in bweb, fix warning

diff --git a/gui/bweb/cgi/bgraph.pl b/gui/bweb/cgi/bgraph.pl
index dd3b22e84161c982ce80b7c3da2ff137abab9b43..c3e429d950f7dc4c4c27a4617b5569ad62844871 100755 (executable)
--- a/gui/bweb/cgi/bgraph.pl
+++ b/gui/bweb/cgi/bgraph.pl
@@ -228,7 +228,7 @@ sub get_graph
                 ],
                @options,
                );
-    if (-f $conf->{graph_font}) {
+    if ($conf->{graph_font} && -f $conf->{graph_font}) {
         $graph->set_title_font([$conf->{graph_font}], 12);
         $graph->set_legend_font([$conf->{graph_font}], 11);
     }