在NSImage内部使用NSStrings拍摄屏幕截图 [英] Adorning screenshots with NSStrings inside an NSImage

问题描述

我试图从NSView抓取屏幕截图，使用NSImage缓冲区在屏幕截图的顶部绘制一个字符串，然后保存所有内容。视图抓取是一个普通的NSPanel内容视图，托管单个NSImageView。

I'm trying to grab a screenshot from a NSView, draw a string on top of the screenshot using the NSImage buffer then saving everything. The view grabbed from is a plain NSPanel contentview that hosts a single NSImageView.

不幸的是，输出文件是我的字符串在所有的黑色背景，没有屏幕截图的标志。

Unfortunately the output file is my string on an all black background with no sign of the screenshot.

这是代码：

NSImage *screenshot = [[NSImage alloc] initWithData:[mView dataWithPDFInsideRect:[mView bounds]]];

NSString *frameCounterString = @"123";
[screenshot lockFocus];
[frameCounterString drawAtPoint:NSMakePoint(10, 10) withAttributes:nil];
[screenshot unlockFocus];

有什么想法吗？

一旦lockFocus / unlockFocus调用添加到结果中就变成黑色..

As soon as the lockFocus/unlockFocus calls are added in the result goes black..

使用NSBitmapImageRep：initWithFocusedViewRect：捕获的技术在这种情况下无效，例如：

Using the NSBitmapImageRep:initWithFocusedViewRect: technique for capturing doesn't work either in this case, i.e.:

  screenshot = [[NSImage alloc] initWithSize:[mView bounds].size];
  [mView lockFocus];
  NSBitmapImageRep *bits = [[NSBitmapImageRep alloc] initWithFocusedViewRect:[mView bounds]];
  [mView unlockFocus];
  [screenshot addRepresentation:bits];

推荐答案

正确 - 现在合成几个NSImages docs。
一个用于屏幕截图，而不是将该字符串加上一个新的空NSImage。

Right - now compositing several NSImages as suggested by the Apple docs. One for the screenshot, than drawing that plus the string into a new empty NSImage.

仍为黑色。

要捕获的视图包含一个NSImageView，它必须是关于其内部图像表示的东西：将NSImageView边框设置为none不会产生任何截图。将边框设置为Photo允许使用dataWithPDFInsideRect方法捕获边框。

The view to be captured contains a NSImageView and it must be something about its internal image representations: setting the NSImageView border to none doesn't yield any screenshot, ever. Setting the border to 'Photo' allows it to be captured using the dataWithPDFInsideRect method.

无论显示模式是什么，都需要找到一个更通用的方法来捕获它。 。

Need to find a more generic way to capture it no matter what the display mode is..

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