Re: [Lcms-user] Device space float ranges

[<mar...@li...>]

Hi,

Problem is if I change this 100 scaling, I break photoshop notation, and many people is using that.

A neat solution would be writing a formatter plug-in to replace double encoding to the scale you need.  You could copy & paste the formatters code you want to change from cmspack.c and modify it.

You probably not need all the variants, so you could simplify the code and get some throughput boost.
See some examples on plug-ins manual, "Formatters plug-in"

Regards
Marti Maria
The LittleCMS Project
https://www.littlecms.com



> -----Original Message-----
> From: John Jefferies via Lcms-user <lcm...@li...>
> Sent: Thursday, May 4, 2023 2:13 PM
> To: lcm...@li...
> Subject: [Lcms-user] Device space float ranges
> 
> Hello Marti,
> I have a system where all colour spaces are device spaces (PT_GRAY, PT_RGB,
> PT_CMYK, PT_MCH*), and all colour values are floats in the range of 0-1. I
> therefore need a formatter to handle this, so I use this
> formatter:
>      cmsFormatterForColorspaceOfProfile(hProfile, sizeof(float), TRUE)
> 
> It appears that lcms assumes that the client's float colour values are in the
> range 0-100 if colour space is an IsInkSpace(). The problem then becomes
> how to marshal my float values into and out of lcms. It appears that in client
> code, I have to ensure the values are *100 or /100 as appropriate if the colour
> space I have is an ink space.
> 
> For my purposes, that's a bit daft. Firstly, IsInkSpace() isn't an exported
> function so the client code has to duplicate the function itself. Secondly, it's
> rather inefficient. Thirdly, the client code is uglier than it needs to be. Finally,
> the assumed range of 0-100 isn't documented anywhere that I could find;
> apologies if it is somewhere blindingly obvious.
> 
> Is there any other way to use float values in the range 0-1?
> 
> Regards + many thanks
> John
> 
> 
> 
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