IncrementalHitTester 类

定义

Stroke 动态执行命中测试。

public ref class IncrementalHitTester abstract
public abstract class IncrementalHitTester
type IncrementalHitTester = class
Public MustInherit Class IncrementalHitTester
继承
IncrementalHitTester
派生

示例

以下示例演示如何在用户使用触笔输入数据时向 添加点 IncrementalHitTester 。 该示例包含一个 StrokeHit 事件处理程序,用于清除用户相交的 部分 Stroke 。 若要创建允许用户擦除墨迹的控件,请参阅 如何:擦除自定义控件上的墨迹


// Prepare to collect stylus packets. Get the 
// IncrementalHitTester from the InkPresenter's 
// StrokeCollection and subscribe to its StrokeHitChanged event.
protected override void OnStylusDown(StylusDownEventArgs e)
{
    base.OnStylusDown(e);

    EllipseStylusShape eraserTip = new EllipseStylusShape(3, 3, 0);
    eraseTester = 
        presenter.Strokes.GetIncrementalStrokeHitTester(eraserTip);
    eraseTester.StrokeHit += new StrokeHitEventHandler(eraseTester_StrokeHit);
    eraseTester.AddPoints(e.GetStylusPoints(this));
}

// Collect the StylusPackets as the stylus moves.
protected override void OnStylusMove(StylusEventArgs e)
{
    if (eraseTester.IsValid)
    {
        eraseTester.AddPoints(e.GetStylusPoints(this));
    }
}

// Unsubscribe from the StrokeHitChanged event when the
// user lifts the stylus.
protected override void OnStylusUp(StylusEventArgs e)
{

    eraseTester.AddPoints(e.GetStylusPoints(this));
    eraseTester.StrokeHit -= new
        StrokeHitEventHandler(eraseTester_StrokeHit);
    eraseTester.EndHitTesting();
}

// When the stylus intersects a stroke, erase that part of
// the stroke.  When the stylus dissects a stoke, the 
// Stroke.Erase method returns a StrokeCollection that contains
// the two new strokes.
void eraseTester_StrokeHit(object sender,
    StrokeHitEventArgs args)
{
    StrokeCollection eraseResult =
        args.GetPointEraseResults();
    StrokeCollection strokesToReplace = new StrokeCollection();
    strokesToReplace.Add(args.HitStroke);
   
    // Replace the old stroke with the new one.
    if (eraseResult.Count > 0)
    {
        presenter.Strokes.Replace(strokesToReplace, eraseResult);
    }
    else
    {
        presenter.Strokes.Remove(strokesToReplace);
    }
}

     ' Prepare to collect stylus packets. Get the 
     ' IncrementalHitTester from the InkPresenter's 
     ' StrokeCollection and subscribe to its StrokeHitChanged event.
     Protected Overrides Sub OnStylusDown(ByVal e As StylusDownEventArgs)

         MyBase.OnStylusDown(e)

         Dim eraserTip As New EllipseStylusShape(3, 3, 0)
         eraseTester = presenter.Strokes.GetIncrementalStrokeHitTester(eraserTip)
         AddHandler eraseTester.StrokeHit, _
             AddressOf eraseTester_StrokeHit
         eraseTester.AddPoints(e.GetStylusPoints(Me))

     End Sub

     ' Collect the StylusPackets as the stylus moves.
     Protected Overrides Sub OnStylusMove(ByVal e As StylusEventArgs)

         If eraseTester.IsValid Then
             eraseTester.AddPoints(e.GetStylusPoints(Me))
         End If

     End Sub

     ' Unsubscribe from the StrokeHitChanged event when the
     ' user lifts the stylus.
     Protected Overrides Sub OnStylusUp(ByVal e As StylusEventArgs)

         eraseTester.AddPoints(e.GetStylusPoints(Me))

         RemoveHandler eraseTester.StrokeHit, _
             AddressOf eraseTester_StrokeHit
         eraseTester.EndHitTesting()

     End Sub


     ' When the stylus intersects a stroke, erase that part of
     ' the stroke.  When the stylus dissects a stoke, the 
     ' Stroke.Erase method returns a StrokeCollection that contains
     ' the two new strokes.
     Private Sub eraseTester_StrokeHit(ByVal sender As Object, _
             ByVal args As StrokeHitEventArgs)

         Dim eraseResult As StrokeCollection = _
             args.GetPointEraseResults()
         Dim strokesToReplace As New StrokeCollection()
         strokesToReplace.Add(args.HitStroke)

         ' Replace the old stroke with the new one.
         If eraseResult.Count > 0 Then
             presenter.Strokes.Replace(strokesToReplace, eraseResult)
         Else
             presenter.Strokes.Remove(strokesToReplace)
         End If

     End Sub

注解

动态 IncrementalHitTester 确定用户是否“命中”了 Stroke。 此类使你能够在选择和擦除墨迹等情况下向用户提供即时反馈。

有两个继承自 IncrementalHitTester的类:

下表列出了在何处了解如何管理自定义控件上的数字墨迹。

要实现的目的… 参考文章
创建用于收集数字墨迹的控件 创建墨迹输入控件
创建允许用户选择墨迹的控件 如何:从自定义控件选择墨迹
创建允许用户对墨迹进行点擦除的控件 如何:清除自定义控件上的墨迹

XAML 文本用法

此类通常不在 XAML 中使用。

属性

IsValid

获取 IncrementalHitTester 是否在进行命中测试。

方法

AddPoint(Point)

Point 中添加一个 IncrementalHitTester

AddPoints(IEnumerable<Point>)

IncrementalHitTester 添加点。

AddPoints(StylusPointCollection)

将指定的 StylusPoint 对象添加到 IncrementalHitTester 中。

AddPointsCore(IEnumerable<Point>)

IncrementalHitTester 添加点。

EndHitTesting()

释放由 IncrementalHitTester 使用的资源。

Equals(Object)

确定指定对象是否等于当前对象。

(继承自 Object)
GetHashCode()

作为默认哈希函数。

(继承自 Object)
GetType()

获取当前实例的 Type

(继承自 Object)
MemberwiseClone()

创建当前 Object 的浅表副本。

(继承自 Object)
ToString()

返回表示当前对象的字符串。

(继承自 Object)

适用于