/*!
  \file
  \brief Create box plots in Scalable Vector Graphic (SVG) format.
  \details Provides @c svg_boxplot data and functions to create plots,
  @c and svg_boxplot_series to allow data values to be added to the boxplot.\n

  Very many functions allow fine control of the appearance and layout of plots and data markers.
  (Items common to 1D, 2D and boxplot use @c axis_plot_frame).

  A convenient way of graphically depicting groups of numerical data through their five-number summaries.\n
  Show 1st quartile, median and 3rd quartile as a box.
  http://en.wikipedia.org/wiki/Boxplot

  \sa Some Implementations of the Boxplot:
  Michael Frigge, David C. Hoaglin and Boris Iglewicz
  The American Statistician, Vol. 43, No. 1 (Feb., 1989), pp. 50-54

  \sa The Bagplot: A Bivariate Boxplot
  Peter J. Rousseeuw, Ida Ruts and John W. Tukey
  The American Statistician, Vol. 53, No. 4 (Nov., 1999), pp. 382-387
 */

// file svg_boxplot.hpp

// Copyright Jacob Voytko 2007
// Copyright Paul A. Bristow 2008, 2009, 2013, 2020

// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt
// or copy at http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_SVG_SVG_BOXPLOT_HPP
#define BOOST_SVG_SVG_BOXPLOT_HPP

#include <boost/iterator/transform_iterator.hpp>

#include <boost/svg_plot/svg.hpp>
#include  <boost/svg_plot/svg_style.hpp>
#include  <boost/svg_plot/detail/numeric_limits_handling.hpp>
#include  <boost/svg_plot/detail/svg_boxplot_detail.hpp>
#include  <boost/svg_plot/detail/functors.hpp>
#include  <boost/svg_plot/detail/axis_plot_frame.hpp>
#include  <boost/svg_plot/detail/auto_axes.hpp>
#include  <boost/svg_plot/quantile.hpp>

#include <boost/quan/unc.hpp> // Values with uncertainty.
// using boost::quan::unc;

#include <vector>
#include <string>
#include <ostream>
#include <algorithm>
#include <iterator>
#include <exception>

namespace boost
{
namespace svg
{
  // Forward declarations (defined below):

//! \cond DETAIL
  //! Box Plot that can display several boxplot data series.
  class svg_boxplot;
  //! Boxplot data series.
  class svg_boxplot_series;
//! \endcond

  // By convention, class data is suffixed by _ to permit function names to be used.
  // For example, string title_, but set with title("my title") and get with title().

  /*! \class boost::svg::svg_boxplot_series
     Information about a series of data values to be displayed as a Box Plot.
     A Box Plot that can contain several boxplot data series.
     Median, whiskers and outliers are computed for each series.
     \sa http://en.wikipedia.org/wiki/Boxplot
  */
  class svg_boxplot_series
  {
  public: // private?
//! \cond DETAIL
    std::vector<double> series_; //!< Data series for the boxplot.
    double whisker_min_; //!< Minimum of whisker.
    double whisker_max_; //!< Maximum of whisker.
    int quartile_definition_; //!< The definition of the quartile can be selected.
    double q1_; //!< 1st lower quartile.
    double median_; //!< 2nd middle quartile.
    double q3_; //!< 3rd upper quartile.
    std::vector<double> outliers_; //!< Any data values that are judged outliers.
    std::vector<double> extreme_outliers_; //!< Any data values that are judged extreme outliers.

    // std::string title_;
    text_style series_style_; //!< Style (font etc) for text.
    text_element series_info_; //!< information about the data series.
    double text_margin_; //!< Margin (SVG units, default pixels) around text items.

    // svg_style(stroke, fill, width)
    double box_width_; //!< Width of boxplot box.
    svg_style box_style_; //!< line widths and colors of box.
    svg_style median_style_; //!< line widths and colors of median marker.
    svg_style axis_style_;//!< line widths and colors of X and Y axes.

    double whisker_length_; //!< Length of boxplot 'whisker'.
    svg_style min_whisker_style_; //!< Color and width etc of boxplot minimum 'whisker'.
    svg_style max_whisker_style_; //!< Color and width etc of boxplot minimum 'whisker'.
    value_style values_style_; //!< Style for data value labels.

    plot_point_style mild_outlier_; //!< Style (shape, color...) for marking 'mild' outliers.
    plot_point_style ext_outlier_; //!< Style (shape, color...) for marking 'extreme' outliers.

    bool outlier_values_on_; //!< True if mild outliers are to have their values labelled.
    bool extreme_outlier_values_on_; //!< True if extreme outliers are to have their values labelled.

//! \endcond

   /*!
     \brief Constructor, providing default values for all data members.\n
     \details Default Constructor sorts a copy of container, and uses the copy for fast lookup of quartile values.

     \tparam T An STL data container type, typically @c double or uncertain.
   */
   template <class T> //
    svg_boxplot_series(
      T begin,  //!< Data container interator begin.
      T end, //!< Data container interator end.
      const std::string& title, //!< Data series title.
      double bw, //!< Box width
      svg_style bs, //!< Box style
      svg_style ms, //!< Median marker style
      svg_style as, //!< Axis style
      double wl, //!< Whisker length
      svg_style minws, //!< Min whisker style
      svg_style maxws, //!< Max whisker style
      plot_point_style os, //!< Mild outlier style
      plot_point_style extos, //!< Extreme outlier style
      int q_def, //!< Quartile definition H&F #
      value_style vs, //!< Style for optional display of data point values.
      text_style ss //!< Series style (font etc) for box labels.
     )
     //! All other parameters can also be added using chainable functions.
     : //
      box_width_(bw), // svg_boxplot::box_width()),
      box_style_(bs), // green, azure, 1), // stroke, fill, width, 1, true, true, margin, border_on, fill_on
      median_style_(ms), // blue, blank, 1),
      axis_style_(as), // black, blank, 1),
      whisker_length_(wl), // 30),
      min_whisker_style_(minws), // magenta, black, 1),
      max_whisker_style_(maxws), // cyan, black, 1),
      mild_outlier_(os), // brown, blank, 5, round),
      ext_outlier_(extos), //  blue, blank, 25, cone),
      values_style_(vs),
      series_style_(ss), // for series_info to control font etc of box labels.
      series_info_(0, 0, title, series_style_, align_style::center_align, horizontal),
      quartile_definition_(q_def), // Default is H&F recommendation.
      text_margin_(2.) // for axis label text, as a multiplier of the font size.
    { // Default Constructor sorts a copy of @c std::vector copy and used for fast lookup of quartile values.
      // std::vector<double> series(begin, end); now a member
      series_.assign(begin, end);

