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//---------------------------------------------------------------------------
//
// File: NativeRecognizer.cs
//
// Description:
// A wrapper class which interoperates with the unmanaged recognition APIS
// in mshwgst.dll
//
// Features:
//
// History:
// 01/14/2005 waynezen: Created
//
// Copyright (C) 2001 by Microsoft Corporation. All rights reserved.
//
//---------------------------------------------------------------------------
using Microsoft.Win32;
using MS.Win32;
using System;
using System.Security;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Runtime.ConstrainedExecution;
using System.Security.Permissions;
using System.Text;
using System.Windows.Media;
using System.Windows.Ink;
using System.Windows.Input;
using MS.Internal.PresentationCore;
using MS.Utility;
using SR = MS.Internal.PresentationCore.SR;
using SRID = MS.Internal.PresentationCore.SRID;
#pragma warning disable 1634, 1691 // suppressing PreSharp warnings
namespace MS.Internal.Ink.GestureRecognition
{
/// <summary>
/// NativeRecognizer class
/// </summary>
internal sealed class NativeRecognizer : IDisposable
{
//-------------------------------------------------------------------------------
//
// Constructors
//
//-------------------------------------------------------------------------------
#region Constructors
/// <summary>
/// Static constructor
/// </summary>
/// <SecurityNote>
/// Critical: Calls a SecurityCritical methods
/// LoadRecognizerDll();
/// </SecurityNote>
[SecurityCritical]
static NativeRecognizer()
{
s_isSupported = LoadRecognizerDll();
}
/// <summary>
/// Private constructor
/// </summary>
/// <SecurityNote>
/// Critical: Calls a SecurityCritical method
/// NativeRecognizer.UnsafeNativeMethods.CreateContext()
/// Accesses the SecurityCritical member
/// _hContext
/// </SecurityNote>
[SecurityCritical]
private NativeRecognizer()
{
Debug.Assert(NativeRecognizer.RecognizerHandleSingleton != null);
int hr = MS.Win32.Recognizer.UnsafeNativeMethods.CreateContext(NativeRecognizer.RecognizerHandleSingleton,
out _hContext);
if (HRESULT.Failed(hr))
{
//don't throw a com exception here, we don't need to pass out any details
throw new InvalidOperationException(SR.Get(SRID.UnspecifiedGestureConstructionException));
}
// We add a reference of the recognizer to the context handle.
// The context will dereference the recognizer reference when it gets disposed.
// This trick will prevent the GC from disposing the recognizer before all contexts.
_hContext.AddReferenceOnRecognizer(NativeRecognizer.RecognizerHandleSingleton);
}
#endregion Constructors
//-------------------------------------------------------------------------------
//
// Internal Methods
//
//-------------------------------------------------------------------------------
#region Internal Methods
/// <summary>
/// Create an Instance of the NativeRecognizer.
/// </summary>
/// <returns>null if it fails</returns>
/// <SecurityNote>
/// Critical: Calls a SecurityCritical method
/// NativeRecognizer();
/// TreatAsSafe: The method is safe because no arguments are passed.
/// The NativeRecognizer return value is protected with SecurityCritical
/// attributes
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
internal static NativeRecognizer CreateInstance()
{
if (NativeRecognizer.RecognizerHandleSingleton != null)
{
return new NativeRecognizer();
}
else
{
return null;
}
}
/// <summary>
/// Set the enabled gestures
/// </summary>
/// <param name="applicationGestures"></param>
/// <SecurityNote>
/// Critical: Handles _hContext, which is SecurityCritical
/// TreatAsSafe: The method is safe because argument passed can not be
/// used maliciously. And we verify the length of the passed in array.
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
internal ApplicationGesture[] SetEnabledGestures(IEnumerable<ApplicationGesture> applicationGestures)
{
if (_disposed)
{
throw new ObjectDisposedException("NativeRecognizer");
}
//validate and get an array out
ApplicationGesture[] enabledGestures =
GetApplicationGestureArrayAndVerify(applicationGestures);
// Set enabled Gestures.
int hr = SetEnabledGestures(_hContext, enabledGestures);
if (HRESULT.Failed(hr))
{
//don't throw a com exception here, we don't need to pass out any details
throw new InvalidOperationException(SR.Get(SRID.UnspecifiedSetEnabledGesturesException));
}
return enabledGestures;
}
/// <summary>
/// Recognize the strokes.
