[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
bug#28400: 26.0.50; lcms2 bindings
From: |
Eli Zaretskii |
Subject: |
bug#28400: 26.0.50; lcms2 bindings |
Date: |
Mon, 11 Sep 2017 18:01:45 +0300 |
> Date: Sun, 10 Sep 2017 18:04:22 -0400
> From: Mark Oteiza <mvoteiza@udel.edu>
> Cc: 28400@debbugs.gnu.org
>
> >Is it really so much better than what we have now to justify requiring
> >yet another library to build Emacs? If it is, could you tell what are
> >the main advantages, or point to where those advantages are described?
>
> It was just much easier for me to hack existing code than figure out adding
> a new file and the configure.ac business. It would be much more
> sensible to offer it as an optional feature and expose color metrics as
> optional arguments, e.g.
>
> (color-distance COLOR1 COLOR2 &optional FRAME METRIC)
>
> where METRIC accepts two colors and returns a number.
Oh, I see. But in that case, I think adding a new file and the
configure.ac business is actually quite easy. Search configure.ac for
"libz", and you will see a typical example: it involves adding a new
"--with-FOO" option to configure, and then some pretty boilerplate
code to test whether some tell-tale header file is present, and tweak
the compilation/linking flags accordingly. The new file then should
have all of its body wrapped in "#ifdef HAVE_FOO..#endif", with only
config.h outside of that condition and maybe some simple predicate to
test for the feature existence; see xml.c for a good example. Then
add that new file to src/Makefile.in, and you are pretty much done.
As for color-distance, did you intend to replace or provide a better
alternative to similar functions in color.el?
> >Btw, 256 colors is not "small" by Emacs standards, because our color
> >approximation should (and does) work in 8-color terminals as well.
>
> Yes, I should have used a different word than "small". Approximations
> for smaller palettes is easier because the differences between
> individual members of the palette are much bigger. The 256 color
> palette (and larger) has many colors much closer to one another, and
> calculating perceptual differences between colors that are close
> requires a more sophisticated model.
So you are saying that tty-colors.el is too simplistic for ncolors
around 256? If so, perhaps this optional feature could provide
compatible alternatives to that?
Thanks.