      if(series_.empty())
      {
        std::string message = "Data series " + title + " is empty!";
        throw std::runtime_error(message.c_str());
      }
      if(series_.size() < 8)
      { // Not enough data values to usefully calculate quartiles.
        throw std::runtime_error("Data series has < 8 values! Not enough data values to usefully calculate quartiles.");
      }
      std::sort(series_.begin(), series_.end());
      // Previous taken out to calculate_quantiles to allow each plot to have their own quartile definition.

    } // svg_boxplot_series constructor.

    void calculate_quantiles()
    { /*!
       \brief Divide sorted data set into four equal parts, called quartiles,
        so each part represent 1/4th of the sampled population.

       \details
        Michael Frigge, David C. Hoaglin and Boris Iglewicz\n
        The American Statistician, Vol. 43, No. 1 (Feb., 1989), pp. 50-54\n
        Tukey, J. W. Exploratory Data Analysis, Addison Wesley (1977, p 33)\n

       "Some Implementations of the Boxplot"

        x[1] .. x[n] == series[0] ... series[n - 1]
        q1_ = (1 - g) * x[j] + g * [j+1];
      */
      median_ = median(series_);
      q1_ = quantile(series_, 0.25, quartile_definition_);
      q3_ = quantile(series_, 0.75, quartile_definition_);

      /*! Fences (beyond which lie outliers) are at q1 - k * (q3 - q1) and q3 - k * (q3 - q1)
        commonly k = 1.5, but can be 2.\n
        Extreme outlier usually set at k = 3.
      */

      //std::cout << "Definition #" << quartile_definition_ << ", q1 " << q1_ << ", median " << median_ << ", q3 " << q3_ << ", IQR " << q3_ - q1_ << std::endl;

      double iqr(q3_ - q1_); // Interquartile range.
      const double k_outlier = 1.5; // 2. also used.
      const double k_extreme_outlier = 3.;

      double min_cutoff = q1_ - k_outlier * iqr;
      double max_cutoff = q3_ + k_outlier * iqr;
      double min_ext_cutoff = q1_ - k_extreme_outlier * iqr;
      double max_ext_cutoff = q3_ + k_extreme_outlier * iqr;

      //std::cout << "Min outlier fences <" << min_cutoff << " or >" << max_cutoff << std::endl;
      //std::cout << "Min extreme fences <" << min_ext_cutoff <<  " or >" << max_ext_cutoff << std::endl;

      std::vector<double>::const_iterator i;
      for(i = series_.begin(); *i < min_cutoff; ++i)
      { // Separate any minimum outliers and extreme outliers.
        if(*i < min_ext_cutoff)
        {
          extreme_outliers_.push_back(*i);
        }
        else if(*i < min_cutoff)
        {
          outliers_.push_back(*i);
        }
      } // for

      whisker_min_ = *i;
      std::vector<double>::const_reverse_iterator j;
      for(j = series_.rbegin(); *j > max_cutoff; ++j)
      { // Separate any maximum outliers and extreme outliers.
        if(*j > max_ext_cutoff)
        {
          extreme_outliers_.push_back(*j);
        }
        else if(*j > max_cutoff)
        {
          outliers_.push_back(*j);
        }
      } // for
      whisker_max_ = *j;
    } //   void calculate_quantiles()

    // Declaration of Set and Get member functions for the boxplot data series class.
    // (Note: identically named functions are provided for the boxplot class).

    svg_boxplot_series& title(const std::string& t); // Set title for data series.
    const std::string title(); // \return  title for boxplot.
    svg_boxplot_series& whisker_length(double l); // Set length of whisker line.
    double whisker_length(); // \return length of whisker line.
    svg_boxplot_series& box_width(double l); // Set width of box.
    double box_width(); // \return  width of box.
    svg_boxplot_series& min_whisker_color(const svg_color& col); // Color of boxplot whisker.
    svg_color min_whisker_color(); // \return  color of boxplot whisker.
    svg_boxplot_series& min_whisker_width(double l); // Set width of whisker line.
    double min_whisker_width(); // \return  width of whisker line.
    svg_boxplot_series& max_whisker_color(const svg_color& col); // Color of whisker.
    svg_color max_whisker_color(); //  Color of whisker.
    svg_boxplot_series& max_whisker_width(double l); // Width of whisker line.
    double max_whisker_width(); //  Width of whisker line.
    svg_boxplot_series& box_fill(const svg_color& color); // Color of box fill, not border.
    svg_color box_fill(); // Color of box fill, not border.
    svg_boxplot_series& box_border(const svg_color& color); // Color of border (not fill) to box.
    svg_color box_border(); // Color of border (not fill) to box.

    svg_boxplot_series& median_color(const svg_color& color); // Color of median line in box.
    svg_color median_color(); // Color of median line in box.
    svg_boxplot_series& median_width(double l); // Width of median line in box.
    double median_width(); //  Width of median line in box.

    svg_boxplot_series& axis_color(const svg_color& color); // Color of vertical axis whisker line in box.
    svg_color axis_color(); // Color of vertical axis whisker line in box.

    svg_boxplot_series& axis_width(double l); // Width of vertical axis whisker line in box.
    double axis_width(); // \return  width of vertical axis whisker line in box.

    svg_style& box_style(); // \return  Reference to style of box.
    svg_boxplot_series& box_style(svg_style& bs); // Set Reference to style of box.

    svg_style& median_style(); // \return  Reference to style of median marker line.
    svg_boxplot_series& median_style(svg_style& ms);
    plot_point_style& outlier_style(); // \return  Reference to style of outlier marker line.
    svg_boxplot_series& outlier_style(plot_point_style& os); // Set Reference to style of outlier marker line.

