[Openicc] Questions about color pickers and graphics libraries under LINUX

[Kai-Uwe Behrmann]

Am 31.01.08, 12:20 +0100 schrieb Jan-Peter Homann:

> The openICC mailinglist is the worldwide only forum / place I have seen 
> in the last 15 years, where developers of buth OS, applications and 
> printer drivers discuss about colormanagement and also some consultants 
> / users give their input. Here I see the potential of a much better 
> colormanagement integration between OS, apps and printer drivers as in 
> Windows or Mac OSX...

As stated from many sides, with less developers working on pure 
colour management projects has to widen very much.
 
> I would be pleased, if somebody would explain to me the actual state of 
> color(management) implementation in KDE, Gnome and 2D graphics libraries 
> according my following questions:
> 
> Color picker on OS level:
> --------------------------
> - Which color picker projects on OS level exist ? (name / url)
> - Which kind of colorspaces are supported in the colorpickers:
>     - RGB
>     - Gray
>     - CMYK
>     - Lab
>     - Spotcolors (described by name, Lab-value, alternative sRGB-value)
> - Do this colorpickes support ICC-profiles for the colorspaces ?
> - Do this colorpickers can make use of a monitor profile ?
> - What desktops can make use of this colorpicker ?

The Create project has a target on a colour list file format. Once the 
format is specified and implemented, this could become a coach to share 
such information.

Oyranos provides in a next release a oyNamedColour object, which holds
XYZ and native channels. It can be used to specify and convert between 
arbitrary colours. It is currently used for colour lists. I hope to be 
able to support the Create colour format once it is released.

A ICC profile is required in both named colour paths.

The place can then be discussed. Probably it can be some X11 atom.

Personally I am not aware of a existing shared colour picker.


> 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
>     - 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
> - Which general colorspaces are supported in the graphics library:
>     - RGB
>     - Gray
>     - CMYK
>     - Lab
>     - Spotcolors (described by name, Lab-value, alternative sRGB-value)
> - What desktops can make use of this 2D graphics libray ?

Cairo has support for many of the basic stuff including the export to PDF.
It is currently 8-bit RGB, or say sRGB and deployed in Mozilla, Gnome/GTK 
and wherever a application uses Cairo directly.

Supporting higher bit depths and CMYK in Cairo could be discussed as a 
this years Google Summer of Code (GSoC) project. To find good students for 
colour projects was not so easy last year.
 
> (For getting first steps beyond RGB-only, it would make support also 
> gray and CMYK in a way, that all objects of a file (images, vector 
> graphics, fonts) must be in the same colorspace with only one 
> icc-profile assigned to the whole file. This would allow easy 
> rasterization without any color transformation. Colormanagement to the 
> display or for print output is applied to the rasterized file.

What would be a good alpha blending colour space? linear XYZ or ECIv2
or simply the actual editing colour space?

> If e.g. the graphics library would support CMYK and PDF export, it would 
> be easily to create files for the graphics arts users.
> 
> It would be nice, to hear whats going on in the LINUX world
> 
> Regards
> Jan-Peter

kind regards
Kai-Uwe Behrmann
--
developing for colour management 
www.behrmann.name + www.oyranos.org