VisualTreeUtils.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Core / MS / Internal / Media / VisualTreeUtils.cs / 2 / VisualTreeUtils.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (c) Microsoft Corporation.  All rights reserved.
//  
//
// History: 
//  6/8/2005 : [....] - Created 
//
//--------------------------------------------------------------------------- 

using MS.Internal;
using System;
using System.Diagnostics; 
using System.Windows;
using System.Windows.Media; 
using System.Windows.Media.Media3D; 
using MS.Internal.PresentationCore;
 
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID;

namespace MS.Internal.Media 
{
    ///  
    ///     Helper methods for interacting with the 2D/3D Visual tree 
    /// 
    internal static class VisualTreeUtils 
    {
        //-----------------------------------------------------
        //
        //  Constructors 
        //
        //----------------------------------------------------- 
 
        //------------------------------------------------------
        // 
        //  Public Methods
        //
        //-----------------------------------------------------
 
        //------------------------------------------------------
        // 
        //  Public Properties 
        //
        //------------------------------------------------------ 

        //-----------------------------------------------------
        //
        //  Public Events 
        //
        //------------------------------------------------------ 
 
        //-----------------------------------------------------
        // 
        //  Internal Methods
        //
        //-----------------------------------------------------
 
        #region Internal Methods
 
        ///  
        ///     This walks up the Visual tree setting the given flags starting at the
        ///     given element. 
        /// 
        internal static void PropagateFlags(
            DependencyObject element,
            VisualFlags flags, 
            VisualProxyFlags proxyFlags)
        { 
            Visual visual; 
            Visual3D visual3D;
 
            AsVisualInternal(element, out visual, out visual3D);

            if (visual != null)
            { 
                Visual.PropagateFlags(visual, flags, proxyFlags);
            } 
            else 
            {
                Visual3D.PropagateFlags(visual3D, flags, proxyFlags); 
            }
        }

        ///  
        ///     Walks up the Visual tree setting or clearing the given flags.  Unlike
        ///     PropagateFlags this does not terminate when it reaches node with 
        ///     the flags already set.  It always walks all the way to the root. 
        /// 
        internal static void SetFlagsToRoot(DependencyObject element, bool value, VisualFlags flags) 
        {
            Visual visual;
            Visual3D visual3D;
 
            AsVisualInternal(element, out visual, out visual3D);
 
            if (visual != null) 
            {
                visual.SetFlagsToRoot(value, flags); 
            }
            else if (visual3D != null)
            {
                visual3D.SetFlagsToRoot(value, flags); 
            }
        } 
 
        /// 
        ///     Finds the first ancestor of the given element which has the given 
        ///     flags set.
        /// 
        internal static DependencyObject FindFirstAncestorWithFlagsAnd(DependencyObject element, VisualFlags flags)
        { 
            Visual visual;
            Visual3D visual3D; 
 
            AsVisualInternal(element, out visual, out visual3D);
 
            if (visual != null)
            {
                return visual.FindFirstAncestorWithFlagsAnd(flags);
            } 
            else if (visual3D != null)
            { 
                return visual3D.FindFirstAncestorWithFlagsAnd(flags); 
            }
 
            Debug.Assert(element == null);

            return null;
        } 

        ///  
        ///     Converts the given point or ray hit test result into a PointHitTestResult. 
        ///     In the case of a RayHitTestResult this is done by walking up the
        ///     transforming the 3D intersection into the coordinate space of the 
        ///     Viewport3DVisual which contains the Visual3D subtree.
        /// 
        internal static PointHitTestResult AsNearestPointHitTestResult(HitTestResult result)
        { 
            if (result == null)
            { 
                return null; 
            }
 
            PointHitTestResult resultAsPointHitTestResult = result as PointHitTestResult;

            if (resultAsPointHitTestResult != null)
            { 
                return resultAsPointHitTestResult;
            } 
 
            RayHitTestResult resultAsRayHitTestResult = result as RayHitTestResult;
 
            if (resultAsRayHitTestResult != null)
            {
                Visual3D current = (Visual3D) resultAsRayHitTestResult.VisualHit;
                Matrix3D worldTransform = Matrix3D.Identity; 

                while (true) 
                { 
                    if (current.Transform != null)
                    { 
                        worldTransform.Append(current.Transform.Value);
                    }

