Xlib voodoo XWidthOfScreen, etc

Jeremy Huddleston jeremyhu at freedesktop.org
Mon May 23 12:34:42 PDT 2011

Yeah, ok.  You know what happens when I assume... ;)

Looks like I need to do some XRRUpdateConfiguration magic in the WM.  Thanks.

On May 23, 2011, at 10:04, Jamey Sharp wrote:

> On Mon, May 23, 2011 at 12:30:03AM -0700, Jeremy Huddleston wrote:
>> I'm having some trouble understanding some of Xlib...
>> After changing resolution with RandR, all the following seem to report the new resolution properly:
>> $ xdpyinfo
>> $ xwininfo -root
>> $ xrandr
>> XineramaQueryScreens() called within my WM
>> however, XWidthOfScreen() and XHeightOfScreen() called from within my
>> WM still report the old resolution.
>> I was under the impression that the internals of Display and Screen
>> were updated "automagically" within Xlib.  Do I need to do something
>> to force the internals to update?
> The connection setup data, which includes per-screen widths and heights,
> is sent only when the connection is set up. Applications that need to
> know about changes to those values need to get RandR events.
> There could be magic in libXrandr to fiddle with the contents of the
> Display, but I'd be surprised... Especially since you'd still need to
> have called into that library to get the magic hooked up.
> Jamey

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