VB.Net Tutorial/2D Graphics/Bezier

Bezier Splines

<source lang="vbnet">Imports System.Drawing.Drawing2D Imports System.Windows.Forms Imports System.Drawing Imports System.Collections public class BezierSplines

  public Shared Sub Main
       Application.Run(New Form1)
  End Sub

End class

Public Class Form1

   Dim BendPoints As New Generic.List(Of Point)
   Private Sub Form1_MouseClick(ByVal sender As Object, _
         ByVal e As System.Windows.Forms.MouseEventArgs) _
         Handles Me.MouseClick
       BendPoints.Add(New Point(e.X, e.Y))
       Me.Refresh()
   End Sub
   Private Sub Form1_Paint(ByVal sender As Object, _
         ByVal e As System.Windows.Forms.PaintEventArgs) _
         Handles Me.Paint
       Dim canvas As Graphics = e.Graphics
       If (BendPoints.Count >= 4) Then
           canvas.DrawBezier(Pens.Black, BendPoints(0), BendPoints(1), BendPoints(2), BendPoints(3))
           BendPoints.Clear()
       End If
   End Sub

End Class

<Global.Microsoft.VisualBasic.rupilerServices.DesignerGenerated()> _ Partial Class Form1

   Inherits System.Windows.Forms.Form
   "Form overrides dispose to clean up the component list.
   <System.Diagnostics.DebuggerNonUserCode()> _
   Protected Overrides Sub Dispose(ByVal disposing As Boolean)
       If disposing AndAlso components IsNot Nothing Then
           components.Dispose()
       End If
       MyBase.Dispose(disposing)
   End Sub
   "Required by the Windows Form Designer
   Private components As System.ruponentModel.IContainer
   "NOTE: The following procedure is required by the Windows Form Designer
   "It can be modified using the Windows Form Designer.  
   "Do not modify it using the code editor.
   <System.Diagnostics.DebuggerStepThrough()> _
   Private Sub InitializeComponent()
       Me.SuspendLayout()
       "
       "Form1
       "
       Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
       Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
       Me.ClientSize = New System.Drawing.Size(531, 394)
       Me.Name = "Form1"
       Me.Text = "Drawing Bezier Splines"
       Me.ResumeLayout(False)
   End Sub

End Class</source>

Draw Beziers 1

<source lang="vbnet">Imports System.Drawing Imports System.Drawing.Drawing2D Imports System.Windows.Forms public class DrawBeziers1

  public Shared Sub Main
       Application.Run(New BeziersForm)
  End Sub

End class

Public Class BeziersForm

   Inherits System.Windows.Forms.Form

1. Region " Windows Form Designer generated code "

   Public Sub New()
       MyBase.New()
       "This call is required by the Windows Form Designer.
       InitializeComponent()
       "Add any initialization after the InitializeComponent() call
   End Sub
   "Form overrides dispose to clean up the component list.
   Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
       If disposing Then
           If Not (components Is Nothing) Then
               components.Dispose()
           End If
       End If
       MyBase.Dispose(disposing)
   End Sub
   "Required by the Windows Form Designer
   Private components As System.ruponentModel.IContainer
   "NOTE: The following procedure is required by the Windows Form Designer
   "It can be modified using the Windows Form Designer.  
   "Do not modify it using the code editor.
   <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
       components = New System.ruponentModel.Container()
       Me.Text = "BeziersForm"
   End Sub

1. End Region

   Private Sub ClosedCurves_Paint(ByVal sender As Object, ByVal e As PaintEventArgs) Handles MyBase.Paint
       Dim g As Graphics = e.Graphics
       Dim x As Integer = 0
       Dim y As Integer = 0
       Dim width As Integer = Me.ClientRectangle.Width / 3
       Dim height As Integer = Me.ClientRectangle.Height
       Dim pen As Pen = New Pen(Color.Red, 4)
       Dim pointPen As Pen = New Pen(Color.Black, 3)
       pointPen.StartCap = pointPen.EndCap = LineCap.SquareAnchor
       Dim points As PointF() = New PointF() {New PointF(x + 25, y + height - 25), New PointF(x + width - 25, y + height - 25), New PointF(x + 25, y + 25), New PointF(x + width - 25, y + 25)}
       g.DrawBeziers(pen, points)
       
   End Sub

End Class</source>

Draw Beziers 2

<source lang="vbnet">Imports System.Drawing Imports System.Drawing.Drawing2D Imports System.Windows.Forms public class DrawBeziers2

  public Shared Sub Main
       Application.Run(New BeziersForm)
  End Sub

End class

Public Class BeziersForm

   Inherits System.Windows.Forms.Form

1. Region " Windows Form Designer generated code "

   Public Sub New()
       MyBase.New()
       "This call is required by the Windows Form Designer.
       InitializeComponent()
       "Add any initialization after the InitializeComponent() call
   End Sub
   "Form overrides dispose to clean up the component list.
   Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
       If disposing Then
           If Not (components Is Nothing) Then
               components.Dispose()
           End If
       End If
       MyBase.Dispose(disposing)
   End Sub
   "Required by the Windows Form Designer
   Private components As System.ruponentModel.IContainer
   "NOTE: The following procedure is required by the Windows Form Designer
   "It can be modified using the Windows Form Designer.  
   "Do not modify it using the code editor.
   <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
       components = New System.ruponentModel.Container()
       Me.Text = "BeziersForm"
   End Sub

