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//---------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation. All rights reserved.
//
// File: TextElementAutomationPeer.cs
//
// Description: AutomationPeer associated with TextElements.
//
//---------------------------------------------------------------------------
using System.Collections;
using System.Collections.Generic; // List<T>
using System.Security; // SecurityCritical
using System.Windows.Documents; // ITextContainer
using System.Windows.Media; // Geometry
using System.Windows.Interop; // HwndSource
using MS.Internal.Automation; // TextAdaptor
using MS.Internal;
using MS.Internal.Documents; // TextContainerHelper
namespace System.Windows.Automation.Peers
{
/// <summary>
/// AutomationPeer associated with TextElements.
/// </summary>
public class TextElementAutomationPeer : ContentTextAutomationPeer
{
/// <summary>
/// Constructor.
/// </summary>
/// <param name="owner">Owner of the AutomationPeer.</param>
public TextElementAutomationPeer(TextElement owner)
: base(owner)
{ }
/// <summary>
/// <see cref="AutomationPeer.GetChildrenCore"/>
/// </summary>
/// <remarks>
/// Since DocumentAutomationPeer gives access to its content through
/// TextPattern, this method always returns null.
/// </remarks>
protected override List<AutomationPeer> GetChildrenCore()
{
TextElement textElement = (TextElement)Owner;
return TextContainerHelper.GetAutomationPeersFromRange(textElement.ContentStart, textElement.ContentEnd, null);
}
/// <summary>
/// <see cref="AutomationPeer.GetBoundingRectangleCore"/>
/// </summary>
/// <SecurityNote>
/// Critical - Calls PresentationSource.CriticalFromVisual to get the source for this visual
/// TreatAsSafe - The returned PresenationSource object is not exposed and is only used for converting
/// co-ordinates to screen space.
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
protected override Rect GetBoundingRectangleCore()
{
TextElement textElement = (TextElement)Owner;
ITextView textView = textElement.TextContainer.TextView;
if (textView == null || !textView.IsValid)
{
return Rect.Empty;
}
Geometry geometry = textView.GetTightBoundingGeometryFromTextPositions(textElement.ContentStart, textElement.ContentEnd);
if (geometry != null)
{
PresentationSource presentationSource = PresentationSource.CriticalFromVisual(textView.RenderScope);
if (presentationSource == null)
{
return Rect.Empty;
}
HwndSource hwndSource = presentationSource as HwndSource;
// If the source isn't an HwnSource, there's not much we can do, return empty rect
if (hwndSource == null)
{
return Rect.Empty;
}
Rect rectElement = geometry.Bounds;
Rect rectRoot = PointUtil.ElementToRoot(rectElement, textView.RenderScope, presentationSource);
Rect rectClient = PointUtil.RootToClient(rectRoot, presentationSource);
Rect rectScreen = PointUtil.ClientToScreen(rectClient, hwndSource);
return rectScreen;
}
else
{
return Rect.Empty;
}
}
/// <summary>
/// <see cref="AutomationPeer.GetClickablePointCore"/>
/// </summary>
/// <SecurityNote>
/// Critical - Calls PresentationSource.CriticalFromVisual to get the source for this visual
/// TreatAsSafe - The returned PresenationSource object is not exposed and is only used for converting
/// co-ordinates to screen space.
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
protected override Point GetClickablePointCore()
{
Point pt = new Point();
TextElement textElement = (TextElement)Owner;
ITextView textView = textElement.TextContainer.TextView;
if (textView == null || !textView.IsValid || (!textView.Contains(textElement.ContentStart) && !textView.Contains(textElement.ContentEnd)))
{
return pt;
}
PresentationSource presentationSource = PresentationSource.CriticalFromVisual(textView.RenderScope);
if (presentationSource == null)
{
return pt;
}
HwndSource hwndSource = presentationSource as HwndSource;
// If the source isn't an HwnSource, there's not much we can do, return empty rect
if (hwndSource == null)
{
return pt;
}
TextPointer endPosition = textElement.ContentStart.GetNextInsertionPosition(LogicalDirection.Forward);
if (endPosition == null || endPosition.CompareTo(textElement.ContentEnd) > 0)
endPosition = textElement.ContentEnd;
Rect rectElement = CalculateVisibleRect(textView, textElement, textElement.ContentStart, endPosition);
Rect rectRoot = PointUtil.ElementToRoot(rectElement, textView.RenderScope, presentationSource);
Rect rectClient = PointUtil.RootToClient(rectRoot, presentationSource);
Rect rectScreen = PointUtil.ClientToScreen(rectClient, hwndSource);
pt = new Point(rectScreen.Left + rectScreen.Width * 0.5, rectScreen.Top + rectScreen.Height * 0.5);
return pt;
}
/// <summary>
/// <see cref="AutomationPeer.IsOffscreenCore"/>
/// </summary>
/// <returns></returns>
protected override bool IsOffscreenCore()
{
IsOffscreenBehavior behavior = AutomationProperties.GetIsOffscreenBehavior(Owner);
switch (behavior)
{
case IsOffscreenBehavior.Onscreen :
return false;
case IsOffscreenBehavior.Offscreen :
return true;
default:
{
TextElement textElement = (TextElement)Owner;
ITextView textView = textElement.TextContainer.TextView;
if (textView == null || !textView.IsValid || (!textView.Contains(textElement.ContentStart) && !textView.Contains(textElement.ContentEnd)))
{
return true;
}
if (CalculateVisibleRect(textView, textElement, textElement.ContentStart, textElement.ContentEnd) == Rect.Empty)
{
return true;
}
return false;
}
}
}
/// <summary>
/// Compute visible rectangle.
/// </summary>
private Rect CalculateVisibleRect(ITextView textView, TextElement textElement, TextPointer startPointer, TextPointer endPointer)
{
Geometry geometry = textView.GetTightBoundingGeometryFromTextPositions(startPointer, endPointer);
Rect visibleRect = (geometry != null) ? geometry.Bounds : Rect.Empty;
Visual visual = textView.RenderScope;
while (visual != null && visibleRect != Rect.Empty)
{
if (VisualTreeHelper.GetClip(visual) != null)
{
GeneralTransform transform = textView.RenderScope.TransformToAncestor(visual).Inverse;
// Safer version of transform to descendent (doing the inverse ourself),
// we want the rect inside of our space. (Which is always rectangular and much nicer to work with)
if (transform != null)
{
Rect rectBounds = VisualTreeHelper.GetClip(visual).Bounds;
rectBounds = transform.TransformBounds(rectBounds);
visibleRect.Intersect(rectBounds);
}
else
{
// No visibility if non-invertable transform exists.
return Rect.Empty;
}
}
visual = VisualTreeHelper.GetParent(visual) as Visual;
}
return visibleRect;
}
/// <summary>
/// Gets collection of AutomationPeers for given text range.
/// </summary>
internal override List<AutomationPeer> GetAutomationPeersFromRange(ITextPointer start, ITextPointer end)
{
// Force children connection to automation tree.
GetChildren();
TextElement textElement = (TextElement)Owner;
return TextContainerHelper.GetAutomationPeersFromRange(start, end, textElement.ContentStart);
}
/// <summary>
/// Gets the visibility of the TextElement owner based on its TextView
/// </summary>
internal bool? IsTextViewVisible
{
get
{
TextElement textElement = (TextElement)Owner;
ITextView textView = textElement?.TextContainer?.TextView;
UIElement uiElement = textView?.RenderScope;
return uiElement?.IsVisible;
}
}
}
}
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