source: branches/HeuristicLab.Problems.GrammaticalOptimization/DynamicDataDisplay/ViewportConstraints/ProportionsConstraint.cs @ 13780

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;

namespace Microsoft.Research.DynamicDataDisplay.ViewportConstraints
{
  public sealed class ProportionsConstraint : ViewportConstraint
  {
    private double widthToHeightRatio = 1;
    public double WidthToHeightRatio
    {
      get { return widthToHeightRatio; }
      set
      {
        if (widthToHeightRatio != value)
        {
          widthToHeightRatio = value;
          RaiseChanged();
        }
      }
    }

    public override DataRect Apply(DataRect oldDataRect, DataRect newDataRect, Viewport2D viewport)
    {
      double ratio = newDataRect.Width / newDataRect.Height;
      double coeff = Math.Sqrt(ratio);

      double newWidth = newDataRect.Width / coeff;
      double newHeight = newDataRect.Height * coeff;

      Point center = newDataRect.GetCenter();
      DataRect res = DataRect.FromCenterSize(center, newWidth, newHeight);
      return res;
    }
  }
}