    svg_boxplot_series& outlier_color(const svg_color& color); // Set color of outlier marker.
    svg_color outlier_color(); // \return  color of outlier marker.
    svg_boxplot_series& outlier_fill(const svg_color& color); // Set fill color of outlier marker.
    svg_color outlier_fill(); // \return  fill color of outlier marker.
    svg_boxplot_series& extreme_outlier_color(const svg_color& color); // Set color of extreme outlier marker.
    svg_color extreme_outlier_color(); // \return  color of extreme outlier marker.
    svg_boxplot_series& extreme_outlier_fill(const svg_color& color); // Set color of extreme outlier marker.
    svg_color extreme_outlier_fill(); // \return  color of extreme outlier marker.
    svg_boxplot_series& outlier_shape(point_shape shape); // Set shape of outlier marker.
    point_shape outlier_shape(); // \return  shape of outlier marker.
    svg_boxplot_series& outlier_size(int size); // Set size of outlier marker.
    int outlier_size(); // \return  size of outlier marker.
    svg_boxplot_series& extreme_outlier_shape(point_shape shape); // Set shape of extreme outlier marker.                      !
    point_shape extreme_outlier_shape(); // \return  Shape of extreme outlier marker.
    svg_boxplot_series& extreme_outlier_size(int size); // Set size of extreme outlier marker.
    int extreme_outlier_size(); // \return  Size of extreme outlier marker.
    // Not implemented yet - settings are boxplot wide.
    //svg_boxplot_series& outlier_values_on(bool cmd);// If values to be shown alongside outlier markers.
    //bool outlier_values_on(); // If values to be shown alongside outlier markers.
    //svg_boxplot_series& extreme_outlier_values_on(bool cmd); // If values to be shown alongside extreme outlier markers.
    //bool extreme_outlier_values_on(); // If values to be shown alongside extreme outlier markers.
    svg_boxplot_series& quartile_definition(int def); // Set H&F quartile definition.
    int quartile_definition(); // \return H&F quartile definition.
//! \cond DETAIL

//! \endcond
  }; // struct svg_boxplot_series

  // svg_boxplot_series *Definitions*.

  const std::string svg_boxplot_series::title()
  { /*! Obtain current series title.
        \return  title of a @b data series.
  */
    return series_info_.text();
  }

  svg_boxplot_series& svg_boxplot_series::title(const std::string& t)
  { //! Set title of a @b data series.
    series_info_.text(t);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_boxplot_series& svg_boxplot_series::whisker_length(double width)
  { //! Set minimum and maximum whisker length.
    // Applies to BOTH min and max whisker.
    whisker_length_ = width;
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  //! Get current whisker length (Applies to BOTH min and max whisker).
  double svg_boxplot_series::whisker_length()
  {
    return whisker_length_; //! \return Both minimum and maximum whisker length.
  }

  svg_boxplot_series& svg_boxplot_series::min_whisker_width(double width)
  { //! Set line width of minimum whisker.
    min_whisker_style_.stroke_width(width);
    return *this;  //! \return Reference to @c svg_boxplot_series to make chainable..
  }

  double svg_boxplot_series::min_whisker_width()
  { //! \return line width of minimum whisker.
    return min_whisker_style_.stroke_width();
  }

  svg_boxplot_series& svg_boxplot_series::min_whisker_color(const svg_color& color)
  { //! Set color of minimum whisker.
    min_whisker_style_.stroke_color(color);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }
  svg_color svg_boxplot_series::min_whisker_color()
  { //! \return color of minimum whisker.
    return min_whisker_style_.stroke_color();
  }

  svg_boxplot_series& svg_boxplot_series::max_whisker_width(double width)
  { //! \return line width of maximum whisker.
    max_whisker_style_.stroke_width(width);
    return *this;  //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  double svg_boxplot_series::max_whisker_width()
  { //! \return line width of maximum whisker.
    return max_whisker_style_.stroke_width();
  }

  svg_boxplot_series& svg_boxplot_series::max_whisker_color(const svg_color& color)
  { //! Set color of minimum whisker.
    max_whisker_style_.stroke_color(color);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_color svg_boxplot_series::max_whisker_color()
  { //! \return color of maximum whisker.
    return max_whisker_style_.stroke_color();
  }

  double svg_boxplot_series::box_width()
  { //! \return width of the box.
    // width of the box, not the margin.
    return box_width_;
  }

  svg_boxplot_series&  svg_boxplot_series::box_width(double l)
  { //! Set width of the box.
    // width of the box, not the margin.
    box_width_ = l;
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_style& svg_boxplot_series::box_style()
  { //! \return box style.
    return box_style_;
  }

  svg_boxplot_series& svg_boxplot_series::box_style(svg_style& bs)
  { //! Set entire box style.
    box_style_ = bs;
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_style& svg_boxplot_series::median_style()
  { //! \return median style.
    return median_style_;
  }

  svg_boxplot_series& svg_boxplot_series::median_style(svg_style& ms)
  { //! Set entire median style.
    median_style_ = ms;
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  /*!
    Set entire outlier style..
  */
  svg_boxplot_series& svg_boxplot_series::outlier_style(plot_point_style& os)
  { //! Set entire outlier style.
    mild_outlier_ = os;
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  /*!
    Get current outlier style.
  */
  plot_point_style& svg_boxplot_series::outlier_style()
  {
    return mild_outlier_; //! \return outlier_style.
  }

  svg_boxplot_series& svg_boxplot_series::box_fill(const svg_color& color)
  { //! Set color of box fill (not border).
    box_style_.fill_color(color);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_color svg_boxplot_series::box_fill()
  { //! \return color of box fill.
    return box_style_.fill_color();
  }

  svg_boxplot_series& svg_boxplot_series::box_border(const svg_color& color)
  { //! Set color of box border.
    box_style_.stroke_color(color);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_color svg_boxplot_series::box_border()
  { //! \return color of box border.
    return box_style_.stroke_color();
  }