/// </summary>
/// <param name="strokes"></param>
/// <returns></returns>
/// <SecurityNote>
/// Critical: Calls a SecurityCritical method
/// NativeRecognizer.UnsafeNativeMethods.ResetContext,
/// AddStrokes,
/// NativeRecognizer.UnsafeNativeMethods.Process
/// InvokeGetAlternateList
/// InvokeGetLatticePtr
/// </SecurityNote>
[SecurityCritical]
internal GestureRecognitionResult[] Recognize(StrokeCollection strokes)
{
if (_disposed)
{
throw new ObjectDisposedException("NativeRecognizer");
}
//
// note that we validate this argument from GestureRecognizer
// but since this is marked TAS, we want to do it here as well
//
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");
}
// Create an empty result.
GestureRecognitionResult[] recResults = new GestureRecognitionResult[]{};
if ( strokes.Count == 0 )
{
return recResults;
}
int hr = 0;
try
{
// Reset the context
hr = MS.Win32.Recognizer.UnsafeNativeMethods.ResetContext(_hContext);
if (HRESULT.Failed(hr))
{
//finally block will clean up and throw
return recResults;
}
// Add strokes
hr = AddStrokes(_hContext, strokes);
if (HRESULT.Failed(hr))
{
//AddStrokes's finally block will clean up this finally block will throw
return recResults;
}
// recognize the ink
bool bIncremental;
hr = MS.Win32.Recognizer.UnsafeNativeMethods.Process(_hContext, out bIncremental);
if (HRESULT.Succeeded(hr))
{
if ( s_GetAlternateListExists )
{
recResults = InvokeGetAlternateList();
}
else
{
recResults = InvokeGetLatticePtr();
}
}
}
finally
{
// Check if we should report any error.
if ( HRESULT.Failed(hr) )
{
//don't throw a com exception here, we don't need to pass out any details
throw new InvalidOperationException(SR.Get(SRID.UnspecifiedGestureException));
}
}
return recResults;
}
internal static ApplicationGesture[] GetApplicationGestureArrayAndVerify(IEnumerable<ApplicationGesture> applicationGestures)
{
if (applicationGestures == null)
{
// Null is not allowed as the argument value
throw new ArgumentNullException("applicationGestures");
}
uint count = 0;
//we need to make a disconnected copy
ICollection<ApplicationGesture> collection = applicationGestures as ICollection<ApplicationGesture>;
if (collection != null)
{
count = (uint)collection.Count;
}
else
{
foreach (ApplicationGesture gesture in applicationGestures)
{
count++;
}
}
// Cannot be empty
if (count == 0)
{
// An empty array is not allowed.
throw new ArgumentException(SR.Get(SRID.ApplicationGestureArrayLengthIsZero), "applicationGestures");
}
bool foundAllGestures = false;
List<ApplicationGesture> gestures = new List<ApplicationGesture>();
foreach (ApplicationGesture gesture in applicationGestures)
{
if (!ApplicationGestureHelper.IsDefined(gesture))
{
throw new ArgumentException(SR.Get(SRID.ApplicationGestureIsInvalid), "applicationGestures");
}
//check for allgestures
if (gesture == ApplicationGesture.AllGestures)
{
foundAllGestures = true;
}
//check for dupes
if (gestures.Contains(gesture))
{
throw new ArgumentException(SR.Get(SRID.DuplicateApplicationGestureFound), "applicationGestures");
}
gestures.Add(gesture);
}
// AllGesture cannot be specified with other gestures
if (foundAllGestures && gestures.Count != 1)
{
// no dupes allowed
throw new ArgumentException(SR.Get(SRID.AllGesturesMustExistAlone), "applicationGestures");
}
return gestures.ToArray();
}
#endregion Internal Methods
//-------------------------------------------------------------------------------
//
// IDisposable
//
//-------------------------------------------------------------------------------
#region IDisposable
/// <summary>
/// A simple pattern of the dispose implementation.
