TextRunCache.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Core / CSharp / System / Windows / Media / textformatting / TextRunCache.cs / 1305600 / TextRunCache.cs
                        

                        
                            //------------------------------------------------------------------------ 
//
//  Microsoft Windows Client Platform
//  Copyright (C) Microsoft Corporation, 2001
// 
//  File:      TextRunCache.cs
// 
//  Contents:  Cache of text and text properties of run 
//
//  Spec:      http://team/sites/Avalon/Specs/Text%20Formatting%20API.doc 
//
//  Created:   2-25-2003 Worachai Chaoweeraprasit (wchao)
//
//----------------------------------------------------------------------- 

 
using System; 
using System.Collections.Generic;
 
using MS.Internal.PresentationCore;
using MS.Internal.TextFormatting;

namespace System.Windows.Media.TextFormatting 
{
    ///  
    /// TextFormatter caches runs it receives from GetTextRun callback. This cache 
    /// object is managed by text layout client.
    /// 
    /// This method is used to improve performance in application whose fetching the
    /// run has significant performance implication. Application using this caching
    /// mechanism is responsible for invalidating the content in the cache when
    /// its changed. 
    /// 
    public sealed class TextRunCache 
    { 
        /// 
        /// Constructing text run cache 
        /// 
        public TextRunCache() {}

 

        ///  
        /// Client to notify change in part of the cache when text or 
        /// properties of the run is being added, removed or replaced.
        ///  
        /// text source character index to specify where in the source text the change starts.
        /// the number of text source characters to be added in the source text
        /// the number of text source characters to be removed in the source text
        public void Change( 
            int     textSourceCharacterIndex,
            int     addition, 
            int     removal 
            )
        { 
            if(_imp != null)
            {
                _imp.Change(
                    textSourceCharacterIndex, 
                    addition,
                    removal 
                    ); 
            }
        } 



        ///  
        /// Client to invalidate the whole cache, in effect emptying the cache and
        /// cause the cache refill in subsequent call to Text Formatting API. 
        ///  
        public void Invalidate()
        { 
            if(_imp != null)
            {
                _imp = null;
            } 
        }
 
 
        /// 
        /// Return all cached TextRun in a TextSpan list. If TextRun is not cached for a particular character range, 
        /// the TextSpan would contain null TextRun object.
        /// 
#if OPTIMALBREAK_API
        public IList> GetTextRunSpans() 
#else
        [FriendAccessAllowed] 
        internal IList> GetTextRunSpans() 
#endif
        { 
            if (_imp != null)
            {
                return _imp.GetTextRunSpans();
            } 

            // otherwise, return an empty collection 
            return new TextSpan[0]; 
        }
 

        /// 
        /// Get/set the actual cache instance
        ///  
        internal TextRunCacheImp Imp
        { 
            get { return _imp; } 
            set { _imp = value; }
        } 

        private TextRunCacheImp   _imp;
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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