Loewensberg Square

#r "System.Drawing.dll"
#r "System.Windows.Forms.dll"

open System
open System.Drawing
open System.Windows.Forms

let width, height = 512, 512

let black = 0,0,0
let red = 183,51,32
let green = 45, 140, 108
let blue = 68, 116, 178

let toBrush (r,g,b) =
   let color = Color.FromArgb(255,r,g,b)
   new SolidBrush(color)

let draw (a:int) =
   let a = (float a * Math.PI) / 180.0
   let image = new Bitmap(width, height)
   use graphics = Graphics.FromImage(image)
   let brush = toBrush black
   graphics.FillRectangle(brush, 0, 0, width, height)

   let n = 50
   let points =
      [|n, -n;
       width+n, n;
       width-n, height+n;
       -n,height-n|]
      |> Array.map (fun (x,y) -> Point(x,y))

   let r = float width / 2.0
   let transform (x,y) = x*cos(a)-y*sin(a), x*sin(a)+y*cos(a)
   let translate (x,y) = Point(int (x*r) + width/2,int (y*r)+height/2)

   let rectangle points color =
      let points =
         points
         |> Array.map transform
         |> Array.map translate
      let brush = toBrush color
      graphics.FillPolygon(brush,points)

   let points =
      [|-1.0,-1.0;
         1.0,-1.0;
         1.0, 1.0;
        -1.0, 1.0|]
   rectangle points red

   let points =
      [|-1.0,-2.0;
         1.0,-2.0;
         1.0,-1.0;
        -1.0,-1.0|]
   rectangle points blue

   let points =
      [| 1.0,-1.0;
         2.0,-1.0;
         2.0, 1.0;
         1.0, 1.0|]
   rectangle points blue

   let points =
      [| -1.0,-1.0;
         -2.0,-1.0;
         -2.0, 1.0;
         -1.0, 1.0|]
   rectangle points green

   let points =
      [|-1.0, 2.0;
         1.0, 2.0;
         1.0, 1.0;
        -1.0, 1.0|]
   rectangle points green

   image

let show () =
   let image = draw 45
   let form = new Form (Text="Loewensberg Lines", Width=width+16, Height=height+36)
   let picture = new PictureBox(Dock=DockStyle.Fill, Image=image)
   image.Save(@"C:\app\Loewensberg Square.png", Imaging.ImageFormat.Png)
   do  form.Controls.Add(picture)
   form.ShowDialog() |> ignore

show()


#r @"Gif.Components.dll"

open Gif.Components

let encoder = AnimatedGifEncoder()

if encoder.Start(@"c:\temp\Loewensberg square.gif") then
   encoder.SetFrameRate(10.0f)
   encoder.SetRepeat 0
   for angle in 0..5..360 do
      encoder.AddFrame(draw angle) |> ignore
   encoder.Finish() |> ignore