GestureRecognizer.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Core / System / Windows / Ink / GestureRecognizer.cs / 1 / GestureRecognizer.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// File: GestureRecognizer.cs
//
// Description: 
//      The implementation of GestureRecognizer class
// 
// Features: 
//
// History: 
//  01/14/2005 [....]:       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 MS.Internal.PresentationCore; 
 
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID; 

namespace System.Windows.Ink
{
    ///  
    /// Performs gesture recognition on a StrokeCollection
    ///  
    ///  
    ///     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.
    ///  
    public sealed class GestureRecognizer : DependencyObject, IDisposable
    { 
        //------------------------------------------------------------------------------- 
        //
        // Constructors 
        //
        //-------------------------------------------------------------------------------

        #region Constructors 

        ///  
        /// The default constructor which enables all the application gestures. 
        /// 
        public GestureRecognizer() : this ( new ApplicationGesture[] { ApplicationGesture.AllGestures } ) 
        {
        }

        ///  
        /// The constructor which take an array of the enabled application gestures.
        ///  
        ///  
        public GestureRecognizer(IEnumerable 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
 
        /// 
        /// Set the enabled gestures
        /// 
        ///  
        /// 
        ///     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.);
        ///     } 
        ///     } 
        ///
        ///  
        public void SetEnabledGestures(IEnumerable 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;
 
        }

        /// 
        /// Get the enabled gestures 
        /// 
        ///  
        public ReadOnlyCollection GetEnabledGestures() 
        {
            VerifyAccess(); 
            VerifyDisposed();
            VerifyRecognizerAvailable();

            //can be null if the call to SetEnabledGestures failed 
            if (_enabledGestures == null)
            { 
                _enabledGestures = new ApplicationGesture[] { }; 
            }
            return new ReadOnlyCollection(_enabledGestures); 
        }

        /// 
        /// 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. 
        ///
        ///  
        /// The StrokeCollection to perform gesture recognition on
        /// 
        /// Callers must have UnmanagedCode permission to call this API.
        ///  
        ///     Critical: Calls SecurityCritical method RecognizeImpl
        /// 
        ///     PublicOK: We demand UnmanagedCode before proceeding and 
        ///             UnmanagedCode is the only permission we assert.
        ///  
        [SecurityCritical]
        public ReadOnlyCollection 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);
        }

        ///  
        /// 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.
        ///  
        /// The StrokeCollection to perform gesture recognition on
        /// 
        /// 
        ///     Critical: Calls a SecurityCritical method RecognizeImpl. 
        ///
        ///     FriendAccess is allowed so the critical method InkCanvas.RaiseGestureOrStrokeCollected 
        ///         can use this method 
        /// 
        [SecurityCritical, FriendAccessAllowed]// Built into Core, also used by Framework. 
        internal ReadOnlyCollection CriticalRecognize(StrokeCollection strokes)
        {
            return RecognizeImpl(strokes);
        } 

        ///  
        /// Performs gesture recognition on the StrokeCollection if a gesture recognizer 
        /// is present and installed on the system.
        ///  
        /// The StrokeCollection to perform gesture recognition on
        /// 
        /// 
        ///     Critical: Calls SecurityCritical method NativeRecognizer.Recognize 
        /// 
        [SecurityCritical] 
        private ReadOnlyCollection 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(_nativeRecognizer.Recognize(strokes));
        } 

 
 
        #endregion Public Methods
 
        //--------------------------------------------------------------------------------
        //
        // Public Properties
        // 
        //--------------------------------------------------------------------------------
 
        #region Public Properties 

        ///  
        /// Indicates if a GestureRecognizer is present and installed on the system.
        /// 
        public bool IsRecognizerAvailable
        { 
            get
            { 
                VerifyAccess(); 
                VerifyDisposed();
 
                if (_nativeRecognizer == null)
                {
                    return false;
                } 
                return true;
            } 
        } 
        #endregion Public Properties
 
        //-------------------------------------------------------------------------------
        //
        // IDisposable
        // 
        //--------------------------------------------------------------------------------
 
        #region IDisposable 

        ///  
        /// Dispose this GestureRecognizer
        /// 
        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;
            }
 
            //
 
 

            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
 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

Link Menu

Network programming in C#, Network Programming in VB.NET, Network Programming in .NET
This book is available now!
Buy at Amazon US or
Buy at Amazon UK