HwndStylusInputProvider.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Core / System / Windows / InterOp / HwndStylusInputProvider.cs / 2 / HwndStylusInputProvider.cs
                        
                        
                            using System.Runtime.InteropServices; 
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Threading;
using System.Diagnostics; 
using MS.Win32;
using MS.Internal; 
using MS.Internal.PresentationCore;                        // SecurityHelper 
using MS.Utility;
using System.Security; 
using System.Security.Permissions;

using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID; 

namespace System.Windows.Interop 
{ 
    /////////////////////////////////////////////////////////////////////////
 
    internal sealed class HwndStylusInputProvider : DispatcherObject, IInputProvider, IDisposable
    {
        private const uint TABLET_PRESSANDHOLD_DISABLED = 0x00000001;
        private const uint TABLET_TAPFEEDBACK_DISABLED  = 0x00000008; 
        private const uint TABLET_TOUCHUI_FORCEON        = 0x00000100;
        private const uint TABLET_TOUCHUI_FORCEOFF       = 0x00000200; 
        private const uint TABLET_FLICKS_DISABLED        = 0x00010000; 

        ///////////////////////////////////////////////////////////////////// 
        /// 
        ///     Accesses and stores critical data (_site, _source, _stylusLogic).
        /// 
        [SecurityCritical] 
        internal HwndStylusInputProvider(HwndSource source)
        { 
            InputManager inputManager = InputManager.Current; 
            StylusLogic stylusLogic = inputManager.StylusLogic;
 
            (new UIPermission(PermissionState.Unrestricted)).Assert();
            try //Blessed Assert this is for RegisterInputManager and RegisterHwndforinput
            {
                // Register ourselves as an input provider with the input manager. 
                _site = new SecurityCriticalDataClass(inputManager.RegisterInputProvider(this));
            } 
            finally 
            {
                UIPermission.RevertAssert(); 
            }

            stylusLogic.RegisterHwndForInput(inputManager, source);
            _source = new SecurityCriticalDataClass(source); 
            _stylusLogic = new SecurityCriticalDataClass(stylusLogic);
 
            //UnsafeNativeMethods.SetProp(new HandleRef(this, _hwnd.Value), "MicrosoftTabletPenServiceProperty", new HandleRef(null, new IntPtr(0x20000))); 
        }
 
        /////////////////////////////////////////////////////////////////////


        ///  
        ///     Critical:This class accesses critical data, _site
        ///     TreatAsSafe: This class does not expose the critical data. 
        ///  
        [SecurityCritical,SecurityTreatAsSafe]
        public void Dispose() 
        {
            if(_site != null)
            {
                _site.Value.Dispose(); 
                _site = null;
 
                _stylusLogic.Value.UnRegisterHwndForInput(_source.Value); 
                _stylusLogic = null;
                _source = null; 
            }
        }

        ///////////////////////////////////////////////////////////////////// 
        /// 
        ///     Critical: This method acceses critical data hwndsource 
        ///     TreatAsSafe:Information about whether a given input provider services 
        ///     a visual is safe to expose. This method does not expose the critical data either.
        ///  
        [SecurityCritical,SecurityTreatAsSafe]
        bool IInputProvider.ProvidesInputForRootVisual(Visual v)
        {
            Debug.Assert( null != _source ); 
            return _source.Value.RootVisual == v;
        } 
 
        void IInputProvider.NotifyDeactivate() {}
 
        /////////////////////////////////////////////////////////////////////
        //[CodeAnalysis("AptcaMethodsShouldOnlyCallAptcaMethods")] //Tracking Bug: 29647
        /// 
        ///     Critical: This code is critical since it handles all stylus messages and could be used to spoof input 
        /// 
        [SecurityCritical] 
        internal IntPtr FilterMessage(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled) 
        {
            IntPtr result = IntPtr.Zero ; 

