Make pict-attr safe.

1 files changed, 3 insertions, 2 deletions

diff --git a/pict.scm b/pict.scm
index 6c7bef6..bc33314 100644
--- a/pict.scm
+++ b/pict.scm
@@ -582,10 +582,11 @@ strings that are built from the list of attributes LST."
 
 (define (pict-attr attr pict)
   "Return the value of the selected ATTRIBUTE of the outermost element
-of the SVG of PICT."
+of the SVG of PICT or #F."
   (and=> ((sxpath `(@ ,attr *any*))
           (pict-sxml pict))
-         car))
+         (lambda (m) (and (pair? m)
+                          (car m)))))
 
 (define (pict-height pict)
   "Return the height of PICT."