source: branches/2929_PrioritizedGrammarEnumeration/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Rendering/ColumnRulerRenderer.cs @ 16452

// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
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// 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.Windows;
using System.Windows.Media;

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

namespace ICSharpCode.AvalonEdit.Rendering
{
  /// <summary>
  /// Renders a ruler at a certain column.
  /// </summary>
  sealed class ColumnRulerRenderer : IBackgroundRenderer
  {
    Pen pen;
    int column;
    TextView textView;
    
    public static readonly Color DefaultForeground = Colors.LightGray;
    
    public ColumnRulerRenderer(TextView textView)
    {
      if (textView == null)
        throw new ArgumentNullException("textView");
      
      this.pen = new Pen(new SolidColorBrush(DefaultForeground), 1);
      this.pen.Freeze();
      this.textView = textView;
      this.textView.BackgroundRenderers.Add(this);
    }
    
    public KnownLayer Layer {
      get { return KnownLayer.Background; }
    }
    
    public void SetRuler(int column, Pen pen)
    {
      if (this.column != column) {
        this.column = column;
        textView.InvalidateLayer(this.Layer);
      }
      if (this.pen != pen) {
        this.pen = pen;
        textView.InvalidateLayer(this.Layer);
      }
    }
    
    public void Draw(TextView textView, System.Windows.Media.DrawingContext drawingContext)
    {
      if (column < 1) return;
      double offset = textView.WideSpaceWidth * column;
      Size pixelSize = PixelSnapHelpers.GetPixelSize(textView);
      double markerXPos = PixelSnapHelpers.PixelAlign(offset, pixelSize.Width);
      markerXPos -= textView.ScrollOffset.X;
      Point start = new Point(markerXPos, 0);
      Point end = new Point(markerXPos, Math.Max(textView.DocumentHeight, textView.ActualHeight));
      
      drawingContext.DrawLine(pen, start, end);
    }
  }
}