Improve documentation

[gnu-emacs-elpa] / beacon.el

diff --git a/beacon.el b/beacon.el
index 6433ba054505d1eb2fcd022c8b5ab3d4454db2d5..ffdbcbc3b63821ea841747b9edafeff02b2c6575 100644 (file)
--- a/beacon.el
+++ b/beacon.el
@@ -103,6 +103,13 @@ If it is a string, it is a color name or specification,
 e.g. \"#666600\"."
   :type '(choice number color))
 
+(defface beacon-fallback-background
+  '((((class color) (background light)) (:background "black"))
+    (((class color) (background dark)) (:background "white")))
+  "Fallback beacon background color.
+Used in cases where the color can't be determined by Emacs.
+Only the background of this face is used.")
+
 (defvar beacon-dont-blink-predicates nil
   "A list of predicates that prevent the beacon blink.
 These predicate functions are called in order, with no
@@ -221,7 +228,10 @@ Only returns `beacon-size' elements."
 
 (defun beacon--color-range ()
   "Return a list of background colors for the beacon."
-  (let* ((bg (color-values (face-attribute 'default :background)))
+  (let* ((default-bg (face-attribute 'default :background))
+         (bg (color-values (if (string-match "\\`unspecified-" default-bg)
+                               (face-attribute 'beacon-fallback-background :background)
+                             default-bg)))
          (fg (cond
               ((stringp beacon-color) (color-values beacon-color))
               ((< (color-distance "black" bg)