master babfb064c4 1/2: Make string-pixel-width slightly speedier

[Lars Ingebrigtsen]

branch: master
commit babfb064c48e621ab7ad43b380ed1fdb0a6904a8
Author: Lars Ingebrigtsen <larsi@gnus.org>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Make string-pixel-width slightly speedier
    
    * lisp/emacs-lisp/subr-x.el (string-pixel-width): Speed up
    string-pixel-width in the zero-length string case.
---
 lisp/emacs-lisp/subr-x.el | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/lisp/emacs-lisp/subr-x.el b/lisp/emacs-lisp/subr-x.el
index 1f69850958..647397e7f7 100644
--- a/lisp/emacs-lisp/subr-x.el
+++ b/lisp/emacs-lisp/subr-x.el
@@ -444,9 +444,11 @@ is inserted before adjusting the number of empty lines."
 ;;;###autoload
 (defun string-pixel-width (string)
   "Return the width of STRING in pixels."
-  (with-temp-buffer
-    (insert string)
-    (car (buffer-text-pixel-size nil nil t))))
+  (if (zerop (length string))
+      0
+    (with-temp-buffer
+      (insert string)
+      (car (buffer-text-pixel-size nil nil t)))))
 
 ;;;###autoload
 (defun string-glyph-split (string)