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@ptrelford
Last active December 15, 2015 19:01
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Falling Snowflakes F# script using WriteableBitmapEx
#r "PresentationCore.dll"
#r "PresentationFramework.dll"
#r "WindowsBase.dll"
#r "WriteableBitmapEx.Wpf.dll" // requires custom version with DrawString
open System
open System.Windows
open System.Windows.Controls
open System.Windows.Media
open System.Windows.Media.Imaging
open System.Windows.Threading
let w, h = 800.0, 600.0
let rnd = Random()
type flake = { mutable X:float; mutable Y:float; V:float; A:float }
let render (context:BitmapContext) flakes =
let bitmap = context.WriteableBitmap
bitmap.Clear()
let color = Colors.Gray
let fontSize = 16
let font = PortableFontDesc("Arial", fontSize, true, false,false)
for flake in flakes do
bitmap.DrawString(int flake.X, int flake.Y, color, font, "F#") |> ignore
let draw (bitmap:WriteableBitmap) flakes =
using (bitmap.GetBitmapContext()) (fun context -> render context flakes)
let update (flakes:ResizeArray<_>) =
if (rnd.Next(5)= 0) then
let x, y = rnd.NextDouble() * w, -16.0
let a = 45.0 + rnd.NextDouble() * 90.0
let v = (0.5 + rnd.NextDouble())*2.0
let flake = { X=x; Y=y; V=v; A=a }
flakes.Add(flake)
let onScreen, offScreen = flakes |> Seq.toList |> List.partition (fun flake -> flake.Y < h)
for flake in onScreen do
let r = flake.A * Math.PI / 180.0
flake.X <- flake.X + ((cos r) * flake.V)
flake.Y <- flake.Y + ((sin r) * flake.V)
for flake in offScreen do
flakes.Remove(flake) |> ignore
do
let window = Window(SizeToContent = SizeToContent.WidthAndHeight)
let view = Image(Width=w,Height=h)
window.Content <- view
let dispatcherTimer = new DispatcherTimer()
dispatcherTimer.Interval <- new TimeSpan(0, 0, 0, 0, 15)
dispatcherTimer.Start()
let flakes = ResizeArray<_>()
window.Loaded.Add(fun _ ->
let bitmap = BitmapFactory.New(int w, int h)
view.Source <- bitmap
dispatcherTimer.Tick.Add(fun _ ->
update flakes
draw bitmap flakes
)
)
window.Show()
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