diff --git a/src/Chart.vala b/src/Chart.vala
index b2a6683..432b05c 100644
--- a/src/Chart.vala
+++ b/src/Chart.vala
@@ -335,10 +335,10 @@ namespace CairoChart {
 			color = border_color;
 			ctx.set_dash(null, 0);
 			ctx.move_to (plarea.x, plarea.y);
-			ctx.line_to (plarea.x, plarea.y + plarea.height);
-			ctx.line_to (plarea.x + plarea.width, plarea.y + plarea.height);
-			ctx.line_to (plarea.x + plarea.width, plarea.y);
-			ctx.line_to (plarea.x, plarea.y);
+			ctx.rel_line_to (0, plarea.height);
+			ctx.rel_line_to (plarea.width, 0);
+			ctx.rel_line_to (0, - plarea.height);
+			ctx.rel_line_to (-plarea.x, 0);
 			ctx.stroke ();
 		}
 		protected virtual void draw_title () {