StylusPlugIn Classe

Definição

public ref class StylusPlugIn abstract

public abstract class StylusPlugIn

type StylusPlugIn = class

Public MustInherit Class StylusPlugIn

Herança

Object

StylusPlugIn

Derivado

System.Windows.Input.StylusPlugIns.DynamicRenderer

Exemplos

O exemplo seguinte cria um costume StylusPlugIn que limita a tinta a uma certa área no controlo.

// EventArgs for the StrokeRendered event.
public class StrokeRenderedEventArgs : EventArgs
{
    StylusPointCollection strokePoints;

    public StrokeRenderedEventArgs(StylusPointCollection points)
    {
        strokePoints = points;
    }

    public StylusPointCollection StrokePoints
    {
        get
        {
            return strokePoints;
        }
    }
}

// EventHandler for the StrokeRendered event.
public delegate void StrokeRenderedEventHandler(object sender, StrokeRenderedEventArgs e);

// A StylusPlugin that restricts the input area
class FilterPlugin : StylusPlugIn
{
    StylusPointCollection collectedPoints;
    int currentStylus = -1;
    public event StrokeRenderedEventHandler StrokeRendered;

    protected override void OnStylusDown(RawStylusInput rawStylusInput)
    {
        // Run the base class before modifying the data
        base.OnStylusDown(rawStylusInput);

        if (currentStylus == -1)
        {
            StylusPointCollection pointsFromEvent = rawStylusInput.GetStylusPoints();

            // Create an emtpy StylusPointCollection to contain the filtered
            // points.
            collectedPoints = new StylusPointCollection(pointsFromEvent.Description);
            
            // Restrict the stylus input and add the filtered 
            // points to collectedPoints. 
            StylusPointCollection points = FilterPackets(pointsFromEvent);
            rawStylusInput.SetStylusPoints(points);
            collectedPoints.Add(points);

            currentStylus = rawStylusInput.StylusDeviceId;
        }
    }

    protected override void OnStylusMove(RawStylusInput rawStylusInput)
    {
        // Run the base class before modifying the data
        base.OnStylusMove(rawStylusInput);

        if (currentStylus == rawStylusInput.StylusDeviceId)
        {
            StylusPointCollection pointsFromEvent = rawStylusInput.GetStylusPoints();

            // Restrict the stylus input and add the filtered 
            // points to collectedPoints. 
            StylusPointCollection points = FilterPackets(pointsFromEvent);
            rawStylusInput.SetStylusPoints(points);
            collectedPoints.Add(points);
        }
    }

    protected override void OnStylusUp(RawStylusInput rawStylusInput)
    {
        // Run the base class before modifying the data
        base.OnStylusUp(rawStylusInput);

        if (currentStylus == rawStylusInput.StylusDeviceId)
        {
            StylusPointCollection pointsFromEvent = rawStylusInput.GetStylusPoints();

            // Restrict the stylus input and add the filtered 
            // points to collectedPoints. 
            StylusPointCollection points = FilterPackets(pointsFromEvent);
            rawStylusInput.SetStylusPoints(points);
            collectedPoints.Add(points);

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

            currentStylus = -1;
        }
    }

    private StylusPointCollection FilterPackets(StylusPointCollection stylusPoints)
    {
        // Modify the (X,Y) data to move the points 
        // inside the acceptable input area, if necessary
        for (int i = 0; i < stylusPoints.Count; i++)
        {
            StylusPoint sp = stylusPoints[i];
            if (sp.X < 50) sp.X = 50;
            if (sp.X > 250) sp.X = 250;
            if (sp.Y < 50) sp.Y = 50;
            if (sp.Y > 250) sp.Y = 250;
            stylusPoints[i] = sp;
        }

        // Return the modified StylusPoints.
        return stylusPoints;
    }

    // This 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)
        {
            StylusPointCollection strokePoints = callbackData as StylusPointCollection;

            if (strokePoints == null)
            {
                return;
            }

            // Raise the StrokeRendered event so the consumer of the plugin can
            // add the filtered stroke to its StrokeCollection.
            StrokeRenderedEventArgs e = new StrokeRenderedEventArgs(strokePoints);
            OnStrokeRendered(e);
        }
    }

    protected virtual void OnStrokeRendered(StrokeRenderedEventArgs e)
    {
        if (StrokeRendered != null)
        {
            StrokeRendered(this, e);
        }
    }
}

' EventArgs for the StrokeRendered event.
Public Class StrokeRenderedEventArgs
    Inherits EventArgs

    Private currentStrokePoints As StylusPointCollection

    Public Sub New(ByVal points As StylusPointCollection)

        currentStrokePoints = points

    End Sub


    Public ReadOnly Property StrokePoints() As StylusPointCollection
        Get
            Return currentStrokePoints
        End Get
    End Property
End Class

' EventHandler for the StrokeRendered event.
Public Delegate Sub StrokeRenderedEventHandler(ByVal sender As Object, ByVal e As StrokeRenderedEventArgs) 


' A StylusPlugin that restricts the input area
Class FilterPlugin
    Inherits StylusPlugIn

    Private collectedPoints As StylusPointCollection
    Private currentStylus As Integer = -1
    Public Event StrokeRendered As StrokeRenderedEventHandler


    Protected Overrides Sub OnStylusDown(ByVal rawStylusInput As RawStylusInput)

        ' Run the base class before we modify the data
        MyBase.OnStylusDown(rawStylusInput)

        If currentStylus = -1 Then

            Dim pointsFromEvent As StylusPointCollection = rawStylusInput.GetStylusPoints()

