InkCollector.NewPackets 事件

InkCollector 对象接收到数据包时发生。

命名空间:  Microsoft.Ink
程序集:  Microsoft.Ink(在 Microsoft.Ink.dll 中)

语法

声明
Public Event NewPackets As InkCollectorNewPacketsEventHandler
用法
Dim instance As InkCollector
Dim handler As InkCollectorNewPacketsEventHandler

AddHandler instance.NewPackets, handler
public event InkCollectorNewPacketsEventHandler NewPackets
public:
 event InkCollectorNewPacketsEventHandler^ NewPackets {
    void add (InkCollectorNewPacketsEventHandler^ value);
    void remove (InkCollectorNewPacketsEventHandler^ value);
}
/** @event */
public void add_NewPackets (InkCollectorNewPacketsEventHandler value)
/** @event */
public void remove_NewPackets (InkCollectorNewPacketsEventHandler value)
JScript 不支持事件。

备注

在收集笔画时,InkCollector 对象接收到数据包。数据包事件会快速发生,NewPackets 事件处理程序必须快速执行,否则会降低性能。

事件处理程序接收 InkCollectorNewPacketsEventArgs 类型的参数,该参数包含有关此事件的数据。

创建 InkCollectorNewPacketsEventHandler 委托时,需要标识将处理该事件的方法。若要将该事件与事件处理程序关联,请将该委托的一个实例添加到事件中。除非移除了该委托,否则每当发生该事件时就会调用此事件处理程序。出于性能方面的原因,默认事件关注处于关闭状态,但如果添加事件处理程序,它将自动打开。

如果在事件处理程序中执行太多代码,则此事件可能对墨迹 性能产生不利影响。

示例

此示例演示如何订阅 CursorInRange 事件,NewPackets 事件如何获取墨迹压力数据,以及如何使用该信息操作 DrawingAttributes 对象。

CursorInRange 事件激发时,将检查 InkCollector 对象是否第一次与此特定 Cursor 对象相联系。如果是,则将 DefaultDrawingAttributes 属性的复本分配给 DrawingAttributes 属性。这将确保对 DrawingAttributes 属性的后续访问不会引发 null 引用异常。

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;
        }
    }
}

当 NewPackets 事件激发时,将检查数据包数据中是否包含 NormalPressure。如果包含,则在状态标签上显示压力信息,并修改 DrawingAttributes 属性。

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;
        }
    }
}

平台

Windows Vista

.NET Framework 和 .NET Compact Framework 并不是对每个平台的所有版本都提供支持。有关支持的版本的列表,请参见.NET Framework 系统要求

版本信息

.NET Framework

受以下版本支持:3.0

另请参见

参考

InkCollector 类

InkCollector 成员

Microsoft.Ink 命名空间

InkCollectorNewPacketsEventArgs

Cursor

InkCollector.NewPackets

InkCollector.DesiredPacketDescription