source: branches/HeuristicLab.Problems.GrammaticalOptimization/DynamicDataDisplay/Charts/Axes/RoundingHelper.cs @ 13847

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

namespace Microsoft.Research.DynamicDataDisplay.Charts
{
  internal static class RoundingHelper
  {
    internal static int GetDifferenceLog(double min, double max)
    {
      return (int)Math.Round(Math.Log10(Math.Abs(max - min)));
    }

    internal static double Round(double number, int rem)
    {
      if (rem <= 0)
      {
        rem = MathHelper.Clamp(-rem, 0, 15);
        return Math.Round(number, rem);
      }
      else
      {
        double pow = Math.Pow(10, rem - 1);
        double val = pow * Math.Round(number / Math.Pow(10, rem - 1));
        return val;
      }
    }

    internal static double Round(double value, Range<double> range)
    {
      int log = GetDifferenceLog(range.Min, range.Max);

      return Round(value, log);
    }

    internal static RoundingInfo CreateRoundedRange(double min, double max)
    {
      double delta = max - min;

      if (delta == 0)
        return new RoundingInfo { Min = min, Max = max, Log = 0 };

      int log = (int)Math.Round(Math.Log10(Math.Abs(delta))) + 1;

      double newMin = Round(min, log);
      double newMax = Round(max, log);
      if (newMin == newMax)
      {
        log--;
        newMin = Round(min, log);
        newMax = Round(max, log);
      }

      return new RoundingInfo { Min = newMin, Max = newMax, Log = log };
    }
  }

  [DebuggerDisplay("{Min} - {Max}, Log = {Log}")]
  internal sealed class RoundingInfo
  {
    public double Min { get; set; }
    public double Max { get; set; }
    public int Log { get; set; }
  }
}