  svg_boxplot_series& svg_boxplot_series::median_color(const svg_color& color)
  { //! Set color of median line in box.
    median_style_.stroke_color(color);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_color svg_boxplot_series::median_color()
  { //! \return color of median line in box.
    return median_style_.stroke_color();
  }

  svg_boxplot_series& svg_boxplot_series::median_width(double width)
  { //! Set width of median line in box.
    median_style_.stroke_width(width);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable..
  }

  double svg_boxplot_series::median_width()
  { //! \return Width of median line in box.
    return  median_style_.stroke_width();
  }

  svg_boxplot_series& svg_boxplot_series::axis_color(const svg_color& color)
  { //! Set color of axis line.
    axis_style_.stroke_color(color);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_color svg_boxplot_series::axis_color()
  { //! \return Color of axis line.
    return axis_style_.stroke_color();
  }

  svg_boxplot_series& svg_boxplot_series::axis_width(double width)
  { //! Set width of axis line.
    axis_style_.stroke_width(width);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  double svg_boxplot_series::axis_width()
  { //! \return width of axis line.
    return  axis_style_.stroke_width();
  }

  svg_boxplot_series& svg_boxplot_series::outlier_color(const svg_color& color)
  { //! Set color of outlier line in box.
    mild_outlier_.stroke_color(color);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_color svg_boxplot_series::outlier_color()
  {  //! \return color of outlier line in box.
    return mild_outlier_.stroke_color();
  }

  svg_boxplot_series& svg_boxplot_series::outlier_fill(const svg_color& color)
  { //! Set fill color of mild outlier line in box.
    mild_outlier_.fill_color(color);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_color svg_boxplot_series::outlier_fill()
  { //! \return fill color of mild outlier line in box.
    return mild_outlier_.fill_color();
  }

  svg_boxplot_series& svg_boxplot_series::extreme_outlier_color(const svg_color& color)
  { //! Set fill color of extreme outlier line in box.
    ext_outlier_.stroke_color(color);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_color svg_boxplot_series::extreme_outlier_color()
  { //! \return fill color of extreme outlier line in box.
    return ext_outlier_.stroke_color();
  }

  svg_boxplot_series& svg_boxplot_series::extreme_outlier_fill(const svg_color& color)
  { //! Set fill color of extreme outlier line in box.
    ext_outlier_.fill_color(color);
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  svg_color svg_boxplot_series::extreme_outlier_fill()
  { //! \return fill color of extreme outlier line in box.
    return ext_outlier_.fill_color();
  }

  svg_boxplot_series& svg_boxplot_series::outlier_shape(point_shape shape)
  { //! Set shape of outlier marker.
    mild_outlier_.shape_ = shape;
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  point_shape svg_boxplot_series::outlier_shape()
  { //! \return shape of outlier marker.
    return mild_outlier_.shape_;
  }

  svg_boxplot_series& svg_boxplot_series::outlier_size(int size)
  { //! Set size of outlier marker.
    mild_outlier_.size_ = size;
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  int svg_boxplot_series::outlier_size()
  { //! \return Size of outlier marker.
    return mild_outlier_.size_;
  }

  svg_boxplot_series& svg_boxplot_series::extreme_outlier_shape(point_shape shape)
  { //! Set shape of extreme outlier marker.
    ext_outlier_.shape_ = shape;
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  point_shape svg_boxplot_series::extreme_outlier_shape()
  { //! \return shape of extreme outlier marker.
    return ext_outlier_.shape_ ;
  }

  svg_boxplot_series& svg_boxplot_series::extreme_outlier_size(int size)
  { //! Set size of extreme outlier marker.
    ext_outlier_.size_ = size;
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable..
  }

  int svg_boxplot_series::extreme_outlier_size()
  { //! \return Size of extreme outlier marker.
    return ext_outlier_.size_;
  }

  svg_boxplot_series& svg_boxplot_series::quartile_definition(int def)
  { //! set Choice of H&F quartile definition.
    quartile_definition_ = def;
    return *this; //! \return Reference to @c svg_boxplot_series to make chainable.
  }

  int svg_boxplot_series::quartile_definition()
  { //! \return Choice of H&F quartile definition.
    return quartile_definition_;
  }

  // Not implemented yet - so these are only available for ALL *series* boxplot.
  //svg_boxplot_series& svg_boxplot_series::outlier_values_on(bool cmd)
  //{
  //  outlier_values_on_ = cmd;
  //  return *this;
  //}

  //svg_boxplot_series& svg_boxplot_series::extreme_outlier_values_on(bool cmd)
  //{
  //  extreme_outlier_values_on_ = cmd;
  //  return *this;
  //}

  //bool svg_boxplot_series::outlier_values_on()
  //{
  //  return outlier_values_on_;
  //}

  //bool svg_boxplot_series::extreme_outlier_values_on()
  //{
  //  return extreme_outlier_values_on_;
  //}

// End of svg_boxplot_series Definitions.

/*!
    \brief A plot that can display boxplots of several data series.\n
    Holds all info about the plot (but not any data series - see @c svg_boxplot_series)\n
    \details (@c axis_plot_frame.hpp contains functions common to 1 and 2-D, and boxplot).
*/
class svg_boxplot : public detail::axis_plot_frame<svg_boxplot>
{
  friend class svg_boxplot_series;
  friend class detail::axis_plot_frame<svg_boxplot>;
  // axis_plot_frame.hpp contains functions common to 1 and 2-D, and boxplot.

  public: //temporary for experimental gil was private:
//! \cond DETAIL

  svg image_; //!< svg image data (stored so as to avoid rewriting style information constantly).

  double x_scale_; //!< Used by function transform()
  double x_shift_; //!< to go from Cartesian to SVG coordinates.
  double y_scale_; //!< SVG coordinates origin is at top left,
  double y_shift_;  //!< and y coordinates increase DOWN the page!

  double x_axis_position_; //!< Intersection of X axis, or not.
  double y_axis_position_; //!< Intersection of Y axis, or not.

