InkCollectorNewInAirPacketsEventHandler Delegate
InkCollectorNewInAirPacketsEventHandler Delegate |
Represents the method that handles the NewInAirPackets event of an InkCollector.
Definition
Visual Basic .NET Public Delegate Sub InkCollectorNewInAirPacketsEventHandler( _
ByVal sender As Object, _
ByVal e As InkCollectorNewInAirPacketsEventArgs _
)C# public delegate void InkCollectorNewInAirPacketsEventHandler(
object sender,
InkCollectorNewInAirPacketsEventArgs e
);Managed C++ public: __gc __delegate void InkCollectorNewInAirPacketsEventHandler(
Object *sender,
InkCollectorNewInAirPacketsEventArgs *e
);
Parameters
sender System.Object. [in] Specifies the source InkCollector of this event. e Microsoft.Ink.InkCollectorNewInAirPacketsEventArgs. [in] Specifies the InkCollectorNewInAirPacketsEventArgs 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
An in-air packet is created when a user moves a pen near the tablet and the cursor is within the InkCollector object's window or the user moves a mouse within the InkCollector object's associated window. NewInAirPackets events are generated rapidly, and the event handler must be fast or performance suffers.
When you create an InkCollectorNewInAirPacketsEventHandler 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.
The NewInAirPackets event is fired even when in select or erase mode, not just when inserting ink. This requires that you monitor the editing mode (which you are responsible for setting) and be aware of the mode before interpreting the event. The advantage of this requirement is greater freedom to innovate on the platform through greater awareness of platform events.
Examples
[C#]
This C# example draws a rectangle on the form with a bold outline when the in-air 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 CSInAirPacketEvents { 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 in-air packets theInkCollector.NewInAirPackets += new InkCollectorNewInAirPacketsEventHandler(NewInAirPackets_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 NewInAirPackets_Event(object sender, InkCollectorNewInAirPacketsEventArgs 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 in-air 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.NewInAirPackets, AddressOf NewInAirPackets_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 NewInAirPackets_Event(ByVal sender As Object, _ ByVal e As InkCollectorNewInAirPacketsEventArgs) '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