我已经实现了一些屏幕捕获代码，可以是viewed here
我正在使用this article
中的GetTimeInNanoseconds每100ms调用一次该函数。我已经计算了执行部分函数需要多少毫秒，即：
screenShotStart = GetTimeInNanoseconds();
CGImageRef image = CGWindowListCreateImage(rect, kCGWindowListOptionIncludingWindow|kCGWindowListOptionOnScreenBelowWindow, 0, kCGWindowImageDefault);
CGImageRelease(image);
screenShotStop = GetTimeInNanoseconds();
screenShotElapsed = screenShotStop - screenShotStart;
/* Current Delta Time */
screenShotElapsedF = ((float) screenShotElapsed)/1000000.0f;
/* Smooth Delta Time */
screenShotTime = 0.9f*screenShotTime + 0.1f*screenShotElapsedF;
下面的时间测量显示结果。我很惊讶它有多慢，我想知道为什么。是否有经验丰富的Cocoa / Core Graphics OSX开发人员可以向我解释一下？并且可能告诉我应该如何修复它？
平滑：平均增量时间（以毫秒为单位）。 当前：最新，最新的增量时间（以毫秒为单位）。
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编辑：下载profile results
答案 0 :(得分：2)
CGWindow API不适用于高帧率捕获。首先，它没有捕获当前显示的屏幕图像。它被概括为潜在地捕获内容的各个部分。它可以包括或排除窗口，桌面元素，阴影等。这意味着它为每个调用组成一个新图像。并且，是的，这意味着它必须锁定所有窗口的后备缓冲区。
Apple提供了一对关于捕获屏幕内容的技术Q＆amp; A文章。一个是捕获单个图像，他们建议使用CGDisplayCreateImage()。另一种是随着时间的推移捕获屏幕活动的电影，他们建议使用AV基金会。
Technical Q&A QA1741: How to take an image snapshot of the screen on Mac OS X Lion
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