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//---------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation. All rights reserved.
//
// Description: BaseParagraph represents a paragraph corresponding to part
// of a text based content.
//
// History:
// 05/05/2003 : Microsoft - moving from Avalon branch.
// 10/30/2004 : Microsoft - ElementReference cleanup.
//
//---------------------------------------------------------------------------
using System;
using System.Diagnostics;
using System.Windows;
using System.Windows.Documents;
using MS.Internal.Documents;
using MS.Internal.Text;
using MS.Internal.PtsHost.UnsafeNativeMethods;
namespace MS.Internal.PtsHost
{
/// <summary>
/// BaseParagraph represents a paragraph corresponding to part of a text
/// based content.
/// </summary>
internal abstract class BaseParagraph : UnmanagedHandle
{
//-------------------------------------------------------------------
//
// Constructors
//
//-------------------------------------------------------------------
#region Constructors
/// <summary>
/// Constructor.
/// </summary>
/// <param name="element">
/// Element associated with paragraph.
/// </param>
/// <param name="structuralCache">
/// Content's structural cache
/// </param>
protected BaseParagraph(DependencyObject element, StructuralCache structuralCache)
: base(structuralCache.PtsContext)
{
_element = element;
_structuralCache = structuralCache;
_changeType = PTS.FSKCHANGE.fskchNone;
_stopAsking = false;
UpdateLastFormatPositions();
}
#endregion Constructors
// ------------------------------------------------------------------
//
// PTS callbacks
//
// ------------------------------------------------------------------
#region PTS callbacks
/// <summary>
/// UpdGetParaChange
/// </summary>
/// <param name="fskch">
/// OUT: kind of change
/// </param>
/// <param name="fNoFurtherChanges">
/// OUT: no changes after?
/// </param>
internal virtual void UpdGetParaChange(
out PTS.FSKCHANGE fskch,
out int fNoFurtherChanges)
{
fskch = _changeType;
fNoFurtherChanges = PTS.FromBoolean(_stopAsking);
#if TEXTPANELLAYOUTDEBUG
if (StructuralCache.CurrentFormatContext.IncrementalUpdate)
{
TextPanelDebug.Log("Para.UpdGetParaChange, Para=" + this.GetType().Name + " Change=" + _changeType.ToString(), TextPanelDebug.Category.ContentChange);
}
#endif
}
/// <summary>
/// Collapse margins
/// </summary>
/// <param name="paraClient">
/// IN: Paragraph's para client
/// </param>
/// <param name="mcs">
/// IN: input margin collapsing state
/// </param>
/// <param name="fswdir">
/// IN: current direction (of the track, in which margin collapsing is happening)
/// </param>
/// <param name="suppressTopSpace">
/// IN: suppress empty space at the top of page
/// </param>
/// <param name="dvr">
/// OUT: dvr, calculated based on margin collapsing state
/// </param>
internal virtual void CollapseMargin(
BaseParaClient paraClient,
MarginCollapsingState mcs,
uint fswdir,
bool suppressTopSpace,
out int dvr)
{
// Suppress top space only in paginated scenarios.
dvr = (mcs == null || (suppressTopSpace)) ? 0 : mcs.Margin;
}
/// <summary>
/// Get Para Properties
/// </summary>
/// <param name="fspap">
/// OUT: paragraph properties
/// </param>
internal abstract void GetParaProperties(
ref PTS.FSPAP fspap);
/// <summary>
/// CreateParaclient
/// </summary>
/// <param name="pfsparaclient">
/// OUT: opaque to PTS paragraph client
/// </param>
internal abstract void CreateParaclient(
out IntPtr pfsparaclient);
#endregion PTS callbacks
// ------------------------------------------------------------------
//
// Internal Methods
//
// ------------------------------------------------------------------
#region Internal Methods
/// <summary>
/// Set update info. Those flags are used later by PTS to decide
/// if paragraph needs to be updated and when to stop asking for
/// update information.
/// </summary>
/// <param name="fskch">
/// Type of change within the paragraph.
/// </param>
/// <param name="stopAsking">
/// Synchronization point is reached?
/// </param>
internal virtual void SetUpdateInfo(PTS.FSKCHANGE fskch, bool stopAsking)
{
_changeType = fskch;
_stopAsking = stopAsking;
}
/// <summary>
/// Clear previously accumulated update info.
/// </summary>
internal virtual void ClearUpdateInfo()
{
_changeType = PTS.FSKCHANGE.fskchNone;
_stopAsking = true;
}
/// <summary>
/// Invalidate content's structural cache. Returns: 'true' if entire paragraph
/// is invalid.
/// </summary>
/// <param name="startPosition">
/// Position to start invalidation from.
