ios 7 drawViewHierarchyInRect：afterScreenUpdates：仅限iPad上的黑屏

Question

我有非常奇怪的情况......我试图通过调用drawViewHierarchyInRect: afterScreenUpdates:来捕获滚动视图中的contentSize （ contentSize超过屏幕边界三次） drawViewHierarchyInRect: afterScreenUpdates:如下所示：

+ (UIImage *) imageFromScrollView: (UIScrollView *) scrollView {

    UIGraphicsBeginImageContext(size);

    [view drawViewHierarchyInRect: CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height)
               afterScreenUpdates: YES];

    UIImage * image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();  

    return image;  
}

它适用于：iPhone设备，iPhone和iPad模拟器，但不适用于iPad 设备 。 你有过类似的问题吗？ 我将不胜感激任何帮助！

Answer 1

使用

UIGraphicsBeginImageContextWithOptions(size, NO, [UIScreen mainScreen].scale);

NO在这里很重要，因为它返回非不透明图像。

Answer 2

这段代码适合我。

UIImage *image = [SnapShotter snapShotEntireScrollingView:self.receiptTableView];


+ (UIImage *)snapShotEntireScrollingView:(UIScrollView *)view
{
    return [self snapShotEntireScrollingView:view withEdgeInsets:UIEdgeInsetsZero];
}


+ (UIImage *)snapShotEntireScrollingView:(UIScrollView *)view withEdgeInsets:(UIEdgeInsets)insets
{
    CGRect currentFrame = view.frame;

    CGRect fullFrame = view.frame;
    fullFrame.size.width = MAX(currentFrame.size.width, view.contentSize.width);
    fullFrame.size.height = MAX(currentFrame.size.height, view.contentSize.height);
    view.frame = fullFrame;

    UIImage *image = [self snapShotView:view withEdgeInsets:insets];

    view.frame = currentFrame;
    return image;
}