f64/d2/rect.go
func (r Rectangle) Dx() float64 {
	return r.Max.X - r.Min.X
}
func (r Rectangle) Dx() float64 {
	return r.Max.X - r.Min.X
}
func ( r Rectangle ) Dx ( ) float64 { return r . Max . X - r . Min . X }
// Dx returns r's width.
Dx returns r s width .