Great that you discuss colour management in Qt. Niels Ole Salscheider niels_ole at salscheider-online.de Thu Sep 22 12:45:35 CEST 2011:
> it might be a good idea to make QImage colorspace aware and add some > other color formats (like 30 bit or floating point formats). A 30-bit format will be from the point of keeping a 32-bit per pixel format ideal. But for linear images and colour management it might be too less. It is not the best editing format, as applications might want to route 30-bit to monitors but need headroom for compositing to avoid banding. Correct would be a full 16-bit per channel format, not only 10-bit per channel. Floating point is of course appreciated. > This might be useful for a fully color managed desktop environment, too. > I am not sure how this will work in wayland. Either the compositor > applies the color conversion (what happens if the client uses several > QImage with different colorspaces?) or it has to be done by the client > (it should use a shader to do so nevertheless). > How does it work on other platforms? The correct time for colour conversion is at blending time in the decided blending space. This can be sRGB or a linear blending space or whatever, but idealy not a device dependent colour space. For instance, compositing of a transparent CIE*Lab image over printer Cmyk or video Yuv and colour converting afterward blending from, I do not know which space to select, to a actual monitor space will result in garbage. Note the X Color Mangagement spec works because it assumes there is no blending involved. However the window manager can do compositing in monitor space like for transparent windows, which is kind of ok with very minor artefacts only. kind regards Kai-Uwe Behrmann -- developing for colour management oyranos-cms.blogspot.com oy@freenode#openicc _______________________________________________ Qt5-feedback mailing list [email protected] http://lists.qt.nokia.com/mailman/listinfo/qt5-feedback
