hi ! can I find some configs to make desaturation/fade (like logout effect ) of desktop, persistanly?
something like the brightness effect in Terminology emulator ( Enlightenment)...

You can adjust brightness and gamma of X11, but not the saturation - though the nvidia driver has a proprietary setting called "digital vibrance" in "nvidia-settings" that effectively controls saturation.

It would be possible to write a compositor effect (simple glsl shader) to do this but that requires a running compositor and is a rather expensive solution.
=> Why do you want to change the saturation (do you actually at all, or just reduce the gamma?)

luebking wrote:You can adjust brightness and gamma of X11, but not the saturation - though the nvidia driver has a proprietary setting called "digital vibrance" in "nvidia-settings" that effectively controls saturation.

It would be possible to write a compositor effect (simple glsl shader) to do this but that requires a running compositor and is a rather expensive solution.
=> Why do you want to change the saturation (do you actually at all, or just reduce the gamma?)

i have Plasma 5.X ...and I just like the effect during the logout dialog...workspace/desktop behavior/desktop effects/logout (desaturate the desktop when displaying the logout dialog author:KWin development team)....its not just brightnes/gama , its the smooth dark edges and bright/regular center of display...the question is how can I use that effect on working desktop? is there effect for KWin or some command code for CLI ?
P.S. i have ATI/Radeon vcard

You'd have to write a persistent kwin effect that copies and uses the shader from the logout effect.
There's no way to invoke that directly, the logout effect waits for the logout window to appear - you'd have to fake such window, what's probably not a good idea.

In either case, it will require som C++ code.