Public Class Line
        Public Loc As Point                                         'Koordinaten
        Public Line_Type As Integer                                 'Linientyp 
        ' nach dem Punkt (0 = nix; 1 = Linie; 2 = Béziere)
        Public Tangente_before As Point                             _
          'Tangentenstützpunkt nach vorne
        Public Tangente_after As Point                              _
        'tangentenstützpunkt nach hinten
        Public Type As Integer                                      'Art des 
        ' Punktes (0 = Eckig; 1 = tangential; 3 = symetrisch)
        Public Line_Points As New List(Of Point)                    'Verlauf 
        ' des Splines
        Public Line_Points_inv As New List(Of Point)                'Verlauf 
        ' des Splines
    End Class
    Public points As New List(Of Line)
 
    Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
        If mode = Program_mode.draw Then
            If e.Button = Windows.Forms.MouseButtons.Left Then
                '***neuen Punkt hinzufügen***
                points.Add(New Line)
                points(points.Count - 1).Loc.Y = PictureBox1.Height - e.Y
                points(points.Count - 1).Loc.X = e.X
                points(points.Count - 1).Line_Type = 2
                '***Tangenpunke erzeugen***
                'Tangente nach vorne 
                If points.Count > 2 Then
                    calculate_tangentes_before(points.Count - 1)
                    calculate_Tangentes_both(points.Count - 2)
                    Calculate_Spline(points.Count - 3)
                    Calculate_Spline(points.Count - 2)
                ElseIf points.Count = 2 Then
                    calculate_tangentes_after(0)
                    calculate_tangentes_before(1)
                    Calculate_Spline(0)
                End If
            ElseIf e.Button = Windows.Forms.MouseButtons.Right Then
                end_line(points.Count - 1)
            End If
 
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