public void FillOval (float x, float y, float width, float height)
{
var rx = width / 2;
var ry = height / 2;
var cx = x + rx;
var cy = y + ry;
WriteLine("<ellipse cx=\"{0}\" cy=\"{1}\" rx=\"{2}\" ry=\"{3}\" fill=\"{4}\" fill-opacity=\"{5}\" stroke=\"none\" />",
cx, cy, rx, ry, _lastColor, _lastColorOp);
}