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/*++
File: FixedSOMSemanticBox.cs
Copyright (C) 2005 Microsoft Corporation. All rights reserved.
Description:
This class is the abstract base class for all the objects in SOM. It consists of a bounding rectangle, and
implements IComparable interface to figure out content ordering on the page
History:
05/17/2005: agurcan - Created
--*/
namespace System.Windows.Documents
{
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.Windows.Media;
using System.Windows.Markup;
internal abstract class FixedSOMSemanticBox : IComparable
{
//--------------------------------------------------------------------
//
// Constructors
//
//---------------------------------------------------------------------
#region Constructors
public FixedSOMSemanticBox()
{
_boundingRect = Rect.Empty;
}
public FixedSOMSemanticBox(Rect boundingRect)
{
_boundingRect = boundingRect;
}
#endregion Constructors
//--------------------------------------------------------------------
//
// Public Properties
//
//---------------------------------------------------------------------
#region Public Properties
public Rect BoundingRect
{
get
{
return _boundingRect;
}
set
{
_boundingRect = value;
}
}
#endregion Public Properties
//--------------------------------------------------------------------
//
// Public Methods
//
//---------------------------------------------------------------------
#region Public Methods
#if DEBUG
//For visualization purposes
public abstract void Render(DrawingContext dc, string label, DrawDebugVisual debugVisuals) ;
public void RenderLabel(DrawingContext dc, string label)
{
// This code only runs in DEBUG mode, and looks like has been abandoned for a while.
// Initializing PixelsPerDip to system dpi as a safeguard, however, doesn't look like this is going to be used at all.
FormattedText ft = new FormattedText(label,
System.Windows.Markup.TypeConverterHelper.InvariantEnglishUS,
FlowDirection.LeftToRight,
new Typeface("Arial"),
10,
Brushes.White,
MS.Internal.FontCache.Util.PixelsPerDip);
Point labelLocation = new Point(_boundingRect.Left-25, (_boundingRect.Bottom + _boundingRect.Top)/2 - 10);
Geometry geom = ft.BuildHighlightGeometry(labelLocation);
Pen backgroundPen = new Pen(Brushes.Black,1);
dc.DrawGeometry(Brushes.Black, backgroundPen, geom);
dc.DrawText(ft, labelLocation);
}
#endif
public virtual void SetRTFProperties(FixedElement element)
{
}
public int CompareTo(object o)
{
Debug.Assert(o != null);
if (!(o is FixedSOMSemanticBox))
{
throw new ArgumentException(SR.Get(SRID.UnexpectedParameterType, o.GetType(), typeof(FixedSOMSemanticBox)), "o");
}
SpatialComparison compareHor = _CompareHorizontal(o as FixedSOMSemanticBox, false);
SpatialComparison compareVer = _CompareVertical(o as FixedSOMSemanticBox);
Debug.Assert(compareHor != SpatialComparison.None && compareVer != SpatialComparison.None);
int result;
if (compareHor == SpatialComparison.Equal && compareVer == SpatialComparison.Equal)
{
result = 0;
}
else if (compareHor == SpatialComparison.Equal)
{
if (compareVer == SpatialComparison.Before || compareVer == SpatialComparison.OverlapBefore)
{
result = -1;
}
else
{
result = 1;
}
}
else if (compareVer == SpatialComparison.Equal)
{
if (compareHor == SpatialComparison.Before || compareHor == SpatialComparison.OverlapBefore)
{
result = -1;
}
else
{
result = 1;
}
}
else if (compareHor == SpatialComparison.Before)
{
result = -1;
}
else if (compareHor == SpatialComparison.After)
{
result = 1;
}
else
{
//Objects overlap
if (compareVer == SpatialComparison.Before)
{
result = -1;
}
else if (compareVer == SpatialComparison.After)
{
result = 1;
}
//These objects intersect.
