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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.
// Microsoft Windows Presentation Foudnation
//
using System.Diagnostics;
using System.Windows;
using System.Windows.Threading;
using System.Windows.Media.Media3D;
using System.Windows.Media.Composition;
using System.Windows.Media.Animation;
using System.Security;
using SR=MS.Internal.PresentationCore.SR;
namespace System.Windows.Media
{
public partial class BitmapCacheBrush : Brush, ICyclicBrush
{
#region Constructors
public BitmapCacheBrush()
{
}
/// <summary>
/// VisualBrush Constructor where the image is set to the parameter's value
/// </summary>
/// <param name="visual"> The Visual representing the contents of this Brush. </param>
public BitmapCacheBrush(Visual visual)
{
if (this.Dispatcher != null)
{
MediaSystem.AssertSameContext(this, visual);
Target = visual;
}
}
#endregion Constructors
private ContainerVisual AutoWrapVisual
{
get
{
// Lazily create the dummy visual instance.
if (_dummyVisual == null)
{
_dummyVisual = new ContainerVisual();
}
return _dummyVisual;
}
}
// NOTE: This class is basically identical to VisualBrush, it should be refactored to
// a common place to prevent code duplication (maybe Brush.cs?)
void ICyclicBrush.FireOnChanged()
{
// Simple loop detection to avoid stack overflow in cyclic VisualBrush
// scenarios. This fix is only aimed at mitigating a very common
// VisualBrush scenario.
bool canEnter = Enter();
if (canEnter)
{
try
{
FireChanged();
// Register brush's visual tree for Render().
RegisterForAsyncRenderForCyclicBrush();
}
finally
{
Exit();
}
}
}
/// <summary>
/// Calling this will make sure that the render request
/// is registered with the MediaContext.
/// </summary>
private void RegisterForAsyncRenderForCyclicBrush()
{
DUCE.IResource resource = this as DUCE.IResource;
if (resource != null)
{
if ((Dispatcher != null) && !_isAsyncRenderRegistered)
{
MediaContext mediaContext = MediaContext.From(Dispatcher);
//
// Only register for a deferred render if this visual brush
// is actually on the channel.
//
if (!resource.GetHandle(mediaContext.Channel).IsNull)
{
// Add this handler to this event means that the handler will be
// called on the next UIThread render for this Dispatcher.
ICyclicBrush cyclicBrush = this as ICyclicBrush;
mediaContext.ResourcesUpdated += new MediaContext.ResourcesUpdatedHandler(cyclicBrush.RenderForCyclicBrush);
_isAsyncRenderRegistered = true;
}
}
}
}
void ICyclicBrush.RenderForCyclicBrush(DUCE.Channel channel, bool skipChannelCheck)
{
Visual vVisual = InternalTarget;
// The Visual may have been registered for an asynchronous render, but may have been
// disconnected from the VisualBrush since then. If so, don't bother to render here, if
// the Visual is visible it will be rendered elsewhere.
if (vVisual != null && vVisual.CheckFlagsAnd(VisualFlags.NodeIsCyclicBrushRoot))
{
// ------------------------------------------------------------------------------------
// 1) Prepare the visual for rendering.
//
// Updates bounding boxes.
//
vVisual.Precompute();
// ------------------------------------------------------------------------------------
// 2) Prepare the render context.
//
RenderContext rc = new RenderContext();
rc.Initialize(channel, DUCE.ResourceHandle.Null);
// ------------------------------------------------------------------------------------
// 3) Compile the scene.
if (channel.IsConnected)
{
vVisual.Render(rc, 0);
}
else
{
// We can issue the release here instead of putting it in queue
// since we are already in Render walk.
((DUCE.IResource)vVisual).ReleaseOnChannel(channel);
}
}
_isAsyncRenderRegistered = false;
}
// Implement functions used to addref and release resources in codegen that need
// to be specialized for Visual which doesn't implement DUCE.IResource
internal void AddRefResource(Visual visual, DUCE.Channel channel)
{
if (visual != null)
{
visual.AddRefOnChannelForCyclicBrush(this, channel);
}
}
internal void ReleaseResource(Visual visual, DUCE.Channel channel)
{
if (visual != null)
{
visual.ReleaseOnChannelForCyclicBrush(this, channel);
}
}
/// <summary>
/// Implementation of <see cref="System.Windows.DependencyObject.OnPropertyChanged">DependencyObject.OnPropertyInvalidated</see>.