            // It is possible to be re-entered during disposal.  Just return.
            if(null == _source || null == _source.Value)
            { 
                return result;
            } 
 
            switch(msg)
            { 
                case NativeMethods.WM_ENABLE:
                    _stylusLogic.Value.OnWindowEnableChanged(hwnd, (int)NativeMethods.IntPtrToInt32(wParam) == 0);
                    break;
 
                case NativeMethods.WM_QUERYSYSTEMGESTURESTATUS:
                    handled = true; 
 
                    NativeMethods.POINT pt1 = new NativeMethods.POINT(
                                            NativeMethods.SignedLOWORD(lParam), 
                                            NativeMethods.SignedHIWORD(lParam));
                    SafeNativeMethods.ScreenToClient(new HandleRef(this, hwnd), pt1);
                    Point ptClient1 = new Point(pt1.x, pt1.y);
 
                    IInputElement inputElement = StylusDevice.LocalHitTest(_source.Value, ptClient1);
                    if (inputElement != null) 
                    { 
                        // walk up the parent chain
                        DependencyObject elementCur = (DependencyObject)inputElement; 
                        bool isPressAndHoldEnabled = Stylus.GetIsPressAndHoldEnabled(elementCur);
                        bool isFlicksEnabled = Stylus.GetIsFlicksEnabled(elementCur);
                        bool isTapFeedbackEnabled = Stylus.GetIsTapFeedbackEnabled(elementCur);
                        bool isTouchFeedbackEnabled = Stylus.GetIsTouchFeedbackEnabled(elementCur); 

                        uint flags = 0; 
 
                        if (!isPressAndHoldEnabled)
                        { 
                            flags |= TABLET_PRESSANDHOLD_DISABLED;
                        }

                        if (!isTapFeedbackEnabled) 
                        {
                            flags |= TABLET_TAPFEEDBACK_DISABLED; 
                        } 

                        if (isTouchFeedbackEnabled) 
                        {
                            flags |= TABLET_TOUCHUI_FORCEON;
                        }
                        else 
                        {
                            flags |= TABLET_TOUCHUI_FORCEOFF; 
                        } 

                        if (!isFlicksEnabled) 
                        {
                            flags |= TABLET_FLICKS_DISABLED;
                        }
 
                        result = new IntPtr(flags);
                    } 
                    break; 

                case NativeMethods.WM_FLICK: 
                    handled = true;

                    int flickData = NativeMethods.IntPtrToInt32(wParam);
 
                    // We always handle any scroll actions if we are enabled.  We do this when we see the SystemGesture Flick come through.
                    // Note: Scrolling happens on window flicked on even if it is not the active window. 
                    if(_stylusLogic != null && _stylusLogic.Value.Enabled && (StylusLogic.GetFlickAction(flickData) == 1)) 
                    {
                        result = new IntPtr(0x0001); // tell UIHub the flick has already been handled. 
                    }
                    break;
            }
 
            if (handled && EventTrace.IsEnabled(EventTrace.Flags.performance, EventTrace.Level.normal))
            { 
                EventTrace.EventProvider.TraceEvent(EventTrace.GuidFromId(EventTraceGuidId.HWNDMESSAGEGUID), 
                                                     MS.Utility.EventType.Info,
                                                     (_source.Value.CompositionTarget != null ? _source.Value.CompositionTarget.Dispatcher.GetHashCode() : 0), 
                                                     hwnd.ToInt64(),
                                                     msg,
                                                     (int)wParam,
                                                     (int)lParam); 
            }
 
            return result; 
        }
 
        /////////////////////////////////////////////////////////////////////

        private SecurityCriticalDataClass        _stylusLogic;
        ///  
        ///     Critical: This is the HwndSurce object , not ok to expose
        ///  
        private SecurityCriticalDataClass        _source; 
        /// 
        ///     This data is critical and should never be exposed 
        /// 
        private SecurityCriticalDataClass _site;
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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HwndStylusInputProvider.cs source code in C# .NET

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