Learning WPF - Working with Brush Basics

Going through Chapter 2 of Charles Petzold's "Applications = Code + Markup" book. The RotateTheGradientOrigin code sample looks different from the example in the book because I'm leveraging F# anonymous functions, or also known as lambda functions in the functional programming circles. According to Robert Pickering in chapter 4 of the the book "Foundations of F#", all events exposes a method called Add and that its common to place the handler method inside the Add method itself.

VaryTheBackground

#light 
#I @"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0"
#r @"WindowsBase.dll"
#r @"PresentationCore.dll"
#r @"PresentationFramework.dll"

open System
open System.Windows
open System.Windows.Input
open System.Windows.Media

(* From Chap 2 - VaryTheBackground.cs *)

type VaryTheBackground = class
   inherit Window as base
   
   val mutable brush : SolidColorBrush

   new () as this = {brush=new SolidColorBrush(Colors.Black)} then
      this.Title <- "Vary the Background"
      this.Width <- 384.0
      this.Height <- 384.0
      this.Background <- this.brush
      

   override this.OnMouseMove (args:MouseEventArgs) =
      let width = this.ActualWidth – 
                  2.0 * SystemParameters.ResizeFrameVerticalBorderWidth 
      let height = this.ActualHeight – 
                   2.0 * SystemParameters.ResizeFrameHorizontalBorderHeight –
                   SystemParameters.CaptionHeight
      let ptMouse = args.GetPosition(this)
      let ptCenter = new Point(width/2.0,height/2.0)
      let vectMouse = ptMouse - ptCenter
      let angle = Math.Atan2(vectMouse.Y, vectMouse.X)
      let vectEllipse = new Vector (width/2.0*Math.Cos(angle), 
                                    height/2.0*Math.Sin(angle))
      let ratio = vectMouse.Length/vectEllipse.Length
      let byLevel:Byte = Byte.of_int(Float.to_int(255.0 * (1.0-Math.Min(1.0,ratio))))
      let clr = Color.FromRgb(byLevel,byLevel,byLevel)
      this.Title <- Byte.to_string(byLevel)
      this.brush.Color <- clr
         
end

#if COMPILED
[<STAThread()>]
do 
    let app =  new Application() in
    app.Run(new VaryTheBackground()) |> ignore
#endif


FlipThroughTheBrushes

#light 
#I @"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0"
#r @"WindowsBase.dll"
#r @"PresentationCore.dll"
#r @"PresentationFramework.dll"

open System
open System.Reflection
open System.Windows
open System.Windows.Input
open System.Windows.Media

(* From Chap 2 - FlipThroughTheBrushes.cs *)
let indexcalc (keypress:Key) (props:PropertyInfo []) =
   match keypress with
   | Key.Up -> 1
   | _ -> props.Length -1


type FlipThroughTheBrushes = class
   inherit Window as base
   
   val mutable index : int
   val mutable props : PropertyInfo []

   new () as this = {index=0;props=null} then
      let brushtype = typeof<Brushes>   
      this.props <- brushtype.GetProperties(Enum.combine [BindingFlags.Public;
                                                          BindingFlags.Static ])
      this.SetTitleAndBackground()
   
   member this.SetTitleAndBackground() =
      this.Title <- "Flip through the Brushes - " + this.props.[this.index].Name
      this.Background <- unbox<Brush> (this.props.[this.index].GetValue(null,null))

   override this.OnKeyDown (args:KeyEventArgs) =
      if (args.Key = Key.Down || args.Key = Key.Up) then
         this.index <- (this.index + 
                        (indexcalc args.Key this.props)) % this.props.Length
         this.SetTitleAndBackground()
      base.OnKeyDown(args)         
      
end

#if COMPILED
[<STAThread()>]
do 
    let app =  new Application() in
    app.Run(new FlipThroughTheBrushes()) |> ignore
#endif



GradiateTheBrush
#light 
#I @"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0"
#r @"WindowsBase.dll"
#r @"PresentationCore.dll"
#r @"PresentationFramework.dll"

open System
open System.Windows
open System.Windows.Input
open System.Windows.Media

