source: trunk/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Folding/FoldingElementGenerator.cs @ 18190

// 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
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

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

using ICSharpCode.AvalonEdit.Rendering;
using ICSharpCode.AvalonEdit.Utils;

namespace ICSharpCode.AvalonEdit.Folding
{
  /// <summary>
  /// A <see cref="VisualLineElementGenerator"/> that produces line elements for folded <see cref="FoldingSection"/>s.
  /// </summary>
  public sealed class FoldingElementGenerator : VisualLineElementGenerator, ITextViewConnect
  {
    readonly List<TextView> textViews = new List<TextView>();
    FoldingManager foldingManager;
    
    #region FoldingManager property / connecting with TextView
    /// <summary>
    /// Gets/Sets the folding manager from which the foldings should be shown.
    /// </summary>
    public FoldingManager FoldingManager {
      get {
        return foldingManager;
      }
      set {
        if (foldingManager != value) {
          if (foldingManager != null) {
            foreach (TextView v in textViews)
              foldingManager.RemoveFromTextView(v);
          }
          foldingManager = value;
          if (foldingManager != null) {
            foreach (TextView v in textViews)
              foldingManager.AddToTextView(v);
          }
        }
      }
    }
    
    void ITextViewConnect.AddToTextView(TextView textView)
    {
      textViews.Add(textView);
      if (foldingManager != null)
        foldingManager.AddToTextView(textView);
    }
    
    void ITextViewConnect.RemoveFromTextView(TextView textView)
    {
      textViews.Remove(textView);
      if (foldingManager != null)
        foldingManager.RemoveFromTextView(textView);
    }
    #endregion
    
    /// <inheritdoc/>
    public override void StartGeneration(ITextRunConstructionContext context)
    {
      base.StartGeneration(context);
      if (foldingManager != null) {
        if (!foldingManager.textViews.Contains(context.TextView))
          throw new ArgumentException("Invalid TextView");
        if (context.Document != foldingManager.document)
          throw new ArgumentException("Invalid document");
      }
    }
    
    /// <inheritdoc/>
    public override int GetFirstInterestedOffset(int startOffset)
    {
      if (foldingManager != null) {
        foreach (FoldingSection fs in foldingManager.GetFoldingsContaining(startOffset)) {
          // Test whether we're currently within a folded folding (that didn't just end).
          // If so, create the fold marker immediately.
          // This is necessary if the actual beginning of the fold marker got skipped due to another VisualElementGenerator.
          if (fs.IsFolded && fs.EndOffset > startOffset) {
            //return startOffset;
          }
        }
        return foldingManager.GetNextFoldedFoldingStart(startOffset);
      } else {
        return -1;
      }
    }
    
    /// <inheritdoc/>
    public override VisualLineElement ConstructElement(int offset)
    {
      if (foldingManager == null)
        return null;
      int foldedUntil = -1;
      FoldingSection foldingSection = null;
      foreach (FoldingSection fs in foldingManager.GetFoldingsContaining(offset)) {
        if (fs.IsFolded) {
          if (fs.EndOffset > foldedUntil) {
            foldedUntil = fs.EndOffset;
            foldingSection = fs;
          }
        }
      }
      if (foldedUntil > offset && foldingSection != null) {
        // Handle overlapping foldings: if there's another folded folding
        // (starting within the foldingSection) that continues after the end of the folded section,
        // then we'll extend our fold element to cover that overlapping folding.
        bool foundOverlappingFolding;
        do {
          foundOverlappingFolding = false;
          foreach (FoldingSection fs in FoldingManager.GetFoldingsContaining(foldedUntil)) {
            if (fs.IsFolded && fs.EndOffset > foldedUntil) {
              foldedUntil = fs.EndOffset;
              foundOverlappingFolding = true;
            }
          }
        } while (foundOverlappingFolding);
        
        string title = foldingSection.Title;
        if (string.IsNullOrEmpty(title))
          title = "...";
        var p = new VisualLineElementTextRunProperties(CurrentContext.GlobalTextRunProperties);
        p.SetForegroundBrush(textBrush);
        var textFormatter = TextFormatterFactory.Create(CurrentContext.TextView);
        var text = FormattedTextElement.PrepareText(textFormatter, title, p);
        return new FoldingLineElement(foldingSection, text, foldedUntil - offset) { textBrush = textBrush };
      } else {
        return null;
      }
    }
    
    sealed class FoldingLineElement : FormattedTextElement
    {
      readonly FoldingSection fs;
      
      internal Brush textBrush;
      
      public FoldingLineElement(FoldingSection fs, TextLine text, int documentLength) : base(text, documentLength)
      {
        this.fs = fs;
      }
      
      public override TextRun CreateTextRun(int startVisualColumn, ITextRunConstructionContext context)
      {
        return new FoldingLineTextRun(this, this.TextRunProperties) { textBrush = textBrush };
      }
      
      protected internal override void OnMouseDown(MouseButtonEventArgs e)
      {
        if (e.ClickCount == 2 && e.ChangedButton == MouseButton.Left) {
          fs.IsFolded = false;
          e.Handled = true;
        } else {
          base.OnMouseDown(e);
        }
      }
    }
    
    sealed class FoldingLineTextRun : FormattedTextRun
    {
      internal Brush textBrush;
      
      public FoldingLineTextRun(FormattedTextElement element, TextRunProperties properties)
        : base(element, properties)
      {
      }
      
      public override void Draw(DrawingContext drawingContext, Point origin, bool rightToLeft, bool sideways)
      {
        var metrics = Format(double.PositiveInfinity);
        Rect r = new Rect(origin.X, origin.Y - metrics.Baseline, metrics.Width, metrics.Height);
        drawingContext.DrawRectangle(null, new Pen(textBrush, 1), r);
        base.Draw(drawingContext, origin, rightToLeft, sideways);
      }
    }
    
    /// <summary>
    /// Default brush for folding element text. Value: Brushes.Gray
    /// </summary>
    public static readonly Brush DefaultTextBrush = Brushes.Gray;
    
    static Brush textBrush = DefaultTextBrush;
    
    /// <summary>
    /// Gets/sets the brush used for folding element text.
    /// </summary>
    public static Brush TextBrush {
      get { return textBrush; }
      set { textBrush = value; }
    }
  }
}