/// There is no finalizer since the SafeHandle will take care of releasing the context.
/// </summary>
/// <SecurityNote>
/// Critical: Calls a SecurityCritical method and the SecurityCritical handle
/// _hContext.Dispose()
/// TreatAsSafe: The method is safe because no arguments are passed. We guard
/// against dispose being called twice.
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
public void Dispose()
{
if (_disposed)
{
return;
}
_hContext.Dispose();
_disposed = true;
}
#endregion IDisposable
//-------------------------------------------------------------------------------
//
// Private Methods
//
//-------------------------------------------------------------------------------
#region Private Methods
/// <summary>
/// Load the mshwgst.dll from the path in the registry. Make sure this loading action prior to invoking
/// any native functions marked with DllImport in mshwgst.dll
/// This method is called from the NativeRecognizer's static construtor.
/// </summary>
/// <SecurityNote>
/// Critical: Requires read registry and unmanaged code access
/// </SecurityNote>
[SecurityCritical]
private static bool LoadRecognizerDll()
{
// ISSUE-2005/01/14-WAYNEZEN,
// We may hit the problem when an application already load mshwgst.dll from somewhere rather than the
// directory we are looking for. The options to resolve this -
// 1. We fail the recognition functionality.
// 2. We unload the previous mshwgst.dll
// 3. We switch the DllImport usage to the new dynamic PInvoke mechanism in Whidbey. Please refer to the blog
// http://blogs.msdn.com/junfeng/archive/2004/07/14/181932.aspx. Then we don't have to unload the existing
// mshwgst.dll.
String path = null;
System.Security.PermissionSet permissionSet = new PermissionSet(null);
permissionSet.AddPermission(new RegistryPermission(RegistryPermissionAccess.Read,
System.Security.AccessControl.AccessControlActions.View,
GestureRecognizerFullPath));
permissionSet.AddPermission(new EnvironmentPermission(PermissionState.Unrestricted));
permissionSet.Assert(); // BlessedAssert:
try
{
RegistryKey regkey = Registry.LocalMachine;
RegistryKey recognizerKey = regkey.OpenSubKey(GestureRecognizerPath);
if (recognizerKey != null)
{
try
{
// Try to read the recognizer path subkey
path = recognizerKey.GetValue(GestureRecognizerValueName) as string;
if (path == null)
{
return false;
}
}
finally
{
recognizerKey.Close();
}
}
else
{
// we couldn't find the path in the registry
// no key to close
return false;
}
}
finally
{
CodeAccessPermission.RevertAssert();
}
if (path != null)
{
IntPtr hModule = MS.Win32.UnsafeNativeMethods.LoadLibrary(path);
// Check whether GetAlternateList exists in the loaded Dll.
s_GetAlternateListExists = false;
if ( hModule != IntPtr.Zero )
{
s_GetAlternateListExists = MS.Win32.UnsafeNativeMethods.GetProcAddressNoThrow(
new HandleRef(null, hModule), "GetAlternateList") != IntPtr.Zero ?
true : false;
}
return hModule != IntPtr.Zero ? true : false;
}
return false; //path was null
}
/// <summary>
/// Set the enabled gestures.
/// This method is called from the internal SetEnabledGestures method.
/// </summary>
/// <SecurityNote>
/// Critical: Calls a critical pinvoke
/// NativeRecognizer.UnsafeNativeMethods.SetEnabledUnicodeRanges
/// </SecurityNote>
[SecurityCritical]
private int SetEnabledGestures(MS.Win32.Recognizer.ContextSafeHandle recContext, ApplicationGesture[] enabledGestures)
{
Debug.Assert(recContext != null && !recContext.IsInvalid);
// NOTICE-2005/01/11-WAYNEZEN,
// The following usage was copied from drivers\tablet\recognition\ink\core\twister\src\wispapis.c
// SetEnabledUnicodeRanges
// Set ranges of gestures enabled in this recognition context
// The behavior of this function is the following:
// (a) (A part of) One of the requested ranges lies outside
// gesture interval---currently [GESTURE_NULL, GESTURE_NULL + 255)
// return E_UNEXPECTED and keep the previously set ranges
// (b) All requested ranges are within the gesture interval but
// some of them are not supported:
// return S_TRUNCATED and set those requested gestures that are
// supported (possibly an empty set)
// (c) All requested gestures are supported
// return S_OK and set all requested gestures.
