Imports System.Drawing.Drawing2D
Public Class Form1
    Dim pt() As Point = {New Point(100, 400), New Point(250, 250), New Point( _
      400, 100)}
    Dim gp, gpath As New GraphicsPath
    Dim curpoint As Int32
    Dim ptsvisible As Boolean = True
    Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown
        curpoint = -1
        If ptsvisible AndAlso gpath.IsVisible(e.Location) Then
            For i As Int32 = 0 To 2
                If Math.Abs(e.X - pt(i).X) < 6 AndAlso Math.Abs(e.Y - pt(i).Y) _
                  < 6 Then
                    curpoint = i
                End If
            Next
        End If
        If e.Button = Windows.Forms.MouseButtons.Right Then
            ptsvisible = Not ptsvisible
            Me.Refresh()
        End If
    End Sub
    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        e.Graphics.SmoothingMode = SmoothingMode.HighQuality
        If ptsvisible Then
            e.Graphics.DrawCurve(New Pen(Color.Yellow, 2), pt)
            gpath.Reset()
            For i As Int32 = 0 To 2
                gpath.AddEllipse(pt(i).X - 5, pt(i).Y - 5, 10, 10)
            Next
            e.Graphics.FillPath(Brushes.Red, gpath)
        Else
            Dim plist As New List(Of PointF)
            gp.Reset()
            gp.AddCurve(pt)
            plist.AddRange(gp.PathPoints)
            e.Graphics.DrawBezier(New Pen(Color.Red, 2), plist(0), plist(1), _
              plist(2), plist(3))
            e.Graphics.DrawBezier(New Pen(Color.Blue, 2), plist(3), plist(4), _
            plist(5), plist(6))
            For Each p As PointF In gp.PathPoints
                e.Graphics.FillEllipse(Brushes.Green, p.X - 4, p.Y - 4, 8, 8)
            Next
        End If
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.Text = "Demo Kurve"
        Me.SetStyle(ControlStyles.DoubleBuffer Or ControlStyles.UserPaint Or _
          ControlStyles.AllPaintingInWmPaint, True)
        Me.SetBounds(100, 100, 500, 500)
        Me.BackColor = Color.Black
    End Sub
    Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
        If ptsvisible AndAlso curpoint > -1 AndAlso e.Button = _
        Windows.Forms.MouseButtons.Left Then
            pt(curpoint) = New Point(e.X, e.Y)
            Me.Refresh()
        End If
    End Sub
End Class

Imports System.Drawing.Drawing2D
Public Class Form1
    Dim bzpoints() As Point = {New Point(50, 400), New Point(250, 400), New _
      Point(400, 400), New Point(450, 100)}
    Dim gpath As New GraphicsPath
    Dim curpoint As Int32
    Dim ptsvisible As Boolean
    Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown
        curpoint = -1
        If ptsvisible AndAlso gpath.IsVisible(e.Location) Then
            For i As Int32 = 0 To 3
                If Math.Abs(e.X - bzpoints(i).X) < 6 AndAlso Math.Abs(e.Y - _
                  bzpoints(i).Y) < 6 Then
                    curpoint = i
                End If
            Next
        End If
        If e.Button = Windows.Forms.MouseButtons.Right Then
            ptsvisible = Not ptsvisible
            Me.Refresh()
        End If
    End Sub
    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        e.Graphics.SmoothingMode = SmoothingMode.HighQuality
        e.Graphics.DrawBezier(New Pen(Color.Yellow, 2), bzpoints(0), bzpoints( _
          1), bzpoints(2), bzpoints(3))
        If ptsvisible Then
            gpath.Reset()
            For i As Int32 = 0 To 3
                gpath.AddEllipse(bzpoints(i).X - 5, bzpoints(i).Y - 5, 10, 10)
            Next
            e.Graphics.FillPath(Brushes.Red, gpath)
        End If
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.SetStyle(ControlStyles.DoubleBuffer Or ControlStyles.UserPaint Or _
        ControlStyles.AllPaintingInWmPaint, True)
        Me.SetBounds(100, 100, 500, 500)
        Me.BackColor = Color.Black
    End Sub
    Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
        If ptsvisible AndAlso curpoint > -1 AndAlso e.Button = _
        Windows.Forms.MouseButtons.Left Then
            bzpoints(curpoint) = New Point(e.X, e.Y)
            Me.Refresh()
        End If
    End Sub
End Class

Zitat:

