If a Windows CE–based platform includes a display, Windows CE loads the default, or primary, display driver when the system boots. By default, GWES loads a display driver named Ddi.dll. If the optional HKEY_LOCAL_MACHINE\System\GDI\Drivers\Display registry key is present, GWES loads the display driver indicated by that key. If the platform’s version of Windows CE is configured to include windowing, the Window Manager uses the frame buffer supported by the primary display driver for all on-screen drawing.
In order to perform a drawing operation, an application must first get a device context (DC) for a window or the desktop, by calling the CreateWindow and GetDC functions. The resulting DC is the application’s drawing surface. If the application’s Windows CE–based platform does not include support for windowing, and thus has no Window Manager, the application must call the CreateDC function with the name of the primary display driver’s .dll file to create a DC directly.