Re: [Lcms-user] Serializing CIELab to buffer

[Aaron B. <bo...@gm...>]

Thanks, Noel, I will do that.

Another question: there seems to be two ways of defining the CIELab
profile, a default profile
and also a custom profile determined by the 7 values stored in the JP2 file.

The logic is:

        int row[9];
        if(default_type == 0x44454600) { /* DEF : default */
            rl = 100;
            ra = 170;
            rb = 200;
            ol = 0;
            oa = pow(2, prec1 - 1);
            ob = pow(2, prec2 - 2) +  pow(2, prec2 - 3);
        } else {
            rl = row[2];
            ra = row[4];
            rb = row[6];
            ol = row[3];
            oa = row[5];
            ob = row[7];
        }

For the custom profile, can I get LCMS to save this into a single buffer?

Thanks a lot,
Aaron



On Fri, Feb 9, 2018 at 8:43 AM, Noel Carboni <
NCa...@pr...> wrote:

> Look into the cmsSaveProfile.... functions.
>
>
>
> By the way (for Marti) there's a typo in the documentation for
> cmsSaveProfileToMem; "guareanteed" should be "guaranteed".
>
>
>
> -Noel
>
>
>
> *From:* Aaron Boxer [mailto:bo...@gm...]
> *Sent:* Fri, February 9, 2018 8:33 AM
> *To:* lcm...@li...
> *Subject:* [Lcms-user] Serializing CIELab to buffer
>
>
>
> Hello Everyone,
>
> I have a JPEG 2000 image with a stored CIELab color profile.
>
> This profile is determined by 7 32 bit values.
>
> My code currently uses LCMS to apply the profile to the image before
> decoding to TIFF.
>
> I would prefer to store this color profile in the TIFF image.
>
> I can do that if I can serialize the profile into a buffer of bytes.
>
> I am using LCMS to apply the CIELab as follows:
>
>         cmsHPROFILE in = cmsCreateLab4Profile(nullptr);
>         cmsHPROFILE out = cmsCreate_sRGBProfile();
>         cmsHTRANSFORM transform =
>             cmsCreateTransform(in, TYPE_Lab_DBL, out, TYPE_RGB_16,
> INTENT_PERCEPTUAL, 0);
>
>
>
> and then applying the transform to each pixel.
>
> Is there a way of serializing this profile to a memory buffer, so that I
> can store it in the TIFF file?
>
>
>
> Thanks so much,
>
> Aaron
>
>
>
>
>
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