The last blog posts about KDE and colour management might have been irritating about what actual happens on colour managed desktops. Here come some clarifications and thoughts from the Oyranos CMS maintainer. The project name starts with Oy (Oyranos like sky), hence my nick oy on IRC
Colour Management Systems (CMS) are a precondition to do colour correction of input and output devices. But this is not sufficient for having a colour corrected desktop. The claim was made, that Gnome is the first colour managed desktop on Linux. But Gnomes window manger mutter has no means to use ICC profiles. The same is true for all other window managers with an exception of old Compiz. A CMS selects only the needed ICC profile and does the configuration in that field. But the background, applications like the dock and most others are not colour corrected by standard ICC profiles mechanisms in Linux. The only thing users can do since many years on Linux is to do monitor calibration setup per single channel. This helps for better grayscale, but not for compensating of colour gamuts. Calibration is only a first step, but not sufficient for ICC colour correction. So Gnome users have today no colour corrected desktop like all other Linux users.
What is needed to get to a End to End colour corrected desktop in KDE? A more general Overview can be found here.
- KWin needs ICC support, in order to colour correct the KDE desktop in a reasonable time frame. That will help with the output side in a fast way by using the GPU during compositing while using few resources. If you feel it is time to do something, here is a Google Summer of Code CM project idea for KWin. With my experience from the CompICC project, I would be glad to help any such project.
- An other project I would find really helpful is to provide colour correction to KDE’s primary image viewer gwenview. If people could help with a hackfest, that would be cool. We have such thing in mind and some ideas about, maybe you like to join us.
- Qt/KDE needs to explore how to do own fast colour correction of a complete window to be prepared for the future. Here are two project ideas.
- OpenICC did investigate to get print colour management right. There are currently two approaches who are promising. OpenICC has one project idea to introduce colour managed printing into Krita and one for user profile setup for colour managed print queues with KolorManager. These are two complementing, maintainable and robust paths for getting printing CM right.
Now some clarifications about Oyranos itself, as in the kde-planet where many wrong statements transported intermixed with half true claims.
- Core is a toolkit independent library
- KDE, Qt and FLTK front ends exist like KolorManager. Other native ones are possible.
- The Elektra API and library is used for format independent configuration DB access.
- Oyranos is planed to switch to a OpenICC JSON DB format to converge with ArgyllCMS and other interested CMS’es
- Oyranos is a cross platform project
- A DBus API would be welcome on top of the basic library but not in its core
- Oyranos forces no one to use the CPU or prohibit to use the GPU
- The CMS provides means to do optional multi monitor colour correction and other conversions.
- CompICC uses Oyranos and does colour correction on the GPU
- Oyranos developers belief in collaboration
- Self containment in Oyranos results from adhering to and work on interoperable standards.
- User configurations belong to users in Oyranos, so it needs no special root rights, which exposes security and privacy risks.
- Oyranos provides optional policies for grouping single settings. That is a additional feature not a limitation.
- Oyranos uses many advanced automatism’s to do it’s work successful
- The CMS is designed to work with default settings.
- Advanced manual configurations are supported and part of Oyranos’ user centrism.
- Oyranos cares about quality and requires a careful selected and peer reviewed profile set that comes with no Fakes and no wrong colorimetry.
- Licensing fits most open source and commercial projects with a newBSD style license.
Choice is a good thing for users. As a CMS author I have no problems, that an other CMS comes to KDE too on Linux. Many Linux CM standards I initiated or helped with allow for such interoperability, which is in the spirit of the ICC standard.