diff --git display/simgraph.h display/simgraph.h
index 74c3b3ddf..306c2aeaa 100644
--- display/simgraph.h
+++ display/simgraph.h
@@ -16,15 +16,16 @@
 
 
 #if COLOUR_DEPTH != 0
-
 extern int default_font_ascent;
 extern int default_font_linespace;
 
 #  define LINEASCENT (default_font_ascent)
 #  define LINESPACE  (default_font_linespace)
 #else
+// Note: The values here are arbitrary, however LINESPACE must not be 0
+// to prevent division by zero.
 #  define LINEASCENT 0
-#  define LINESPACE  0
+#  define LINESPACE  1
 #endif