Index: web/client/scripts/draw.js
===================================================================
--- web/client/scripts/draw.js	(revision 6885)
+++ web/client/scripts/draw.js	(revision 6886)
@@ -135,7 +135,6 @@
 	if (!this.enableDrawing) {
 		return;
 	}
-	// note: expect xr and yr being equal
 	this.selectGC(gci);
 	this.cc.beginPath();
 	if (deltaAngle > 360 || deltaAngle < -360) {
@@ -145,8 +144,14 @@
 	startAngle = (-startAngle + 180) * Math.PI / 180;
 	deltaAngle = -deltaAngle * Math.PI / 180;
 	if (deltaAngle !== 0) {
-		this.cc.arc(x1, y1, xr, startAngle, startAngle + deltaAngle, deltaAngle <= 0);
-		this.cc.stroke();
+		if (this.cc.ellipse) {
+			this.cc.ellipse(x1, y1, xr, yr, 0, startAngle, startAngle + deltaAngle, deltaAngle <= 0);
+			this.cc.stroke();
+		} else {
+			// note: expect xr and yr being equal
+			this.cc.arc(x1, y1, xr, startAngle, startAngle + deltaAngle, deltaAngle <= 0);
+			this.cc.stroke();
+		}
 	} else {
 		// this is a workaround, see http://stackoverflow.com/questions/7812514/drawing-a-dot-on-html5-canvas
 		x1 += xr * Math.cos(startAngle);