racket/draw: avoid an internal error on a bad bitmap

2014-08-13 09:14:04 +01:00 · 2014-08-13 09:14:04 +01:00 · 864d165c24
commit 864d165c24
parent c359f7ac29
1 changed files with 2 additions and 1 deletions
--- a/pkgs/draw-pkgs/draw-lib/racket/draw/private/bitmap.rkt
+++ b/pkgs/draw-pkgs/draw-lib/racket/draw/private/bitmap.rkt
@ -903,7 +903,8 @@

    (define/public (prep-alpha width height)
      (when (and (not b&w?)
-                 (not alpha-channel?))
+                 (not alpha-channel?)
+                 s)
        (unless alpha-s-up-to-date?
          (unless alpha-s
            (set! alpha-s (cairo_image_surface_create CAIRO_FORMAT_ARGB32