--- src/graphics.cc.orig	2009-08-07 11:35:01.000000000 +0200
+++ src/graphics.cc	2009-08-07 11:35:36.000000000 +0200
@@ -476,6 +476,8 @@
 	    eminp = e;
 	}
     }
+  if (emax <= 0)
+    eminp = 0.1;
 }
 
 static bool