Kann ich die Spline automatisch reseten, damit es eine Gerade von Anfang zu Ende ergibt. Die zwei mittleren Punkte müßten genau auf der Linie plaziert werden, damit es eine gerade ergibt. Kann ich das auch irgendwie zuweisen?

http://www.ullala.at/experiments/movement/bew_bez.html

        Dim ay, ax, by, bx, cy, cx, pty, ptx, t As Double
        CheckPoint.Clear()
        For t = 0 To 1 Step 0.2
            cx = 3 * (bzpoints(1).X - bzpoints(0).X)
            bx = 3 * (bzpoints(2).X - bzpoints(1).X) - cx
            ax = bzpoints(3).X - bzpoints(0).X - cx - bx
            ptx = ax * t ^ 3 + bx * t ^ 2 + cx * t + bzpoints(0).X
 
            cy = 3 * (bzpoints(1).Y - bzpoints(0).Y)
            by = 3 * (bzpoints(2).Y - bzpoints(1).Y) - cy
            ay = bzpoints(3).Y - bzpoints(0).Y - cy - by
            pty = ay * t ^ 3 + by * t ^ 2 + cy * t + bzpoints(0).Y
 
            CheckPoint.Add(New Point(ptx, pty))
        Next
        Refresh()

Function BezierPos(ByVal t As Double) As Point
Dim p As Point
p.X = bzpoints(0).X * t ^ 3 + bzpoints(1).X * 3 * t ^ 2 * (1 - t) + bzpoints( _
  2).X * 3 * t * (1 - t) ^ 2 + bzpoints(3).X * (1 - t) ^ 3
p.Y = bzpoints(0).Y * t ^ 3 + bzpoints(1).Y * 3 * t ^ 2 * (1 - t) + bzpoints( _
2).Y * 3 * t * (1 - t) ^ 2 + bzpoints(3).Y * (1 - t) ^ 3
  Return p
End Function

http://www.codeworx.org/opengl_tut28.php

    Dim bzpoints() As Point = {New Point(50, 400), New Point(250, 400), New _
      Point(400, 400), New Point(450, 100)}
    Dim CheckPoint As New ArrayList
 
    Dim gpath As New GraphicsPath
    Dim curpoint As Int32
    Dim ptsvisible As Boolean
    Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseDown
        curpoint = -1
        If ptsvisible AndAlso gpath.IsVisible(New Point(e.X, e.Y)) Then
            For i As Int32 = 1 To 2
                If Math.Abs(e.X - bzpoints(i).X) < 6 AndAlso Math.Abs(e.Y - _
                  bzpoints(i).Y) < 6 Then
                    curpoint = i
                End If
            Next
        End If
        If e.Button = Windows.Forms.MouseButtons.Right Then
            ptsvisible = Not ptsvisible
            Me.Refresh()
        End If
    End Sub
    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        e.Graphics.SmoothingMode = SmoothingMode.HighQuality
        For Each h As Point In CheckPoint
            e.Graphics.DrawPie(Pens.Green, h.X - 5, h.Y - 5, 10, 10, 0, 360)
 
        Next
        e.Graphics.DrawBezier(New Pen(Color.Yellow, 2), bzpoints(0), bzpoints( _
          1), bzpoints(2), bzpoints(3))
        If ptsvisible Then
            gpath.Reset()
            For i As Int32 = 0 To 3
                gpath.AddEllipse(bzpoints(i).X - 5, bzpoints(i).Y - 5, 10, 10)
            Next
            e.Graphics.FillPath(Brushes.Red, gpath)
        End If
 
 
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        CheckPoint.Add(New Point(0, 0))
 
        Me.SetStyle(ControlStyles.DoubleBuffer Or ControlStyles.UserPaint Or _
          ControlStyles.AllPaintingInWmPaint, True)
        Me.SetBounds(100, 100, 500, 500)
        Me.BackColor = Color.Black
    End Sub
    Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseMove
        If ptsvisible AndAlso curpoint > -1 AndAlso e.Button = _
        Windows.Forms.MouseButtons.Left Then
            bzpoints(curpoint) = New Point(e.X, e.Y)
            Me.Refresh()
        End If
    End Sub
 
