Skip to content

Revert "Use the window system's color transform matrix, when available"

Sebastian Wick requested to merge swick/gnome-settings-daemon:ctm-revert into master

This reverts commit e90a75fd.

This approach has three problems which unfortunately can't be fixed:

  1. Applying the profile means color managed applications may not apply the profile. Setting the X11 _ICC_PROFILE atom to sRGB only works as long as the application actually uses the atom, and only the atom. If the app uses colord to fetch the profile or the user manually selects the correct display ICC profile the CTM gets applied twice.

  2. The CTM seems to correspond to a relative colorimetric intent. There is other intents (ways to do the color correction) which an app now can't provide.

  3. This assumes all content is sRGB (and if all color managed apps would use the sRGB profile that would have been a valid assumption) so it's impossible to represent anything outside that sRGB gamut whereas previously color managed apps were able to use the whole display gamut.

Essentially, if you want this behavior you can calibrate the display to sRGB (using the profile VCGT tag which gets loaded into the CRTC GAMMA LUT) and then it would work correctly with color managed apps (but still with limited gamut).

@aaronp24 @bberg

Merge request reports