/// If the property is the Visual or the AutoLayoutContent property, we re-layout the Visual if
/// possible.
/// </summary>
protected override void OnPropertyChanged(DependencyPropertyChangedEventArgs e)
{
base.OnPropertyChanged(e);
if (e.IsAValueChange || e.IsASubPropertyChange)
{
if ((e.Property == TargetProperty) || (e.Property == AutoLayoutContentProperty))
{
// Should we wrap the visual in a dummy visual node for rendering?
if (e.Property == TargetProperty && e.IsAValueChange)
{
if (AutoWrapTarget)
{
Debug.Assert(InternalTarget == AutoWrapVisual,
"InternalTarget should point to our dummy visual AutoWrapVisual when AutoWrapTarget is true.");
// Change the value being wrapped by AutoWrapVisual.
AutoWrapVisual.Children.Remove((Visual)e.OldValue);
AutoWrapVisual.Children.Add((Visual)e.NewValue);
}
else
{
// Target just passes through to InternalTarget.
InternalTarget = Target;
}
}
// Should we initiate a layout on this Visual?
// Yes, if AutoLayoutContent is true and if the Visual is a UIElement not already in
// another tree (i.e. the parent is null) or its not the hwnd root.
if (AutoLayoutContent)
{
Debug.Assert(!_pendingLayout);
UIElement element = Target as UIElement;
if ((element != null)
&&
((VisualTreeHelper.GetParent(element) == null && !(element.IsRootElement)) // element is not connected to visual tree, OR
|| (VisualTreeHelper.GetParent(element) is Visual3D) // element is a 2D child of a 3D object, OR
|| (VisualTreeHelper.GetParent(element) == InternalTarget))) // element is only connected to visual tree via our wrapper Visual
{
//
// We need 2 ways of initiating layout on the VisualBrush root.
// 1. We add a handler such that when the layout is done for the
// main tree and LayoutUpdated is fired, then we do layout for the
// VisualBrush tree.
// However, this can fail in the case where the main tree is composed
// of just Visuals and never does layout nor fires LayoutUpdated. So
// we also need the following approach.
// 2. We do a BeginInvoke to start layout on the Visual. This approach
// alone, also falls short in the scenario where if we are already in
// MediaContext.DoWork() then we will do layout (for main tree), then look
// at Loaded callbacks, then render, and then finally the Dispather will
// fire us for layout. So during loaded callbacks we would not have done
// layout on the VisualBrush tree.
//
// Depending upon which of the two layout passes comes first, we cancel
// the other layout pass.
//
element.LayoutUpdated += OnLayoutUpdated;
_DispatcherLayoutResult = Dispatcher.BeginInvoke(
DispatcherPriority.Normal,
new DispatcherOperationCallback(LayoutCallback),
element);
_pendingLayout = true;
}
}
}
else if (e.Property == AutoWrapTargetProperty)
{
// If our AutoWrap behavior changed, wrap/unwrap the target here.
if (AutoWrapTarget)
{
InternalTarget = AutoWrapVisual;
AutoWrapVisual.Children.Add(Target);
}
else
{
AutoWrapVisual.Children.Remove(Target);
InternalTarget = Target;
}
}
}
}
/// <summary>
/// We initiate the layout on the tree rooted at the Visual to which BitmapCacheBrush points.
/// </summary>
private void DoLayout(UIElement element)
{
Debug.Assert(element != null);
DependencyObject parent = VisualTreeHelper.GetParent(element);
if (!(element.IsRootElement)
&& (parent == null || parent is Visual3D || parent == InternalTarget))
{
//
// PropagateResumeLayout sets the LayoutSuspended flag to false if it were true.
