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//---------------------------------------------------------------------------
//
// File: GestureRecognizer.cs
//
// Description:
// The implementation of GestureRecognizer class
//
// Features:
//
// History:
// 01/14/2005 waynezen: Created
//
// Copyright (C) 2001 by Microsoft Corporation. All rights reserved.
//
//---------------------------------------------------------------------------
using MS.Utility;
using MS.Internal.Ink.GestureRecognition;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Runtime.InteropServices;
using System;
using System.Security;
using System.Security.Permissions;
using SecurityHelper=MS.Internal.SecurityHelper;
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID;
namespace System.Windows.Ink
{
/// <summary>
/// Performs gesture recognition on a StrokeCollection
/// </summary>
/// <remarks>
/// No finalizer is defined because all unmanaged resources are wrapped in SafeHandle's
/// NOTE: this class provides the public APIs that call into unmanaged code to perform
/// recognition. There are two inputs that are accepted:
/// ApplicationGesture[] and StrokeCollection.
/// This class verifies the ApplicationGesture[] and StrokeCollection / Stroke are validated.
/// </remarks>
public sealed class GestureRecognizer : DependencyObject, IDisposable
{
//-------------------------------------------------------------------------------
//
// Constructors
//
//-------------------------------------------------------------------------------
#region Constructors
/// <summary>
/// The default constructor which enables all the application gestures.
/// </summary>
public GestureRecognizer() : this ( new ApplicationGesture[] { ApplicationGesture.AllGestures } )
{
}
/// <summary>
/// The constructor which take an array of the enabled application gestures.
/// </summary>
/// <param name="enabledApplicationGestures"></param>
public GestureRecognizer(IEnumerable<ApplicationGesture> enabledApplicationGestures)
{
_nativeRecognizer = NativeRecognizer.CreateInstance();
if (_nativeRecognizer == null)
{
//just verify the gestures
NativeRecognizer.GetApplicationGestureArrayAndVerify(enabledApplicationGestures);
}
else
{
//
// we only set this if _nativeRecognizer is non null
// (available) because there is no way to use this state
// otherwise.
//
SetEnabledGestures(enabledApplicationGestures);
}
}
#endregion Constructors
//-------------------------------------------------------------------------------
//
// Public Methods
//
//-------------------------------------------------------------------------------
#region Public Methods
/// <summary>
/// Set the enabled gestures
/// </summary>
/// <param name="applicationGestures"></param>
/// <remarks>
/// We wrap the System.Runtime.InteropServices.COMException with a more specific one
///
/// Do wrap specific exceptions in a more descriptive exception when appropriate.
/// public Int32 GetInt(Int32[] array, Int32 index){
/// try{
/// return array[index];
/// }catch(IndexOutOfRangeException e){
/// throw new ArgumentOutOfRangeException(
/// Parameter index is out of range.);
/// }
/// }
///
/// </remarks>
public void SetEnabledGestures(IEnumerable<ApplicationGesture> applicationGestures)
{
VerifyAccess();
VerifyDisposed();
VerifyRecognizerAvailable();
//don't verfify the gestures, NativeRecognizer.SetEnabledGestures does it
// since it is the TAS boundary
//
// we don't wrap the COM exceptions generated from the Recognizer
// with our own exception
//
ApplicationGesture[] enabledGestures =
_nativeRecognizer.SetEnabledGestures(applicationGestures);
//only update the state when SetEnabledGestures succeeds (since it verifies the array)
_enabledGestures = enabledGestures;
}
/// <summary>
/// Get the enabled gestures
/// </summary>
/// <returns></returns>
public ReadOnlyCollection<ApplicationGesture> GetEnabledGestures()
{
VerifyAccess();
VerifyDisposed();
VerifyRecognizerAvailable();
//can be null if the call to SetEnabledGestures failed
if (_enabledGestures == null)
{
_enabledGestures = new ApplicationGesture[] { };
}
return new ReadOnlyCollection<ApplicationGesture>(_enabledGestures);
}
/// <summary>
/// Performs gesture recognition on the StrokeCollection if a gesture recognizer
/// is present and installed on the system. If not, this method throws an InvalidOperationException.
/// To determine if this method will throw an exception, only call this method if
/// the RecognizerAvailable property returns true.
///
/// </summary>
/// <param name="strokes">The StrokeCollection to perform gesture recognition on</param>
/// <returns></returns>
/// <remarks>Callers must have UnmanagedCode permission to call this API.</remarks>
/// <SecurityNote>
/// Critical: Calls SecurityCritical method RecognizeImpl
///
/// PublicOK: We demand UnmanagedCode before proceeding and
/// UnmanagedCode is the only permission we assert.
