twm and intel dual head using xrandr
Eeri.Kask at inf.tu-dresden.de
Tue Jun 10 05:12:40 PDT 2008
Hugo.Jacques at verint.com:
> The only problem I have is that the top left corner of each of
> my windows always end up on my first screen when I try to move
> them on my secondary screen.
> I am using 1280x768 resolution on my first screen and 1024x768
> on my second one. My Virtual screen size as set in Xorg.conf
> is 2048x2048. I am using TWM.
> Would that be a TWM limitation? (I could not find anything
> while searching the web)
Not having recent enough hardware which is supported by xrandr dynamic
screen management nevertheless let me explain what twm-1.0.4 probably does.
During startup the screen width/height are detected by
functions and any further access to the screen size is done by reading
these values saved during startup. Next, if one tries to put a window
to the far right or bottom off screen (there is no test in respect to
top/left screen edges in the twm code though), i.e. having the window
top/left corner beyond one of the values above, the corresponding
coordinate of the window origin is shifted "back", resulting in being
slightly "on screen".
Now if during runtime the X server or whoever decides to enlarge/shrink
the screen, i.e. any further executing of the above functions would
return greater/smaller values, the twm's knowledge about the screen size
is not updated. (Probably manually checking by 'xdpyinfo' would
disclose any X11-screen size change?)
Recently I added Xinerama support to twm, download the script
and run this, this downloads the Xorg twm-1.0.4 sources, a smaller patch
set (www1.inf.tu-dresden.de/~ek1/twm-1.0.4-tweaked-diffs.tar) and
compiles a twm with Xinerama support included.
Not surprisingly twm's internal architecture does not manage screens
"dynamically" (even does not favor such management) and a major code
redesign in that respect does not make that much sense (to me).
For now it is much easier to catch the RRScreenChangeNotify event and
then automatically execute f.restart: so if you put
'RestartOnScreenChangeNotify' into .twmrc then XRANDR minimalistic
support in twm is activated in form of this small feature. Beware, all
'zoomed' windows are unzoomed first, as their unzoomed size/position
would not survive f.restart otherwise.
(The patchset includes a .twmrc with other twm novel features as well.)
If starting twm with '-xinerama' then the geometrical tile arrangement
is not scanned by XineramaQueryScreens() but with
XRRGetScreenResources() and by successive XRRGetCrtcInfo(); and if given
'-v' the detected arrangement is printed to the screen on startup.
As I am not in position to investigate your issue due to lack of
hardware, I am very glad if you could help me carry out some
'experiments' if problems exist with the above applied patches.
P.S. In the iconmanager I corrected thousand bugs and introduced one
which I am currently chasing, so the painting in rare cases in
SloppyFocus mode paints kind of too much; don't be surprised. :-) :-)
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