//
UIElement.PropagateResumeLayout(null, element);
element.Measure(new Size(Double.PositiveInfinity, Double.PositiveInfinity));
element.Arrange(new Rect(element.DesiredSize));
}
}
/// <summary>
/// LayoutUpdate event handler.
/// </summary>
private void OnLayoutUpdated(object sender, EventArgs args)
{
Debug.Assert(_pendingLayout);
// Target has to be a UIElement since the handler was added to it.
UIElement element = (UIElement)Target;
Debug.Assert(element != null);
// Unregister for the event
element.LayoutUpdated -= OnLayoutUpdated;
_pendingLayout = false;
//
// Since we are in this function that means that layoutUpdated fired before
// Dispatcher.BeginInvoke fired. So we can abort the DispatcherOperation as
// we will do the layout here.
//
Debug.Assert(_DispatcherLayoutResult != null);
Debug.Assert(_DispatcherLayoutResult.Status == DispatcherOperationStatus.Pending);
bool abortStatus = _DispatcherLayoutResult.Abort();
Debug.Assert(abortStatus);
DoLayout(element);
}
/// <summary>
/// DispatcherOperation callback to initiate layout.
/// </summary>
/// <param name="arg">The Visual root</param>
private object LayoutCallback(object arg)
{
Debug.Assert(_pendingLayout);
UIElement element = arg as UIElement;
Debug.Assert(element != null);
//
// Since we are in this function that means that Dispatcher.BeginInvoke fired
// before LayoutUpdated fired. So we can remove the LayoutUpdated handler as
// we will do the layout here.
//
element.LayoutUpdated -= OnLayoutUpdated;
_pendingLayout = false;
DoLayout(element);
return null;
}
/// <summary>
/// Enter is used for simple cycle detection in BitmapCacheBrush. If the method returns false
/// the brush has already been entered and cannot be entered again. Matching invocation of Exit
/// must be skipped if Enter returns false.
/// </summary>
internal bool Enter()
{
if (_reentrancyFlag)
{
return false;
}
else
{
_reentrancyFlag = true;
return true;
}
}
/// <summary>
/// Exits the BitmapCacheBrush. For more details see Enter method.
/// </summary>
internal void Exit()
{
Debug.Assert(_reentrancyFlag); // Exit must be matched with Enter. See Enter comments.
_reentrancyFlag = false;
}
private static object CoerceOpacity(DependencyObject d, object value)
{
if ((double)value != (double)OpacityProperty.GetDefaultValue(typeof(BitmapCacheBrush)))
{
throw new InvalidOperationException(SR.BitmapCacheBrush_OpacityChanged);
}
return 1.0;
}
private static object CoerceTransform(DependencyObject d, object value)
{
if ((Transform)value != (Transform)TransformProperty.GetDefaultValue(typeof(BitmapCacheBrush)))
{
throw new InvalidOperationException(SR.BitmapCacheBrush_TransformChanged);
}
return null;
}
private static object CoerceRelativeTransform(DependencyObject d, object value)
{
if ((Transform)value != (Transform)RelativeTransformProperty.GetDefaultValue(typeof(BitmapCacheBrush)))
{
throw new InvalidOperationException(SR.BitmapCacheBrush_RelativeTransformChanged);
}
return null;
}
private static void StaticInitialize(Type typeofThis)
{
OpacityProperty.OverrideMetadata(typeofThis, new IndependentlyAnimatedPropertyMetadata(1.0, /* PropertyChangedHandle */ null, CoerceOpacity));
TransformProperty.OverrideMetadata(typeofThis, new UIPropertyMetadata(null, /* PropertyChangedHandle */ null, CoerceTransform));
RelativeTransformProperty.OverrideMetadata(typeofThis, new UIPropertyMetadata(null, /* PropertyChangedHandle */ null, CoerceRelativeTransform));
}
private ContainerVisual _dummyVisual;
private DispatcherOperation _DispatcherLayoutResult;
private bool _pendingLayout;
private bool _reentrancyFlag;
private bool _isAsyncRenderRegistered = false;
}
}
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