[argyllcms] Re: Dispwin vs. xscreensaver
- From: Geoff Kuenning <geoff@xxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 03 Mar 2015 00:14:46 -0800
Thanks, Graeme! That does indeed help.
(Now all I have to do is find time to write an xscreensaver patch, since
I probably can't talk Jamie Z into doing it.)
> Geoff Kuenning wrote:
>
> Hi,
>
>> It appears that on modern RandR setups, dispwin uses XRRSetCrtcGamma to
>> set the gamma curve. However, xscreensaver uses XF86VidModeGetGammaRamp
>> to read the current gamma, and the XF86VidModeSetGammaRamp to perform a
>> fadeout. Unfortunately, it seems that GetGammaRamp doesn't return the
>> ramp set by SetCrtcGamma. So the SetGammaRamp works like "dispwin -c".
>
> Right.
>
>> My feeling is that this is either an X server bug (on the theory that
>> the two interfaces should be compatible) or an xscreensaver bug (on the
>> theory that it should use SetCrtcGamme if it's available. But I also
>> think that I'm more likely to find the necessary expertise on this list,
>> so I'm starting here.
>
> Both theories have merit. In practice though, XRandR is pretty fundamental
> to a modern X11 server, while XF86VidModeSetGammaRamp is part of the
> XVidMode extension. So to make these two be consistent implies
> making the XVidMode extension XRandR aware. I would guess that
> the XVidMode extension is tweaked with each HW implementation,
> and is in a "legacy maintanence" mode with the arrival of XRandR,
> so getting this updated would seem to be hard.
>
> xscreensaver on the other hand, is a stand alone application
> that (presumably) is still being maintained, so I think that
> making it XRandR aware would be the appropriate and practical
> fix.
>
> Hope that helps,
>
> Graeme Gill.
>
--
Geoff Kuenning geoff@xxxxxxxxxx http://www.cs.hmc.edu/~geoff/
"Du kannst dem Leben nicht mehr Tage geben, aber den Tag mehr Leben."
-- Anonymous
(You can't give your life more days, but you can give your days more life.)
Other related posts:
