gistfile1.txt

    UIGraphicsBeginImageContext(CGSizeMake(320, 480));
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    [controller.view setNeedsDisplay];
    [controller.view.layer renderInContext:context];

    UIImage *anImage = UIGraphicsGetImageFromCurrentImageContext();
    NSData *png = UIImagePNGRepresentation(anImage);
    UIGraphicsEndImageContext();