source: trunk/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Rendering/VisualLineText.cs @ 18209

// 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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// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using System.Windows.Documents;
using System.Windows.Media.TextFormatting;

using ICSharpCode.AvalonEdit.Document;
using ICSharpCode.AvalonEdit.Utils;

namespace ICSharpCode.AvalonEdit.Rendering
{
  /// <summary>
  /// VisualLineElement that represents a piece of text.
  /// </summary>
  public class VisualLineText : VisualLineElement
  {
    VisualLine parentVisualLine;
    
    /// <summary>
    /// Gets the parent visual line.
    /// </summary>
    public VisualLine ParentVisualLine {
      get { return parentVisualLine; }
    }
    
    /// <summary>
    /// Creates a visual line text element with the specified length.
    /// It uses the <see cref="ITextRunConstructionContext.VisualLine"/> and its
    /// <see cref="VisualLineElement.RelativeTextOffset"/> to find the actual text string.
    /// </summary>
    public VisualLineText(VisualLine parentVisualLine, int length) : base(length, length)
    {
      if (parentVisualLine == null)
        throw new ArgumentNullException("parentVisualLine");
      this.parentVisualLine = parentVisualLine;
    }
    
    /// <summary>
    /// Override this method to control the type of new VisualLineText instances when
    /// the visual line is split due to syntax highlighting.
    /// </summary>
    protected virtual VisualLineText CreateInstance(int length)
    {
      return new VisualLineText(parentVisualLine, length);
    }
    
    /// <inheritdoc/>
    public override TextRun CreateTextRun(int startVisualColumn, ITextRunConstructionContext context)
    {
      if (context == null)
        throw new ArgumentNullException("context");
      
      int relativeOffset = startVisualColumn - VisualColumn;
      StringSegment text = context.GetText(context.VisualLine.FirstDocumentLine.Offset + RelativeTextOffset + relativeOffset, DocumentLength - relativeOffset);
      return new TextCharacters(text.Text, text.Offset, text.Count, this.TextRunProperties);
    }
    
    /// <inheritdoc/>
    public override bool IsWhitespace(int visualColumn)
    {
      int offset = visualColumn - this.VisualColumn + parentVisualLine.FirstDocumentLine.Offset + this.RelativeTextOffset;
      return char.IsWhiteSpace(parentVisualLine.Document.GetCharAt(offset));
    }
    
    /// <inheritdoc/>
    public override TextSpan<CultureSpecificCharacterBufferRange> GetPrecedingText(int visualColumnLimit, ITextRunConstructionContext context)
    {
      if (context == null)
        throw new ArgumentNullException("context");
      
      int relativeOffset = visualColumnLimit - VisualColumn;
      StringSegment text = context.GetText(context.VisualLine.FirstDocumentLine.Offset + RelativeTextOffset, relativeOffset);
      CharacterBufferRange range = new CharacterBufferRange(text.Text, text.Offset, text.Count);
      return new TextSpan<CultureSpecificCharacterBufferRange>(range.Length, new CultureSpecificCharacterBufferRange(this.TextRunProperties.CultureInfo, range));
    }
    
    /// <inheritdoc/>
    public override bool CanSplit {
      get { return true; }
    }
    
    /// <inheritdoc/>
    public override void Split(int splitVisualColumn, IList<VisualLineElement> elements, int elementIndex)
    {
      if (splitVisualColumn <= VisualColumn || splitVisualColumn >= VisualColumn + VisualLength)
        throw new ArgumentOutOfRangeException("splitVisualColumn", splitVisualColumn, "Value must be between " + (VisualColumn + 1) + " and " + (VisualColumn + VisualLength - 1));
      if (elements == null)
        throw new ArgumentNullException("elements");
      if (elements[elementIndex] != this)
        throw new ArgumentException("Invalid elementIndex - couldn't find this element at the index");
      int relativeSplitPos = splitVisualColumn - VisualColumn;
      VisualLineText splitPart = CreateInstance(DocumentLength - relativeSplitPos);
      SplitHelper(this, splitPart, splitVisualColumn, relativeSplitPos + RelativeTextOffset);
      elements.Insert(elementIndex + 1, splitPart);
    }
    
    /// <inheritdoc/>
    public override int GetRelativeOffset(int visualColumn)
    {
      return this.RelativeTextOffset + visualColumn - this.VisualColumn;
    }
    
    /// <inheritdoc/>
    public override int GetVisualColumn(int relativeTextOffset)
    {
      return this.VisualColumn + relativeTextOffset - this.RelativeTextOffset;
    }
    
    /// <inheritdoc/>
    public override int GetNextCaretPosition(int visualColumn, LogicalDirection direction, CaretPositioningMode mode)
    {
      int textOffset = parentVisualLine.StartOffset + this.RelativeTextOffset;
      int pos = TextUtilities.GetNextCaretPosition(parentVisualLine.Document, textOffset + visualColumn - this.VisualColumn, direction, mode);
      if (pos < textOffset || pos > textOffset + this.DocumentLength)
        return -1;
      else
        return this.VisualColumn + pos - textOffset;
    }
  }
}