source: stable/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Highlighting/RichText.cs @ 17932

// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Windows.Documents;
using ICSharpCode.AvalonEdit.Document;
using ICSharpCode.AvalonEdit.Utils;

namespace ICSharpCode.AvalonEdit.Highlighting
{
  /// <summary>
  /// Represents a immutable piece text with highlighting information.
  /// </summary>
  public class RichText
  {
    /// <summary>
    /// The empty string without any formatting information.
    /// </summary>
    public static readonly RichText Empty = new RichText(string.Empty);
    
    readonly string text;
    internal readonly int[] stateChangeOffsets;
    internal readonly HighlightingColor[] stateChanges;
    
    /// <summary>
    /// Creates a RichText instance with the given text and RichTextModel.
    /// </summary>
    /// <param name="text">
    /// The text to use in this RichText instance.
    /// </param>
    /// <param name="model">
    /// The model that contains the formatting to use for this RichText instance.
    /// <c>model.DocumentLength</c> should correspond to <c>text.Length</c>.
    /// This parameter may be null, in which case the RichText instance just holds plain text.
    /// </param>
    public RichText(string text, RichTextModel model = null)
    {
      if (text == null)
        throw new ArgumentNullException("text");
      this.text = text;
      if (model != null) {
        var sections = model.GetHighlightedSections(0, text.Length).ToArray();
        stateChangeOffsets = new int[sections.Length];
        stateChanges = new HighlightingColor[sections.Length];
        for (int i = 0; i < sections.Length; i++) {
          stateChangeOffsets[i] = sections[i].Offset;
          stateChanges[i] = sections[i].Color;
        }
      } else {
        stateChangeOffsets = new int[] { 0 };
        stateChanges = new HighlightingColor[] { HighlightingColor.Empty };
      }
    }
    
    internal RichText(string text, int[] offsets, HighlightingColor[] states)
    {
      this.text = text;
      Debug.Assert(offsets[0] == 0);
      Debug.Assert(offsets.Last() <= text.Length);
      this.stateChangeOffsets = offsets;
      this.stateChanges = states;
    }
    
    /// <summary>
    /// Gets the text.
    /// </summary>
    public string Text {
      get { return text; }
    }
    
    /// <summary>
    /// Gets the text length.
    /// </summary>
    public int Length {
      get { return text.Length; }
    }
    
    int GetIndexForOffset(int offset)
    {
      if (offset < 0 || offset > text.Length)
        throw new ArgumentOutOfRangeException("offset");
      int index = Array.BinarySearch(stateChangeOffsets, offset);
      if (index < 0) {
        // If no color change exists directly at offset,
        // return the index of the color segment that contains offset.
        index = ~index - 1;
      }
      return index;
    }
    
    int GetEnd(int index)
    {
      // Gets the end of the color segment no. index.
      if (index + 1 < stateChangeOffsets.Length)
        return stateChangeOffsets[index + 1];
      else
        return text.Length;
    }
    
    /// <summary>
    /// Gets the HighlightingColor for the specified offset.
    /// </summary>
    public HighlightingColor GetHighlightingAt(int offset)
    {
      return stateChanges[GetIndexForOffset(offset)];
    }
    
    /// <summary>
    /// Retrieves the highlighted sections in the specified range.
    /// The highlighted sections will be sorted by offset, and there will not be any nested or overlapping sections.
    /// </summary>
    public IEnumerable<HighlightedSection> GetHighlightedSections(int offset, int length)
    {
      int index = GetIndexForOffset(offset);
      int pos = offset;
      int endOffset = offset + length;
      while (pos < endOffset) {
        int endPos = Math.Min(endOffset, GetEnd(index));
        yield return new HighlightedSection {
          Offset = pos,
          Length = endPos - pos,
          Color = stateChanges[index]
        };
        pos = endPos;
        index++;
      }
    }
    
