Re: Frame background mode

[Juri Linkov <juri@jurta.org>]

Luc Teirlinck <teirllm@dms.auburn.edu> writes:
> Juri Linkov wrote:
>    +		   (>= (+ (* (nth 0 bg-color-values) 0.30)
>    +			  (* (nth 1 bg-color-values) 0.59)
>    +			  (* (nth 2 bg-color-values) 0.11))
>
> Where did you get the .30 .59 .11 from?

When I looked at different colors in the GIMP color selector,
I noticed that the graphical marker changes its color to black
on light colors, and to white on dark colors.  Then I looked
at the GIMP source code for its idea about color intensity and
found that it uses these numbers.

But these coefficients were not invented by GIMP authors, of course.
They are scientifically measured weightings that reflect the relative
sensitivity of human vision to red, green, and blue.  These numbers
work for the average person who didn't change the default relative
brightness of monitor color components.  That is why they are good
for the default formula.

The strongest argument so far to not change the formula now is that it
will change background modes for some users.

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