  // Plot window (calculate_plot_window() sets these values).
  double plot_left_; //!< SVG coordinate of left of plot window.
  double plot_top_; //!< SVG coordinate of top of plot window.
  double plot_right_;  //!< SVG coordinate of right of plot window.
  double plot_bottom_; //!< SVG coordinate of bottom of plot window.

  // Order of these declarations (not definitions) seems to matter - styles 1st.
 // text_style contains font size & type etc.
  text_style a_style_; //!< Default text style (font etc).
  text_style title_style_; //!< text style (font) used for plot title.
  text_style x_axis_label_style_; //!< text style (font) used for Y axis label.
  text_style x_ticks_value_label_style_; //!< text style (font) used for X data point value label.
  text_style y_axis_label_style_; //!< text style (font) used for Y axis label.
  text_style y_ticks_value_label_style_; //!< text style (font) used for Y data point value label.
  text_style point_symbols_style_; //!< text style (font) used for symbol used for data point marking.
  text_style value_style_; //!< style used for data point value label.

  axis_line_style x_axis_; //!< style of X axis line.
  axis_line_style y_axis_; //!< style of Y axis line.

 // text_style contains font size & type etc.
  value_style values_style_; //!< Data point value marking style.

  text_element title_info_; //!< plot title info.
  text_element x_label_info_; //!< X axis label info.
  text_element y_label_info_; //!< Y axis label info (used for 2-D only).
  text_element x_units_info_; //!< X axis unit label, For example: "mm"
  text_element y_units_info_; //!< Y axis unit label (used for 2-D only).

  // Should use axis_style?
  //  x_axis_(X, -10., +10., black, 1, 0, true, false, true),
  box_style image_border_; //!< rectangular border of all image width, color...
  box_style plot_window_border_; //!< rectangular border of plot window width, color...

  ticks_labels_style x_ticks_; //!< style of X axis ticks.
  ticks_labels_style y_ticks_; //!< style of X axis ticks. (Added to permit shared code!)

  bool autoscale_check_limits_; //!< If true then to check autoscale values for infinity, NaN, max, min.
  bool x_autoscale_; //!< If thrue then to use any X-axis autoscale values.
  bool x_include_zero_; //!< If true and autoscaled, include zero.
  int  x_min_ticks_;  //!< If autoscaled, set a minimum number of X ticks.
  double x_tight_; //!< How much a point is allowed beyond the X  minimum or maximum before another tick is used.
  int x_steps_;  //!< If autoscaled, set any prescaling to decimal 1, 2, 5, 10 etc.

  // Values calculated by scale_axis, and is used only if x_autoscale == true.
  double x_auto_min_value_; //!< Value calculated by scale_axis, and is used only if x_autoscale == true.
  double x_auto_max_value_; //!< Value calculated by scale_axis, and is used only if x_autoscale == true.
  double x_auto_tick_interval_; //!< tick major interval calculated by scale_axis.
  int x_auto_ticks_; //!< Number of ticks calculated by scale_axis.

  bool y_autoscale_; //!< If true then to use any y_axis autoscale values.
  double autoscale_plusminus_; //!< For uncertain values, allow for text_plusminus ellipses showing 67%, 95% and 99% confidence limits.\n
  //!< For example, if a max value is 1.2 +or- 0.02, then 1.4 will be used for autoscaling the maximum.\n
  //!< Similarly, if a min value is 1.2 +or- 0.02, then 1.0 will be used for autoscaling the minimum.

  double plusminus_sds_; //!< Nominal factor of 1. standard deviation uncertainty (default) corresponds to 67% confidence limit.
//!< Optionally can two two or three (for 95% or 99.7%).
//!< Must apply to both 1D and both axes of 2D plots.

  double text_plusminus_; /*!< Number of standard deviations used for text_plusminus text display.\n
    Nominal factor of 1. (default) corresponds to 67% confidence limit,
    2 (strictly 1.96) corresponds to 95% confidence limit. */

  bool y_include_zero_; //!< If autoscaled, include zero.
  int  y_min_ticks_;  //!< If autoscaled, set a minimum number of Y ticks.
  double y_tight_; //!< How much a point is allowed beyond the Y minimum or maximum before another tick is used.
  int y_steps_;  //!< If autoscaled, set any prescaling to decimal 1, 2, 5, 10 etc.

  double y_auto_min_value_; //!< Value calculated by scale_axis, and is used only if y_autoscale == true.
  double y_auto_max_value_; //!< Value calculated by scale_axis, and is used only if y_autoscale == true.
  double y_auto_tick_interval_; //!< tick major interval calculated by scale_axis.
  int y_auto_ticks_; //!< Number of ticks calculated by scale_axis.

  double text_margin_; //!< Marginal character space around text items like title,
                       //!< (Use text_margin_ * font_size to get distance in svg units).
  bool title_on_; //!< If true then should the plot title (set true if a title requested).

  std::string plot_window_clip_; //!< name of plot window clip (all lines and text is clipped outside).
  bool plot_window_on_; //!< true if a central plot window (rather than the whole image rectangle) to be used.
  bool median_values_on_; //!< true if median of data is shown as well as a line marker.
  bool outlier_values_on_; //!< true if outlier values of data are shown.
  bool extreme_outlier_values_on_; //!< true if values of extreme outlier data are shown.

  // Parameters for calculating confidence intervals (for both X and Y values).
  // These might be picked up from uncertain types.
  double alpha_; //!< for calculating confidence intervals (for both X and Y values), default = 0.05;
  // oss.iword(confidenceIndex) / 1.e6; // Pick up alpha.
  double epsilon_; //!< for calculating confidence intervals (for both X and Y values). default= 0.01;
  // = oss.iword(roundingLossIndex) / 1.e3; // Pick up rounding loss.
  int uncSigDigits_; //!< significant digits for uncertainty. default = 2;
  // = oss.iword(setUncSigDigitsIndex);  // Pick up significant digits for uncertainty.
  bool isNoisyDigit_; //!< If extra 'noisy' digit is required, default = false;
  // Pick up?
  /*
  Parameters for calculating confidence intervals (for both X and Y values).
  These might be picked up from uncertain types.
  double alpha_; // = 0.05; // oss.iword(confidenceIndex) / 1.e6; // Pick up alpha.
  double epsilon_; // = 0.01; // = oss.iword(roundingLossIndex) / 1.e3; // Pick up rounding loss.
  int uncSigDigits_; // = 2; // = oss.iword(setUncSigDigitsIndex);  // Pick up significant digits for uncertainty.
  bool isNoisyDigit_; // = false; // Pick up?
  */

  std::vector<svg_boxplot_series> series; //!< Storing the data points for sorting by value.

