func drawPolygon(ctxt draw2d.GraphicContext, g *geos.Geometry, fillColor color.Color, strokeColor color.Color, width float64, scale func(x, y float64) (float64, float64)) {
ctxt.SetFillColor(fillColor)
ctxt.SetStrokeColor(strokeColor)
ctxt.SetLineWidth(width)
// exterior ring
ring := geos.Must(g.ExteriorRing())
cs, err := ring.coordSeq()
if err != nil {
log.Fatal(err)
}
lineCoordSeq(ctxt, cs, scale)
ctxt.FillStroke()
// interior rings...
}
