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...
}
func drawLine(ctxt draw2d.GraphicContext, g *geos.Geometry, c color.Color, width float64, scale func(x, y float64) (float64, float64)) {
if c != nil {
ctxt.SetStrokeColor(c)
}
if width != 0.0 {
ctxt.SetLineWidth(width)
}
// XXX: should get a [] of points
cs, err := g.coordSeq()
if err != nil {
log.Fatal(err)
}
lineCoordSeq(ctxt, cs, scale)
ctxt.Stroke()
}
func drawPoint(ctxt draw2d.GraphicContext, g *geos.Geometry, c color.Color, radius float64, scale func(x, y float64) (float64, float64)) {
if c != nil {
ctxt.SetFillColor(c)
}
x, err := g.X()
if err != nil {
log.Fatal(err)
}
y, err := g.Y()
if err != nil {
log.Fatal(err)
}
x, y = scale(x, y)
ctxt.MoveTo(x, y)
ctxt.ArcTo(x, y, radius, radius, 0, 2*math.Pi)
ctxt.Fill()
}
func envelope(g *geos.Geometry) Envelope {
env, err := g.Envelope()
if err != nil {
log.Fatal(err)
}
ring, err := env.ExteriorRing()
if err != nil {
log.Fatal(err)
}
cs, err := ring.coordSeq()
if err != nil {
log.Fatal(err)
}
getX := getOrd(cs, (*geos.CoordSeq).GetX)
getY := getOrd(cs, (*geos.CoordSeq).GetY)
return Env(getX(0), getY(0), getX(2), getY(2))
}