Draw an arc at x and y.
Source
GraphicsCommandArcElliptical arcElliptical(
double x, double y, double radiusX, double radiusY, double rotation,
double startAngle, double endAngle, [bool antiClockwise = false]) {
var command = new GraphicsCommandArcElliptical(
x, y, radiusX, radiusY, rotation, startAngle, endAngle, antiClockwise);
this.addCommand(command);
return command;
}