Provided by: freetype2-demos_2.11.1+dfsg-1ubuntu0.3_amd64 

NAME
ftgamma - screen gamma calibration helper
SYNOPSIS
ftgamma
DESCRIPTION
The ftgamma demo program opens a window showing series of gray stripes filled with solid color and
checkered pattern of pixels. Your monitor's gamma value roughly corresponds to the horizontal position
where the solid and checkered stripes are equally bright when seen from some distance. Three brightness
targets are explored: 33%, 50%, and 67%. If the input-output curve of your monitor does not follow ideal
power law relationship, you might observe slightly different gamma values at different brightness levels.
It is also possible to examine gamma values for basic colors.
Two alternative patterns relevant to font rendering are also provided, where slightly slanted lines are
rendered using grayscale and subpixel anti-aliasing. In the grayscale case, the correct gamma helps to
achieve uniform perceived thickness of the lines. The gamma value that corresponds to vanishing moiré
pattern is ideal for anti-aliased font rendering. In the subpixel case, the correct gamma removes color
fringes that remain even after LCD filtering.
This program does not have any options.
This program is part of the FreeType demos package.
FreeType 2.11.1 December 2021 FTGAMMA(1)