            ' Create an emtpy StylusPointCollection to contain the filtered
            ' points.
            collectedPoints = New StylusPointCollection(pointsFromEvent.Description)

            ' Restrict the stylus input and add the filtered 
            ' points to collectedPoints. 
            Dim points As StylusPointCollection = FilterPackets(pointsFromEvent)
            rawStylusInput.SetStylusPoints(points)
            collectedPoints.Add(points)

            currentStylus = rawStylusInput.StylusDeviceId

        End If

    End Sub


    Protected Overrides Sub OnStylusMove(ByVal rawStylusInput As RawStylusInput)

        ' Run the base class before we modify the data
        MyBase.OnStylusMove(rawStylusInput)

        If currentStylus = rawStylusInput.StylusDeviceId Then

            Dim pointsFromEvent As StylusPointCollection = rawStylusInput.GetStylusPoints()

            ' Restrict the stylus input and add the filtered 
            ' points to collectedPoints. 
            Dim points As StylusPointCollection = FilterPackets(pointsFromEvent)
            rawStylusInput.SetStylusPoints(points)
            collectedPoints.Add(points)

        End If

    End Sub

    Protected Overrides Sub OnStylusUp(ByVal rawStylusInput As RawStylusInput)

        ' Run the base class before we modify the data
        MyBase.OnStylusUp(rawStylusInput)

        If currentStylus = rawStylusInput.StylusDeviceId Then

            Dim pointsFromEvent As StylusPointCollection = rawStylusInput.GetStylusPoints()

            ' Restrict the stylus input and add the filtered 
            ' points to collectedPoints. 
            Dim points As StylusPointCollection = FilterPackets(pointsFromEvent)
            rawStylusInput.SetStylusPoints(points)
            collectedPoints.Add(points)

            RecordPoints(collectedPoints, "collectPoints - StylusUp")
            ' Subscribe to the OnStylusUpProcessed method.
            rawStylusInput.NotifyWhenProcessed(collectedPoints)

            currentStylus = -1

        End If

    End Sub


    Private Function FilterPackets(ByVal stylusPoints As StylusPointCollection) As StylusPointCollection

        ' Modify the (X,Y) data to move the points 
        ' inside the acceptable input area, if necessary.
        Dim i As Integer

        For i = 0 To stylusPoints.Count - 1

            Dim sp As StylusPoint = stylusPoints(i)

            If sp.X < 50 Then
                sp.X = 50
            End If

            If sp.X > 250 Then
                sp.X = 250
            End If

            If sp.Y < 50 Then
                sp.Y = 50
            End If

            If sp.Y > 250 Then
                sp.Y = 250
            End If

            stylusPoints(i) = sp

        Next i

        ' Return the modified StylusPoints.
        Return stylusPoints

    End Function 'FilterPackets

    ' This is called on the application thread.
    Protected Overrides Sub OnStylusUpProcessed(ByVal callbackData As Object, _
                                                ByVal targetVerified As Boolean)

        ' Check that the element actually receive the OnStylusUp input.
        If targetVerified Then
            Dim strokePoints As StylusPointCollection

            strokePoints = CType(callbackData, StylusPointCollection)

            If strokePoints Is Nothing Then
                Return
            End If

            ' Raise the StrokeRendered event so the consumer of the plugin can
            ' add the filtered stroke to its StrokeCollection.
            RecordPoints(strokePoints, "onStylusUpProcessed")
            Dim e As New StrokeRenderedEventArgs(strokePoints)
            OnStrokeRendered(e)
        End If

    End Sub


    Protected Overridable Sub OnStrokeRendered(ByVal e As StrokeRenderedEventArgs)

        RaiseEvent StrokeRendered(Me, e)

    End Sub

    Public Sub RecordPoints(ByVal points As StylusPointCollection, ByVal name As String)

        System.Diagnostics.Debug.WriteLine(name)
        For Each point As StylusPoint In points
            System.Diagnostics.Debug.WriteLine("   x: " & point.X & " y: " & point.Y)
        Next
    End Sub
End Class

Observações

Permite-te StylusPlugIn manipular StylusPoint objetos em threads separados. São usados threads separados para que a tinta continue a ser renderizada à medida que a caneta do tablet insere dados, mesmo que a aplicação esteja a fazer outra coisa.

Para intercetar pontos de stylus do hardware, crie uma classe que herde da StylusPlugIn classe. A StylusPlugIn classe tem os seguintes métodos que podes sobrepor para manipular StylusPoint objetos numa thread no pool de canetas thread.

• OnStylusDown

• OnStylusUp

• OnStylusMove

• OnStylusEnter

• OnStylusLeave

A entrada da caneta é encaminhada para um elemento StylusPlugIn na linha da caneta. Como não é possível realizar testes de acerto precisos na linha de canetas, alguns elementos podem ocasionalmente receber entrada da stylus destinada a outros elementos. Se você precisar se certificar de que a entrada foi roteada corretamente antes de executar uma operação, inscreva-se e execute a operação no método OnStylusDownProcessed, OnStylusMoveProcessedou OnStylusUpProcessed. Estes métodos são invocados pelo tópico principal de aplicação após a realização de testes de acerto precisos. Para subscrever a esses métodos, invoque o método NotifyWhenProcessed no método que ocorre na sequência do pen. Por exemplo, se chamar NotifyWhenProcessed em OnStylusMove, ocorre.OnStylusMoveProcessed

Utilização de Texto XAML

Esta classe não é normalmente usada em XAML.