This is similar to the 'drawCircle' method, except it allows you to specify a separate width and height for the circle drawn (which makes it become an ellipse).
Draws an ellipse at the x/y location given. If 'isCentred' is true, then x/y is the centre of the ellipse. If it is false, then it refers to the top-left corner.
The same 'drawEllipse' method, but with x and y alignment options. See the article on How Alignment Works for details.