如何在OSX中访问NSWindow的像素缓冲区？

Question

我正在寻找一种方法来获取像CamTwist'Desktop +'功能一样的窗口内容.这可以抓住任何窗口,即使它在后台.

Apple的OpenGLScreenCapture示例显示了如何从主屏幕捕获而不是从隐藏表面捕获.

知道CamTwist如何访问NSWindow的像素缓冲区吗？

Answer 1

AFAIK,官方API可以在CGWindow.h中找到,作为CoreGraphics的一部分:

/* Create an image containing a composite of the specified set of windows
   contained within a rectangular area. The set of windows is specified
   using options from `CGWindowListOption', along with an optional
   additional window ID.

   The windows list options are:

   --- kCGWindowListOptionAll, kCGWindowListOptionOnScreenOnly: Use all
   on-screen windows in this user session to construct the image. The
   parameter `windowID' should be `kCGNullWindowID'.

   --- kCGWindowListOptionOnScreenAboveWindow: Use all on-screen windows in
   this user session above the window specified by `windowID', ordered from
   front to back, to construct the image. To include the window specified by
   `windowID', add the flag `kCGWindowListOptionIncludingWindow'.

   --- kCGWindowListOptionOnScreenBelowWindow: Use all on-screen windows in
   this user session below the window specified by `windowID', ordered from
   front to back, to construct the image. To include the window specified by
   `windowID', add the flag `kCGWindowListOptionIncludingWindow'.

   --- kCGWindowListOptionIncludingWindow: Use only the window specified by
   `windowID' to construct the image.

   The parameter `screenBounds' specifies the rectangle in screen space
   (origin at the upper-left; y-value increasing downward). Setting
   `screenBounds' to `CGRectInfinite' will include all the windows on the
   entire desktop. Setting `screenBounds' to `CGRectNull' will use the
   bounding box of the specified windows as the screen space rectangle.

打破

   /* The parameter `imageOptions' allows you to specify whether the window
   frame ornamentation, such as a shadow or similar effect, should be
   included or excluded in the bounds calculation when `CGRectNull' is
   specified for the window bounds.

   If no windows meet the specified criteria, or the windows can't be read,
   then a transparent black image will be returned.

   Any on-screen window with sharing type `kCGWindowSharingNone' will not
   be included in the image.

   This function returns NULL if the caller is not running within a Quartz
   GUI session or the window server is disabled. */

CG_EXTERN CGImageRef CGWindowListCreateImage(CGRect screenBounds,
  CGWindowListOption listOption, CGWindowID windowID,
  CGWindowImageOption imageOption)
  CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);

/* Create an image containing a composite of the specified set of windows
   contained within a rectangular area à la `CGWindowListCreateImage'. The
   set of windows is specified by `windowArray', an array of window IDs. */

CG_EXTERN CGImageRef CGWindowListCreateImageFromArray(CGRect screenBounds,
  CFArrayRef windowArray, CGWindowImageOption imageOption)
  CG_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);

抱歉,找不到Apple网站上文档的链接.但是,它们似乎在Son of Grab中有示例代码.