StrokeCollection.HitTest Method

Parameters

• stylusPointCollection
  Type: System.Windows.Input.StylusPointCollection
  The StylusPointCollection used to check for intersection with the Stroke object.

Return Value

Type: System.Windows.Ink.StrokeCollection
A StrokeCollection that contains the strokes that intersect with the points in the specified StylusPointCollection.

<Canvas>
    <Rectangle Height="500" Width="500" Stroke="Black" Margin="50,50,0,0" />
    <InkPresenter x:Name="MyIP" Height="500" Width="500" Background="Transparent" Margin="50,50,0,0"
              MouseLeftButtonDown="MyIP_MouseLeftButtonDown"
              MouseMove="MyIP_MouseMove"
              LostMouseCapture="MyIP_LostMouseCapture" />
</Canvas>

    Private MyStroke As Stroke

    Public Sub New()
        MyBase.New()
        InitializeComponent()
        SetBoundary()
    End Sub

    'A new stroke object, MyStroke, is created and is added to the StrokeCollection object
    'of the InkPresenter, MyIP
    Private Sub MyIP_MouseLeftButtonDown(ByVal sender As Object, ByVal e As MouseEventArgs)
        MyIP.CaptureMouse()
        Dim MyStylusPointCollection As StylusPointCollection = New StylusPointCollection
        MyStylusPointCollection.Add(e.StylusDevice.GetStylusPoints(MyIP))
        MyStroke = New Stroke(MyStylusPointCollection)
        MyStroke.DrawingAttributes.Color = Colors.Yellow
        MyStroke.DrawingAttributes.Width = 8
        MyIP.Strokes.Add(MyStroke)
    End Sub

    'StylusPoint objects are collected from the MouseEventArgs and added to MyStroke.
    Private Sub MyIP_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs)
        If (Not (MyStroke) Is Nothing) Then
            MyStroke.StylusPoints.Add(e.StylusDevice.GetStylusPoints(MyIP))
            Dim HitStrokes As StrokeCollection = New StrokeCollection
            HitStrokes = MyIP.Strokes.HitTest(e.StylusDevice.GetStylusPoints(MyIP))
            'Change the color of the strokes that the new strokes intersects with.
            Dim i As Integer = 0
            Do While (i _
                        < (HitStrokes.Count - 1))
                HitStrokes(i).DrawingAttributes.Color = Colors.Red
                i = (i + 1)
            Loop
        End If
    End Sub

    'MyStroke is completed
    Private Sub MyIP_LostMouseCapture(ByVal sender As Object, ByVal e As MouseEventArgs)
        MyStroke = Nothing
    End Sub

Stroke MyStroke;

//A new stroke object named MyStroke is created. MyStroke is added to the StrokeCollection of the InkPresenter named MyIP
private void MyIP_MouseLeftButtonDown(object sender, MouseEventArgs e)
{
    MyIP.CaptureMouse();

    StylusPointCollection MyStylusPointCollection = new StylusPointCollection();
    MyStylusPointCollection.Add(e.StylusDevice.GetStylusPoints(MyIP));

    MyStroke = new Stroke(MyStylusPointCollection);
    MyStroke.DrawingAttributes.Color = Colors.Yellow;
    MyStroke.DrawingAttributes.Width = 8;

    MyIP.Strokes.Add(MyStroke);
}

//StylusPoint objects are collected from the MouseEventArgs and added to MyStroke.
private void MyIP_MouseMove(object sender, MouseEventArgs e)
{
    if (MyStroke != null)
    {
        MyStroke.StylusPoints.Add(e.StylusDevice.GetStylusPoints(MyIP));
        StrokeCollection HitStrokes = new StrokeCollection();
        HitStrokes = MyIP.Strokes.HitTest(e.StylusDevice.GetStylusPoints(MyIP));
        //Change the color of the strokes that the new strokes intersects with.
        for (int i = 0; i < HitStrokes.Count - 1; i++)
        {
            HitStrokes[i].DrawingAttributes.Color = Colors.Red;
        }

    }
}

//MyStroke is completed
private void MyIP_LostMouseCapture(object sender, MouseEventArgs e)
{
    MyStroke = null;
}