Function Reference


_WinAPI_GetWindowDC

Retrieves the device context (DC) for the entire window

#include <WinAPI.au3>
_WinAPI_GetWindowDC ( $hWnd )

Parameters

$hWnd Handle of window

Return Value

Success: The handle of a device context for the specified window
Failure: 0

Remarks

GetWindowDC is intended for special painting effects within a window's nonclient area. Painting in nonclient
areas of any window is normally not recommended. The GetSystemMetrics function can be used to retrieve the
dimensions of various parts of the nonclient area, such as the title bar, menu, and scroll bars. After
painting is complete, the _WinAPI_ReleaseDC() function must be called to release the device context. Not releasing
the window device context has serious effects on painting requested by applications.

Related

_WinAPI_ReleaseDC

See Also

Search GetWindowDC in MSDN Library.

Example

#include <WinAPI.au3>
#include <WindowsConstants.au3>

ShowCross(@DesktopWidth / 2, @DesktopHeight / 2, 20, 2, 0xFF, 3000)

Func ShowCross($iStart_x, $iStart_y, $iLength, $iWidth, $iColor, $iTime)
    Local $hDC, $hPen, $o_Orig

    $hDC = _WinAPI_GetWindowDC(0) ; DC of entire screen (desktop)
    $hPen = _WinAPI_CreatePen($PS_SOLID, $iWidth, $iColor)
    $o_Orig = _WinAPI_SelectObject($hDC, $hPen)

    _WinAPI_DrawLine($hDC, $iStart_x - $iLength, $iStart_y, $iStart_x - 5, $iStart_y) ; horizontal left
    _WinAPI_DrawLine($hDC, $iStart_x + $iLength, $iStart_y, $iStart_x + 5, $iStart_y) ; horizontal right
    _WinAPI_DrawLine($hDC, $iStart_x, $iStart_y - $iLength, $iStart_x, $iStart_y - 5) ; vertical up
    ;   _WinAPI_DrawLine($hDC, $iStart_x, $iStart_y + $iLength, $iStart_x, $iStart_y + 5) ; vertical down
    _WinAPI_MoveTo($hDC, $iStart_x, $iStart_y + $iLength)
    _WinAPI_LineTo($hDC, $iStart_x, $iStart_y + 5)

    Sleep($iTime) ; show cross over screen for defined seconds

    ; refresh desktop (clear cross)
    _WinAPI_RedrawWindow(_WinAPI_GetDesktopWindow(), 0, 0, $RDW_INVALIDATE + $RDW_ALLCHILDREN)

    ; clear resources
    _WinAPI_SelectObject($hDC, $o_Orig)
    _WinAPI_DeleteObject($hPen)
    _WinAPI_ReleaseDC(0, $hDC)
EndFunc   ;==>ShowCross