(* From Chap 2 - GradiateTheBrush.cs *)
type GradiateTheBrush  = class
   inherit Window as base
   
   new () as this = {} then
      this.Title <- "Gradiate the Brush"
      let brush = new LinearGradientBrush(Colors.Red,
                                          Colors.Blue,
                                          new Point(0.0,0.0),
                                          new Point(1.0,1.0))
      this.Background <- brush
      
end

#if COMPILED
[<STAThread()>]
do 
    let app =  new Application() in
    app.Run(new GradiateTheBrush()) |> ignore
#endif

AdjustTheGradient
#light 
#I @"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0"
#r @"WindowsBase.dll"
#r @"PresentationCore.dll"
#r @"PresentationFramework.dll"

open System
open System.Windows
open System.Windows.Input
open System.Windows.Media

(* From Chap 2 - AdjustTheGradient.cs *)
type AdjustTheGradient  = class
   inherit Window as base
   
   val mutable brush : LinearGradientBrush
   
   new () as this = {brush=null} then
      this.Title <- "Adjust the Gradient"
      this.add_SizeChanged(new SizeChangedEventHandler(this.WindowOnSizeChanged))
      this.brush <- new LinearGradientBrush(Colors.Red,Colors.Blue,0.0)
      this.brush.MappingMode <- BrushMappingMode.Absolute      
      this.Background <- this.brush
   
   member this.WindowOnSizeChanged sender (args:SizeChangedEventArgs) =
      let width = this.ActualWidth -
                  2.0 * SystemParameters.ResizeFrameVerticalBorderWidth
      let height = this.ActualHeight -
                   2.0 * SystemParameters.ResizeFrameHorizontalBorderHeight
                   - SystemParameters.CaptionHeight
      let ptCenter = new Point(width/2.0, height/2.0)
      let vectDiag = new Vector(width,-height)
      let mutable vectPerp = new Vector(vectDiag.Y, -vectDiag.X)
      vectPerp.Normalize()
      vectPerp <- vectPerp * width * height / vectDiag.Length
      this.brush.StartPoint <- ptCenter + vectPerp
      this.brush.EndPoint <- ptCenter - vectPerp   
      
end

#if COMPILED
[<STAThread()>]
do 
    let app =  new Application() in
    app.Run(new AdjustTheGradient()) |> ignore
#endif

FollowTheRainbow
#light 
#I @"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0"
#r @"WindowsBase.dll"
#r @"PresentationCore.dll"
#r @"PresentationFramework.dll"

open System
open System.Windows
open System.Windows.Input
open System.Windows.Media

(* From Chap 2 - FollowTheRainbow.cs *)

type FollowTheRainbow  = class
   inherit Window as base   
   
   new () as this = {} then
      this.Title <- "Follow the Rainbow"
      let mutable brush = new LinearGradientBrush()
      brush.StartPoint <- new Point(0.0,0.0)
      brush.EndPoint <- new Point (1.0,0.0)
      this.Background <- brush
      brush.GradientStops.Add(new GradientStop(Colors.Red, 0.0));
      brush.GradientStops.Add(new GradientStop(Colors.Orange, 0.17));
      brush.GradientStops.Add(new GradientStop(Colors.Yellow, 0.33));
      brush.GradientStops.Add(new GradientStop(Colors.Green, 0.5));
      brush.GradientStops.Add(new GradientStop(Colors.Blue, 0.67));
      brush.GradientStops.Add(new GradientStop(Colors.Indigo, 0.84));
      brush.GradientStops.Add(new GradientStop(Colors.Violet, 1.0));      
      
end

#if COMPILED
[<STAThread()>]
do 
    let app =  new Application() in
    app.Run(new FollowTheRainbow()) |> ignore
#endif

CircleTheRainbow 
#light 
#I @"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0"
#r @"WindowsBase.dll"
#r @"PresentationCore.dll"
#r @"PresentationFramework.dll"

open System
open System.Windows
open System.Windows.Input
open System.Windows.Media

