From bf79fb427cc1c14594a2f2e209f231a5b36159d6 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Tue, 4 Aug 2015 15:45:30 -0600
Subject: [PATCH] ignore system scaling factor if it's not a positive rational

---
 gui-lib/mred/private/wx/gtk/resolution.rkt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gui-lib/mred/private/wx/gtk/resolution.rkt b/gui-lib/mred/private/wx/gtk/resolution.rkt
index c387b572..ab22f615 100644
--- a/gui-lib/mred/private/wx/gtk/resolution.rkt
+++ b/gui-lib/mred/private/wx/gtk/resolution.rkt
@@ -43,4 +43,6 @@
 	 (g_variant_get_double
 	  (g_settings_get_value gs "text-scaling-factor"))))
     (g_object_unref gs)
-    v))
+    (and (rational? v)
+	 (positive? v)
+	 v)))