Only display temperature graph if we have temperature data

Commit b625332ca5ff "Display even constant temperature graph" was a little
too aggressive. If we have no temperature data at all it caused us to plot
a temperature line for absolute zero...

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/profile.c b/profile.c
index 2dce8003b..4b04d68ce 100644
--- a/profile.c
+++ b/profile.c
@@ -883,7 +883,7 @@ static int setup_temperature_limits(struct graphics_context *gc, struct plot_inf
 		gc->bottomy = mintemp - delta / 3;
 
 	pi->endtempcoord = SCALEY(gc, pi->mintemp);
-	return maxtemp >= mintemp;
+	return maxtemp && maxtemp >= mintemp;
 }
 
 static void plot_single_temp_text(struct graphics_context *gc, int sec, int mkelvin)