How To: Recognize Application Gestures
The following example demonstrates how to erase ink when a user makes a ScratchOut gesture on an InkCanvas. This example assumes an InkCanvas, called inkCanvas1, is declared in the XAML file.
Example
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Ink;
using System.Collections.ObjectModel;
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
if (inkCanvas1.IsGestureRecognizerAvailable)
{
inkCanvas1.EditingMode = InkCanvasEditingMode.InkAndGesture;
inkCanvas1.Gesture += new InkCanvasGestureEventHandler(inkCanvas1_Gesture);
inkCanvas1.SetEnabledGestures(
new ApplicationGesture[] { ApplicationGesture.ScratchOut });
}
}
void inkCanvas1_Gesture(object sender, InkCanvasGestureEventArgs e)
{
ReadOnlyCollection<GestureRecognitionResult> gestureResults =
e.GetGestureRecognitionResults();
// Check the first recognition result for a gesture.
if ((gestureResults[0].RecognitionConfidence ==
RecognitionConfidence.Strong) &&
(gestureResults[0].ApplicationGesture ==
ApplicationGesture.ScratchOut))
{
StrokeCollection hitStrokes = inkCanvas1.Strokes.HitTest(
e.Strokes.GetBounds(), 10);
if (hitStrokes.Count > 0)
{
inkCanvas1.Strokes.Remove(hitStrokes);
}
}
}
}
Imports System
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Ink
Imports System.Collections.ObjectModel
Class Window1
Inherits Window
Public Sub New()
InitializeComponent()
If inkCanvas1.IsGestureRecognizerAvailable Then
inkCanvas1.EditingMode = InkCanvasEditingMode.InkAndGesture
AddHandler inkCanvas1.Gesture, AddressOf inkCanvas1_Gesture
inkCanvas1.SetEnabledGestures(New ApplicationGesture() {ApplicationGesture.ScratchOut})
End If
End Sub 'New
Sub inkCanvas1_Gesture(ByVal sender As Object, ByVal e As InkCanvasGestureEventArgs)
Dim gestureResults As ReadOnlyCollection(Of GestureRecognitionResult) = _
e.GetGestureRecognitionResults()
' Check the first recognition result for a gesture.
If gestureResults(0).RecognitionConfidence = _
RecognitionConfidence.Strong AndAlso _
gestureResults(0).ApplicationGesture = _
ApplicationGesture.ScratchOut Then
Dim hitStrokes As StrokeCollection = _
inkCanvas1.Strokes.HitTest(e.Strokes.GetBounds(), 10)
If hitStrokes.Count > 0 Then
inkCanvas1.Strokes.Remove(hitStrokes)
End If
End If
End Sub 'inkCanvas1_Gesture
End Class 'Window1