joint.all.js
function ellipse(c, a, b) {
        if (!(this instanceof ellipse))
            return new ellipse(c, a, b);
        c = point(c);
        this.x = c.x;
        this.y = c.y;
        this.a = a;
        this.b = b;
    }
function ellipse(c, a, b) {
        if (!(this instanceof ellipse))
            return new ellipse(c, a, b);
        c = point(c);
        this.x = c.x;
        this.y = c.y;
        this.a = a;
        this.b = b;
    }
Ellipse. --------