1 files changed, 6 insertions, 0 deletions
diff --git a/pict.scm b/pict.scm
index 7ea2905..916d527 100644
--- a/pict.scm
+++ b/pict.scm
@@ -801,6 +801,12 @@ filled with black."
   "Render the provided string TXT.  The keywords COLOR (a string),
 FONT-FAMILY (a string), FONT-SIZE (an integer), FONT-STYLE (a symbol),
 and FONT-WEIGHT (also a symbol) can be used to change the appearance."
+  (define validate-weight
+    (or (member font-weight '(normal bold bolder lighter))
+        (error "font-weight must be one of: normal, bold, bolder, lighter.")))
+  (define validate-style
+    (or (member font-style '(normal italic oblique))
+        (error "font-style must be one of: normal, italic, oblique.")))
   ;; Return ascent, descent, height, max_x_advance, max_y_advance
   (define (font-extents)
     (call-with-values