// Note: An easy way to set all supported gestures as enabled is to use
// SetEnabledUnicodeRanges() with one range=(GESTURE_NULL,255).
// Enabel gestures
uint cRanges = (uint)( enabledGestures.Length );
MS.Win32.Recognizer.CHARACTER_RANGE[] charRanges = new MS.Win32.Recognizer.CHARACTER_RANGE[cRanges];
if ( cRanges == 1 && enabledGestures[0] == ApplicationGesture.AllGestures )
{
charRanges[0].cChars = MAX_GESTURE_COUNT;
charRanges[0].wcLow = GESTURE_NULL;
}
else
{
for ( int i = 0; i < cRanges; i++ )
{
charRanges[i].cChars = 1;
charRanges[i].wcLow = (ushort)( enabledGestures[i] );
}
}
int hr = MS.Win32.Recognizer.UnsafeNativeMethods.SetEnabledUnicodeRanges(recContext, cRanges, charRanges);
return hr;
}
/// <summary>
/// Add the strokes to the recoContext.
/// The method is called from the internal Recognize method.
/// </summary>
/// <SecurityNote>
/// Critical: Calls a critical PInvoke
/// GetPacketData,
/// NativeRecognizer.UnsafeNativeMethods.AddStroke,
/// ReleaseResourcesinPacketDescription
/// </SecurityNote>
[SecurityCritical]
private int AddStrokes(MS.Win32.Recognizer.ContextSafeHandle recContext, StrokeCollection strokes)
{
Debug.Assert(recContext != null && !recContext.IsInvalid);
int hr;
foreach ( Stroke stroke in strokes )
{
MS.Win32.Recognizer.PACKET_DESCRIPTION packetDescription =
new MS.Win32.Recognizer.PACKET_DESCRIPTION();
IntPtr packets = IntPtr.Zero;
try
{
int countOfBytes;
NativeMethods.XFORM xForm;
GetPacketData(stroke, out packetDescription, out countOfBytes, out packets, out xForm);
if (packets == IntPtr.Zero)
{
return -2147483640; //E_FAIL - 0x80000008. We never raise this in an exception
}
hr = MS.Win32.Recognizer.UnsafeNativeMethods.AddStroke(recContext, ref packetDescription, (uint)countOfBytes, packets, xForm);
if ( HRESULT.Failed(hr) )
{
// Return from here. The finally block will free the memory and report the error properly.
return hr;
}
}
finally
{
// Release the resources in the finally block
ReleaseResourcesinPacketDescription(packetDescription, packets);
}
}
return MS.Win32.Recognizer.UnsafeNativeMethods.EndInkInput(recContext);
}
/// <summary>
/// Retrieve the packet description, packets data and XFORM which is the information the native recognizer needs.
/// The method is called from AddStrokes.
