ScreenToClient( hWnd, aPoint )-> <nil>
------------------------------------------------------------------------------


 PARAMETER:

  <hWnd>        Is the handle that identifies the window whose client area
                is used for the conversion.

  <aPoint>      Is an array of two elements that contains the coordinates of
                the point. The two elements of this array are transformed
                according to the new calculated values.
                After the function call, this array contains the resulting
                client coordinates


 DESCRIPTION:

  This function converts the screen coordinates of a given point on the
  screen to client coordinates, and places the result inside the <aPoint>
  array. The new coordinates are relative to the upper-left corner of the
  given window's client area. 


 EXAMPLE:


    +--------------------------------------------------------------+
    |  /* Convert coordinates  */                                  |
    |  LOCAL ;                                                     |
    |     aPoint := { 100, 120 }                                   |
    |     ScreenToClient( ::oWnd:hWnd, aPoint )                    |
    |                                                              |
    |     MsgInfo( aPoint[1] )                                     |
    +--------------------------------------------------------------+


 SOURCE:

  SOURCE\WINAPI\WNDSCROL.C