                    Visual3D parent3D = current.InternalVisualParent as Visual3D; 

                    if (parent3D == null) 
                    { 
                        break;
                    } 

                    current = parent3D;
                }
 
                Viewport3DVisual viewport = current.InternalVisualParent as Viewport3DVisual;
 
                if (viewport != null) 
                {
                    Point4D worldPoint = ((Point4D)resultAsRayHitTestResult.PointHit) * worldTransform; 
                    Point viewportPoint = viewport.WorldToViewport(worldPoint);

                    return new PointHitTestResult(viewport, viewportPoint);
                } 

                Debug.Fail("How did a ray hit a Visual3D not parented to a Viewport3DVisual?"); 
 
                return null;
            } 

            Debug.Fail(String.Format("Unhandled HitTestResult type '{0}'", result.GetType().Name));

            return null; 
        }
 
        ///  
        ///     Throws if the given element is null or is not a Visual or Visual3D
        ///     or if the Visual is on the wrong thread. 
        /// 
        internal static void EnsureNonNullVisual(DependencyObject element)
        {
            EnsureVisual(element, /* allowNull = */ false); 
        }
 
        ///  
        ///     Throws if the given element is null or is not a Visual or Visual3D
        ///     or if the Visual is on the wrong thread. 
        /// 
        internal static void EnsureVisual(DependencyObject element)
        {
            EnsureVisual(element, /* allowNull = */ true); 
        }
 
        ///  
        ///     Throws if the given element is not a Visual or Visual3D
        ///     or if the Visual is on the wrong thread. 
        /// 
        private static void EnsureVisual(DependencyObject element, bool allowNull)
        {
            if (element == null) 
            {
                if (!allowNull) 
                { 
                    throw new ArgumentNullException("element");
                } 

                return;
            }
 
            //
            if (!(element is Visual || element is Visual3D)) 
            { 
                throw new ArgumentException(SR.Get(SRID.Visual_NotAVisual));
            } 

            element.VerifyAccess();
        }
 
        /// 
        ///     Throws if the given element is null or not a visual type, otherwise 
        ///     either visual or visual3D will be non-null on exit. 
        /// 
        internal static void AsNonNullVisual(DependencyObject element, out Visual visual, out Visual3D visual3D) 
        {
            if (element == null)
            {
                throw new ArgumentNullException("element"); 
            }
 
            AsVisual(element, out visual, out visual3D); 

            Debug.Assert((visual == null) != (visual3D == null), 
                "Either visual or visual3D exclusively should be non-null.");
        }

        ///  
        ///     Returns null if the given element is null, otherwise visual or visual3D
        ///     will be the strong visual type on exit. 
        /// 
        ///     Throws an exception if element is a non-Visual type.
        ///  
        internal static void AsVisual(DependencyObject element, out Visual visual, out Visual3D visual3D)
        {
            bool castSucceeded = AsVisualHelper(element, out visual, out visual3D);
 
            if (element != null)
            { 
                if (!castSucceeded) 
                {
                    throw new System.InvalidOperationException(SR.Get(SRID.Visual_NotAVisual, element.GetType())); 
                }

                Debug.Assert(castSucceeded && ((visual == null) != (visual3D == null)),
                    "Either visual or visual3D exclusively should be non-null."); 

                element.VerifyAccess(); 
            } 
            else
            { 
                Debug.Assert(!castSucceeded && visual == null && visual3D == null,
                    "How did the cast succeed if the element was null going in?");
            }
        } 

        ///  
        ///     Internal helper to cast to DO to Visual or Visual3D.  Asserts 
        ///     that the DO is really a Visual type.  Null is allowed.  Does not
        ///     VerifyAccess. 
        ///
        ///     Caller is responsible for guaranteeing that element is a Visual type.
        /// 
        internal static bool AsVisualInternal(DependencyObject element, out Visual visual, out Visual3D visual3D) 
        {
            bool castSucceeded = AsVisualHelper(element, out visual, out visual3D); 
 
            if (!(castSucceeded || element == null))
            { 
                Debug.Fail(String.Format(
                               "'{0}' is not a Visual or Visual3D. Caller is responsible for guaranteeing that element is a Visual type.",
                               element != null ? element.GetType() : null));
            } 

            return castSucceeded; 
        } 

        #endregion Internal Methods 

        //-----------------------------------------------------
        //
        //  Private Methods 
        //
        //------------------------------------------------------ 
 
        #region Private Methods
 
        // Common code for AsVisual and AsVisualInternal -- Don't call this.
        private static bool AsVisualHelper(DependencyObject element, out Visual visual, out Visual3D visual3D)
        {
            Visual elementAsVisual = element as Visual; 

            if (elementAsVisual != null) 
            { 
                visual = elementAsVisual;
                visual3D = null; 
                return true;
            }

            Visual3D elementAsVisual3D = element as Visual3D; 

            if (elementAsVisual3D != null) 
            { 
                visual = null;
                visual3D = elementAsVisual3D; 
                return true;
            }

            visual = null; 
            visual3D = null;
            return false; 
        } 

        #endregion Private Methods 
    }
}

 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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