/// </param>
internal virtual bool InvalidateStructure(int startPosition)
{
Debug.Assert(ParagraphEndCharacterPosition >= startPosition);
int openEdgeCp = TextContainerHelper.GetCPFromElement(StructuralCache.TextContainer, Element, ElementEdge.BeforeStart);
return (openEdgeCp == startPosition);
}
/// <summary>
/// Invalidate accumulated format caches.
/// </summary>
internal virtual void InvalidateFormatCache()
{
}
/// <summary>
/// Update number of characters consumed by the paragraph.
/// </summary>
internal void UpdateLastFormatPositions()
{
_lastFormatCch = Cch;
}
#endregion Internal Methods
//-------------------------------------------------------------------
//
// Protected Methods
//
//-------------------------------------------------------------------
#region Protected Methods
/// <summary>
/// Retrieve PTS paragraph properties.
/// </summary>
/// <param name="fspap">
/// Paragraph properties to initialize.
/// </param>
/// <param name="ignoreElementProps">
/// Ignore element properties?
/// </param>
protected void GetParaProperties(ref PTS.FSPAP fspap, bool ignoreElementProps)
{
if (!ignoreElementProps)
{
fspap.fKeepWithNext = PTS.FromBoolean(DynamicPropertyReader.GetKeepWithNext(_element));
// Can be broken only if Block.BreakPageBefore is set
fspap.fBreakPageBefore = _element is Block ? PTS.FromBoolean(StructuralCache.CurrentFormatContext.FinitePage && ((Block)_element).BreakPageBefore) : PTS.FromBoolean(false);
// Can be broken only if Block.BreakColumnBefore is set
fspap.fBreakColumnBefore = _element is Block ? PTS.FromBoolean(((Block)_element).BreakColumnBefore) : PTS.FromBoolean(false);
}
}
#endregion Protected Methods
//-------------------------------------------------------------------
//
// Properties / Fields
//
//-------------------------------------------------------------------
#region Properties / Fields
/// <summary>
/// CharacterPosition at the start of paragraph.
/// </summary>
internal int ParagraphStartCharacterPosition
{
get
{
// This is done here, rather than deriving for two reasons - This is special cased for text paragraph - no other
// paras should use their cps in this way, and this is also not a virtual method, so can be used from C'Tor.
if(this is TextParagraph)
{
return TextContainerHelper.GetCPFromElement(StructuralCache.TextContainer, Element, ElementEdge.AfterStart);
}
else
{
return TextContainerHelper.GetCPFromElement(StructuralCache.TextContainer, Element, ElementEdge.BeforeStart);
}
}
}
/// <summary>
/// CharacterPosition at the end of paragraph. The first character
/// that does not belong to the paragraph.
/// </summary>
internal int ParagraphEndCharacterPosition
{
get
{
// This is done here, rather than deriving for two reasons - This is special cased for text paragraph - no other
// paras should use their cps in this way, and this is also not a virtual method, so can be used from C'Tor.
if(this is TextParagraph)
{
return TextContainerHelper.GetCPFromElement(StructuralCache.TextContainer, Element, ElementEdge.BeforeEnd);
}
else
{
return TextContainerHelper.GetCPFromElement(StructuralCache.TextContainer, Element, ElementEdge.AfterEnd);
}
}
}
/// <summary>
/// Incremental update information for the paragraph.
/// Those fields are used only during incremental update process.
/// </summary>
protected PTS.FSKCHANGE _changeType;
protected bool _stopAsking;
/// <summary>
/// Number of characters consumed by the paragraph.
/// </summary>
internal int Cch
{
get
{
int cch = TextContainerHelper.GetCchFromElement(StructuralCache.TextContainer, Element);
// This is done here, rather than deriving for two reasons - This is special cased for text paragraph - no other
// paras should use their cps in this way, and this is also not a virtual method, so can be used from C'Tor.
if (this is TextParagraph && Element is TextElement)
{
Invariant.Assert(cch >= 2);
cch -= 2;
}
return cch;
}
}
/// <summary>
/// Cch paragraph had during last format
/// </summary>
internal int LastFormatCch
{
get
{
return _lastFormatCch;
}
}
protected int _lastFormatCch;
/// <summary>
/// The next and previous sibling in paragraph list.
/// </summary>
internal BaseParagraph Next;
internal BaseParagraph Previous;
/// <summary>
/// Content's structural cache.
/// </summary>
internal StructuralCache StructuralCache
{
get
{
return _structuralCache;
}
}
protected readonly StructuralCache _structuralCache;
/// <summary>
/// Object associated with the paragraph.
/// </summary>
internal DependencyObject Element
{
get
{
return _element;
}
}
protected readonly DependencyObject _element;
#endregion Properties / Fields
}
}
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