Re: Does Freetype work best with gamma 2.2, and how does it interact with KDE gamma setting?

[Allan Sandfeld Jensen]

I would leave it at 1.0. Not sure what it is supposed to affect now though. It 
used to do something directly to the screen (to counter screen glare in bright 
sunlight for instance). Now it seems unresponsive/dead to me though. You 
should probably ask KDE/Plasma.

Allan

On Dienstag, 4. Mai 2021 12:33:54 CEST Rob wrote:
> Perhaps it's outside the scope of this mailing list, but in that case should
> I calibrate my monitor to a gamma of 1.7 to get the best text rendering?
> 
> On the other hand, this link indicates that a relative system gamma of "1.0"
> is equivalent to 2.2 on windows, so perhaps a monitor calibrated to 2.2 is
> actually correct.
> https://docs.kde.org/stable5/en/kgamma5/kcontrol/kgamma5/index.html
> (https://link.getmailspring.com/link/E256C570-0F27-4E81-8AF8-8EF045BB93CC@g
> etmailspring.com/0?redirect=https%3A%2F%2Fdocs.kde.org%2Fstable5%2Fen%2Fkgam
> ma5%2Fkcontrol%2Fkgamma5%2Findex.html&recipient=bGludXhAY2FyZXdvbGYuY29t)
> On May 4 2021, at 11:29 am, Allan Sandfeld Jensen <linux@carewolf.com> 
wrote:
> > Qt5 uses a gamma of 1.7 for text rendering on X11.
> > 
> > The KDE gamma slider is an effect on the whole screen, not how elements
> > are
> > blended together inside singular apps.
> > 
> > Not sure there is any other place we could read an expected gamma from on
> > Linux, the only other source is using real gamma from monitors EDID, but
> > that would result in a much higher gamma and lighter text, probably not
> > fitting user expectations. Though perhaps we ought to have a switch
> > allowing users to use real numbers instead of simulating traditional
> > mistakes.
> > 
> > Allan
> > 
> > On Dienstag, 4. Mai 2021 12:20:38 CEST Rob wrote:
> > > Ok, I understand.
> > > 
> > > I am using KDE so I guess qt5 is responsible for gamma correction (and
> > > probably assumes monitor is 2.2).
> > > 
> > > On May 4 2021, at 10:53 am, Werner LEMBERG <wl@gnu.org> wrote:
> > > > > But if it is correcting the gamma it must assume that my monitor has
> > > > > a certain gamma?
> > > > 
> > > > As Allan has written: FreeType does *not* interact with gamma at all!
> > > > If you want to be very precise you could say that FreeType doesn't
> > > > return bitmaps with color or grayscale pixels. Instead, it returns
> > > > *coverage* values (i.e., how much area of a pixel is covered by ink),
> > > > and the calling graphics library has to further process it. This
> > > > includes application of gamma correction.
> > > > 
> > > > 
> > > > Werner