lcms-user

[Lcms-user] Serializing CIELab to buffer

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

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

Re: [Lcms-user] Serializing CIELab to buffer

[Noel C. <NCa...@Pr...>]

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

 

 

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
>
>
>
>
>
> ------------------------------------------------------------
> ------------------
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> _______________________________________________
> Lcms-user mailing list
> Lcm...@li...
> https://lists.sourceforge.net/lists/listinfo/lcms-user
>
>

Re: [Lcms-user] Serializing CIELab to buffer

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

Alright, I now get it : these are the range and offset values for the L,a
and b coordinates in Lab space;
the first block sets the values for Lab space with default illuminant D50.
The second block
is for a non-default Lab space (Jab space, for example ?)

On Fri, Feb 9, 2018 at 9:10 AM, Aaron Boxer <bo...@gm...> wrote:

> 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 <NCarboni@prodigitalsoftware.
> com> 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
>>
>>
>>
>>
>>
>> ------------------------------------------------------------
>> ------------------
>> Check out the vibrant tech community on one of the world's most
>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
>> _______________________________________________
>> Lcms-user mailing list
>> Lcm...@li...
>> https://lists.sourceforge.net/lists/listinfo/lcms-user
>>
>>
>