(* From Chap 2 - CircleTheRainbow .cs *)

type CircleTheRainbow   = class
   inherit Window as base
   
   new () as this = {} then
      this.Title <- "Circle the Rainbow"
      let mutable brush = new RadialGradientBrush()
      this.Background <- brush
      brush.GradientStops.Add(new GradientStop(Colors.Red, 0.0));
      brush.GradientStops.Add(new GradientStop(Colors.Orange, 0.17));
      brush.GradientStops.Add(new GradientStop(Colors.Yellow, 0.33));
      brush.GradientStops.Add(new GradientStop(Colors.Green, 0.5));
      brush.GradientStops.Add(new GradientStop(Colors.Blue, 0.67));
      brush.GradientStops.Add(new GradientStop(Colors.Indigo, 0.84));
      brush.GradientStops.Add(new GradientStop(Colors.Violet, 1.0));      
      
end

#if COMPILED
[<STAThread()>]
do 
    let app =  new Application() in
    app.Run(new CircleTheRainbow ()) |> ignore
#endif

ClickTheGradientCenter
#light 
#I @"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0"
#r @"WindowsBase.dll"
#r @"PresentationCore.dll"
#r @"PresentationFramework.dll"

open System
open System.Windows
open System.Windows.Input
open System.Windows.Media

(* From Chap 2 - ClickTheGradientCenter .cs *)

type ClickTheGradientCenter   = class
   inherit Window as base
   
   val mutable brush : RadialGradientBrush 
   
   new () as this = {brush=null} then
      this.Title <- "Click the "
      this.brush <- new RadialGradientBrush(Colors.White, Colors.Red)
      this.brush.RadiusX <- 0.10
      this.brush.RadiusY <- 0.10
      this.brush.SpreadMethod <- GradientSpreadMethod.Repeat;      
      this.Background <- this.brush

   override this.OnMouseDown (args:MouseButtonEventArgs) =
      let width = this.ActualWidth -
                  2.0 * SystemParameters.ResizeFrameVerticalBorderWidth
      let height = this.ActualHeight -
                   2.0 * SystemParameters.ResizeFrameHorizontalBorderHeight -
                   SystemParameters.CaptionHeight                               
      let currentPt = args.GetPosition(this)
      let ptMouse = new Point(currentPt.X/width,currentPt.Y/height)
      if (args.ChangedButton = MouseButton.Left) then
         this.brush.Center <- ptMouse
         this.brush.GradientOrigin <- ptMouse
      else if (args.ChangedButton = MouseButton.Right) then
         this.brush.GradientOrigin <- ptMouse
      
      
end

#if COMPILED
[<STAThread()>]
do 
    let app =  new Application() in
    app.Run(new ClickTheGradientCenter()) |> ignore
#endif

RotateTheGradientOrigin
#light 
#I @"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0"
#r @"WindowsBase.dll"
#r @"PresentationCore.dll"
#r @"PresentationFramework.dll"

open System
open System.Windows
open System.Windows.Input
open System.Windows.Media
open System.Windows.Threading

(* From Chap 2 - RotateTheGradientOrigin.cs *)

type RotateTheGradientOrigin  = class
   inherit Window as base
   
   val mutable brush : RadialGradientBrush 
   val mutable angle : double
   
   new () as this = {brush=null;angle=0.0} then
      this.Title <- "Rotate the Gradient Origin"
      this.WindowStartupLocation <- WindowStartupLocation.CenterScreen
      this.Height <- 384.0
      this.Width <- 384.0
      this.brush <- new RadialGradientBrush(Colors.White, Colors.Red)
      this.brush.Center <- new Point(0.5,0.5)
      this.brush.GradientOrigin <- new Point(0.5,0.5)
      this.brush.RadiusX <- 0.10
      this.brush.RadiusY <- 0.10
      this.brush.SpreadMethod <- GradientSpreadMethod.Repeat;      
      this.Background <- this.brush
      
      let tmr = new DispatcherTimer()
      tmr.Interval <- TimeSpan.FromMilliseconds(100.0)
      
      // Using anonymous function (aka lambda functions) instead of explicitly
      // defining a TimerOnTick member method   
      tmr.Tick.Add
        (fun e ->
            let pt = new Point(0.5 + 0.05 * Math.Cos(this.angle),
                               0.5 + 0.05 * Math.Sin(this.angle))
            this.brush.GradientOrigin <- pt
            this.angle <- this.angle + Math.PI/6.0)
            
      tmr.Start()

      
end

#if COMPILED
[<STAThread()>]
do 
    let app =  new Application() in
    app.Run(new RotateTheGradientOrigin()) |> ignore
#endif