/// </summary>
/// <SecurityNote>
/// Critical: Contains unsafe code
/// </SecurityNote>
[SecurityCritical]
private void GetPacketData
(
Stroke stroke,
out MS.Win32.Recognizer.PACKET_DESCRIPTION packetDescription,
out int countOfBytes,
out IntPtr packets,
out NativeMethods.XFORM xForm
)
{
int i;
countOfBytes = 0;
packets = IntPtr.Zero;
packetDescription = new MS.Win32.Recognizer.PACKET_DESCRIPTION();
Matrix matrix = Matrix.Identity;
xForm = new NativeMethods.XFORM((float)(matrix.M11), (float)(matrix.M12), (float)(matrix.M21),
(float)(matrix.M22), (float)(matrix.OffsetX), (float)(matrix.OffsetY));
StylusPointCollection stylusPoints = stroke.StylusPoints;
if (stylusPoints.Count == 0)
{
return; //we'll fail when the calling routine sees that packets is IntPtr.Zer
}
if (stylusPoints.Description.PropertyCount > StylusPointDescription.RequiredCountOfProperties)
{
//
// reformat to X, Y, P
//
StylusPointDescription reformatDescription
= new StylusPointDescription(
new StylusPointPropertyInfo[]{
new StylusPointPropertyInfo(StylusPointProperties.X),
new StylusPointPropertyInfo(StylusPointProperties.Y),
stylusPoints.Description.GetPropertyInfo(StylusPointProperties.NormalPressure)});
stylusPoints = stylusPoints.Reformat(reformatDescription);
}
//
// now make sure we only take a finite amount of data for the stroke
//
if (stylusPoints.Count > MaxStylusPoints)
{
stylusPoints = stylusPoints.Clone(MaxStylusPoints);
}
Guid[] propertyGuids = new Guid[]{ StylusPointPropertyIds.X, //required index for SPD
StylusPointPropertyIds.Y, //required index for SPD
StylusPointPropertyIds.NormalPressure}; //required index for SPD
Debug.Assert(stylusPoints != null);
Debug.Assert(propertyGuids.Length == StylusPointDescription.RequiredCountOfProperties);
// Get the packet description
packetDescription.cbPacketSize = (uint)(propertyGuids.Length * Marshal.SizeOf(typeof(Int32)));
packetDescription.cPacketProperties = (uint)propertyGuids.Length;
//
// use X, Y defaults for metrics, sometimes mouse metrics can be bogus
// always use NormalPressure metrics, though.
//
StylusPointPropertyInfo[] infosToUse = new StylusPointPropertyInfo[StylusPointDescription.RequiredCountOfProperties];
infosToUse[StylusPointDescription.RequiredXIndex] = StylusPointPropertyInfoDefaults.X;
infosToUse[StylusPointDescription.RequiredYIndex] = StylusPointPropertyInfoDefaults.Y;
infosToUse[StylusPointDescription.RequiredPressureIndex] =
stylusPoints.Description.GetPropertyInfo(StylusPointProperties.NormalPressure);
MS.Win32.Recognizer.PACKET_PROPERTY[] packetProperties =
new MS.Win32.Recognizer.PACKET_PROPERTY[packetDescription.cPacketProperties];
StylusPointPropertyInfo propertyInfo;
for ( i = 0; i < packetDescription.cPacketProperties; i++ )
{
packetProperties[i].guid = propertyGuids[i];
propertyInfo = infosToUse[i];
MS.Win32.Recognizer.PROPERTY_METRICS propertyMetrics = new MS.Win32.Recognizer.PROPERTY_METRICS( );
propertyMetrics.nLogicalMin = propertyInfo.Minimum;
propertyMetrics.nLogicalMax = propertyInfo.Maximum;
propertyMetrics.Units = (int)(propertyInfo.Unit);
propertyMetrics.fResolution = propertyInfo.Resolution;
packetProperties[i].PropertyMetrics = propertyMetrics;
}
unsafe
{
int allocationSize = (int)(Marshal.SizeOf(typeof(MS.Win32.Recognizer.PACKET_PROPERTY)) * packetDescription.cPacketProperties);
packetDescription.pPacketProperties = Marshal.AllocCoTaskMem(allocationSize);
MS.Win32.Recognizer.PACKET_PROPERTY* pPacketProperty =
(MS.Win32.Recognizer.PACKET_PROPERTY*)(packetDescription.pPacketProperties.ToPointer());
MS.Win32.Recognizer.PACKET_PROPERTY* pElement = pPacketProperty;
for ( i = 0 ; i < packetDescription.cPacketProperties ; i ++ )
{
Marshal.StructureToPtr(packetProperties[i], new IntPtr(pElement), false);
pElement++;
}
}
// Get packet data
int[] rawPackets = stylusPoints.ToHiMetricArray();
int packetCount = rawPackets.Length;
if (packetCount != 0)
{
countOfBytes = packetCount * Marshal.SizeOf(typeof(Int32));
packets = Marshal.AllocCoTaskMem(countOfBytes);
Marshal.Copy(rawPackets, 0, packets, packetCount);
}
}
/// <summary>
/// Release the memory blocks which has been created for mashalling purpose.
/// The method is called from AddStrokes.