  // Defaults (see below) for the box'n'whiskers
  // can be changed by functions like boxplot.box_width(50)
  // for all following plot(data,"title") calls
  // But can also change each plot data series separately.
  double box_width_; //!< Width of box used to show limit of most data items.
  svg_style box_style_; //!< style (color ...) of box used to show limit of most data items.
  svg_style median_style_; //!< style (color ...) used to show median.
  text_style series_style_; //!< font style for name of series.
  svg_style axis_style_; //!< line style for axis.
  double whisker_length_; //!< length of whisker showing outliers.
  svg_style min_whisker_style_; //!< line style for minimum whisker.
  svg_style max_whisker_style_; //!< line style for maximum whisker.
  int quartile_definition_; //!< Quartile definition type.
  plot_point_style mild_outlier_; //!< Style of points that are mild outliers.
  plot_point_style ext_outlier_; //!< Style of points that are extreme outliers.

//! \endcond
public:
 // text_element(double x = 0., double y = 0., const std::string text = "", text_style ts = no_text_style, align_style align = left_align, rotate_style rotate = horizontal)

  svg_boxplot()
  :
  title_style_(18, default_font_family, "", "", "", ""),
  value_style_(10, default_font_family, "", "", "", ""), // Data values
  title_info_(0, 0, "", title_style_, align_style::center_align, horizontal),
  title_on_(true),
  x_label_info_(0, 0, "", x_axis_label_style_ , align_style::center_align, horizontal),
  x_units_info_(0, 0, "", x_ticks_value_label_style_, align_style::center_align, horizontal),
  y_label_info_(0, 0, "", y_axis_label_style_, align_style::center_align, upward),
  y_units_info_(0, 0, "", y_axis_label_style_, align_style::center_align, upward),
  x_axis_(X, -10., +10., black, 1, 0, true, false, true),
  y_axis_(Y,   0.,  +1., black, 1, 0, true, false, true),
  x_axis_label_style_(14, default_font_family, "", ""),
  x_ticks_value_label_style_(12, default_font_family, "", ""),
  y_axis_label_style_(14, default_font_family, "", ""),
  y_ticks_value_label_style_(12, default_font_family, "", ""),
  point_symbols_style_(12, "Lucida Sans Unicode"), // Used for data point marking to try to get in right place.
  // try to center accurately on the point's value.
  values_style_(rightward, align_style::left_align, 3, std::ios::dec, true, value_style_, black, black, false, false),

  x_ticks_(X, x_ticks_value_label_style_),// so for other defaults see ticks_labels_style.
  y_ticks_(Y, y_ticks_value_label_style_),

  autoscale_check_limits_(true), // Do check all value for limits, infinity, max, min, NaN.
  x_autoscale_(false),
  autoscale_plusminus_(3.), // Allow 3 uncertainty (standard deviation) for 99% confidence ellipse.
  plusminus_sds_(1.), // Default 1 uncertainty or standard deviation, but optionally two or three.

  x_include_zero_(false), // If autoscaled, include zero.
  x_min_ticks_(6),  // If autoscaled, set a minimum number of ticks, default 6.
  x_steps_(0),  // If autoscaled, set any prescaling to decimal 1, 2, 5, 10 etc, default none (0).
  x_tight_(1e-6), // margin that point can lie outside top and bottom tick.

  y_include_zero_(false), // If autoscaled, include zero on Y-axis.
  y_min_ticks_(6),  // If autoscaled, set a minimum number of ticks, default 6.
  y_steps_(0),  // If autoscaled, set any prescaling to decimal 1, 2, 5, 10 etc, default none.
  y_tight_(1e-6), // margin that point can lie outside top and bottom tick.

  y_autoscale_(false), // Not used for 1-D.

  text_margin_(2.), // for axis label text, as a multiplier of the font size.
  image_border_(yellow, white, 2, 10, true, true), // margin should be about axis label font size.
  plot_window_border_(yellow, svg_color(255, 255, 255), 1, 3, true, false),

  plot_window_clip_("plot_window"),
  plot_window_on_(true),
  median_values_on_(false), // If values of data are shown as well as a marker like square.
  outlier_values_on_(false), // If values of data are shown as well as a marker like square.
  extreme_outlier_values_on_(false), // If values of data are shown as well.
  quartile_definition_(8), // Default H&F quartile definition.  This might be changed to 7 to match Excel and others?
  plot_left_(0.), plot_top_(0.), plot_right_(0.), plot_bottom_(0.),

  // Used to transform Cartesian to SVG.
  x_scale_(1.), x_shift_(0.),
  y_scale_(1.), y_shift_(0.),
  x_axis_position_(bottom),  // Default, but can be changed to top.
  y_axis_position_(left), // Default, but can be changed to right.

  // Box'n'whiskers default values (used in svg_boxplot_series construction).
  // Can be changed for all plots using svg_boxplot member functions.
  // Can be changed for individual data series using svg_boxplot_series member functions.
  box_width_(30), // can be changed with svg_boxplot::box_width()),
  series_style_(x_axis_label_style_), // want to use the x_label style here
  whisker_length_(30),
  box_style_(green, azure, 1), // stroke, fill, width, 1, true, true, margin, border_on, fill_on
  median_style_(blue, blank, 1),
  axis_style_(black, blank, 1),
  min_whisker_style_(magenta, black, 1),
  max_whisker_style_(cyan, black, 1),
  mild_outlier_(brown, blank, 5, circlet),
  ext_outlier_(red, blank, 5, cone)
  { //! Default constructor providing all the default colors, style etc,
    using std::cout;
    using std::endl;
    size(500, 350);

