1  #region License Information


2 


3  /* HeuristicLab


4  * Copyright (C) 20022016 Heuristic and Evolutionary Algorithms Laboratory (HEAL)


5  *


6  * This file is part of HeuristicLab.


7  *


8  * HeuristicLab is free software: you can redistribute it and/or modify


9  * it under the terms of the GNU General Public License as published by


10  * the Free Software Foundation, either version 3 of the License, or


11  * (at your option) any later version.


12  *


13  * HeuristicLab is distributed in the hope that it will be useful,


14  * but WITHOUT ANY WARRANTY; without even the implied warranty of


15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the


16  * GNU General Public License for more details.


17  *


18  * You should have received a copy of the GNU General Public License


19  * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.


20  */


21 


22  #endregion


23 


24  using System;


25 


26  namespace HeuristicLab.Visualization.ChartControlsExtensions {


27  public static class ChartUtil {


28  public static void CalculateAxisInterval(double min, double max, int ticks, out double axisMin, out double axisMax, out double axisInterval) {


29  var dmin = (max  min).Decimals();


30  axisMin = min.Floor(dmin);


31  var range = max  axisMin;


32  var slice = range / ticks;


33  var dslice = slice.Decimals();


34  var floor = slice.Floor(dslice);


35  var ceil = slice.Ceil(dslice);


36  var axisRange = floor * ticks;


37  axisInterval = floor;


38  if (axisRange < max  axisMin) {


39  axisRange = ceil * ticks;


40  axisInterval = ceil;


41  }


42  axisMax = axisMin + axisRange;


43  }


44 


45  // this method tries to find an axis interval with as few fractional digits as possible (because it looks nicer)


46  // we only try between 3 and 5 ticks (inclusive) because it wouldn't make sense to exceed this interval


47  public static void CalculateOptimalAxisInterval(double min, double max, out double axisMin, out double axisMax, out double axisInterval) {


48  CalculateAxisInterval(min, max, 5, out axisMin, out axisMax, out axisInterval);


49  int bestLsp = int.MaxValue;


50  for (int ticks = 3; ticks <= 5; ++ticks) {


51  double aMin, aMax, aInterval;


52  CalculateAxisInterval(min, max, ticks, out aMin, out aMax, out aInterval);


53  var x = aInterval;


54  int lsp = 0; // position of the least significant fractional digit


55  while (x  Math.Floor(x) > 0) {


56  ++lsp;


57  x *= 10;


58  }


59  if (lsp <= bestLsp) {


60  axisMin = aMin;


61  axisMax = aMax;


62  axisInterval = aInterval;


63  bestLsp = lsp;


64  }


65  }


66  }


67 


68  private static int Decimals(this double x) {


69  if (x.IsAlmost(0)  double.IsInfinity(x)  double.IsNaN(x))


70  return 0;


71 


72  var v = Math.Abs(x);


73  int d = 1;


74  while (v < 1) {


75  v *= 10;


76  d++;


77  }


78  return d;


79  }


80 


81  // rounds down to the nearest value according to the given number of decimal precision


82  private static double Floor(this double value, int precision) {


83  var n = Math.Pow(10, precision);


84  return Math.Round(Math.Floor(value * n) / n, precision);


85  }


86 


87  private static double Ceil(this double value, int precision) {


88  var n = Math.Pow(10, precision);


89  return Math.Round(Math.Ceiling(value * n) / n, precision);


90  }


91 


92  private static double Round(this double value, int precision) {


93  var n = Math.Pow(10, precision);


94  return Math.Round(Math.Round(value * n) / n, precision);


95  }


96 


97  private static bool IsAlmost(this double value, double other, double eps = 1e12) {


98  return Math.Abs(value  other) < eps;


99  }


100  }


101  }