/// </summary>
/// <SecurityNote>
/// Critical: Calls unsafe code, requires UnmanageCode permission
/// </SecurityNote>
[SecurityCritical]
private void ReleaseResourcesinPacketDescription(MS.Win32.Recognizer.PACKET_DESCRIPTION pd, IntPtr packets)
{
if ( pd.pPacketProperties != IntPtr.Zero )
{
unsafe
{
MS.Win32.Recognizer.PACKET_PROPERTY* pPacketProperty =
(MS.Win32.Recognizer.PACKET_PROPERTY*)( pd.pPacketProperties.ToPointer( ) );
MS.Win32.Recognizer.PACKET_PROPERTY* pElement = pPacketProperty;
for ( int i = 0; i < pd.cPacketProperties; i++ )
{
Marshal.DestroyStructure(new IntPtr(pElement), typeof(MS.Win32.Recognizer.PACKET_PROPERTY));
pElement++;
}
}
Marshal.FreeCoTaskMem(pd.pPacketProperties);
pd.pPacketProperties = IntPtr.Zero;
}
if ( pd.pguidButtons != IntPtr.Zero )
{
Marshal.FreeCoTaskMem(pd.pguidButtons);
pd.pguidButtons = IntPtr.Zero;
}
if ( packets != IntPtr.Zero )
{
Marshal.FreeCoTaskMem(packets);
packets = IntPtr.Zero;
}
}
/// <summary>
/// Invokes GetAlternateList in the native dll
/// </summary>
/// <returns></returns>
/// <SecurityNote>
/// Critical: Calls the native methods
/// NativeRecognizer.UnsafeNativeMethods.GetAlternateList
/// NativeRecognizer.UnsafeNativeMethods.GetString
/// NativeRecognizer.UnsafeNativeMethods.GetConfidenceLevel
/// NativeRecognizer.UnsafeNativeMethods.DestroyAlternate
/// </SecurityNote>
[SecurityCritical]
private GestureRecognitionResult[] InvokeGetAlternateList()
{
GestureRecognitionResult[] recResults = new GestureRecognitionResult[] { };
int hr = 0;
MS.Win32.Recognizer.RECO_RANGE recoRange;
recoRange.iwcBegin = 0;
recoRange.cCount = 1;
uint countOfAlternates = IRAS_DefaultCount;
IntPtr[] pRecoAlternates = new IntPtr[IRAS_DefaultCount];
try
{
hr = MS.Win32.Recognizer.UnsafeNativeMethods.GetAlternateList(_hContext, ref recoRange, ref countOfAlternates, pRecoAlternates, MS.Win32.Recognizer.ALT_BREAKS.ALT_BREAKS_SAME);
if ( HRESULT.Succeeded(hr) && countOfAlternates != 0 )
{
List<GestureRecognitionResult> resultList = new List<GestureRecognitionResult>();
for ( int i = 0; i < countOfAlternates; i++ )
{
uint size = 1; // length of string == 1 since gesture id is a single WCHAR
StringBuilder recoString = new StringBuilder(1);
RecognitionConfidence confidenceLevel;
if ( HRESULT.Failed(MS.Win32.Recognizer.UnsafeNativeMethods.GetString(pRecoAlternates[i], out recoRange, ref size, recoString))
|| HRESULT.Failed(MS.Win32.Recognizer.UnsafeNativeMethods.GetConfidenceLevel(pRecoAlternates[i], out recoRange, out confidenceLevel)) )
{
// Fail to retrieve the reco result, skip this one
continue;
}
ApplicationGesture gesture = (ApplicationGesture)recoString[0];
Debug.Assert(ApplicationGestureHelper.IsDefined(gesture));
if (ApplicationGestureHelper.IsDefined(gesture))
{
resultList.Add(new GestureRecognitionResult(confidenceLevel, gesture));
}
}
recResults = resultList.ToArray();
}
}
finally
{
// Destroy the alternates
for ( int i = 0; i < countOfAlternates; i++ )
{
if (pRecoAlternates[i] != IntPtr.Zero)
{
#pragma warning suppress 6031, 56031 // Return value ignored on purpose.