    /// <summary>
    /// Creates a new RichTextModel with the formatting from this RichText.
    /// </summary>
    public RichTextModel ToRichTextModel()
    {
      return new RichTextModel(stateChangeOffsets, stateChanges.Select(ch => ch.Clone()).ToArray());
    }
    
    /// <summary>
    /// Gets the text.
    /// </summary>
    public override string ToString()
    {
      return text;
    }
    
    /// <summary>
    /// Creates WPF Run instances that can be used for TextBlock.Inlines.
    /// </summary>
    public Run[] CreateRuns()
    {
      Run[] runs = new Run[stateChanges.Length];
      for (int i = 0; i < runs.Length; i++) {
        int startOffset = stateChangeOffsets[i];
        int endOffset = i + 1 < stateChangeOffsets.Length ? stateChangeOffsets[i + 1] : text.Length;
        Run r = new Run(text.Substring(startOffset, endOffset - startOffset));
        HighlightingColor state = stateChanges[i];
        ApplyColorToTextElement(r, state);
        runs[i] = r;
      }
      return runs;
    }

    internal static void ApplyColorToTextElement(TextElement r, HighlightingColor state)
    {
      if (state.Foreground != null)
        r.Foreground = state.Foreground.GetBrush(null);
      if (state.Background != null)
        r.Background = state.Background.GetBrush(null);
      if (state.FontWeight != null)
        r.FontWeight = state.FontWeight.Value;
      if (state.FontStyle != null)
        r.FontStyle = state.FontStyle.Value;
    }
    
    /// <summary>
    /// Produces HTML code for the line, with &lt;span style="..."&gt; tags.
    /// </summary>
    public string ToHtml(HtmlOptions options = null)
    {
      StringWriter stringWriter = new StringWriter(CultureInfo.InvariantCulture);
      using (var htmlWriter = new HtmlRichTextWriter(stringWriter, options)) {
        htmlWriter.Write(this);
      }
      return stringWriter.ToString();
    }
    
    /// <summary>
    /// Produces HTML code for a section of the line, with &lt;span style="..."&gt; tags.
    /// </summary>
    public string ToHtml(int offset, int length, HtmlOptions options = null)
    {
      StringWriter stringWriter = new StringWriter(CultureInfo.InvariantCulture);
      using (var htmlWriter = new HtmlRichTextWriter(stringWriter, options)) {
        htmlWriter.Write(this, offset, length);
      }
      return stringWriter.ToString();
    }
    
    /// <summary>
    /// Creates a substring of this rich text.
    /// </summary>
    public RichText Substring(int offset, int length)
    {
      if (offset == 0 && length == this.Length)
        return this;
      string newText = text.Substring(offset, length);
      RichTextModel model = ToRichTextModel();
      OffsetChangeMap map = new OffsetChangeMap(2);
      map.Add(new OffsetChangeMapEntry(offset + length, text.Length - offset - length, 0));
      map.Add(new OffsetChangeMapEntry(0, offset, 0));
      model.UpdateOffsets(map);
      return new RichText(newText, model);
    }
    
    /// <summary>
    /// Concatenates the specified rich texts.
    /// </summary>
    public static RichText Concat(params RichText[] texts)
    {
      if (texts == null || texts.Length == 0)
        return Empty;
      else if (texts.Length == 1)
        return texts[0];
      string newText = string.Concat(texts.Select(txt => txt.text));
      RichTextModel model = texts[0].ToRichTextModel();
      int offset = texts[0].Length;
      for (int i = 1; i < texts.Length; i++) {
        model.Append(offset, texts[i].stateChangeOffsets, texts[i].stateChanges);
        offset += texts[i].Length;
      }
      return new RichText(newText, model);
    }
    
    /// <summary>
    /// Concatenates the specified rich texts.
    /// </summary>
    public static RichText operator +(RichText a, RichText b)
    {
      return RichText.Concat(a, b);
    }
    
    /// <summary>
    /// Implicit conversion from string to RichText.
    /// </summary>
    public static implicit operator RichText(string text)
    {
      if (text != null)
        return new RichText(text);
      else
        return null;
    }
  }
}