Re: [Lcms-user] ver 1.12 release candidate

[Marti M. <ma...@li...>]

Hi

I've managed to set correct permissions. Seems latest versions of Cygwin does support atributtes too. So, many thanks for point this
out.

Regarding floating point, I really appreciate any contribution. But I'm afraid this would be a bit dangerous :-)

Please note than changing mode from assembler to floating point does result in nothing but a general slowdown.
There was a lot of work to assure fixed and floating point math were giving same results, so, you will not get any extra precission
by compiling in floating point mode. All will work same, but slower. The floating point mode is intended as a way to describe
algorithms. Then, the optimized version of these algorithms is provided for speed. Donald E.Knuth said "premature optimization is
the source of all evil" so, I keep original algorithms under USE_FLOAT compilation mode. Just for clarity sake. The accurancy of
lcms is 16 bit, a lot more than strictly needed, which would be 11-12 bit at most.  You can still use TYPE_RGB_DBL, etc. despite the
engine are using fixed point.

Thanks again!
Regards,
Marti Maria
The little cms project
http://www.littlecms.com
ma...@li...


----- Original Message ----- 
From: "Kai-Uwe Behrmann" <we...@ti...>
To: "Marti Maria" <ma...@li...>
Cc: "Lcms-User" <lcm...@li...>
Sent: Wednesday, December 03, 2003 11:36 AM
Subject: Re: [Lcms-user] ver 1.12 release candidate


Hi Marti,

I attached an patch to the current 1.12 candidate.
It introduces an switch for configure to decide which kind of
optimization/precission should be compiled in.
Cinepaint will need float precission for its upcoming cms. Hope it
works correctly and You like to include it. Tested on linux.

files changed:
configure         -- reprocessed with autoconf
configure.ac      -- the main part
include/lcms.h    -- USE_ASSEBMLER out commented

regards
Kai-Uwe


Am 29.11.03, 16:15 +0100 schrieb Marti Maria:

> Hi,
>
> >configures/compiles without problems. Displaying is ok.
>
> Many thanks for the testing!
>
> >Would it be possible to change the file permissions? They are nearly
> >all set to executeable. Only configure and the other scripts would need
> >this flag been set.
>
> Oh, the old problem again. Well, I could try to do the tarball on a true linux
> machine ... but is this really necessary?
>
> >An further question I like to ask:
> >When does You think will floating point calculations get introduced in
> >lcms? In preperation of this: Are there any thoughts about how to handle
> >values of over paper white? This would be interessting for HDR scenes.
>
> Floating point support is already implemented. If you mean floating point
> as the internal way to make calculations, just use the USE_FLOAT toggle
> on lcms.h
>
> If you mean to pass floating point values to the color transform, take a look
> on the specifiers:
>
> TYPE_RGB_DBL
> TYPE_CMYK_DBL
> TYPE_Lab_DBL
> TYPE_XYZ_DBL
> TYPE_GRAY_DBL
>
> These are using double values instead on encoded ones. Of course at speed cost.
>
> >In preperation of this: Are there any thoughts about how to handle
> >values of over paper white? This would be interessting for HDR scenes.
>
> Well, this is largely left to the profile side. ICC spec doesn't allow highlights
> on Lab PCS with L* > 100, but nothing prevents you to build a profile
> on, say XYZ, that use Y > 100. Remember a CMM is really a "dumb"
> interpolation engine that knows nothing about the colorspace being handled.
> If you build a profile capable to handle highlights, the CMM will then
> understand highlights. I must add I've not seen any profile with such behavior,
> but it is theoretically possible.
>
>
> Best regards, and thanks again for the testing.
> Marti Maria
> The little cms project
> http://www.littlecms.com
> ma...@li...
>
>
>
>
> ----- Original Message -----
> From: "Kai-Uwe Behrmann" <we...@ti...>
> To: "Marti Maria" <ma...@li...>
> Cc: "Lcms-User" <lcm...@li...>
> Sent: Wednesday, November 26, 2003 8:19 PM
> Subject: Re: [Lcms-user] ver 1.12 release candidate
>
>
> Marti,
>
> Am 26.11.03, 18:40 +0100 schrieb Marti Maria:
>
> > I've posted the 1.12 release candidates in site:
> >
> > http://www.littlecms.com/lcms112.zip
> > http://www.littlecms.com/lcms-1.12.tar.gz
>
> configures/compiles without problems. Displaying is ok.
> Would it be possible to change the the file permissions? They are nearly
> all set to executeable. Only configure and the other scripts would need
> this flag been set.
>
> An further question I like to ask:
> When does You think will floating point calculations get introduced in
> lcms? In preperation of this: Are there any thoughts about how to handle
> values of over paper white? This would be interessting for HDR scenes.
>
> Many thanks
> Kai-Uwe Behrmann
>