[Openicc] Questions about... QT and colormanagement

[Jan-Peter Homann]

Hello Cyrill, hello list,
Did I understand, that QT is able e.g. to handle Images and 
Vectorgraphics in the CMYK colorspace and to rasterize an esemble of 
this objects to a CMYK bytemap file. (Same as for RGB).

Would it be e.g. possible to create some kind of " virtual output 
device" for QT Which buffers the rasterized bytemap. For displaying the 
virtual bytemap on the monitor, a source profile is assigned to the 
bytemap and from this it will be transformed to the monitor profile.
For printing the bytemap, we would have a similar workflow.
For PDF export, the assigned profile would be embedded as PDF/X output 
intent.

In Oyranos we could make e.g. different colorsettings, which define, 
what source profile will be assigned to the virtual output device from 
QT and the monitor profile. As littleCMS should be quite fast in 
transformimg bytemaps, this could may be a way for adding some basic 
colormanagement to QT and all applications, which are making use of the 
graphics library from QT.

How much work would it be to realize such kind of basic colormanagement 
on top of QT ?

By the way, are there any color pickers, which make use of the RGB, Gray 
and CMYK colorspaces of QT ?

Regards
Jan-Peter


Cyrille Berger wrote:
>
>> 2D graphics libraries on OS level (name and URL)
>> ------------------------------
>> - Which 2D graphics libraries exist on OS level, which deliver following
>> functionalities:
>>     - representing pixel images, vector graphics and fonts
>>     
> A lot, among which the most famous are Qt, Cairo.
>
> For fonts, everyone use the FreeType library.
>
>   
>>     - rasterizing a file containing images, vectorgraphic and fonts to a
>> bytemap image (for display, print, file export)
>>     - exporting a file containing images, vectorgraphic and fonts as PDF
>>     
> Well the above mentioned libraries do that.
>
>   
>> - Which general colorspaces are supported in the graphics library:
>>     - RGB
>>     - Gray
>>     - CMYK
>>     - Lab
>>     - Spotcolors (described by name, Lab-value, alternative sRGB-value)
>>     
> Can't say for Cairo, but Qt accept to take values in RGB, Gray and Cmyk. Not 
> sure about the internal logic, but as there is no profile it's not that 
> usefull anyway.
>
>   
>> - What desktops can make use of this 2D graphics libray ?
>>     
> All.
>
>
>
>   


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