MS.Win32.Recognizer.UnsafeNativeMethods.DestroyAlternate(pRecoAlternates[i]);
pRecoAlternates[i] = IntPtr.Zero;
}
}
}
return recResults;
}
/// <summary>
/// Invokes GetLatticePtr in the native dll
/// </summary>
/// <returns></returns>
/// <SecurityNote>
/// Critical: Calls the native methods
/// NativeRecognizer.UnsafeNativeMethods.GetLatticePtr
/// And uses unsafe code
/// </SecurityNote>
[SecurityCritical]
private GestureRecognitionResult[] InvokeGetLatticePtr()
{
GestureRecognitionResult[] recResults = new GestureRecognitionResult[] { };
// int hr = 0;
IntPtr ptr = IntPtr.Zero;
// NOTICE-2005/07/11-WAYNEZEN,
// There is no need to free the returned the structure.
// The memory will be released when ResetContext, which is invoked in the callee - Recognize, is called.
if ( HRESULT.Succeeded(
MS.Win32.Recognizer.UnsafeNativeMethods.GetLatticePtr(
_hContext, ref ptr)) )
{
unsafe
{
MS.Win32.Recognizer.RECO_LATTICE* pRecoLattice = (MS.Win32.Recognizer.RECO_LATTICE*)ptr;
uint bestResultColumnCount = pRecoLattice->ulBestResultColumnCount;
Debug.Assert(!(bestResultColumnCount != 0 && pRecoLattice->pLatticeColumns == IntPtr.Zero), "Invalid results!");
if ( bestResultColumnCount > 0 && pRecoLattice->pLatticeColumns != IntPtr.Zero )
{
List<GestureRecognitionResult> resultList = new List<GestureRecognitionResult>();
MS.Win32.Recognizer.RECO_LATTICE_COLUMN* pLatticeColumns =
(MS.Win32.Recognizer.RECO_LATTICE_COLUMN*)(pRecoLattice->pLatticeColumns);
ulong* pulBestResultColumns = (ulong*)(pRecoLattice->pulBestResultColumns);
for ( uint i = 0; i < bestResultColumnCount; i++ )
{
ulong column = pulBestResultColumns[i];
MS.Win32.Recognizer.RECO_LATTICE_COLUMN recoColumn = pLatticeColumns[column];
Debug.Assert(0 < recoColumn.cLatticeElements, "Invalid results!");
for ( int j = 0; j < recoColumn.cLatticeElements; j++ )
{
MS.Win32.Recognizer.RECO_LATTICE_ELEMENT recoElement =
((MS.Win32.Recognizer.RECO_LATTICE_ELEMENT*)(recoColumn.pLatticeElements))[j];
Debug.Assert((RECO_TYPE)(recoElement.type) == RECO_TYPE.RECO_TYPE_WCHAR, "The Application gesture has to be WCHAR type" );
if ( (RECO_TYPE)(recoElement.type) == RECO_TYPE.RECO_TYPE_WCHAR )
{
// Retrieve the confidence lever
RecognitionConfidence confidenceLevel = RecognitionConfidence.Poor;
MS.Win32.Recognizer.RECO_LATTICE_PROPERTIES recoProperties = recoElement.epProp;
uint propertyCount = recoProperties.cProperties;
MS.Win32.Recognizer.RECO_LATTICE_PROPERTY** apProps =
(MS.Win32.Recognizer.RECO_LATTICE_PROPERTY**)recoProperties.apProps;
for ( int k = 0; k < propertyCount; k++ )
{
MS.Win32.Recognizer.RECO_LATTICE_PROPERTY* pProps = apProps[k];
if ( pProps->guidProperty == GUID_CONFIDENCELEVEL )
{
Debug.Assert(pProps->cbPropertyValue == sizeof(uint) / sizeof(byte));
RecognitionConfidence level = (RecognitionConfidence)(((uint*)pProps->pPropertyValue))[0];
if ( level >= RecognitionConfidence.Strong && level <= RecognitionConfidence.Poor )
{
confidenceLevel = level;
}
break;
}
}
ApplicationGesture gesture = (ApplicationGesture)((char)(recoElement.pData));
Debug.Assert(ApplicationGestureHelper.IsDefined(gesture));
if (ApplicationGestureHelper.IsDefined(gesture))
{
// Get the gesture result
resultList.Add(new GestureRecognitionResult(confidenceLevel,gesture));
}
}
}
}
recResults = (GestureRecognitionResult[])(resultList.ToArray());
}
}
}
return recResults;
}
#endregion Private Methods
/// <summary>
/// RecognizerHandle is a static property. But it's a SafeHandle.
