nanogui: other fltk issues
Subject:
other fltk issues
From:
"Greg Haerr" ####@####.####
Date:
8 Mar 2000 17:13:29 -0000
Message-Id: <00e601bf8920$02915160$15320cd0@gregh>
Shane,
I think I finally understand what fltk is doing internally,
and why all the strange clipregion klugery.
Very late last night I implemented CS_OWNDC dc's, which
basically are private DC's that don't need getting and releasing.
This was done because fltk is built around X11, and the private
DC model is closer to X11.
The problem is, that, without private DC's fltk will crash in
certain circumstances because ReleaseDC is called twice.
(ReleaseDC does nothing for private DC's.) So I added
private DC's and now the clock demo runs without crashing.
Now, at 2 am I found myself reading the win32 tech manual,
and it says: when private dc's are used, the update region is
not kept up, the user application has to intersect the update
region with the clip region themselves [snip]...
Well, when I had SelectClipRgn commented in, nothing
ran because it was selecting in a empty region, which clipped
all drawing, since I commented out all the other region code.
So, tonight, I'm going to add GetUpdateRgn, the only api
piece still missing, then add all the region code back in, and
I think then everything will be groovy ;-)
If you want to get the clock demo running better, you might
hack a PeekMessage for Microwindows. Also, I haven't
been able to figure out why it draws on top of itself...
This also happens with the valuators dial control. I think
this might be related to the region clipping, I'm hoping.
Regards,
Greg
