Handle pulse-background being nil

* lisp/cedet/pulse.el (pulse-lighten-highlight): Inherit
pulse-background, handle it being nil.

1 files changed, 22 insertions, 19 deletions

diff --git a/lisp/cedet/pulse.el b/lisp/cedet/pulse.el
index 39ba13c33df..dea73a06e2a 100644
--- a/lisp/cedet/pulse.el
+++ b/lisp/cedet/pulse.el
@@ -131,25 +131,28 @@ Return t if there is more drift to do, nil if completed."
   (if (>= (get 'pulse-highlight-face :iteration) pulse-iterations)
       nil
     (let* ((frame (color-values (face-background 'default)))
-           (start (color-values (face-background
-                                 (get 'pulse-highlight-face
-                                      :startface)
-                                 nil t)))
-           (frac  (list (/ (- (nth 0 frame) (nth 0 start)) pulse-iterations)
-                        (/ (- (nth 1 frame) (nth 1 start)) pulse-iterations)
-                        (/ (- (nth 2 frame) (nth 2 start)) pulse-iterations)))
-           (it (get 'pulse-highlight-face :iteration))
-           )
-      (set-face-background 'pulse-highlight-face
-                           (pulse-color-values-to-hex
-                            (list
-                             (+ (nth 0 start) (* (nth 0 frac) it))
-                             (+ (nth 1 start) (* (nth 1 frac) it))
-                             (+ (nth 2 start) (* (nth 2 frac) it)))))
-      (put 'pulse-highlight-face :iteration (1+ it))
-      (if (>= (1+ it) pulse-iterations)
-          nil
-        t))))
+           (pulse-background (face-background
+                              (get 'pulse-highlight-face
+                                   :startface)
+                              nil t)));; can be nil
+      (when pulse-background
+        (let* ((start (color-values pulse-background))
+               (frac  (list (/ (- (nth 0 frame) (nth 0 start)) pulse-iterations)
+                            (/ (- (nth 1 frame) (nth 1 start)) pulse-iterations)
+                            (/ (- (nth 2 frame) (nth 2 start)) pulse-iterations)))
+               (it (get 'pulse-highlight-face :iteration))
+               )
+          (set-face-background 'pulse-highlight-face
+                               (pulse-color-values-to-hex
+                                (list
+                                 (+ (nth 0 start) (* (nth 0 frac) it))
+                                 (+ (nth 1 start) (* (nth 1 frac) it))
+                                 (+ (nth 2 start) (* (nth 2 frac) it)))))
+          (put 'pulse-highlight-face :iteration (1+ it))
+          (if (>= (1+ it) pulse-iterations)
+              nil
+            t)))
+      )))
 
 (defun pulse-reset-face (&optional face)
   "Reset the pulse highlighting FACE."