InkCollectorNewPacketsEventHandler Delegate

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InkCollectorNewPacketsEventHandler Delegate

Represents the method that handles the NewPackets event of an InkCollector.

Definition

Visual Basic .NET Public Delegate Sub InkCollectorNewPacketsEventHandler( _
ByVal sender As Object, _
ByVal e As InkCollectorNewPacketsEventArgs _
)
C# public delegate void InkCollectorNewPacketsEventHandler(
object sender,
InkCollectorNewPacketsEventArgs e
);
Managed C++ public: __gc __delegate void InkCollectorNewPacketsEventHandler(
Object *sender,
InkCollectorNewPacketsEventArgs *e
);

Parameters

sender System.Object. [in] Specifies the source InkCollector of this event.
e Microsoft.Ink.InkCollectorNewPacketsEventArgs. [in] Specifies the InkCollectorNewPacketsEventArgs object that contains the event data.

Delegate Information

Namespace Microsoft.Ink
Assembly Microsoft.Ink (microsoft.ink.dll)
Strong Name Microsoft.Ink, Version=1.7.4009.0, Culture=neutral, PublicKeyToken=a2870d9cc4d021c8

Remarks

When you create an InkCollectorNewPacketsEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For performance reasons, the default event interest is off but is turned on automatically in managed code if you add an event handler.

Packets are received while a stroke is being collected. Packet events occur rapidly, and a NewPackets event handler must be fast or ink performance suffers.

Examples

[C#]

This C# example draws a rectangle on the form with a bold outline when the packets are within the rectangle or with a narrow outline when the packets are outside the rectangle. This demonstrates how to use the packet events to control application behaviors.

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using Microsoft.Ink;

namespace CSNewPacketEvents
{
    public class Form1 : System.Windows.Forms.Form
    {
    //...

        InkCollector theInkCollector;
        int indexX, indexY;
        Rectangle rectInterest;
        bool thickBorder;

        public Form1()
        {
            //...

            //Initialize the InkCollector object.
            theInkCollector = new InkCollector(Handle);
            theInkCollector.Enabled = true;

            //Initialize the target rectangle
            rectInterest = new Rectangle(40, 40, 200, 80);
            thickBorder = false;

            //Save the X and Y data locations within the packet data.
            GetXYIndexes(ref indexX, ref indexY);

            //Add the event handler for new packets
            theInkCollector.NewPackets += new InkCollectorNewPacketsEventHandler(NewPackets_Event);
        }

//...

        private void GetXYIndexes(ref int theXIndex, ref int theYIndex)
        {
            // Get the indexes of the X and Y data within the raw
            // packet data array.
            Guid [] theGuids = theInkCollector.DesiredPacketDescription;
            for (int i = 0; i < theGuids.Length; i++)
            {
                if (theGuids[i].Equals(PacketProperty.X))
                    theXIndex = i;
                if (theGuids[i].Equals(PacketProperty.Y))
                    theYIndex = i;
            }
        }

        private void NewPackets_Event(object sender, InkCollectorNewPacketsEventArgs e)
        {
            Graphics g = this.CreateGraphics();
            Point [] pt = new Point [1];
            pt[0].X = e.PacketData[indexX];
            pt[0].Y = e.PacketData[indexY];
            theInkCollector.Renderer.InkSpaceToPixel(g, ref pt);

            // The event may return with data for multiple packets.
            // To simplify things, we'll only look at the first.
            if (rectInterest.Contains(pt[0].X, pt[0].Y))
            {
                if (!thickBorder)
                {
                    thickBorder = true;
                    Refresh();
                }
            }
            else
            {
                if (thickBorder)
                {
                    thickBorder = false;
                    Refresh();
                }
            }
        }

        private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            Pen thePen = new Pen(Color.Black, 2);
            if (thickBorder)
                thePen.Width = 5;
            g.DrawRectangle(thePen, rectInterest);
        }

        // Event handler for the form's closed event
        private void Form1_Closed(object sender, System.EventArgs e)
        {
            theInkCollector.Dispose();
            theInkCollector = null;
        }
    }
}

[Visual Basic .NET]

This Microsoft® Visual Basic® .NET example draws a rectangle on the form with a bold outline when the packets are within the rectangle or with a narrow outline when the packets are outside the rectangle. This demonstrates how to use the packet events to control application behaviors.

Imports Microsoft.Ink
Public Class Form1
    Inherits System.Windows.Forms.Form

    Dim theInkCollector As InkCollector
    Dim indexX, indexY As Integer
    Dim rectInterest As Rectangle
    Dim thickBorder As Boolean

'...

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Initialize the InkCollector object.
        theInkCollector = New InkCollector(Handle)
        theInkCollector.Enabled = True

        'Initialize the target rectangle
        rectInterest = New Rectangle(40, 40, 200, 80)
        thickBorder = False

        'Save the X and Y data locations within the packet data.
        GetXYIndexes(indexX, indexY)

        'Add the event handler for in air packets
        AddHandler theInkCollector.NewPackets, AddressOf NewPackets_Event

    End Sub

'...

    Private Sub GetXYIndexes(ByRef theXIndex As Integer, _
        ByRef theYIndex As Integer)
        ' Get the indexes of the X and Y data within the raw
        ' packet data array.
        Dim theGuids() As Guid = theInkCollector.DesiredPacketDescription
        Dim i As Integer
        For i = 0 To theGuids.Length - 1
            If theGuids(i).Equals(PacketProperty.X) Then
                theXIndex = i
            End If
            If theGuids(i).Equals(PacketProperty.Y) Then
                theYIndex = i
            End If
        Next
    End Sub

    Private Sub NewPackets_Event(ByVal sender As Object, _
        ByVal e As InkCollectorNewPacketsEventArgs)
        'The event may return with data for multiple packets.
        'To simplify things, we'll only look at the first.
        If rectInterest.Contains( _
            e.PacketData(indexX), e.PacketData(indexY)) Then
            If thickBorder = False Then
                thickBorder = True
                Refresh()
            End If
        Else
            If thickBorder = True Then
                thickBorder = False
                Refresh()
            End If
        End If
    End Sub

    Private Sub Form1_Paint(ByVal sender As Object, _
        ByVal e As System.Windows.Forms.PaintEventArgs) _
        Handles MyBase.Paint
        Dim g As Graphics = e.Graphics
        Dim thePen As New Pen(Color.Black, 2)
        If thickBorder Then
            thePen.Width = 5
        End If
        g.DrawRectangle(thePen, rectInterest)
    End Sub

    'Event handler for the form's closed event
    Private Sub Form1_Closed(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Closed
        theInkCollector.Dispose()
        Set theInkCollector = Nothing
    End Sub
End Class

See Also