IncrementalHitTester.AddPoints Method

Definition

Namespace:

System.Windows.Ink

Assembly:

PresentationCore.dll

Adds points to the IncrementalHitTester.

Overloads

AddPoints(IEnumerable<Point>)	Adds points to the IncrementalHitTester.
AddPoints(StylusPointCollection)	Adds the specified StylusPoint objects to the IncrementalHitTester.

AddPoints(IEnumerable<Point>)

Adds points to the IncrementalHitTester.

C#

public void AddPoints(System.Collections.Generic.IEnumerable<System.Windows.Point> points);

Parameters

points

IEnumerable<Point>

An array of type Point to add to the IncrementalHitTester.

Examples

The following example demonstrates how to add points to the IncrementalHitTester when the user inputs data with the stylus. The example includes a StrokeHit event handler that erases the part of the Stroke that the user intersects. To create a control that enables a user to erase ink, see How to: Erase Ink on a Custom Control.

C#

// Prepare to collect stylus packets. Get the 
// IncrementalHitTester from the InkPresenter's 
// StrokeCollection and subscribe to its StrokeHitChanged event.
protected override void OnStylusDown(StylusDownEventArgs e)
{
    base.OnStylusDown(e);

    EllipseStylusShape eraserTip = new EllipseStylusShape(3, 3, 0);
    eraseTester = 
        presenter.Strokes.GetIncrementalStrokeHitTester(eraserTip);
    eraseTester.StrokeHit += new StrokeHitEventHandler(eraseTester_StrokeHit);
    eraseTester.AddPoints(e.GetStylusPoints(this));
}

// Collect the StylusPackets as the stylus moves.
protected override void OnStylusMove(StylusEventArgs e)
{
    if (eraseTester.IsValid)
    {
        eraseTester.AddPoints(e.GetStylusPoints(this));
    }
}

// Unsubscribe from the StrokeHitChanged event when the
// user lifts the stylus.
protected override void OnStylusUp(StylusEventArgs e)
{

    eraseTester.AddPoints(e.GetStylusPoints(this));
    eraseTester.StrokeHit -= new
        StrokeHitEventHandler(eraseTester_StrokeHit);
    eraseTester.EndHitTesting();
}

// When the stylus intersects a stroke, erase that part of
// the stroke.  When the stylus dissects a stoke, the 
// Stroke.Erase method returns a StrokeCollection that contains
// the two new strokes.
void eraseTester_StrokeHit(object sender,
    StrokeHitEventArgs args)
{
    StrokeCollection eraseResult =
        args.GetPointEraseResults();
    StrokeCollection strokesToReplace = new StrokeCollection();
    strokesToReplace.Add(args.HitStroke);
   
    // Replace the old stroke with the new one.
    if (eraseResult.Count > 0)
    {
        presenter.Strokes.Replace(strokesToReplace, eraseResult);
    }
    else
    {
        presenter.Strokes.Remove(strokesToReplace);
    }
}

AddPoints(StylusPointCollection)

Adds the specified StylusPoint objects to the IncrementalHitTester.

C#

public void AddPoints(System.Windows.Input.StylusPointCollection stylusPoints);

Parameters

stylusPoints

StylusPointCollection

A collection of StylusPoint objects to add to the IncrementalHitTester.

Examples

The following example demonstrates how to add points to the IncrementalStrokeHitTester when the user inputs data with the stylus. The example includes a StrokeHit event handler that erases the part of the Stroke that the user intersects. To create a control that enables a user to erase ink, see How to: Erase Ink on a Custom Control.

C#

// Prepare to collect stylus packets. Get the 
// IncrementalHitTester from the InkPresenter's 
// StrokeCollection and subscribe to its StrokeHitChanged event.
protected override void OnStylusDown(StylusDownEventArgs e)
{
    base.OnStylusDown(e);

    EllipseStylusShape eraserTip = new EllipseStylusShape(3, 3, 0);
    eraseTester = 
        presenter.Strokes.GetIncrementalStrokeHitTester(eraserTip);
    eraseTester.StrokeHit += new StrokeHitEventHandler(eraseTester_StrokeHit);
    eraseTester.AddPoints(e.GetStylusPoints(this));
}

// Collect the StylusPackets as the stylus moves.
protected override void OnStylusMove(StylusEventArgs e)
{
    if (eraseTester.IsValid)
    {
        eraseTester.AddPoints(e.GetStylusPoints(this));
    }
}

// Unsubscribe from the StrokeHitChanged event when the
// user lifts the stylus.
protected override void OnStylusUp(StylusEventArgs e)
{

    eraseTester.AddPoints(e.GetStylusPoints(this));
    eraseTester.StrokeHit -= new
        StrokeHitEventHandler(eraseTester_StrokeHit);
    eraseTester.EndHitTesting();
}

// When the stylus intersects a stroke, erase that part of
// the stroke.  When the stylus dissects a stoke, the 
// Stroke.Erase method returns a StrokeCollection that contains
// the two new strokes.
void eraseTester_StrokeHit(object sender,
    StrokeHitEventArgs args)
{
    StrokeCollection eraseResult =
        args.GetPointEraseResults();
    StrokeCollection strokesToReplace = new StrokeCollection();
    strokesToReplace.Add(args.HitStroke);
   
    // Replace the old stroke with the new one.
    if (eraseResult.Count > 0)
    {
        presenter.Strokes.Replace(strokesToReplace, eraseResult);
    }
    else
    {
        presenter.Strokes.Remove(strokesToReplace);
    }
}