RawStylusInput Class

Definition

Namespace:

System.Windows.Input.StylusPlugIns

Assembly:

PresentationCore.dll

Provides information about input from a StylusDevice to a StylusPlugIn.

C#

public class RawStylusInput

Inheritance

Object

RawStylusInput

Examples

The following example creates a StylusPlugIn that checks for the Down gesture. The StylusPlugIn calls NotifyWhenProcessed in OnStylusUp to subscribe to the OnStylusUpProcessed method, which is called from the application thread.

C#

class RecognizerPlugin : StylusPlugIn
{
    GestureRecognizer recognizer;
    
    // StylusPointCollection that contains the stylus points of the current
    // stroke.
    StylusPointCollection points;

    // Keeps track of the stylus to check whether two styluses are used on the
    // digitizer.
    int currentStylus;

    public RecognizerPlugin()
        : base()
    {
        recognizer = new GestureRecognizer();
    }

    // Collect the points as the user draws the stroke.
    protected override void OnStylusDown(RawStylusInput rawStylusInput)
    {
        // If points is not null, there is already a stroke taking place
        // on the digitizer, so don't create a new StylusPointsCollection.
        if (points == null)
        {
            points = new StylusPointCollection(rawStylusInput.GetStylusPoints().Description);
            points.Add(rawStylusInput.GetStylusPoints());
            currentStylus = rawStylusInput.StylusDeviceId;
        }
    }

    // Collect the points as the user draws the stroke.
    protected override void OnStylusMove(RawStylusInput rawStylusInput)
    {
        // Check whether the stylus that started the stroke is the same, and
        // that the element hasn't lost focus since the stroke began.
            if (points != null && currentStylus == rawStylusInput.StylusDeviceId)
        {
            points.Add(rawStylusInput.GetStylusPoints());
        }
    }

    // Collect the points as the user draws the stroke.
    protected override void OnStylusUp(RawStylusInput rawStylusInput)
    {
        // Check whether the stylus that started the stroke is the same, and
        // that the element hasn't lost focus since the stroke began.
        if (points != null && currentStylus == rawStylusInput.StylusDeviceId)
        {
            points.Add(rawStylusInput.GetStylusPoints());

            // Subscribe to the OnStylusUpProcessed method.
            rawStylusInput.NotifyWhenProcessed(points);
        }

        points = null;
        currentStylus = 0;
    }
        
    // If the element loses focus, stop collecting the points and don't
    // perform gesture recognition.
    protected override void OnStylusLeave(RawStylusInput rawStylusInput, bool confirmed)
    {
        if (confirmed)
        {
            // Clear the StylusPointCollection
            points = null;
            currentStylus = 0;
        }
    }

    // This method is called on the application thread.
    protected override void OnStylusUpProcessed(object callbackData, bool targetVerified)
    {
        // Check that the element actually receive the OnStylusUp input.
        if (targetVerified && recognizer.IsRecognizerAvailable)
        {
            StylusPointCollection strokePoints = callbackData as StylusPointCollection;

            if (strokePoints == null)
            {
                return;
            }

            // Create a StrokeCollection to pass to the GestureRecognizer.
            Stroke newStroke = new Stroke(strokePoints);
            StrokeCollection strokes = new StrokeCollection();
            strokes.Add(newStroke);

            ReadOnlyCollection<GestureRecognitionResult> results = recognizer.Recognize(strokes);

            // If the GestureRecognizer recognizes the stroke as a Down
            // gesture with strong confidence, raise an event.
            if (results[0].ApplicationGesture == ApplicationGesture.Down &&
                results[0].RecognitionConfidence == RecognitionConfidence.Strong)
            {
                //raise event
            }
        }
    }
}

Remarks

Use the RawStylusInput to get information about the input the StylusPlugIn receives when the user moves the stylus.

Properties

StylusDeviceId	Gets the identifier of the current stylus device.
TabletDeviceId	Gets the identifier of the current tablet device.
Timestamp	Gets the time at which the input occurred.

Methods

GetStylusPoints()	Gets the stylus points that are collected from the stylus.
NotifyWhenProcessed(Object)	Subscribes to the application thread's corresponding stylus methods.
SetStylusPoints(StylusPointCollection)	Sets the stylus points that are passed to the application thread.

Applies to