Spiral Animation

#r "System.Drawing.dll"
open System.Drawing

let colors = [
   251, 226, 0
   246, 180, 24
   240, 81, 51
   223, 43, 124
   178, 36, 120
   132, 37, 129
   18, 37, 132
   1, 73, 155
   1, 134, 199
   60, 161, 19
   143, 181, 8
   211, 209, 3 ]

let pattern0 =
   [ 1,-2;  1,-1;  1, 0;
     1, 1;  0, 1; -1, 1;
    -2, 1; -2, 0; -2,-1;
    -2,-2; -1,-2;  0,-2]

let pattern1 =
   [-2, 1; -2, 0; -2,-1;
    -2,-2; -1,-2;  0,-2;
     1,-2;  1,-1;  1, 0;
     1, 1;  0, 1; -1, 1 ]

let brushes =
   [for r,g,b in colors -> new SolidBrush(Color.FromArgb(255,r,g,b))]

let width, height = 512,512

let create n =
   let image = new Bitmap(width, height)
   use graphics = Graphics.FromImage(image)
   let mutable size = width/4
   let mutable i = 0
   while size > 0 do
      let d = size
      let n = if i%2 = 0 then n else -n
      if (i+n)%2 = 0 then pattern1 else pattern0
      |> List.iteri (fun i (x,y) ->
         let brush = brushes.[(12+i+n)%brushes.Length]
         graphics.FillRectangle(brush, 256 + (x*d), 256 + (y*d), d, d)
      )
      size <- size / 2
      i <- i + 1
   image

(*
#r "System.Windows.Forms.dll"
open System.Windows.Forms
let show () =
   let image = create 0
   let form = new Form (Text="boxes", Width=width, Height=height)
   let picture = new PictureBox(Dock=DockStyle.Fill, Image=image)
   do  form.Controls.Add(picture)
   form.ShowDialog() |> ignore

show()
*)

#r @"C:\Phil\Root\MLClass\MLClass\lib\Gif.Components.dll"

open Gif.Components

let encoder = AnimatedGifEncoder()
if encoder.Start(@"c:\app\testA.gif") then
   //encoder.SetDelay(1000)
   encoder.SetFrameRate(2.0f)
   encoder.SetRepeat(0)
   for i = 0 to 11 do
      encoder.AddFrame(create i) |> ignore
   encoder.Finish() |> ignore