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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System.Windows.Input.StylusPlugIns;
using System.Windows.Media;
namespace System.Windows.Input.StylusPointer
{
/// <summary>
/// Collection of StylusPlugIn objects
/// </summary>
/// <remarks>
/// The collection order is based on the order that StylusPlugIn objects are
/// added to the collection via the IList interfaces. The order of the StylusPlugIn
/// objects in the collection is modifiable.
/// </remarks>
internal class PointerStylusPlugInCollection : StylusPlugInCollectionBase
{
#region Properties
/// <summary>
/// Gets if the collection is hooked to a PointerStylusPluginManager
/// </summary>
internal override bool IsActiveForInput
{
get
{
return _manager != null;
}
}
/// <summary>
/// WM_POINTER stack needs no sync root object here.
/// </summary>
internal override object SyncRoot
{
get
{
return null;
}
}
#endregion
#region Private APIs
/// <summary>
/// Hooks/Unhooks the plugin collection as needed.
/// </summary>
internal override void UpdateState(UIElement element)
{
bool unhook = true;
// See if we should be enabled
if (element.IsVisible && element.IsEnabled && element.IsHitTestVisible)
{
PresentationSource presentationSource = PresentationSource.CriticalFromVisual(element as Visual);
if (presentationSource != null)
{
unhook = false;
// Are we currently hooked up? If not then hook up.
if (_manager == null)
{
_manager = StylusLogic.GetCurrentStylusLogicAs<PointerLogic>().PlugInManagers[presentationSource];
// _manager must be non null or don't do anything.
if (_manager != null)
{
_manager.AddStylusPlugInCollection(Wrapper);
foreach (StylusPlugIn spi in Wrapper)
{
spi.InvalidateIsActiveForInput();
}
//
// Normally the Rect will be updated when we receive the LayoutUpdate.
// However there could be a race condition which the LayoutUpdate gets received
// before the properties like IsVisible being set.
// So we should always force to call OnLayoutUpdated whenever the input is active.
Wrapper.OnLayoutUpdated(this.Wrapper, EventArgs.Empty);
}
}
}
}
if (unhook)
{
Unhook();
}
}
/// <summary>
/// Unhooks the plugin collection from the manager
/// </summary>
internal override void Unhook()
{
// Are we currently unhooked? If not then unhook.
if (_manager != null)
{
_manager.RemoveStylusPlugInCollection(Wrapper);
// Can't recieve any more input now!
_manager = null;
// Notify after input is disabled to the PlugIns.
foreach (StylusPlugIn spi in Wrapper)
{
spi.InvalidateIsActiveForInput();
}
}
}
#endregion
#region Fields
/// <summary>
/// The manager for stylus plugins
/// </summary>
private PointerStylusPlugInManager _manager;
#endregion
}
}
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