRect(context, mainRect);
    [view.layer renderInContext:context];
   
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
   
    UIGraphicsEndImageContext();
   
    return newImage;

}