Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Core / CSharp / System / Windows / Media / VisualBrush.cs / 1305600 / VisualBrush.cs
//---------------------------------------------------------------------------- // // Copyright (C) Microsoft Corporation. All rights reserved. // // File: VisualBrush.cs // // Description: This file contains the implementation of VisualBrush. // The VisualBrush is a TileBrush which defines its tile content // by use of a Visual. // // History: // //--------------------------------------------------------------------------- using System; using System.ComponentModel; using System.Diagnostics; using System.Runtime.InteropServices; using System.Security; using System.Windows; using System.Windows.Media; using System.Windows.Media.Media3D; using System.Windows.Media.Animation; using System.Windows.Media.Composition; using System.Windows.Threading; using MS.Internal; namespace System.Windows.Media { ////// VisualBrush - This TileBrush defines its content as a Visual /// public sealed partial class VisualBrush : TileBrush, ICyclicBrush { #region Constructors ////// Default constructor for VisualBrush. The resulting Brush has no content. /// public VisualBrush() { } ////// VisualBrush Constructor where the image is set to the parameter's value /// /// The Visual representing the contents of this Brush. public VisualBrush(Visual visual) { if (this.Dispatcher != null) { MediaSystem.AssertSameContext(this, visual); Visual = visual; } } #endregion Constructors 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 { _isCacheDirty = true; FireChanged(); // Register brush's visual tree for Render(). RegisterForAsyncRenderForCyclicBrush(); } finally { Exit(); } } } ////// Calling this will make sure that the render request /// is registered with the MediaContext. /// 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 = Visual; // 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); } } ////// Implementation of protected override void OnPropertyChanged(DependencyPropertyChangedEventArgs e) { base.OnPropertyChanged(e); if (e.IsAValueChange || e.IsASubPropertyChange) { if ((e.Property == VisualProperty) || (e.Property == AutoLayoutContentProperty)) { // 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 = Visual as UIElement; if ((element != null) && ((VisualTreeHelper.GetParent(element) == null && !(element.IsRootElement)) || (VisualTreeHelper.GetParent(element) is Visual3D))) { // // 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; } } } } } ///DependencyObject.OnPropertyInvalidated . /// If the property is the Visual or the AutoLayoutContent property, we re-layout the Visual if /// possible. ////// We initiate the layout on the tree rooted at the Visual to which VisualBrush points. /// private void DoLayout(UIElement element) { Debug.Assert(element != null); DependencyObject parent = VisualTreeHelper.GetParent(element); if (!(element.IsRootElement) && (parent == null || parent is Visual3D)) { // // 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)); } } ////// LayoutUpdate event handler. /// /// event sender (not used) /// event arguments (not used) private void OnLayoutUpdated(object sender, EventArgs args) { Debug.Assert(_pendingLayout); // Visual has to be a UIElement since the handler was added to it. UIElement element = (UIElement)Visual; 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); } ////// DispatcherOperation callback to initiate layout. /// /// The Visual root 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; } ////// Enter is used for simple cycle detection in VisualBrush. 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. /// internal bool Enter() { if (_reentrancyFlag) { return false; } else { _reentrancyFlag = true; return true; } } ////// Exits the VisualBrush. For more details see Enter method. /// internal void Exit() { Debug.Assert(_reentrancyFlag); // Exit must be matched with Enter. See Enter comments. _reentrancyFlag = false; } ////// Obtains the current bounds of the brush's content /// /// Output bounds of content protected override void GetContentBounds(out Rect contentBounds) { // Obtain the current visual's outer space bounding box. We return the outer space // bounding box because we want to have the bounding box of the Visual tree including // transform/offset at the root. if (_isCacheDirty) { _bbox = Visual.CalculateSubgraphBoundsOuterSpace(); _isCacheDirty = false; } contentBounds = _bbox; } private DispatcherOperation _DispatcherLayoutResult; private bool _pendingLayout; private bool _reentrancyFlag; private bool _isAsyncRenderRegistered = false; // Whether we need to re-calculate our content bounds. private bool _isCacheDirty = true; // Keep our content bounds cached. private Rect _bbox = Rect.Empty; } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved. //---------------------------------------------------------------------------- // // Copyright (C) Microsoft Corporation. All rights reserved. // // File: VisualBrush.cs // // Description: This file contains the implementation of VisualBrush. // The VisualBrush is a TileBrush which defines its tile content // by use of a Visual. // // History: // //--------------------------------------------------------------------------- using System; using System.ComponentModel; using System.Diagnostics; using System.Runtime.InteropServices; using System.Security; using System.Windows; using System.Windows.Media; using System.Windows.Media.Media3D; using System.Windows.Media.Animation; using System.Windows.Media.Composition; using System.Windows.Threading; using MS.Internal; namespace System.Windows.Media { ////// VisualBrush - This TileBrush defines its content as a Visual /// public sealed partial class VisualBrush : TileBrush, ICyclicBrush { #region Constructors ////// Default constructor for VisualBrush. The resulting Brush has no content. /// public VisualBrush() { } ////// VisualBrush Constructor where the image is set to the parameter's value /// /// The Visual representing the contents of this Brush. public VisualBrush(Visual visual) { if (this.Dispatcher != null) { MediaSystem.AssertSameContext(this, visual); Visual = visual; } } #endregion Constructors 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 { _isCacheDirty = true; FireChanged(); // Register brush's visual tree for Render(). RegisterForAsyncRenderForCyclicBrush(); } finally { Exit(); } } } ////// Calling this will make sure that the render request /// is registered with the MediaContext. /// 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 = Visual; // 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); } } ////// Implementation of protected override void OnPropertyChanged(DependencyPropertyChangedEventArgs e) { base.OnPropertyChanged(e); if (e.IsAValueChange || e.IsASubPropertyChange) { if ((e.Property == VisualProperty) || (e.Property == AutoLayoutContentProperty)) { // 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 = Visual as UIElement; if ((element != null) && ((VisualTreeHelper.GetParent(element) == null && !(element.IsRootElement)) || (VisualTreeHelper.GetParent(element) is Visual3D))) { // // 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; } } } } } ///DependencyObject.OnPropertyInvalidated . /// If the property is the Visual or the AutoLayoutContent property, we re-layout the Visual if /// possible. ////// We initiate the layout on the tree rooted at the Visual to which VisualBrush points. /// private void DoLayout(UIElement element) { Debug.Assert(element != null); DependencyObject parent = VisualTreeHelper.GetParent(element); if (!(element.IsRootElement) && (parent == null || parent is Visual3D)) { // // 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)); } } ////// LayoutUpdate event handler. /// /// event sender (not used) /// event arguments (not used) private void OnLayoutUpdated(object sender, EventArgs args) { Debug.Assert(_pendingLayout); // Visual has to be a UIElement since the handler was added to it. UIElement element = (UIElement)Visual; 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); } ////// DispatcherOperation callback to initiate layout. /// /// The Visual root 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; } ////// Enter is used for simple cycle detection in VisualBrush. 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. /// internal bool Enter() { if (_reentrancyFlag) { return false; } else { _reentrancyFlag = true; return true; } } ////// Exits the VisualBrush. For more details see Enter method. /// internal void Exit() { Debug.Assert(_reentrancyFlag); // Exit must be matched with Enter. See Enter comments. _reentrancyFlag = false; } ////// Obtains the current bounds of the brush's content /// /// Output bounds of content protected override void GetContentBounds(out Rect contentBounds) { // Obtain the current visual's outer space bounding box. We return the outer space // bounding box because we want to have the bounding box of the Visual tree including // transform/offset at the root. if (_isCacheDirty) { _bbox = Visual.CalculateSubgraphBoundsOuterSpace(); _isCacheDirty = false; } contentBounds = _bbox; } private DispatcherOperation _DispatcherLayoutResult; private bool _pendingLayout; private bool _reentrancyFlag; private bool _isAsyncRenderRegistered = false; // Whether we need to re-calculate our content bounds. private bool _isCacheDirty = true; // Keep our content bounds cached. private Rect _bbox = Rect.Empty; } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
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