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//------------------------------------------------------------------------------
// Microsoft Avalon
// Copyright (c) Microsoft Corporation, 2003
//
// File: VisualTreeHelper
//------------------------------------------------------------------------------
using System;
using System.Windows.Media;
using System.Windows.Media.Media3D;
using System.Windows.Media.Animation;
using System.Windows.Threading;
using System.Security.Permissions;
using System.Windows.Media.Effects;
using System.Collections;
using System.Diagnostics;
using MS.Internal;
using MS.Internal.Media;
using MS.Internal.PresentationCore;
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID;
namespace System.Windows.Media
{
/// <summary>
/// The VisualTreeHelper class contains static methods that are useful for performing
/// common tasks with visual tree nodes. Nodes in the visual tree may be Visual or
/// Visual3Ds.
///
/// When possible methods are typed to DependencyObject and may accept or
/// return either type of visual tree node (e.g. GetParent).
///
/// When the result of the operation is specific to 2D or 3D the methods are typed
/// to Visual or Visual3D (e.g., GetDescendantBounds()).
/// </summary>
public static class VisualTreeHelper
{
private static void CheckVisualReferenceArgument(DependencyObject reference)
{
if (reference == null)
{
throw new ArgumentNullException("reference");
}
}
/// <summary>
/// Return true if the given DependencyObject is a non-null visual type.
/// This is useful as a precondition for many of the VisualTreeHelper methods,
/// to avoid exceptions.
/// </summary>
//
[FriendAccessAllowed]
internal static bool IsVisualType(DependencyObject reference)
{
return (reference is Visual) || (reference is Visual3D);
}
/// <summary>
/// Get the number of children of the specified Visual.
/// </summary>
public static int GetChildrenCount(DependencyObject reference)
{
Visual visual;
Visual3D visual3D;
VisualTreeUtils.AsNonNullVisual(reference, out visual, out visual3D);
// x86 branch prediction skips the branch on first encounter. We favor 2D.
if (visual3D != null)
{
return visual3D.InternalVisual2DOr3DChildrenCount;
}
//
// Even though visual is a 2D visual, it still may have
// 3D children.
//
return visual.InternalVisual2DOr3DChildrenCount;
}
/// <summary>
/// Returns the child of Visual visual at the specified index.
/// </summary>
public static DependencyObject GetChild(DependencyObject reference, int childIndex)
{
Visual visual;
Visual3D visual3D;
VisualTreeUtils.AsNonNullVisual(reference, out visual, out visual3D);
// x86 branch prediction skips the branch on first encounter. We favor 2D.
if (visual3D != null)
{
return visual3D.InternalGet2DOr3DVisualChild(childIndex);
}
//
// Even though visual is a 2D visual, it still may have
// 3D children.
//
return visual.InternalGet2DOr3DVisualChild(childIndex);
}
/// <summary>
/// Returns the DPI information at which this Visual is measured and rendered.
/// </summary>
public static DpiScale GetDpi(Visual visual)
{
return visual.GetDpi();
}
/// <summary>
/// This method updates the DPI information of a visual. It can only be called on a Visual with no parent.
/// </summary>
public static void SetRootDpi(Visual visual, DpiScale dpiInfo)
{
if ((object)dpiInfo == null)
{
throw new NullReferenceException("dpiInfo cannot be null");
}
if (visual.InternalVisualParent != null)
{
throw new InvalidOperationException("UpdateDPI should only be called on the root of a Visual tree");
}
DpiFlags dpiFlags = DpiUtil.UpdateDpiScalesAndGetIndex(dpiInfo.PixelsPerInchX, dpiInfo.PixelsPerInchY);
visual.RecursiveSetDpiScaleVisualFlags(new DpiRecursiveChangeArgs(dpiFlags, visual.GetDpi(), dpiInfo));
}
/// <summary>
/// Visual parent of this Visual.
