On Tuesday 17 July 2012 Jul, you wrote:
> What we presently have in a local branch is:
>
> 1) Grabbing embedded color profiles from PNG and JPEG images (eventually
> support for more formats will come)
That would be excellent.
> 2) Non-Automatic conversion of color profiles at load. This is done through
> the constructor, where when loading an image you specify weather you preserve
> the color profile or you convert to Screen. The default behavior keeps the
> loaded image unchanged.
Hm... I would prefer to be able to specify a working space here -- not just the
screen target. That makes it possible to use a linear rgb profile to convert to
real linear rgb and actually be able to do stuff with the pixels.
>
> What we don't have:
> 1) Exporting images with embedded color profiles
> 2) Modifying a color profile (access only to high level data such as
> description and colorspace)
>
> The API looks as follows:
>
> enum QColorSpace {RGB, CMYK, Invalid}
>
> QColorProfile
> -------------
> QString description()
> QColorSpace colorspace()
For my applications, I would also want to be able to get the original profile
data out of QColorProfile, btw.
Especially when using the QScreen api.
> QImage
> -------------
> QColorProfile colorProfile()
> void setColorProfile(colorProfile)
> void convertToColorProfile(colorProfile)
>
> QScreen
> -------------
> QColorProfile colorProfile()
>
> Windows and Mac OS X have built in support for color profile conversion. For
> linux X11 supports color profiles after loading several modules, otherwise
> uses sRGB. This is where the Oyranos project comes in.
On X11, you can use the X11 atom to check what the user has set -- that works
for both oyranos and colord managed desktops.
> All the color profile conversion takes place using the littleCMS library
> which seems to be sort of standard for that job. Oyranos is also using it.
yes, lcms2 is pretty much the standard. And it's small and excellent.
>
> ________________________________________
> From: development-bounces+alexandros.dermenakis=nokia....@qt-project.org
> [development-bounces+alexandros.dermenakis=nokia....@qt-project.org] on
> behalf of ext Boudewijn Rempt [[email protected]]
> Sent: Monday, July 16, 2012 9:15 PM
> To: [email protected]
> Subject: Re: [Development] Color Profile support on Qt
>
> On Monday 16 July 2012 Jul, Olivier Goffart wrote:
> > All QPainter operations (at least in the raster engine) assume a linear
> > color
> > space. That means that the color conversion need to hapen last, right before
> > being shown to the screen. After all kind of blending operations or anything
> > done with QPainter. (That means it could even been done in the platform
> > plugin)
>
> Are you really sure about that? It's extremely unlikely that one encounters a
> linear light rgb png file in the wild, for instance, most assume sRGB.
> Unmanaged RGB isn't automatically linear, either -- it most likely is just a
> mess.
>
> --
> Boudewijn Rempt
> http://www.valdyas.org, http://www.krita.org, http://www.boudewijnrempt.nl
> _______________________________________________
> Development mailing list
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> http://lists.qt-project.org/mailman/listinfo/development
>
--
Boudewijn Rempt
http://www.valdyas.org, http://www.krita.org, http://www.boudewijnrempt.nl
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