func (p *Path) draw(gc *gg.Context, trans *transformer) {
if len(p.Positions) <= 1 {
return
}
gc.ClearPath()
gc.SetLineWidth(p.Weight)
gc.SetLineCap(gg.LineCapRound)
gc.SetLineJoin(gg.LineJoinRound)
for _, ll := range p.Positions {
gc.LineTo(trans.ll2p(ll))
}
gc.SetColor(p.Color)
gc.Stroke()
}