Re: [Lcms-user] PDF ICCBased color space to RGB

[Dmitry S. <dar...@gm...>]

Hi, Derek.

It was quick!

Yes, this tutorial seems quite straightforward to me.
Thanks for reply.


Regards,

- Dmitry

On Mon, Oct 23, 2017 at 9:03 PM, Derek B. Noonburg <de...@gl...>
wrote:

> Hi Dmitry,
>
> The PDF stream associated with an ICCBased color space is an ICC
> profile.  You can pass that data to cmsOpenProfileFromMem (or
> cmsOpenProfileFromFile, etc.).
>
> Then create an RGB profile, e.g., with cmsCreate_sRGBProfile.
>
> Then create a transform with cmsCreateTransform.
>
> And finally, call cmsDoTransform to convert colors from the PDF color
> space to RGB.
>
> The LittleCMS tutorial
> (http://www.littlecms.com/LittleCMS2.8%20tutorial.pdf) has more detailed
> info on this.  That's probably a better place to start than the API
> Reference.
>
> - Derek
>
>
> On 2017 Oct 23, Dmitry Salychev wrote:
> > Hi, Little CMS users and developers.
> >
> > I just discovered the library and tried to find anything suitable about
> > converting color from one space to other in user manual. There are
> > functions like:
> >
> >         cmsSetColorSpace()
> >         cmsXYZ2Lab()
> >         cmsLab2XYZ()
> >
> > and similar ones. I should create/load a profile, specify color space and
> > feed one of these functions with, say, values for 3 components in
> ICCBased
> > color space to receive a simple RGB values, shouldn't I? I'm talking
> about
> > ICCBased because it's defined in a PDF file as a stream of data. I can
> > extract it and decode, however, I have no clue how to process 3 color
> > components of this space into a simple RGB color using this data.
> >
> > May you point me to a specific page in the manual or describe any details
> > I'm missing?
> > Thanks.
> >
> > Little CMS user manual: http://www.littlecms.com/LittleCMS2.8%20API.pdf
> (p.
> > 51, p. 54)
> > PDF 1.7 reference:
> > https://www.adobe.com/content/dam/acom/en/devnet/acrobat/
> pdfs/pdf_reference_1-7.pdf
> > (p. 252)
> >
> > Regards,
> >
> > - Dmitry
>
>
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