else if (compareHor == SpatialComparison.OverlapBefore)
{
result = -1;
}
else
{
result = 1;
}
}
return result;
}
#endregion Abstract Methods
//--------------------------------------------------------------------
//
// IComparable
//
//---------------------------------------------------------------------
#region IComparable Methods
int IComparable.CompareTo(object o)
{
return this.CompareTo(o);
}
#endregion IComparable Methods
//--------------------------------------------------------------------
//
// Protected Methods
//
//---------------------------------------------------------------------
#region Private Methods
//Method that compares horizontally according to specific reading order
protected SpatialComparison _CompareHorizontal(FixedSOMSemanticBox otherBox, bool RTL)
{
SpatialComparison result = SpatialComparison.None;
Rect thisRect = this.BoundingRect;
Rect otherRect = otherBox.BoundingRect;
double thisRectRefX = RTL ? thisRect.Right : thisRect.Left;
double otherRectRefX = RTL ? otherRect.Right : otherRect.Left;
if (thisRectRefX == otherRectRefX)
{
result = SpatialComparison.Equal;
}
//Easiest way: calculate as if it's LTR and invert the result if RTL
else if (thisRect.Right < otherRect.Left)
{
//Clearly before the other object
result = SpatialComparison.Before;
}
else if (otherRect.Right < thisRect.Left)
{
//Clearly after the other object
result = SpatialComparison.After;
}
else
{
double overlap = Math.Abs(thisRectRefX - otherRectRefX);
double longerWidth = thisRect.Width > otherRect.Width ? thisRect.Width : otherRect.Width;
if (overlap/longerWidth < 0.1)
{
//If less than 10% overlap then assume these are equal in horizontal comparison
result = SpatialComparison.Equal;
}
//Objects overlap
else if (thisRect.Left < otherRect.Left)
{
result = SpatialComparison.OverlapBefore;
}
else
{
result = SpatialComparison.OverlapAfter;
}
}
if (RTL && result != SpatialComparison.Equal)
{
result = _InvertSpatialComparison(result);
}
return result;
}
//Method that compares horizontally according to specific reading order
//In the future we should take into account the document language and plug it into this algorithm
protected SpatialComparison _CompareVertical(FixedSOMSemanticBox otherBox)
{
SpatialComparison result = SpatialComparison.None;
Rect thisRect = this.BoundingRect;
Rect otherRect = otherBox.BoundingRect;
if (thisRect.Top == otherRect.Top)
{
result = SpatialComparison.Equal;
}
else if (thisRect.Bottom <= otherRect.Top)
{
//Clearly before the other object
result = SpatialComparison.Before;
}
else if (otherRect.Bottom <= thisRect.Top)
{
//Clearly after the other object
result = SpatialComparison.After;
}
else
{
//Objects overlap
if (thisRect.Top < otherRect.Top)
{
result = SpatialComparison.OverlapBefore;
}
else
{
result = SpatialComparison.OverlapAfter;
}
}
return result;
}
protected int _SpatialToAbsoluteComparison(SpatialComparison comparison)
{
int result=0;
switch (comparison)
{
case SpatialComparison.Before:
case SpatialComparison.OverlapBefore:
result = -1;
break;
case SpatialComparison.After:
case SpatialComparison.OverlapAfter:
result = 1;
break;
case SpatialComparison.Equal:
result = 0;
break;
default:
Debug.Assert(false);
break;
}
return result;
}
protected SpatialComparison _InvertSpatialComparison(SpatialComparison comparison)
{
SpatialComparison result = comparison;
switch (comparison)
{
case SpatialComparison.Before:
result = SpatialComparison.After;
break;
case SpatialComparison.After:
result = SpatialComparison.Before;
break;
case SpatialComparison.OverlapBefore:
result = SpatialComparison.OverlapAfter;
break;
case SpatialComparison.OverlapAfter:
result = SpatialComparison.OverlapBefore;
break;
default:
break;
}
return result;
}
#endregion Protected Methods
#region enums
protected enum SpatialComparison
{
None =0,
Before,
OverlapBefore,
Equal,
OverlapAfter,
After
};
#endregion enums
//--------------------------------------------------------------------
//
// Protected Fields
//
//---------------------------------------------------------------------
#region Protected Fields
protected Rect _boundingRect;
#endregion Protected Fields
}
}
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