winex11.drv: Make sure that default clipping region exists before calling ExcludeUpdateRgn().

[Alexandre Julliard]

Dmitry Timoshkov <dmitry at codeweavers.com> writes:

> Alexandre Julliard <julliard at winehq.org> wrote:
>
>> > I looks like the default clip region created by ExtSelectClipRgn() uses
>> > the dimensions of the selected bitmap, and it's not large enough.
>> 
>> That's a window DC, it doesn't have a selected bitmap.
>
> You are right. The app creates very large child window to fit the whole map
> inside it (it's at least two times larger than the screen), and moves the child
> window inside the parent window once one presses mouse button and drags the map
> (when I drag the map into the left top corner the coordinates of the child window
> are about -970,-860 while the screen resolution is 1680x1050 in my case). So,
> using the screen size for a default clipping is not enough.

OK, that makes sense. It sounds like a test case for ExtSelectClipRgn is
in order, before we work around it.

-- 
Alexandre Julliard
julliard at winehq.org