InkCollector.DesiredPacketDescription Property
Gets or sets interest in aspects of the packet associated with ink drawn on the InkCollector object.
Namespace: Microsoft.Ink
Assembly: Microsoft.Ink (in Microsoft.Ink.dll)
Syntax
'Declaration
Public Property DesiredPacketDescription As Guid()
'Usage
Dim instance As InkCollector
Dim value As Guid()
value = instance.DesiredPacketDescription
instance.DesiredPacketDescription = value
public Guid[] DesiredPacketDescription { get; set; }
public:
property array<Guid>^ DesiredPacketDescription {
array<Guid>^ get ();
void set (array<Guid>^ value);
}
public function get DesiredPacketDescription () : Guid[]
public function set DesiredPacketDescription (value : Guid[])
Property Value
Type: array<System.Guid[]
The array of Guid objects, each of which represents an aspect of the packet associated with ink drawn on the InkCollector object.
Remarks
The packet description is an array of Guid objects from the PacketProperty object.
By default, DesiredPacketDescription contains X, Y, and NormalPressure from the PacketProperty object. If you set DesiredPacketDescription to anything else, X and Y are also added. For example, if you set DesiredPacketDescription to ButtonPressure only, a get returns {X, Y, ButtonPressure}, not just {ButtonPressure}.
When DesiredPacketDescription is set to something that includes PacketStatus, PacketStatus is added in the third position. For example, if you set DesiredPacketDescription to (a, b, c, d, PacketStatus, e, f), a get returns (X, Y, PacketStatus, a, b, c, d, e, f).
In multitablet mode, this is the packet description for all of the tablet devices. If any of the devices do not support a known packet description property, the property data is not returned.
Changes to this property do not affect incoming packet data until the Enabled property changes from false to true.
Examples
The following example shows how you can use the DesiredPacketDescription property to express interest in specific Guid objects from the PacketProperty object, and then use the exposed packet properties during the NewPackets event.
First, the DesiredPacketDescription property is initialized, and the event handlers are assigned.
' Express interest in PacketStatus, TimerTick, and NormalPressure
' X and Y will be added automatically
Dim PacketDesc As Guid() = New Guid() _
{ _
PacketProperty.PacketStatus, _
PacketProperty.TimerTick, _
PacketProperty.NormalPressure _
}
' mInkObject can be InkCollector, InkOverlay, or InkPicture
mInkObject.DesiredPacketDescription = PacketDesc
' assign event handlers
AddHandler mInkObject.CursorInRange, New InkCollectorCursorInRangeEventHandler(AddressOf mInkObject_CursorInRange)
AddHandler mInkObject.NewPackets, New InkCollectorNewPacketsEventHandler(AddressOf mInkObject_NewPackets)
// Express interest in PacketStatus, TimerTick, and NormalPressure
// X and Y will be added automatically
Guid[] PacketDesc = new Guid[]
{
PacketProperty.PacketStatus,
PacketProperty.TimerTick,
PacketProperty.NormalPressure
};
// mInkObject can be InkCollector, InkOverlay, or InkPicture
mInkObject.DesiredPacketDescription = PacketDesc;
// assign event handlers
mInkObject.CursorInRange += new InkCollectorCursorInRangeEventHandler(mInkObject_CursorInRange);
mInkObject.NewPackets += new InkCollectorNewPacketsEventHandler(mInkObject_NewPackets);
When the CursorInRange event fires, a check is made to see if this is the first time that the InkCollector object has come in contact with this particular Cursor object. If so, the DrawingAttributes property is assigned with a clone of the DefaultDrawingAttributes property. This ensures that subsequent access to the DrawingAttributes property does not throw a null reference exception.
Private Sub mInkObject_CursorInRange(ByVal sender As Object, ByVal e As InkCollectorCursorInRangeEventArgs)
Const MOUSE_CURSOR_ID As Integer = 1
If e.NewCursor Then
' mInkObject can be InkCollector, InkOverlay, or InkPicture
e.Cursor.DrawingAttributes = mInkObject.DefaultDrawingAttributes.Clone()
' if this cursor is the mouse, we'll set color to red
If (MOUSE_CURSOR_ID = e.Cursor.Id) Then
e.Cursor.DrawingAttributes.Color = Color.Red
End If
End If
End Sub
private void mInkObject_CursorInRange(object sender, InkCollectorCursorInRangeEventArgs e)
{
const int MOUSE_CURSOR_ID = 1;
if (e.NewCursor)
{
// mInkObject can be InkCollector, InkOverlay, or InkPicture
e.Cursor.DrawingAttributes = mInkObject.DefaultDrawingAttributes.Clone();
// if this cursor is the mouse, we'll set color to red
if (MOUSE_CURSOR_ID == e.Cursor.Id)
{
e.Cursor.DrawingAttributes.Color = Color.Red;
}
}
}
When the NewPackets event fires, a check is made to see if NormalPressure is included in the packet data. If so, pressure information is displayed on a status label, and the DrawingAttributes property is modified.
Private Sub mInkObject_NewPackets(ByVal sender As Object, ByVal e As InkCollectorNewPacketsEventArgs)
' find the NormalPressure PacketProperty
' Set NormalPressure to -1 if not there, as some digitizers won't support it
Dim PacketDesc As Guid() = e.Stroke.PacketDescription
Dim NormalPressure As Integer = -1
For k As Integer = 0 To PacketDesc.Length - 1
If PacketDesc(k) = PacketProperty.NormalPressure Then
' for simplicity, in case of multiple packets, use the first packet only
NormalPressure = e.PacketData(k)
End If
Next k
' If we have the NormalPressure information
' change DrawingAttributes according to the NormalPressure
' Note that the change does not take effect until the next stroke
If NormalPressure <> -1 Then
' display the pressure on a status label
Me.statusLabelPressure.Text = NormalPressure.ToString()
e.Cursor.DrawingAttributes.Width = NormalPressure * 4
' if pressure is above 127, change color to Red
If NormalPressure > 127 Then
e.Cursor.DrawingAttributes.Color = Color.Red
Else
e.Cursor.DrawingAttributes.Color = mInkObject.DefaultDrawingAttributes.Color
End If
End If
End Sub
private void mInkObject_NewPackets(object sender, InkCollectorNewPacketsEventArgs e)
{
// find the NormalPressure PacketProperty
// Set NormalPressure to -1 if not there, as some digitizers won't support it
Guid[] PacketDesc = e.Stroke.PacketDescription;
int NormalPressure = -1;
for (int k = 0; k < PacketDesc.Length; k++)
{
if (PacketDesc[k] == PacketProperty.NormalPressure)
{
// for simplicity, in case of multiple packets, use the first packet only
NormalPressure = e.PacketData[k];
}
}
// If we have the NormalPressure information
// change DrawingAttributes according to the NormalPressure
// Note that the change does not take effect until the next stroke
if (NormalPressure != -1)
{
// display the pressure on a status label
this.statusLabelPressure.Text = NormalPressure.ToString();
e.Cursor.DrawingAttributes.Width = NormalPressure * 4;
// if pressure is above 127, change color to Red
if (NormalPressure > 127)
{
e.Cursor.DrawingAttributes.Color = Color.Red;
}
else
{
e.Cursor.DrawingAttributes.Color = mInkObject.DefaultDrawingAttributes.Color;
}
}
}
Platforms
Windows 7, Windows Vista, Windows Server 2008 R2, Windows Server 2008
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Version Information
.NET Framework
Supported in: 3.0