The Compiz ICC colour server, or short CompICC, lets you colour manage your whole desktop at once and in hardware. Play movies, watch images on wide or narrow gamut displays. Each connected monitor is colour corrected for its own.
CompICC is written to help the many colour management unaware applications. It takes them off any decision, what to do around monitor profiles. To do so CompICC does its work unquestioned in the compositing window manager. The result is a more consistent desktop.
CompICC follows the opt out colour correction paradigm. Colour management unaware applications can continue to assume they are drawing in sRGB. They do not need any ICC profile nor any new library to do so. sRGB is the standard colour space for the internet. There are some applications, which want to do own colour corrections for displaying large gamut photos, proofing or monitor calibration. Those need to tell CompICC not to colour correct certain regions of their windows. This means slightly more work for aware applications to do advanced colour management other than sRGB.
Technically CompICC uses GPU shaders and the well supported OpenGL extension 3D texture lookup. The lookup texture is generated using the Oyranos CMS.