/// </summary>
public static DependencyObject GetParent(DependencyObject reference)
{
Visual visual;
Visual3D visual3D;
VisualTreeUtils.AsNonNullVisual(reference, out visual, out visual3D);
// x86 branch prediction skips the branch on first encounter. We favor 2D.
if (visual3D != null)
{
return visual3D.InternalVisualParent;
}
return visual.InternalVisualParent;
}
/// <summary>
/// Equivalent to GetParent except that it does not VerifyAccess and only asserts
/// in
[FriendAccessAllowed]
internal static DependencyObject GetParentInternal(DependencyObject reference)
{
Visual visual;
Visual3D visual3D;
VisualTreeUtils.AsVisualInternal(reference, out visual, out visual3D);
if (visual != null)
{
return visual.InternalVisualParent;
}
if (visual3D != null)
{
return visual3D.InternalVisualParent;
}
Debug.Assert(reference == null);
return null;
}
/// <summary>
/// Returns the closest Visual that contains the given DependencyObject
/// </summary>
internal static Visual GetContainingVisual2D(DependencyObject reference)
{
Visual visual = null;
while (reference != null)
{
visual = reference as Visual;
if (visual != null) break;
reference = VisualTreeHelper.GetParent(reference);
}
return visual;
}
/// <summary>
/// Returns the closest Visual3D that contains the given DependencyObject
/// </summary>
internal static Visual3D GetContainingVisual3D(DependencyObject reference)
{
Visual3D visual3D = null;
while (reference != null)
{
visual3D = reference as Visual3D;
if (visual3D != null) break;
reference = VisualTreeHelper.GetParent(reference);
}
return visual3D;
}
internal static bool IsAncestorOf(DependencyObject reference, DependencyObject descendant)
{
Visual visual;
Visual3D visual3D;
VisualTreeUtils.AsNonNullVisual(reference, out visual, out visual3D);
// x86 branch prediction skips the branch on first encounter. We favor 2D.
if (visual3D != null)
{
return visual3D.IsAncestorOf(descendant);
}
return visual.IsAncestorOf(descendant);
}
// a version of IsAncestorOf that stops looking when it finds an ancestor
// of the given type
internal static bool IsAncestorOf(DependencyObject ancestor, DependencyObject descendant, Type stopType)
{
if (ancestor == null)
{
throw new ArgumentNullException("ancestor");
}
if (descendant == null)
{
throw new ArgumentNullException("descendant");
}
VisualTreeUtils.EnsureVisual(ancestor);
VisualTreeUtils.EnsureVisual(descendant);
// Walk up the parent chain of the descendant until we run out of parents,
// or we find the ancestor, or we reach a node of the given type.
DependencyObject current = descendant;
while ((current != null) && (current != ancestor) && !stopType.IsInstanceOfType(current))
{
Visual visual;
Visual3D visual3D;
if ((visual = current as Visual) != null)
{
current = visual.InternalVisualParent;
}
else if ((visual3D = current as Visual3D) != null)
{
current = visual3D.InternalVisualParent;
}
else
{
current = null;
}
}
return current == ancestor;
}
internal static DependencyObject FindCommonAncestor(DependencyObject reference, DependencyObject otherVisual)
{
Visual visual;
Visual3D visual3D;
VisualTreeUtils.AsNonNullVisual(reference, out visual, out visual3D);
// x86 branch prediction skips the branch on first encounter. We favor 2D.
if (visual3D != null)
{
return visual3D.FindCommonVisualAncestor(otherVisual);
}
return visual.FindCommonVisualAncestor(otherVisual);
}
/// <summary>
/// Gets the clip of this Visual.
/// </summary>
public static Geometry GetClip(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualClip;
}
/// <summary>
/// Gets the opacity of the Visual.
/// </summary>
public static double GetOpacity(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualOpacity;
}
/// <summary>
/// Gets the OpacityMask.
/// </summary>
public static Brush GetOpacityMask(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualOpacityMask;
}
/// <summary>
/// Returns the offset of the Visual.
/// </summary>
public static Vector GetOffset(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualOffset;
}
/// <summary>
/// Returns the Visual transform.
/// </summary>
public static Transform GetTransform(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualTransform;
}
/// <summary>
/// Returns X-coordinate (vertical) guideline collection.
/// </summary>
public static DoubleCollection GetXSnappingGuidelines(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualXSnappingGuidelines;
}
/// <summary>
/// Returns Y-coordinate (horizontal) guideline collection.
