[lazarus] ExcludeClipRect function

[Marc Weustink]

+ From: Shane Miller [mailto:SMiller1 at stvgb.org]
+
+ Anyone have an idea on how this works?  Your supposed to send
+ it the hdc, left, right,top, bottom and it'll exclude this
+ rect from the structure that is going to be painted.  The
+ problem is that I don't know where to look for that
+ structure.  I thought it was help in the DC but I don't see
+ it in our implementation.
+
+ Understand what I mean?  If I send you a rect to exclude you
+ need the original rect in order to change it to exclude the
+ one I sent you.  WHere is the original?

I just looked at the docs, and I think I know what you mean. In GDK you can
set the clip_rectangle/clip_region, but you can't get it (as far as I can
see now). This means that functuions like
ExcludeClipRect/IntersectClipRect/SelectClipRgn should maintain a ClipRect
(in TDeviceContext) and pass this one to gdk.

When I'm at home I'll look if it is possible to retrieve the gdk clip rect.

Marc