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        bzpoints(0) = New Point(100, 400)
        bzpoints(1) = New Point(200, 300)
        bzpoints(2) = New Point(300, 200)
        bzpoints(3) = New Point(400, 100)
        Refresh()
    End Sub
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button2.Click
        Dim ay, ax, by, bx, cy, cx, pty, ptx, t As Double
        CheckPoint.Clear()
        For t = 0 To 1 Step 0.2
            CheckPoint.Add(BezierPos(t))
        Next
        Refresh()
    End Sub
    Function BezierPos(ByVal t As Double) As Point
        Dim p As Point
        p.X = bzpoints(0).X * t ^ 3 + bzpoints(1).X * 3 * t ^ 2 * (1 - t) + _
          bzpoints(2).X * 3 * t * (1 - t) ^ 2 + bzpoints(3).X * (1 - t) ^ 3
        p.Y = bzpoints(0).Y * t ^ 3 + bzpoints(1).Y * 3 * t ^ 2 * (1 - t) + _
        bzpoints(2).Y * 3 * t * (1 - t) ^ 2 + bzpoints(3).Y * (1 - t) ^ 3
        Return p
    End Function

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles Button2.Click
        GetPoints()
End Sub
    Sub GetPoints()
        CheckPoint.Clear()
        Dim x As Int32
        Dim p As Point
        For t As Double = 0.1 To 0.9 Step 0.1
            x = bzpoints(0).X + t * (bzpoints(3).X - bzpoints(0).X)
            For i As Double = 1 To 0 Step -0.001
                p.X = bzpoints(0).X * i ^ 3 + bzpoints(1).X * 3 * i ^ 2 * (1 - _
                  i) + bzpoints(2).X * 3 * i * (1 - i) ^ 2 + bzpoints(3).X * (1 _
                  - i) ^ 3
                p.Y = bzpoints(0).Y * i ^ 3 + bzpoints(1).Y * 3 * i ^ 2 * (1 - _
                i) + bzpoints(2).Y * 3 * i * (1 - i) ^ 2 + bzpoints(3).Y * (1 - _
                i) ^ 3
                If p.X >= x Then
                    CheckPoint.Add(p)
                    Exit For
                End If
            Next
        Next
        Refresh()
    End Sub

http://www.vbarchiv.net/forum/id10_i53423t53423.html

For t As Double = 0.1 To 0.9 Step 0.1          ' Test bei  (t * 100) % der 
' Gesamtlänge der Kurve
            x = bzpoints(0).X + t * (bzpoints(3).X - bzpoints(0).X)

Imports System.Drawing.Drawing2D
Public Class Form1
    Dim bzp() As Point = {New Point(50, 450), New Point(100, 400), New Point( _
      400, 100), New Point(450, 50)}
    Dim gp, gpath As New GraphicsPath
    Dim plist As New List(Of RectangleF)
    Dim ts As Int32 = 10                         ' Anzahl der Abschnitte
    Dim curpoint As Int32
    Dim ptsvisible As Boolean
 
    Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown
        curpoint = -1
        If ptsvisible AndAlso gpath.IsVisible(e.Location) Then
            For i As Int32 = 1 To 2
                If Math.Abs(e.X - bzp(i).X) < 6 AndAlso Math.Abs(e.Y - bzp( _
                  i).Y) < 6 Then
                    curpoint = i
                End If
            Next
        End If
        If e.Button = Windows.Forms.MouseButtons.Right Then
            ptsvisible = Not ptsvisible
            If Not ptsvisible Then
                GetPoints()
            End If
            Me.Refresh()
        End If
    End Sub
    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        e.Graphics.SmoothingMode = SmoothingMode.HighQuality
        e.Graphics.DrawRectangle(Pens.DimGray, 50, 50, 400, 400)
        e.Graphics.DrawBezier(New Pen(Color.Yellow, 2), bzp(0), bzp(1), bzp(2), _
          bzp(3))
        If ptsvisible Then
            gpath.Reset()
            For i As Int32 = 0 To 3
                gpath.AddEllipse(bzp(i).X - 5, bzp(i).Y - 5, 10, 10)
            Next
            e.Graphics.FillPath(Brushes.Red, gpath)
        Else
            Dim max As Int32 = plist(plist.Count - 1).Width
            Dim ppos As Int32 = 50
            For i As Int32 = 1 To ts - 1
                For Each r As RectangleF In plist
                    If r.Width >= i * max \ ts Then
                        e.Graphics.FillEllipse(Brushes.Red, r.X - 5, r.Y - 5, _
                          10, 10)
                        e.Graphics.DrawString((r.Height / 10).ToString(Format( _
                        "f2")) & " %", Me.Font, Brushes.Yellow, 2, ppos)
                        ppos += 15
                        Exit For
                    End If
                Next
            Next
        End If
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.SetStyle(ControlStyles.DoubleBuffer Or ControlStyles.UserPaint Or _
        ControlStyles.AllPaintingInWmPaint, True)
        Me.SetBounds(100, 100, 510, 520)
        Me.BackColor = Color.Black
        Me.Text = "Bezierkurve mit linearer Aufteilung der Länge"
        GetPoints()
    End Sub
    Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
        If ptsvisible AndAlso curpoint > -1 AndAlso e.Button = _
        Windows.Forms.MouseButtons.Left Then
            If e.X >= 50 AndAlso e.X <= 450 AndAlso e.Y >= 50 AndAlso e.Y _
            <= 450 Then
                bzp(curpoint) = New Point(e.X, e.Y)
                Me.Refresh()
            End If
        End If
    End Sub
    Sub GetPoints()
        Dim r As RectangleF
        r.Location = bzp(0)
        plist.Clear()
        gp.Reset()
        gp.AddBezier(bzp(0), bzp(1), bzp(2), bzp(3))
        Do
            plist.Add(r)
            Select Case True
                Case gp.IsOutlineVisible(r.X + 1, r.Y - 1, Pens.Black)
                    r.X += 1
                    r.Y -= 1
                    r.Width += 1414
                Case gp.IsOutlineVisible(r.X, r.Y - 1, Pens.Black)
                    r.Y -= 1
                    r.Width += 1000
                Case gp.IsOutlineVisible(r.X + 1, r.Y, Pens.Black)
                    r.X += 1
                    r.Width += 1000
                Case gp.IsOutlineVisible(r.X + 1, r.Y + 1, Pens.Black)
                    r.X += 1
                    r.Y -= 1
                    r.Width += 1414
                Case Else
                    Exit Do
            End Select
            r.Height = (400 - (r.Y - 50)) / 0.4
        Loop
    End Sub

