function drawEllipse(point: Vector, width: number, height: number ) {
this.context.beginPath();
this.context.ellipse(point.x, point.y, width, height, 0, 0, 2 * Math.PI);
this.context.fill();
this.context.stroke();
}
ctx.ellipse(x, y, radiusX, radiusY, rotation, startAngle, endAngle [, counterclockwise]);