winex11: Implement X11DRV_FLUSH_GDI_DISPLAY ExtEscape command

[Alexandre Julliard]

Sebastian Lackner <sebastian at fds-team.de> writes:

> This patch implements an additional ExtEscape command
> X11DRV_FLUSH_GDI_DISPLAY, which can be used by external applications in
> order to flush all drawing operations to the Xserver.
>
> This patch is necessary for a new feature of Pipelight: In NPAPI
> windowlessmode the browser provides an X11 drawable, and expects the
> plugin (= the wine application) to draw on it. The current
> implementation uses CreateDCA() to create a new hDC and then
> X11DRV_SET_DRAWABLE to draw on an arbitrary X11 drawable. The additional
> command implemented in this patch is required to ensure that the drawing
> is finished before the PAINT event returns. Normally an XSync would be
> even better, but a lot of testing shows that XFlush is also sufficient
> (and faster), thats why we decided to use this approach.

You should call MsgWaitForMultipleObjects or some similar function
instead of adding private escapes.

-- 
Alexandre Julliard
julliard at winehq.org