Function: shr-color-check

shr-color-check is a byte-compiled function defined in shr.el.gz.

Signature

(shr-color-check FG BG)

Documentation

Check that FG is visible on BG.

Returns (fg bg) with corrected values. Returns nil if the colors that would be used are the default ones, in case fg and bg are nil.

Source Code

;; Defined in /usr/src/emacs/lisp/net/shr.el.gz
(defun shr-color-check (fg bg)
  "Check that FG is visible on BG.
Returns (fg bg) with corrected values.
Returns nil if the colors that would be used are the default
ones, in case fg and bg are nil."
  (when (or fg bg)
    (let ((fixed (cond ((null fg) 'fg)
                       ((null bg) 'bg))))
      ;; Convert colors to hexadecimal, or set them to default.
      (let ((fg (or (shr-color->hexadecimal fg)
                    (frame-parameter nil 'foreground-color)))
            (bg (or (shr-color->hexadecimal bg)
                    (frame-parameter nil 'background-color))))
        (cond ((eq fixed 'bg)
               ;; Only return the new fg
               (list nil (cadr (shr-color-visible bg fg t))))
              ((eq fixed 'fg)
               ;; Invert args and results and return only the new bg
               (list (cadr (shr-color-visible fg bg t)) nil))
              (t
               (shr-color-visible bg fg)))))))