如何拍摄已变换视图的屏幕截图？ [英] How do I take a screenshot of a view which has transform?

问题描述

我可以使用此代码裁剪视图

I'm able to crop a view with this code

- (UIImage *)captureScreenInRect:(CGRect)captureFrame {
    CALayer *layer;
    layer = self.view.layer;
    UIGraphicsBeginImageContext(self.view.bounds.size);
    CGContextClipToRect (UIGraphicsGetCurrentContext(),captureFrame);
    [layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *screenImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return screenImage;
}

但是我有一个imageview放大了transform，它没有显示

But I have an imageview zoomed in with transform and it isn't shown to scale.

如何准确捕获用户在屏幕上看到的内容

How do I capture EXACTLY what the user sees on the screen

推荐答案

堆栈溢出问题 renderInContext：和CATransform3D 具有更多信息，但要点是：

The Stack Overflow question "renderInContext:" and CATransform3D has more info, but the gist is:

QCCompositionLayer，CAOpenGLLayer和QTMovieLayer层未呈现。此外，不会渲染使用3D变换的图层，也不会渲染指定backgroundFilters，filters，compositingFilter或mask值的图层。

QCCompositionLayer, CAOpenGLLayer, and QTMovieLayer layers are not rendered. Additionally, layers that use 3D transforms are not rendered, nor are layers that specify backgroundFilters, filters, compositingFilter, or a mask values.

（摘自 CALayer文档 ）。

此技术问答中也提供了更多信息： http://developer.apple.com/library/ios/#qa/qa1703/_index.html

More info is also available in this technical Q&A: http://developer.apple.com/library/ios/#qa/qa1703/_index.html

如果您的应用程序不打算进入应用程序商店，则可以使用未记录的 UIGetScreenImage API：

If your app is not going to the app store you can use the undocumented UIGetScreenImage API:

// Define at top of implementation file
CGImageRef UIGetScreenImage(void);

...

- (void)buttonPressed:(UIButton *)button
{
  // Capture screen here...
  CGImageRef screen = UIGetScreenImage();
  UIImage* image = [UIImage imageWithCGImage:screen];
  CGImageRelease(screen);

  // Save the captured image to photo album
  UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
}

（来自 John Muchow ）

但是，使用此API会使您的应用未获得批准。

However, use of this API will make your app not get approved.

我找不到其他解决方法。

I have been unable to find any other workarounds.

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