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//------------------------------------------------------------------------------
//
// <copyright file="VisualTarget.cs" company="Microsoft">
// Copyright (C) Microsoft Corporation. All rights reserved.
// </copyright>
//
// Description:
//
// History:
// 01/06/2005 : ABaioura - Created.
//
//------------------------------------------------------------------------------
using System.Windows.Media;
using System.Windows.Media.Composition;
using System.Security;
using System.Diagnostics;
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID;
namespace System.Windows.Media
{
/// <summary>
///
/// </summary>
public class VisualTarget : CompositionTarget
{
//----------------------------------------------------------------------
//
// Constructors
//
//----------------------------------------------------------------------
#region Constructors
/// <summary>
/// VisualTarget
/// </summary>
public VisualTarget(HostVisual hostVisual)
{
if (hostVisual == null)
{
throw new ArgumentNullException("hostVisual");
}
_hostVisual = hostVisual;
_connected = false;
MediaContext.RegisterICompositionTarget(Dispatcher, this);
}
/// <summary>
/// This function gets called when VisualTarget is created on the channel
/// i.e. from CreateUCEResources.
/// </summary>
private void BeginHosting()
{
Debug.Assert(!_connected);
try
{
//
// Initiate hosting by the specified host visual.
//
_hostVisual.BeginHosting(this);
_connected = true;
}
catch
{
//
// If exception has occurred after we have registered with
// MediaContext, we need to unregister to properly release
// allocated resources.
// NOTE: We need to properly unregister in a disconnected state
//
MediaContext.UnregisterICompositionTarget(Dispatcher, this);
throw;
}
}
internal override void CreateUCEResources(DUCE.Channel channel, DUCE.Channel outOfBandChannel)
{
Debug.Assert(channel != null);
Debug.Assert(outOfBandChannel != null);
_outOfBandChannel = outOfBandChannel;
// create visual target resources
base.CreateUCEResources(channel, outOfBandChannel);
// Update state to propagate flags as necessary
StateChangedCallback(
new object[]
{
HostStateFlags.None
});
//
// Addref content node on the channel. We need extra reference
// on that node so that it does not get immediately released
// when Dispose is called. Actual release of the node needs
// to be synchronized with node disconnect by the host.
//
bool resourceCreated = _contentRoot.CreateOrAddRefOnChannel(this, outOfBandChannel, s_contentRootType);
Debug.Assert(!resourceCreated);
_contentRoot.CreateOrAddRefOnChannel(this, channel, s_contentRootType);
BeginHosting();
}
#endregion Constructors
//----------------------------------------------------------------------
//
// Public Properties
//
//----------------------------------------------------------------------
#region Public Properties
/// <summary>
/// Returns matrix that can be used to transform coordinates from this
/// target to the rendering destination device.
/// </summary>
public override Matrix TransformToDevice
{
get
{
VerifyAPIReadOnly();
Matrix m = WorldTransform;
m.Invert();
return m;
}
}
/// <summary>
/// Returns matrix that can be used to transform coordinates from
/// the rendering destination device to this target.
/// </summary>
public override Matrix TransformFromDevice
{
get
{
VerifyAPIReadOnly();
return WorldTransform;
}
}
#endregion Public Properties
//----------------------------------------------------------------------
//
// Public Methods
//
//----------------------------------------------------------------------
#region Private Fields
/// <summary>
/// Dispose cleans up the state associated with HwndTarget.
/// </summary>
/// <SecurityNote>
/// Critical: Sets RootVisual to null
/// PublicOK: This code has the same affect as removing elements in a window
/// </SecurityNote>
[SecurityCritical]
public override void Dispose()
{
try
{
VerifyAccess();
if (!IsDisposed)
{
if (_hostVisual != null && _connected)
{
RootVisual = null;
//
// Unregister this CompositionTarget from the MediaSystem.
//
// we need to properly unregister in a disconnected state
MediaContext.UnregisterICompositionTarget(Dispatcher, this);
}
}
}
finally
{
base.Dispose();
}
}
/// <summary>
/// This function gets called when VisualTarget is removed on the channel
/// i.e. from ReleaseUCEResources.
/// </summary>
private void EndHosting()
{
Debug.Assert(_connected);
_hostVisual.EndHosting();
_connected = false;
}
/// <summary>
/// This method is used to release all uce resources either on Shutdown or session disconnect
/// </summary>
internal override void ReleaseUCEResources(DUCE.Channel channel, DUCE.Channel outOfBandChannel)
{
EndHosting();
_contentRoot.ReleaseOnChannel(channel);
if (_contentRoot.IsOnChannel(outOfBandChannel))
{
_contentRoot.ReleaseOnChannel(outOfBandChannel);
}
base.ReleaseUCEResources(channel, outOfBandChannel);
}
#endregion Public Methods
#region Internal Properties
/// <summary>
/// The out of band channel on our the MediaContext this
/// resource was created.
/// This is needed by HostVisual for handle duplication.
/// </summary>
internal DUCE.Channel OutOfBandChannel
{
get
{
return _outOfBandChannel;
}
}
#endregion Internal Properties
//----------------------------------------------------------------------
//
// Private Fields
//
//----------------------------------------------------------------------
#region Private Fields
DUCE.Channel _outOfBandChannel;
private HostVisual _hostVisual;
// Flag indicating whether VisualTarget-HostVisual connection exists.
private bool _connected;
#endregion Private Fields
}
}
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