Dim max As Int32 = plist(plist.Count - 1).Width           
For Each r As RectangleF In plist
    If r.Width >= max * 0.333 Then
       e.Graphics.FillEllipse(Brushes.Red, r.X - 5, r.Y - 5, 10, 10)
       e.Graphics.DrawString((r.Height / 10).ToString(Format("f2")) & " %", _
         Me.Font, Brushes.Yellow, 2, 10)
      Exit For
    End If
Next

Zitat:

In plist(plist.Count - 1).Width steht die Gesamtlänge der Kurve Nun brauchst Du nur die Liste nach dem Punkt zu durchsuchen wo die Länge 1/3 ist. Dim max As Int32 = plist(plist.Count - 1).Width For Each r As RectangleF In plist If r.Width >= max * 0.333 Then e.Graphics.FillEllipse(Brushes.Red, r.X - 5, r.Y - 5, 10, 10) e.Graphics.DrawString((r.Height / 10).ToString(Format("f2")) & " %", Me.Font, Brushes.Yellow, 2, 10) Exit For End If Next Die Berechnung erfogt unsichtbar im G-Path und ist unabhängig von der Anzeige MfG GPM

ListBox1.Items.Add(100 - ((r.Y - 10) / ((pic2.Height - 20) / 100)) & " %")

1 To ts-1

0 To ts

Sub GetPoints()
        Dim r As RectangleF
 
        plist.Clear()
        gp.Reset()
        Dim a, b, c, d As PointF
        a.X = bzp(0).X * 1000
        a.Y = bzp(0).Y * 1000
 
        b.X = bzp(1).X * 1000
        b.Y = bzp(1).Y * 1000
 
        c.X = bzp(2).X * 1000
        c.Y = bzp(2).Y * 1000
 
        d.X = bzp(3).X * 1000
        d.Y = bzp(3).Y * 1000
 
        gp.AddBezier(a, b, c, d)
        r.Location = a
        Do
            plist.Add(r)
            Select Case True
                Case gp.IsOutlineVisible(r.X + 1, r.Y - 1, Pens.Black)
                    r.X += 1
                    r.Y -= 1
                    r.Width += 1414
                Case gp.IsOutlineVisible(r.X, r.Y - 1, Pens.Black)
                    r.Y -= 1
                    r.Width += 1000
                Case gp.IsOutlineVisible(r.X + 1, r.Y, Pens.Black)
                    r.X += 1
                    r.Width += 1000
                Case gp.IsOutlineVisible(r.X + 1, r.Y + 1, Pens.Black)
                    r.X += 1
                    r.Y -= 1
                    r.Width += 1414
                Case Else
                    Exit Do
            End Select
            r.Height = (400 - (r.Y - 50)) / 0.4
        Loop
    End Sub