How to Implement Ellipse Shape in WPF using F#

This article contains explanation about how to draw and render Ellipse in F# using WPF. Ellipse shape is like an object which draw Ellipse and contain Height and Width of the Ellipse. The Height and width of the Ellipse is represented by the width and height properties of Ellipse. If you want to set the width of the Outline of the ellipse you will use the stroke property of the Ellipse. It also used to present the thickness and color of the outline. Steps are given below.

Step 1: Firstly Open a new Project in F# using Visual Studio, Select F# WPF application template and named it as shown in below image.

Step 2: Now add below given references in your project by right clicking on your project in solution Explorer.

• PresentationCore

• PresentationFramework

• System

• System.Xaml

• UIAutomationTypes

• WindowsBase

Step 3: When You will add all these References, Your Solution Explorer will look like below.

Step 4: Then click on Program.fs file and write the below code in Program.fs Window, Your Window will look like below.

#light 

open System
open System.Windows
open System.Windows.Controls
open System.Windows.Input
open System.Windows.Media 
 
let mutable private initFillProperty : DependencyProperty = null
let mutable private initStrokeProperty : DependencyProperty = null
     
type Elps() = class                    
   inherit FrameworkElement()
  
   static member FillProperty =
      if initFillProperty = null then
         initFillProperty <- DependencyProperty.Register
            ("Color Filled", typeof<Brush>,typeof<Elps>,
             new FrameworkPropertyMetadata
                (null, FrameworkPropertyMetadataOptions.AffectsRender))        
         initFillProperty
      else
         initFillProperty
 
   static member StrokeProperty  =
      if initStrokeProperty = null then
         initStrokeProperty <- DependencyProperty.Register
            ("Stroke Property", typeof<Pen>,typeof<Elps>,
             new FrameworkPropertyMetadata
                (null, FrameworkPropertyMetadataOptions.AffectsMeasure))        
         initStrokeProperty
      else
         initStrokeProperty
 
   member this.Fill
      with get() = (this.GetValue(Elps.FillProperty) :?> Brush)
      and set (value :Brush) =
         this.SetValue(Elps.FillProperty,value)
     
   member this.Stroke
      with get() = (this.GetValue(Elps.StrokeProperty) :?> Pen )
      and set (value :Pen) =
         this.SetValue(Elps.StrokeProperty,value)
 
  
   override this.MeasureOverride (sizeAvailable:Size) =    
      if this.Stroke <> null then
         new Size(this.Stroke.Thickness,this.Stroke.Thickness)
      else
         base.MeasureOverride(sizeAvailable)
  
   override this.OnRender (dc:DrawingContext) =
      let drawElps widthElps heightElps =
         dc.DrawEllipse
            (this.Fill, this.Stroke,
             new Point(this.RenderSize.Width /2.0, this.RenderSize.Height /2.0),
             widthElps/2.0,heightElps/2.0)
 
      if this.Stroke <> null then
         let widthElps = Math.Max(0.0,this.RenderSize.Width - this.Stroke.Thickness)
         let heightElps = Math.Max(0.0,this.RenderSize.Height - this.Stroke.Thickness)
         drawElps widthElps heightElps
      else
         drawElps this.RenderSize.Width this.RenderSize.Height
         
end  
type WpfElps() as this =
   inherit Window()
   do this.Title <- "Ellipse in WPF using F#"
      let elps = new Elps()
      elps.Fill <- Brushes.Pink
      elps.Stroke <- new Pen
         (new LinearGradientBrush(Colors.SkyBlue, Colors.Yellow,
                                  new Point(1.0, 0.0), new Point(0.0, 1.0)),24.0)
      this.Content <- elps
 
#if COMPILED
[<STAThread()>]
do
    let app =  Application() in
    app.Run(new WpfElps()) |> ignore

#endif

Step 5: Now Press F5 to execute the Code.

Output

Summary

In this article I have discussed that how to draw an Ellipse in F# using WPF.