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

[Dmitry Timoshkov]

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.

-- 
Dmitry.