1. End Region

   Private Sub ClosedCurves_Paint(ByVal sender As Object, ByVal e As PaintEventArgs) Handles MyBase.Paint
       Dim g As Graphics = e.Graphics
       Dim x As Integer = 0
       Dim y As Integer = 0
       Dim width As Integer = Me.ClientRectangle.Width / 3
       Dim height As Integer = Me.ClientRectangle.Height
       Dim pen As Pen = New Pen(Color.Red, 4)
       Dim pointPen As Pen = New Pen(Color.Black, 3)
       pointPen.StartCap = pointPen.EndCap = LineCap.SquareAnchor
       Dim points As PointF()
       points = New PointF() {New PointF(x + 25, y + 25), New PointF(x + width - 25, y + 25), New PointF(x + 25, y + height - 25), New PointF(x + width - 25, y + height - 25)}
       g.DrawBeziers(pen, points)
       
   End Sub

End Class</source>

Draw Beziers 3

<source lang="vbnet">Imports System.Drawing Imports System.Drawing.Drawing2D Imports System.Windows.Forms public class DrawBeziers3

  public Shared Sub Main
       Application.Run(New BeziersForm)
  End Sub

End class

Public Class BeziersForm

   Inherits System.Windows.Forms.Form

1. Region " Windows Form Designer generated code "

   Public Sub New()
       MyBase.New()
       "This call is required by the Windows Form Designer.
       InitializeComponent()
       "Add any initialization after the InitializeComponent() call
   End Sub
   "Form overrides dispose to clean up the component list.
   Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
       If disposing Then
           If Not (components Is Nothing) Then
               components.Dispose()
           End If
       End If
       MyBase.Dispose(disposing)
   End Sub
   "Required by the Windows Form Designer
   Private components As System.ruponentModel.IContainer
   "NOTE: The following procedure is required by the Windows Form Designer
   "It can be modified using the Windows Form Designer.  
   "Do not modify it using the code editor.
   <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
       components = New System.ruponentModel.Container()
       Me.Text = "BeziersForm"
   End Sub

1. End Region

   Private Sub ClosedCurves_Paint(ByVal sender As Object, ByVal e As PaintEventArgs) Handles MyBase.Paint
       Dim g As Graphics = e.Graphics
       Dim x As Integer = 0
       Dim y As Integer = 0
       Dim width As Integer = Me.ClientRectangle.Width / 3
       Dim height As Integer = Me.ClientRectangle.Height
       Dim pen As Pen = New Pen(Color.Red, 4)
       Dim pointPen As Pen = New Pen(Color.Black, 3)
       pointPen.StartCap = pointPen.EndCap = LineCap.SquareAnchor
       Dim points As PointF()
       points = New PointF() {New PointF(x + 25, y + 25), New PointF(x + width - 25, y + 25), New PointF(x + width - 25, y + height - 25), New PointF(x + 25, y + height - 25)}
       g.DrawBeziers(pen, points)
       
   End Sub

End Class</source>

Draw the Bezier curve and its outline

<source lang="vbnet">Imports System.Drawing Imports System.Drawing.Drawing2D Imports System.Windows.Forms public class BezierCurveAndItsOutline

  public Shared Sub Main
       Application.Run(New Form1)
  End Sub

End class public class Form1

 Inherits System.Windows.Forms.Form
 Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
       " Define the Bezier curve"s control points.
       Dim pts() As Point = { _
           New Point(10, 10), _
           New Point(200, 10), _
           New Point(50, 200), _
           New Point(200, 150), _
           New Point(250, 50), _
           New Point(250, 200), _
           New Point(100, 250) _
       }
       Dim dashed_pen As New Pen(Color.Black, 0)
       dashed_pen.DashStyle = Drawing2D.DashStyle.Dash
       For i As Integer = 0 To pts.Length - 2
           e.Graphics.DrawLine(dashed_pen, pts(i), pts(i + 1))
       Next i
       " .
       e.Graphics.SmoothingMode = Drawing2D.SmoothingMode.HighQuality
       Dim bez_pen As New Pen(Color.Black, 3)
       e.Graphics.DrawBeziers(bez_pen, pts)
 End Sub
 Public Sub New()
  
   MyBase.New()
   Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
   Me.ClientSize = New System.Drawing.Size(292, 273)
   Me.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen
 End Sub

End Class</source>