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//-----------------------------------------------------------------------
//
// Microsoft Windows Client Platform
// Copyright (C) Microsoft Corporation, 2001
//
// File: TextFormatter.cs
//
// Contents: Text formatting API
//
// Spec: http://team/sites/Avalon/Specs/Text%20Formatting%20API.doc
//
// Created: 2-25-2003 Worachai Chaoweeraprasit (wchao)
//
//------------------------------------------------------------------------
using System;
using System.Windows.Threading;
using System.Collections.Generic;
using MS.Internal;
using MS.Internal.TextFormatting;
using MS.Internal.PresentationCore;
namespace System.Windows.Media.TextFormatting
{
/// <summary>
/// The TextFormatter is the Windows Client Platform text engine that provides services
/// for formatting text and breaking text lines. It handles different text character
/// formats with different paragraph styles. It also implements all the writing system rules
/// for international text layout.
///
/// Unlike traditional text APIs, the TextFormatter interacts with a text layout client
/// through a set of callback methods. It requires the client to provide these methods
/// in an implementation of the TextSource class.
/// </summary>
public abstract class TextFormatter : IDisposable
{
private static object _staticLock = new object();
/// <summary>
/// Client to create a new instance of TextFormatter
/// </summary>
/// <returns>New instance of TextFormatter</returns>
static public TextFormatter Create(TextFormattingMode textFormattingMode)
{
if ((int)textFormattingMode < 0 || (int)textFormattingMode > 1)
{
throw new System.ComponentModel.InvalidEnumArgumentException("textFormattingMode", (int)textFormattingMode, typeof(TextFormattingMode));
}
// create a new instance of TextFormatter which allows the use of multiple contexts.
return new TextFormatterImp(textFormattingMode);
}
/// <summary>
/// Client to create a new instance of TextFormatter
/// </summary>
/// <returns>New instance of TextFormatter</returns>
static public TextFormatter Create()
{
// create a new instance of TextFormatter which allows the use of multiple contexts.
return new TextFormatterImp();
}
/// <summary>
/// Client to create a new instance of TextFormatter from the specified TextFormatter context
/// </summary>
/// <param name="soleContext">TextFormatter context</param>
/// <returns>New instance of TextFormatter</returns>
#if OPTIMALBREAK_API
static public TextFormatter CreateFromContext(TextFormatterContext soleContext)
#else
[FriendAccessAllowed] // used by Framework
static internal TextFormatter CreateFromContext(TextFormatterContext soleContext)
#endif
{
// create a new instance of TextFormatter for the specified context.
// This creation prohibits the use of multiple contexts within the same TextFormatter via reentrance.
return new TextFormatterImp(soleContext, TextFormattingMode.Ideal);
}
/// <summary>
/// Client to create a new instance of TextFormatter from the specified TextFormatter context
/// </summary>
/// <param name="soleContext">TextFormatter context</param>
/// <returns>New instance of TextFormatter</returns>
#if OPTIMALBREAK_API
static public TextFormatter CreateFromContext(TextFormatterContext soleContext, TextFormattingMode textFormattingMode)
#else
[FriendAccessAllowed] // used by Framework
static internal TextFormatter CreateFromContext(TextFormatterContext soleContext, TextFormattingMode textFormattingMode)
#endif
{
// create a new instance of TextFormatter for the specified context.
// This creation prohibits the use of multiple contexts within the same TextFormatter via reentrance.
return new TextFormatterImp(soleContext, textFormattingMode);
}
/// <summary>
/// Client to get TextFormatter associated with the current dispatcher
/// </summary>
/// <remarks>
/// This method is available internally. It is exclusively used by Presentation Framework UIElement
/// through friend assembly mechanics to quickly reuse the default TextFormatter retained in the current
/// dispatcher of the running thread.
/// </remarks>
[FriendAccessAllowed] // used by Framework
static internal TextFormatter FromCurrentDispatcher()
{
return FromCurrentDispatcher(TextFormattingMode.Ideal);
}
/// <summary>
/// Client to get TextFormatter associated with the current dispatcher
/// </summary>
/// <remarks>
/// This method is available internally. It is exclusively used by Presentation Framework UIElement
/// through friend assembly mechanics to quickly reuse the default TextFormatter retained in the current
/// dispatcher of the running thread.
/// </remarks>
[FriendAccessAllowed] // used by Framework
static internal TextFormatter FromCurrentDispatcher(TextFormattingMode textFormattingMode)
{
Dispatcher dispatcher = Dispatcher.CurrentDispatcher;
if (dispatcher == null)
throw new ArgumentException(SR.Get(SRID.CurrentDispatcherNotFound));
TextFormatter defaultTextFormatter;
if (textFormattingMode == TextFormattingMode.Display)
{
defaultTextFormatter = (TextFormatterImp)dispatcher.Reserved4;
}
else
{
defaultTextFormatter = (TextFormatterImp)dispatcher.Reserved1;
}
if (defaultTextFormatter == null)
{
lock (_staticLock)
{
if (defaultTextFormatter == null)
{
// Default formatter has not been created for this dispatcher,
// create a new one and stick it to the dispatcher.
defaultTextFormatter = Create(textFormattingMode);
if (textFormattingMode == TextFormattingMode.Display)
{
dispatcher.Reserved4 = defaultTextFormatter;
}
else
{
dispatcher.Reserved1 = defaultTextFormatter;
}
}
}
}
Invariant.Assert(defaultTextFormatter != null);
return defaultTextFormatter;
}
/// <summary>
/// Clean up text formatter internal resource
/// </summary>
public virtual void Dispose() {}
/// <summary>
/// Client to format a text line that fills a paragraph in the document.
