Option Strict On
Public Class Form1
    Private dreieck As New System.Drawing.Drawing2D.GraphicsPath 'Dreieck
    Private rechteck As New System.Drawing.Drawing2D.GraphicsPath 'Rechteck
    Private rechteckRegion As System.Drawing.Region 'Region zur Bildung des 
    ' Schnitts
 
    Public Sub New()
        InitializeComponent()
        Me.DoubleBuffered = True
        'Rechteck erstellen
        rechteck.AddRectangle(New Rectangle(New Point(100, 100), New Size(70, _
          60)))
        rechteckRegion = New System.Drawing.Region(rechteck)
    End Sub
 
 
    Private Sub Form1_MouseMove(sender As Object, e As _
      System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
        Dim loc As Point = e.Location
        dreieck.Reset() 'Neues Dreieck an der aktuellen Mausposition
        dreieck.AddPolygon(New Point() {New Point(loc.X - 20, loc.Y - 10), New _
          Point(loc.X + 20, loc.Y - 10), New Point(loc.X + 20, loc.Y + 30)})
        Me.Invalidate() ' Repaint-Ereignis auslösen
 
        Dim regIntersect As New System.Drawing.Region(dreieck) 'Region für das 
        ' Dreieck
        regIntersect.Intersect(rechteck)
        Label1.Text = If(regIntersect.IsEmpty(Me.CreateGraphics()), "Nein", _
          "Ja") 'Ist der Schnitt leer?
 
    End Sub
 
    Private Sub Form1_Paint(sender As Object, e As _
      System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        Dim g As Graphics = e.Graphics
        g.FillPath(Brushes.Black, dreieck)
        g.DrawPath(Pens.Blue, rechteck)
    End Sub
 
End Class