source: stable/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Folding/FoldingMarginMarker.cs

// 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.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;

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

namespace ICSharpCode.AvalonEdit.Folding
{
  sealed class FoldingMarginMarker : UIElement
  {
    internal VisualLine VisualLine;
    internal FoldingSection FoldingSection;
    
    bool isExpanded;
    
    public bool IsExpanded {
      get { return isExpanded; }
      set {
        if (isExpanded != value) {
          isExpanded = value;
          InvalidateVisual();
        }
        if (FoldingSection != null)
          FoldingSection.IsFolded = !value;
      }
    }
    
    protected override void OnMouseDown(MouseButtonEventArgs e)
    {
      base.OnMouseDown(e);
      if (!e.Handled) {
        if (e.ChangedButton == MouseButton.Left) {
          IsExpanded = !IsExpanded;
          e.Handled = true;
        }
      }
    }
    
    const double MarginSizeFactor = 0.7;
    
    protected override Size MeasureCore(Size availableSize)
    {
      double size = MarginSizeFactor * FoldingMargin.SizeFactor * (double)GetValue(TextBlock.FontSizeProperty);
      size = PixelSnapHelpers.RoundToOdd(size, PixelSnapHelpers.GetPixelSize(this).Width);
      return new Size(size, size);
    }
    
    protected override void OnRender(DrawingContext drawingContext)
    {
      FoldingMargin margin = VisualParent as FoldingMargin;
      Pen activePen = new Pen(margin.SelectedFoldingMarkerBrush, 1);
      Pen inactivePen = new Pen(margin.FoldingMarkerBrush, 1);
      activePen.StartLineCap = inactivePen.StartLineCap = PenLineCap.Square;
      activePen.EndLineCap = inactivePen.EndLineCap = PenLineCap.Square;
      Size pixelSize = PixelSnapHelpers.GetPixelSize(this);
      Rect rect = new Rect(pixelSize.Width / 2,
                           pixelSize.Height / 2,
                           this.RenderSize.Width - pixelSize.Width,
                           this.RenderSize.Height - pixelSize.Height);
      drawingContext.DrawRectangle(
        IsMouseDirectlyOver ? margin.SelectedFoldingMarkerBackgroundBrush : margin.FoldingMarkerBackgroundBrush,
        IsMouseDirectlyOver ? activePen : inactivePen, rect);
      double middleX = rect.Left + rect.Width / 2;
      double middleY = rect.Top + rect.Height / 2;
      double space = PixelSnapHelpers.Round(rect.Width / 8, pixelSize.Width) + pixelSize.Width;
      drawingContext.DrawLine(activePen,
                              new Point(rect.Left + space, middleY),
                              new Point(rect.Right - space, middleY));
      if (!isExpanded) {
        drawingContext.DrawLine(activePen,
                                new Point(middleX, rect.Top + space),
                                new Point(middleX, rect.Bottom - space));
      }
    }
    
    protected override void OnIsMouseDirectlyOverChanged(DependencyPropertyChangedEventArgs e)
    {
      base.OnIsMouseDirectlyOverChanged(e);
      InvalidateVisual();
    }
  }
}