Re: Diff mode faces

[Juri Linkov <juri@jurta.org>]

>> Something has to be done about colors of diff context, because
>> currently it is white on black for dark backgrounds, and yellow
>> on white for light backgrounds.
>
> The diff-mode colors on a dark-background terminal (gnome-terminal or
> generic xterm) are:
>
>    Changed lines:  yellow+bold on black
>    Context:            white/grey on black
>    Headers:          green/blue+bold on black
>
> These colors work very well and should not be changed

Bold text is unreadable on terminals with small fonts.

> On the other hand, I find the terminal _light-background_ colors
> almost unreadable.  Certainly the "bold yellow" foreground used in
> headers is absurd on a white background.  In general changed
> foreground colors seem to work less well against a light background
> (perhaps because most terminal colors are fairly bright and don't
> contrast well against a white background) so perhaps it would be
> better to use the default [black] foreground for the context/changed
> text, and rely on making the changed lines bold.

The changed lines is the base text which users mostly read in the
diff-mode, so it makes sense not to highlight it at all and to use the
default foreground.  Most other modes do the same and don't highlight
normal text.  As for the context lines, to distinguish them from the
changed lines, dark-background terminals could use yellow-on-black,
and light-background terminals - maybe, green.

-- 
Juri Linkov
http://www.jurta.org/emacs/