On Thursday 04 October 2001 11:10 pm, Mark Vojkovich wrote:
> On Thu, 4 Oct 2001, Davor Buvinic Gonella wrote:
> > Hi,
> >
> > I have a question with regards to gamma correction support in XFree86
> > that maybe someone in this mailing list can answer me.
> >
> > My problem comes when I change the gamma ramps using
> > XF86VidModeSetGammaRamp(). If after that I query about the gamma
> > correction value using XF86VidModeGetGamma() I get the last value set
> > with
> > XF86VidModeSetGamma(). The new ramp can have totally diferent gamma value
> > if, for example, I change the ramp to adjust not only this value but
> > brightness and contrast too. Or the gamma correction value can makes no
> > sense for a special ramp loaded in the LUT.
> >
> > What is the right way to handle this situation?
>
> Don't know. The Gamma value just doesn't make sense for
> such things. Maybe just ignore it or not report it (leave it
> greyed out or something) when it doesn't match the ramp?
>
>
I was thinking something like that as a solution for the control panel, but
maybe it can be do better:
Why not extend the XF86VidModeGetGamma() function? I would be nice if when I
set the ramps with XF86VidModeSetGammaRamp() a subsequent call to
XF86VidModeGetGamma() reports that the last change to the LUTs was made with
the former. Then I can be sure if the LUTs have a 'typical' gamma curve or
maybe another 'thing'.
Also, as with XF86VidMode{Get|Set}Gamma(), it's would be nice to have
something like XF86VidMode{Get|Set}Brightness and Contrast too.
My question is: worth the effort make such changes? Would you see some
application for this? I can code the changes to the functions if someone
from the developer team of XFree86 give me ideas about how the function
prototypes must lookalike, so I don't break other libraries that relies in
the VidMode extension. I know that SDL use the XF86VidMode{Set|Get}GammaRamp,
maybe Mesa too.
Davor
--
Davor Buvinic
[EMAIL PROTECTED]
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