Re: vc-annotate error, PATCH

[JD Smith <jdsmith@as.arizona.edu>]

On Tue, 11 Apr 2006 12:57:23 -0400, Richard Stallman wrote:

>     To address this, I created a new colormap with 18 entries which fixes
>     saturation at 70%, value at 100%, and rotates from red to blue in
>     equal angle ~14 degree increments of hue.  The saturation of 70% keeps
>     the text light enough to be readable on the default black background,
>     but still usable on a white background.
> 
> How well does it work on a tty?

I hadn't thought of that, but tried and it does a reasonable job.
Less dynamic range in the yellow-green regime, but that is expected
given the small number of colors TTY's support. Here is a side by side
screen shot comparing the X11 vs. terminal annotations of the same
file:

 http://turtle.as.arizona.edu/emacs/annot_color.png

The only drawback is that green doesn't seem to get used much, with
yellow showing up instead for many colors.  I believe this is a
function of how substitute color are approximated, and the 70%
compromise saturation I use (although increasing this doesn't really
help that much).

Is there a canonical set of RGB values that terminals typically can
display?  Perhaps I could tune the map to spread out among the 5
colors more, but at some point you start sacrificing readibility on
full color displays, and over-relying on the algorithm for color
substitution.  Another option: is it possible or desirable to have a
separate color map for TTYs?  I could envision just using all the TTY
colors except the background color, in the order they are presented
from red to blue (now all but magenta are used).  May be more trouble
than it's worth.

JD