   // Build the document tree. add children of the root node.
    for(int i = 0; i < boxplot::BOXPLOT_DOC_CHILDREN; ++i)
    {
      image_.add_g_element();
    }
    //set_ids();
    //  void set_ids()  // This only used once in constructor and IS now inlined.
   // document ids for use in <g id = "PLOT_TITLE".../>
    for(int i = 0; i < boxplot::BOXPLOT_DOC_CHILDREN; ++i)
    { // Order determines the painting order.
      image_.gs(i).id(boxplot::document_ids_[i]);
    }

    // Set boxplot color defaults.
    image_.gs(boxplot::PLOT_BACKGROUND).style().fill_color(image_border_.fill_);
    image_.gs(boxplot::PLOT_BACKGROUND).style().stroke_color(image_border_.stroke_);
    image_.gs(boxplot::PLOT_BACKGROUND).style().stroke_width(image_border_.border_width_);
    image_.gs(boxplot::PLOT_WINDOW_BACKGROUND).style().fill_color(plot_window_border_.fill_);
    image_.gs(boxplot::PLOT_WINDOW_BACKGROUND).style().stroke_width(plot_window_border_.border_width_).stroke_color(plot_window_border_.stroke_);
    image_.gs(boxplot::X_AXIS).style().stroke_color(black).stroke_width(x_axis_.width());
    image_.gs(boxplot::Y_AXIS).style().stroke_color(black).stroke_width(y_axis_.width());

    // Ticks & grids.
    if(x_ticks_.use_up_ticks() || x_ticks_.use_down_ticks())
    {
      image_.gs(boxplot::X_TICKS).style().stroke_width(x_ticks_.minor_tick_width_).stroke_color(black);
    }
    if(y_ticks_.left_ticks_on_ || y_ticks_.right_ticks_on_)
    {
      image_.gs(boxplot::Y_MAJOR_TICKS).style().stroke_width(y_ticks_.major_tick_width_).stroke_color(black);
      image_.gs(boxplot::Y_MINOR_TICKS).style().stroke_width(y_ticks_.minor_tick_width_).stroke_color(black);
      image_.gs(boxplot::Y_MAJOR_GRID).style().stroke_width(y_ticks_.major_grid_width_).stroke_color(svg_color(200, 220, 255));
      image_.gs(boxplot::Y_MINOR_GRID).style().stroke_width(y_ticks_.minor_grid_width_).stroke_color(svg_color(200, 220, 255));
    }

    image_.gs(boxplot::X_LABEL).style().fill_color(black); // for text only specify fill_color (NOT stroke color).
    image_.gs(boxplot::Y_LABEL).style().fill_color(black);
    image_.gs(boxplot::VALUE_LABELS).style().fill_color(black);
    image_.gs(boxplot::PLOT_TITLE).style().fill_color(black);

    image_.gs(boxplot::WHISKER).style().stroke_color(black);
    image_.gs(boxplot::BOX_AXIS).style().stroke_color(black);
    image_.gs(boxplot::BOX).style().stroke_color(black).fill_color(ghostwhite);
    image_.gs(boxplot::MEDIAN).style().stroke_color(red).stroke_width(2);
    image_.gs(boxplot::EXTREME_OUTLIERS).style().stroke_color(purple).fill_color(white);
    image_.gs(boxplot::MILD_OUTLIERS).style().stroke_color(pink).fill_color(black);
    image_.gs(boxplot::DATA_VALUE_LABELS).style().fill_color(black).stroke_on(false);

  } // boxplot constructor.

//! \cond DETAIL
  // Clear Functions.
  void clear_all()
  { /*!
    \brief Clear all the previous information and rebuild the SVG image.
    \details
       When writing to multiple documents, the contents of the plot
       may change significantly between. Rather than figuring out what
       has and has not changed, just erase the contents of the
      legend, title... in the document and start over.
    */
    //clear_legend();
    //clear_background();
    //clear_x_axis();
    //clear_y_axis();
    //clear_title();
    //clear_points();
    //clear_plot_background();
    //clear_grids();
  }

  void transform_x(double& x)
  { //! Transform X coordinate from Cartesian to SVG.
    x = x * x_scale_ + x_shift_;
  }

  void transform_y(double& y)
  { //! Transform Y coordinate from Cartesian to SVG.
    y = y * y_scale_ + y_shift_;
  }

  void calculate_plot_window()
  { //! Calculate the position of the plot window.
    // Start by assuming we can use all the svg image,
    // but reduce by the width of any image border.
    plot_left_ = 0. + image_border_.border_width_; // Top left of image.
    plot_top_ = 0. + image_border_.border_width_;
    plot_right_ = image_.x_size() - image_border_.border_width_; // Bottom right of image.
    plot_bottom_ = image_.y_size() - image_border_.border_width_;
    if(plot_window_on_)
    { // Needed to allow any plot window border rectangle to show OK.
      // A small margin is to prevent it overlapping the image border.
      // Also allows for axis value labels that mark the min and max
      // that must extend half a font width beyond the plot window border.
      plot_left_ +=  image_border_.margin_;
      plot_right_ -=  image_border_.margin_;
      plot_top_ += image_border_.margin_;
      plot_bottom_ -=  image_border_.margin_;
    }
    if(title_on_)
    { // Allow space for plot title (at top).
      plot_top_ += title_info_.textstyle().font_size() * (text_margin_ + 0.5);
    }
    // Assume that axis labels are always at bottom and left.
    if(x_axis_.label_on_)
    { // Move bottom up to leave space at bottom for X axis label.
       plot_bottom_ -= x_axis_label_style_.font_size() * (text_margin_ + 0.5);
    }
    if(y_axis_.label_on_)
    { // Leave space at left for Y axis label.
      plot_left_ += y_axis_label_style_.font_size() * text_margin_;
    }
    if (y_autoscale_) // TODO elsewhere - implement Y autoscale (no x autoscale of course).
    { // Use calculated autoscale values.
      // Autoscale has been done in my_data.y_autoscale(my_data);
      // and saved in y_auto_min_value_, y_auto_max_value_, & y_auto_tick_interval_,
      // so copy these values to use them:
      y_axis_.min_ = y_auto_min_value_;
      y_axis_.max_ = y_auto_max_value_;
      y_ticks_.major_interval_  = y_auto_tick_interval_;
      // else ignore auto values, even if have been calculated.
    }

