shr-color-visible

shr-color-visible is an autoloaded compiled Lisp function in `shr-color.el'.

(shr-color-visible BG FG &optional FIXED-BACKGROUND)

Check that BG and FG colors are visible if they are drawn on each other.
Return (bg fg) if they are. If they are too similar, two new
colors are returned instead.
If FIXED-BACKGROUND is set, and if the color are not visible, a
new background color will not be computed. Only the foreground
color will be adapted to be visible on BG.