diff --git a/src/gui/bubble-bar.vala b/src/gui/bubble-bar.vala
index 44c91f4..e4ff6c3 100644
--- a/src/gui/bubble-bar.vala
+++ b/src/gui/bubble-bar.vala
@@ -22,9 +22,12 @@ class TheCatTools.GUI.BoubleBar : Gtk.DrawingArea, Gtk.Orientable {
         var line_width = height / 120;
         var gap = line_width;;
         var radius = width / 2 - gap;
-        var value = value % 90;
-        value += 90;
-        value *= -1;
+        var val = value + 90;
+        if (val > 180)
+            val = 360 - val;
+        if (val < 0)
+            val = val * -1;
+        var value = val;
         var position = radius + (height - radius * 2) * value / 180;
         message ("%f = %f", value, position);