/// </summary>
/// <param name="textSource">an object representing text layout clients text source for TextFormatter.</param>
/// <param name="firstCharIndex">character index to specify where in the source text the line starts</param>
/// <param name="paragraphWidth">width of paragraph in which the line fills</param>
/// <param name="paragraphProperties">properties that can change from one paragraph to the next, such as text flow direction, text alignment, or indentation.</param>
/// <param name="previousLineBreak">text formatting state at the point where the previous line in the paragraph
/// was broken by the text formatting process, as specified by the TextLine.LineBreak property for the previous
/// line; this parameter can be null, and will always be null for the first line in a paragraph.</param>
/// <returns>object representing a line of text that client interacts with. </returns>
public abstract TextLine FormatLine(
TextSource textSource,
int firstCharIndex,
double paragraphWidth,
TextParagraphProperties paragraphProperties,
TextLineBreak previousLineBreak
);
/// <summary>
/// Client to format a text line that fills a paragraph in the document.
/// </summary>
/// <param name="textSource">an object representing text layout clients text source for TextFormatter.</param>
/// <param name="firstCharIndex">character index to specify where in the source text the line starts</param>
/// <param name="paragraphWidth">width of paragraph in which the line fills</param>
/// <param name="paragraphProperties">properties that can change from one paragraph to the next, such as text flow direction, text alignment, or indentation.</param>
/// <param name="previousLineBreak">text formatting state at the point where the previous line in the paragraph
/// was broken by the text formatting process, as specified by the TextLine.LineBreak property for the previous
/// line; this parameter can be null, and will always be null for the first line in a paragraph.</param>
/// <param name="textRunCache">an object representing content cache of the client.</param>
/// <returns>object representing a line of text that client interacts with. </returns>
public abstract TextLine FormatLine(
TextSource textSource,
int firstCharIndex,
double paragraphWidth,
TextParagraphProperties paragraphProperties,
TextLineBreak previousLineBreak,
TextRunCache textRunCache
);
/// <summary>
/// Client to reconstruct a previously formatted text line
/// </summary>
/// <param name="textSource">an object representing text layout clients text source for TextFormatter.</param>
/// <param name="firstCharIndex">character index to specify where in the source text the line starts</param>
/// <param name="lineLength">character length of the line</param>
/// <param name="paragraphWidth">width of paragraph in which the line fills</param>
/// <param name="paragraphProperties">properties that can change from one paragraph to the next, such as text flow direction, text alignment, or indentation.</param>
/// <param name="previousLineBreak">LineBreak property of the previous text line, or null if this is the first line in the paragraph</param>
/// <param name="textRunCache">an object representing content cache of the client.</param>
/// <returns>object representing a line of text that client interacts with. </returns>
#if OPTIMALBREAK_API
public abstract TextLine RecreateLine(
#else
[FriendAccessAllowed] // used by Framework
internal abstract TextLine RecreateLine(
#endif
TextSource textSource,
int firstCharIndex,
int lineLength,
double paragraphWidth,
TextParagraphProperties paragraphProperties,
TextLineBreak previousLineBreak,
TextRunCache textRunCache
);
/// <summary>
/// Client to cache information about a paragraph to be used during optimal paragraph line formatting
/// </summary>
/// <param name="textSource">an object representing text layout clients text source for TextFormatter.</param>
/// <param name="firstCharIndex">character index to specify where in the source text the line starts</param>
/// <param name="paragraphWidth">width of paragraph in which the line fills</param>
/// <param name="paragraphProperties">properties that can change from one paragraph to the next, such as text flow direction, text alignment, or indentation.</param>
/// <param name="previousLineBreak">text formatting state at the point where the previous line in the paragraph
/// was broken by the text formatting process, as specified by the TextLine.LineBreak property for the previous
/// line; this parameter can be null, and will always be null for the first line in a paragraph.</param>
/// <param name="textRunCache">an object representing content cache of the client.</param>
/// <returns>object representing a line of text that client interacts with. </returns>
#if OPTIMALBREAK_API
public abstract TextParagraphCache CreateParagraphCache(
#else
[FriendAccessAllowed] // used by Framework
internal abstract TextParagraphCache CreateParagraphCache(
#endif
TextSource textSource,
int firstCharIndex,
double paragraphWidth,
TextParagraphProperties paragraphProperties,
TextLineBreak previousLineBreak,
TextRunCache textRunCache
);
/// <summary>
/// Client to ask for the possible smallest and largest paragraph width that can fully contain the passing text content
/// </summary>
/// <param name="textSource">an object representing text layout clients text source for TextFormatter.</param>
/// <param name="firstCharIndex">character index to specify where in the source text the line starts</param>
/// <param name="paragraphProperties">properties that can change from one paragraph to the next, such as text flow direction, text alignment, or indentation.</param>
/// <returns>min max paragraph width</returns>
public abstract MinMaxParagraphWidth FormatMinMaxParagraphWidth(
TextSource textSource,
int firstCharIndex,
TextParagraphProperties paragraphProperties
);
/// <summary>
/// Client to ask for the possible smallest and largest paragraph width that can fully contain the passing text content
/// </summary>
/// <param name="textSource">an object representing text layout clients text source for TextFormatter.</param>
/// <param name="firstCharIndex">character index to specify where in the source text the line starts</param>
/// <param name="paragraphProperties">properties that can change from one paragraph to the next, such as text flow direction, text alignment, or indentation.</param>
/// <param name="textRunCache">an object representing content cache of the client.</param>
/// <returns>min max paragraph width</returns>
public abstract MinMaxParagraphWidth FormatMinMaxParagraphWidth(
TextSource textSource,
int firstCharIndex,
TextParagraphProperties paragraphProperties,
TextRunCache textRunCache
);
}
}
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