/// So, we don't have to worry about releasing the handle since RecognizerSafeHandle when there is no reference on it.
/// </summary>
/// <SecurityNote>
/// Critical: Calls a SecurityCritical pinvoke and accesses SecurityCritical fields
/// </SecurityNote>
private static MS.Win32.Recognizer.RecognizerSafeHandle RecognizerHandleSingleton
{
[SecurityCritical]
get
{
if (s_isSupported && s_hRec == null)
{
lock (_syncRoot)
{
if (s_isSupported && s_hRec == null)
{
if (HRESULT.Failed(MS.Win32.Recognizer.UnsafeNativeMethods.CreateRecognizer(ref s_Gesture, out s_hRec)))
{
s_hRec = null;
}
}
}
}
return s_hRec;
}
}
enum RECO_TYPE : ushort
{
RECO_TYPE_WSTRING = 0,
RECO_TYPE_WCHAR = 1
}
private const string GestureRecognizerPath = @"SOFTWARE\MICROSOFT\TPG\SYSTEM RECOGNIZERS\{BED9A940-7D48-48E3-9A68-F4887A5A1B2E}";
private const string GestureRecognizerFullPath = "HKEY_LOCAL_MACHINE" + @"\" + GestureRecognizerPath;
private const string GestureRecognizerValueName = "RECOGNIZER DLL";
private const string GestureRecognizerGuid = "{BED9A940-7D48-48E3-9A68-F4887A5A1B2E}";
// This constant is an identical value as the one in drivers\tablet\recognition\ink\core\common\inc\gesture\gesturedefs.h
private const ushort MAX_GESTURE_COUNT = 256;
// This constant is an identical value as the one in drivers\tablet\include\sdk\recdefs.h
private const ushort GESTURE_NULL = 0xf000;
// This constant is an identical value as the one in public\internal\drivers\inc\msinkaut.h
private const ushort IRAS_DefaultCount = 10;
private const ushort MaxStylusPoints = 10000;
// The GUID has been copied from public\internal\drivers\inc\tpcguid.h
//// {7DFE11A7-FB5D-4958-8765-154ADF0D833F}
//DEFINE_GUID(GUID_CONFIDENCELEVEL, 0x7dfe11a7, 0xfb5d, 0x4958, 0x87, 0x65, 0x15, 0x4a, 0xdf, 0xd, 0x83, 0x3f);
private static readonly Guid GUID_CONFIDENCELEVEL = new Guid("{7DFE11A7-FB5D-4958-8765-154ADF0D833F}");
/// <summary>
/// IDisposable support
/// </summary>
private bool _disposed = false;
/// <summary>
/// Each NativeRecognizer instance has it's own recognizer context
/// </summary>
/// <SecurityNote>
/// Critical: The SecurityCritical handle
/// </SecurityNote>
[SecurityCritical]
private MS.Win32.Recognizer.ContextSafeHandle _hContext;
/// <summary>
/// Used to lock for instancing the native recognizer handle
/// </summary>
private static object _syncRoot = new object();
/// <summary>
/// All NativeRecognizer share a single handle to the recognizer
/// </summary>
/// <SecurityNote>
/// Critical: The SecurityCritical handle
/// </SecurityNote>
[SecurityCritical]
private static MS.Win32.Recognizer.RecognizerSafeHandle s_hRec;
/// <summary>
/// The Guid of the GestureRecognizer used for registry lookup
/// </summary>
private static Guid s_Gesture = new Guid(GestureRecognizerGuid);
/// <summary>
/// can we load the recognizer?
/// </summary>
private static readonly bool s_isSupported;
/// <summary>
/// A flag indicates whether we can find the entry point of
/// GetAlternateList function in mshwgst.dll
/// </summary>
private static bool s_GetAlternateListExists;
}
}
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