/// </SecurityNote>
[SecurityCritical]
public ReadOnlyCollection<GestureRecognitionResult> Recognize(StrokeCollection strokes)
{
//
// due to possible exploits in the Tablet PC Gesture recognizer's Recognize method,
// we demand unmanaged code.
//
SecurityHelper.DemandUnmanagedCode();
return RecognizeImpl(strokes);
}
/// <summary>
/// Performs gesture recognition on the StrokeCollection if a gesture recognizer
/// is present and installed on the system. If not, this method throws an InvalidOperationException.
/// To determine if this method will throw an exception, only call this method if
/// the RecognizerAvailable property returns true.
/// </summary>
/// <param name="strokes">The StrokeCollection to perform gesture recognition on</param>
/// <returns></returns>
/// <SecurityNote>
/// Critical: Calls a SecurityCritical method RecognizeImpl.
///
/// FriendAccess is allowed so the critical method InkCanvas.RaiseGestureOrStrokeCollected
/// can use this method
/// </SecurityNote>
// Built into Core, also used by Framework.
[SecurityCritical]
internal ReadOnlyCollection<GestureRecognitionResult> CriticalRecognize(StrokeCollection strokes)
{
return RecognizeImpl(strokes);
}
/// <summary>
/// Performs gesture recognition on the StrokeCollection if a gesture recognizer
/// is present and installed on the system.
/// </summary>
/// <param name="strokes">The StrokeCollection to perform gesture recognition on</param>
/// <returns></returns>
/// <SecurityNote>
/// Critical: Calls SecurityCritical method NativeRecognizer.Recognize
/// </SecurityNote>
[SecurityCritical]
private ReadOnlyCollection<GestureRecognitionResult> RecognizeImpl(StrokeCollection strokes)
{
if (strokes == null)
{
throw new ArgumentNullException("strokes"); // Null is not allowed as the argument value
}
if (strokes.Count > 2)
{
throw new ArgumentException(SR.Get(SRID.StrokeCollectionCountTooBig), "strokes");
}
VerifyAccess();
VerifyDisposed();
VerifyRecognizerAvailable();
return new ReadOnlyCollection<GestureRecognitionResult>(_nativeRecognizer.Recognize(strokes));
}
#endregion Public Methods
//-------------------------------------------------------------------------------
//
// Public Properties
//
//-------------------------------------------------------------------------------
#region Public Properties
/// <summary>
/// Indicates if a GestureRecognizer is present and installed on the system.
/// </summary>
public bool IsRecognizerAvailable
{
get
{
VerifyAccess();
VerifyDisposed();
if (_nativeRecognizer == null)
{
return false;
}
return true;
}
}
#endregion Public Properties
//-------------------------------------------------------------------------------
//
// IDisposable
//
//-------------------------------------------------------------------------------
#region IDisposable
/// <summary>
/// Dispose this GestureRecognizer
/// </summary>
public void Dispose()
{
VerifyAccess();
// A simple pattern of the dispose implementation.
// There is no finalizer since the SafeHandle in the NativeRecognizer will release the context properly.
if ( _disposed )
{
return;
}
// NTRAID-WINDOWSBUG#1102945-WAYNEZEN,
// Since the constructor might create a null _nativeRecognizer,
// here we have to make sure we do have some thing to dispose.
// Otherwise just no-op.
if ( _nativeRecognizer != null )
{
_nativeRecognizer.Dispose();
_nativeRecognizer = null;
}
_disposed = true;
}
#endregion IDisposable
//-------------------------------------------------------------------------------
//
// Private Methods
//
//-------------------------------------------------------------------------------
#region Private Methods
//verify that there is a recognizer available, throw if not
private void VerifyRecognizerAvailable()
{
if (_nativeRecognizer == null)
{
throw new InvalidOperationException(SR.Get(SRID.GestureRecognizerNotAvailable));
}
}
// Verify whether this object has been disposed.
private void VerifyDisposed()
{
if ( _disposed )
{
throw new ObjectDisposedException("GestureRecognizer");
}
}
#endregion Private Methods
//-------------------------------------------------------------------------------
//
// Private Fields
//
//-------------------------------------------------------------------------------
#region Private Fields
private ApplicationGesture[] _enabledGestures;
private NativeRecognizer _nativeRecognizer;
private bool _disposed;
#endregion Private Fields
}
}
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