/// </summary>
public static DoubleCollection GetYSnappingGuidelines(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualYSnappingGuidelines;
}
/// <summary>
/// GetDrawing returns the drawing content of the reference Visual
/// </summary>
public static DrawingGroup GetDrawing(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.GetDrawing();
}
/// <summary>
/// GetContentBounds returns the bounding box for the contents of the specified visual.
/// </summary>
public static Rect GetContentBounds(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualContentBounds;
}
/// <summary>
/// GetContentBounds returns the bounding box for the contents of the specified visual.
/// </summary>
public static Rect3D GetContentBounds(Visual3D reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualContentBounds;
}
/// <summary>
/// GetDescendantBounds returns the union of all of the content bounding
/// boxes of the specified Visual's sub-graph.
/// </summary>
public static Rect GetDescendantBounds(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualDescendantBounds;
}
/// <summary>
/// GetDescendantBounds returns the union of all of the content bounding
/// boxes of the specified Visual3D's sub-graph.
/// </summary>
public static Rect3D GetDescendantBounds(Visual3D reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualDescendantBounds;
}
/// <summary>
/// Gets the BitmapEffect.
/// </summary>
public static BitmapEffect GetBitmapEffect(Visual reference)
{
CheckVisualReferenceArgument(reference);
#pragma warning disable 0618
return reference.VisualBitmapEffect;
#pragma warning restore 0618
}
/// <summary>
/// Gets the BitmapEffectInput.
/// </summary>
public static BitmapEffectInput GetBitmapEffectInput(Visual reference)
{
CheckVisualReferenceArgument(reference);
#pragma warning disable 0618
return reference.VisualBitmapEffectInput;
#pragma warning restore 0618
}
/// <summary>
/// Gets the Effect.
/// </summary>
public static Effect GetEffect(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualEffect;
}
/// <summary>
/// Gets the CacheMode.
/// </summary>
public static CacheMode GetCacheMode(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualCacheMode;
}
/// <summary>
/// Gets the EdgeMode of the Visual.
/// </summary>
public static EdgeMode GetEdgeMode(Visual reference)
{
CheckVisualReferenceArgument(reference);
return reference.VisualEdgeMode;
}
/// <summary>
/// Return top most visual of a hit test.
/// </summary>
public static HitTestResult HitTest(Visual reference, Point point)
{
return HitTest(reference, point, true);
}
/// <summary>
/// </summary>
[FriendAccessAllowed]
internal static HitTestResult HitTest(Visual reference, Point point, bool include2DOn3D)
{
CheckVisualReferenceArgument(reference);
return reference.HitTest(point, include2DOn3D);
}
/// <summary>
/// Initiate a hit test using delegates.
/// </summary>
public static void HitTest(
Visual reference,
HitTestFilterCallback filterCallback,
HitTestResultCallback resultCallback,
HitTestParameters hitTestParameters)
{
CheckVisualReferenceArgument(reference);
reference.HitTest(filterCallback, resultCallback, hitTestParameters);
}
/// <summary>
/// Initiate a hit test using delegates.
/// </summary>
public static void HitTest(
Visual3D reference,
HitTestFilterCallback filterCallback,
HitTestResultCallback resultCallback,
HitTestParameters3D hitTestParameters)
{
CheckVisualReferenceArgument(reference);
reference.HitTest(filterCallback, resultCallback, hitTestParameters);
}
#if WCP_MF_ENABLED
/// <summary>
/// Serialize a visual to fixed (S0) XAML
/// </summary>
/// <param name="visual"></param>
/// <param name="writer"></param>
static internal void SaveAsXml(Visual visual, System.Xml.XmlWriter writer)
{
VisualTreeFlattener.SaveAsXml(visual, writer, new FixedXamlDesigner());
}
/// <summary>
/// Walk a visual tree and flatten it to (S0) DrawingContext
/// </summary>
/// <param name="visual"></param>
/// <param name="dc"></param>
//CASRemoval:[StrongNameIdentityPermission(SecurityAction.LinkDemand, PublicKey=Microsoft.Internal.BuildInfo.WCP_PUBLIC_KEY_STRING)]
static public void Walk(Visual visual, DrawingContext dc)
{
VisualTreeFlattener flattener = new VisualTreeFlattener(dc);
flattener.Walk(visual, null);
}
#endif // WCP_MF_ENABLED
}
}
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