Hi,

> How is the value range of the float Lab's?
> What should I deliver to cmsDoTransform()?

The range of Lab as given by cmsCreateLabProfile() is :

CIELAB (16 bit)     L*            0 -> 100.0          0x0000 -> 0xff00
CIELAB (16 bit)     a*            -128.0 -> +127.996  0x0000 -> 0xffff
CIELAB (16 bit)     b*            -128.0 -> +127.996  0x0000 -> 0xffff

This is the encoding used by icc profiles prior to ver 4. Please note that the
encoding on 16 bits is hardly profile dependent. For example, the TIFLab8
profile does not use this scheme.

If you want to encode/decode float values, you can do in two ways:

- using TYPE_Lab_16 and then cmsLabEncoded2Float() / cmsFloat2LabEncoded(),

or

- using TYPE_Lab_DBL and feeding the transform directly with double values. (this only
works on ver 1.10)


> By the way lcms seems fast enough for displaying. Congratulation.

:-) Thanks for let me know

Regards,
Mart� Maria
The little cms project
http://www.littlecms.com
[EMAIL PROTECTED]



----- Original Message -----
From: "Kai-Uwe Behrmann" <[EMAIL PROTECTED]>
To: "Mart� Maria" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Thursday, February 06, 2003 12:22 PM
Subject: Re: [Lcms-user] Are the types right here?


> Hi,
> How is the value range of the float Lab's?
> What should I deliver to cmsDoTransform()?
>
> double[3] Lab; //   L = 0..100
> //   a = -0.5 - 0.5 / -127.0 - +127.0
> //   b = -0.5 - 0.5 / -127.0 - +127.0
>
> (Internally I have to store all three samples as floats 0.0 - 1.0 .)
> By the way lcms seems fast enough for displaying. Congratulation.
>
> regards
> Kai-Uwe
>
>
>



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