ellipse vs circle

        Canvas canvas = Canvas.createIfSupported();开发者_开发技巧

        canvas.setWidth("200px");
        canvas.setHeight("200px");

        RootPanel.get().add(canvas);

        Context2d context = canvas.getContext2d();
        context.setStrokeStyle("black");

        context.arc(50, 50, 20, 0, Math.PI*2);

        context.stroke();

Why I have ellipse instead of circle here?

---

You'll also have to set the coordinate space, to make it match the aspect ratio of your canvas. So you can add the following lines:

canvas.setCoordinateSpaceWidth(200);
canvas.setCoordinateSpaceHeight(200);