IOS 将UIView轉成UIImage

+(UIImage*) imageOfView:(UIView*) view isRetain:(BOOL) retain{

    float scale = 1.0;

    if (retain == YES) {

        scale = 2.0;

    }

    UIGraphicsBeginImageContextWithOptions(view.frame.size, NO, scale); 

    [view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;

}

很簡單，當我們傳入UIWindow的執行個體時，得到的圖檔即是我們的程式截圖了