source: stable/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Rendering/DocumentColorizingTransformer.cs @ 11937

// 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
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// 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
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using System;
using System.Linq;
using ICSharpCode.AvalonEdit.Document;

namespace ICSharpCode.AvalonEdit.Rendering
{
  /// <summary>
  /// Base class for <see cref="IVisualLineTransformer"/> that helps
  /// colorizing the document. Derived classes can work with document lines
  /// and text offsets and this class takes care of the visual lines and visual columns.
  /// </summary>
  public abstract class DocumentColorizingTransformer : ColorizingTransformer
  {
    DocumentLine currentDocumentLine;
    int firstLineStart;
    int currentDocumentLineStartOffset, currentDocumentLineEndOffset;
    
    /// <summary>
    /// Gets the current ITextRunConstructionContext.
    /// </summary>
    protected ITextRunConstructionContext CurrentContext { get; private set; }
    
    /// <inheritdoc/>
    protected override void Colorize(ITextRunConstructionContext context)
    {
      if (context == null)
        throw new ArgumentNullException("context");
      this.CurrentContext = context;
      
      currentDocumentLine = context.VisualLine.FirstDocumentLine;
      firstLineStart = currentDocumentLineStartOffset = currentDocumentLine.Offset;
      currentDocumentLineEndOffset = currentDocumentLineStartOffset + currentDocumentLine.Length;
      int currentDocumentLineTotalEndOffset = currentDocumentLineStartOffset + currentDocumentLine.TotalLength;
      
      if (context.VisualLine.FirstDocumentLine == context.VisualLine.LastDocumentLine) {
        ColorizeLine(currentDocumentLine);
      } else {
        ColorizeLine(currentDocumentLine);
        // ColorizeLine modifies the visual line elements, loop through a copy of the line elements
        foreach (VisualLineElement e in context.VisualLine.Elements.ToArray()) {
          int elementOffset = firstLineStart + e.RelativeTextOffset;
          if (elementOffset >= currentDocumentLineTotalEndOffset) {
            currentDocumentLine = context.Document.GetLineByOffset(elementOffset);
            currentDocumentLineStartOffset = currentDocumentLine.Offset;
            currentDocumentLineEndOffset = currentDocumentLineStartOffset + currentDocumentLine.Length;
            currentDocumentLineTotalEndOffset = currentDocumentLineStartOffset + currentDocumentLine.TotalLength;
            ColorizeLine(currentDocumentLine);
          }
        }
      }
      currentDocumentLine = null;
      this.CurrentContext = null;
    }
    
    /// <summary>
    /// Override this method to colorize an individual document line.
    /// </summary>
    protected abstract void ColorizeLine(DocumentLine line);
    
    /// <summary>
    /// Changes a part of the current document line.
    /// </summary>
    /// <param name="startOffset">Start offset of the region to change</param>
    /// <param name="endOffset">End offset of the region to change</param>
    /// <param name="action">Action that changes an individual <see cref="VisualLineElement"/>.</param>
    protected void ChangeLinePart(int startOffset, int endOffset, Action<VisualLineElement> action)
    {
      if (startOffset < currentDocumentLineStartOffset || startOffset > currentDocumentLineEndOffset)
        throw new ArgumentOutOfRangeException("startOffset", startOffset, "Value must be between " + currentDocumentLineStartOffset + " and " + currentDocumentLineEndOffset);
      if (endOffset < startOffset || endOffset > currentDocumentLineEndOffset)
        throw new ArgumentOutOfRangeException("endOffset", endOffset, "Value must be between " + startOffset + " and " + currentDocumentLineEndOffset);
      VisualLine vl = this.CurrentContext.VisualLine;
      int visualStart = vl.GetVisualColumn(startOffset - firstLineStart);
      int visualEnd = vl.GetVisualColumn(endOffset - firstLineStart);
      if (visualStart < visualEnd) {
        ChangeVisualElements(visualStart, visualEnd, action);
      }
    }
  }
}