There are three functions:

CaptureWindow(hWnd) -> oXbpBitMap

  returns a bitmap object of the selected window

  hWnd can either be the handle of the window (oDlg:getHWnd()), or
  you can just pass the window object in and the function will resolve
  the handle itself.

CaptureWin2File( oDlg, cFile, nImgType ) -> lSuccess

  return TRUE if the file was successfully saved.

  oDlg is either a window object or a window handle.

  cFile is the name of a file to save to.  This is optional, and
  the default will be 'ScreenDump'.  The file extension is dependant
  upon the image format requested.

  nImgType is one of the image types supported by Xbase++. Use one
  of the XBPBMP_FORMAT_* constants.

  If the file extension is specified, it will be used regardless of
  whether it matches the requested format.

  If the file already exists, it will be overwritten.

PrintWindow( hWnd ) -> NIL

  hWnd *must* be a valid window handle.  This is a C function which captures
  the selected window as a bitmap and copies it to the clipboard.

  To use this function, you must include this line in your source:

      #include "printWin.ch"

Note that you can pass controls instead of windows.  The example code shows
firstly a capture of a window, then the capture of a pushbutton.