Color wheel

The following program uses our F# for Visualization library to draw a color wheel:

open System.Windows

open FlyingFrog.Graphics

let brush(r, g, b) =

  let f x = 256.0 * x |> max 0.0 |> min 255.0 |> byte

  Media.SolidColorBrush(Media.Color.FromRgb(f r, f g, f b))

let polygon brush xys =

  Shape([Interior brush], [ Contour.Closed[for x, y in xys -> line_to x y] ])

let wheel m n =

 let a = System.Math.PI / float n

  let ka, sa = cos a, sin a

  let ta = (ka + sa) / (ka - sa)

  let d = ka + sa * ta

  let m = float m

  Group

    [ for e in 0.0..m-1.0 do

        let r = 1.0 / (ka - sa) ** e

        for i in 0..n-1 do

          let t = a * (float(2*i) + e)

          let k, s = r * cos t, r * sin t

          yield

            polygon (brush(float i / float n, 0.5*(1.0 + e/m), 0.5*(2.0 - e/m)))

              [ k, s

                d*k*ka - d*s*sa, d*s*ka + d*k*sa

                ta*k, ta*s

                d*k*ka + d*s*sa, d*s*ka - d*k*sa ] ]

View(wheel 12 16)