RE: Emacs Survey: Toolbars

[Drew Adams]

> > > Do you have suggestion for automatically computing "it's not too hard"
> > > color mapping for "inverse video" "pure" text?
> >
> > Convert the color's YUV and invert the Y.
> 
> Possibly better: keep the hue and saturation and recalculate luminance
> to preserve the relative contrast to background color.

There are lots of ways to "invert" or complement a color.

I just use RGB complementing - good enough for most
purposes for Emacs foregrounds and backgrounds.  Function
`color-complement' in color.el does that.  So does
`hexrgb-complement' in hexrgb.el.

Or I use `hexrgb-hue-complement',
`hexrgb-saturation-complement', or `hexrgb-value-complement'
If I just want to complement one of those components.