    // Check if the axes will intersect.
    // X axis position is determined by the range of Y min and max label values.
    x_axis_position_ = x_intersects_y;  // Assume X-axis will intersect Y-axis (range of Y values includes zero).
    if (y_axis_.min_ > (std::numeric_limits<double>::min)()) // all Y values definitely > zero.
    { // y_min_ > 0, so X-axis will not intersect Y-axis, so use bottom plot window.
      x_axis_position_ = bottom; // X-axis to bottom of plot window.
      x_ticks_.ticks_on_window_or_on_axis_ = -1; // bottom = true;
    }
    else if(y_axis_.max_ < -(std::numeric_limits<double>::min)())  // all Y values definitely < zero.
    { // // y_max_ < 0, so X-axis will not intersect Y-axis, so use top plot window.
      x_axis_position_ = top; // X-axis to top of plot window.
      x_ticks_.ticks_on_window_or_on_axis_ = +1; // top = true;
    }
    // Y axis position is NOT determined by the range of X values.
    //x_axis_position_ = bottom;  // Assume X-axis will intersect Y-axis (X range includes zero).
    //y_axis_position_ = left;  // Assume X-axis will intersect Y-axis (X range includes zero).
    // Default in constructor, but could be changed to top and/or left.

    // Ensure both axis and ticks have the *same* range.
    // (To use the separation, made to give the potential for different ranges,
    // one would have to *not* do this,
    // but to make sure they are both assigned correctly).
    x_ticks_.max_ = x_axis_.max_;
    x_ticks_.min_ = x_axis_.min_;
    y_ticks_.max_ = y_axis_.max_;
    y_ticks_.min_ = y_axis_.min_;

    // Calculate the number of chars of the longest value labels.
    // x_ticks_.longest_label(); // Can't use this for boxplot because
    // it is the length of the value labels.
    y_ticks_.longest_label(); // Updates y_label_max_length_
    size_t longest = 0;
    for (size_t i = 0; i < series.size(); i++)
    {
      std::size_t l = series[i].series_info_.text().size(); // Length of an X label.
      if(l > longest)
      {
        longest = l;
      }
    }
    if (longest == 0)
    {
      std::cout << "No X-axis labels!" << std::endl;
      // No labels provided so switch off labelling.
      x_ticks_.major_value_labels_side_ = 0;
    }
    x_ticks_.label_max_length_ = static_cast<double>(longest);

    // Check that labels won't collide and advise if they will?
    // Change rotation to avoid collision?

    const double wh = 0.6; // TODO width of font?
    y_ticks_.label_max_space_ = 0.; // Space for Y axis labels, depending on orientation.
    if (y_ticks_.label_rotation_ == horizontal)
    { // Move plot left edge right to give space for y_value_precision_ digits.
       y_ticks_.label_max_space_ += y_ticks_.label_max_length_; // SVG units.
    }
    else if((y_ticks_.label_rotation_ == upward) || (y_ticks_.label_rotation_ == downward))
    { // Only need one char & 1 space width from Y-axis label.
      y_ticks_.label_max_space_ += 2 * y_ticks_value_label_style_.font_size() * wh;
    }
    else
    { // Assume some slope 45, so diagonally down from tick,
      // and takes a bit less room.
      y_ticks_.label_max_space_ = y_ticks_.label_max_length_ * sin45;
    }

    if (y_ticks_.major_value_labels_side_ != 0) // != none
    { // Major tick value labels wanted left or right.
      if ((y_ticks_.ticks_on_window_or_on_axis_ < 0) // On left of plot window.
        && (y_ticks_.major_value_labels_side_ < 0) ) // & labels on left.
      {  // Contract plot window left edge to right to make space for value labels on left.
        plot_left_ += y_ticks_.label_max_space_;
      }
      else if ((y_ticks_.ticks_on_window_or_on_axis_ > 0) // On right of plot window.
        && (y_ticks_.major_value_labels_side_ > 0) ) // & labels to right.
      {  // Contract plot window right to left to make space for value labels on right.
       plot_right_ -= y_ticks_.label_max_space_;
      }
      else
      { // y_ticks_.ticks_on_window_or_on_axis_ == 0
        // no value labels on plot window (may be on mid-plot Y-axis line).
        // Ignore the unusual case of Y-axis line too close to the axis label.
        // In this case the value labels may overflow the plot window
        // and collide with the axis label!
        // User must change to put value label downward, or on other side of the axis line.
        // using major_value_labels_side(int d)
        // to set tick value labels to left (<0), none (==0) or right (>0).
      }
    } // y_ticks_. major_value_labels_side

    x_ticks_.label_max_space_ = 0; // Work out the longest value label for X-Axis.
    if (x_ticks_.label_rotation_ == horizontal)
    { // Only 1 char height & 1 space needed if labels are horizontal, regardless of length of string.
      x_ticks_.label_max_space_ = 2 * x_ticks_value_label_style_.font_size() * wh; // 2 SVG chars
    }
    else if ((x_ticks_.label_rotation_ == upward) || (x_ticks_.label_rotation_ == downward))
    { // Not horizontal so will need more than 2 chars worth.
        x_ticks_.label_max_space_ += x_ticks_.label_max_length_ ; // Number of SVG chars.
    }
    else
    { // Assume label is sloping, say 45, so * sin(45) = 0.707.
        x_ticks_.label_max_space_ += x_ticks_.label_max_length_ * sin45; // SVG 'chars'.
    }

    if (x_ticks_.major_value_labels_side_ != 0)
    { // Some tick value labels.
      if ((x_ticks_.ticks_on_window_or_on_axis_ < 0) // on bottom of plot window.
         && (x_ticks_.major_value_labels_side_ < 0) ) // & labels on bottom.
      {  // Contract plot window bottom edge up to make space for x value labels on bottom.
        plot_bottom_ -= x_ticks_.label_max_space_; // Move up.
      }
      else if ((x_ticks_.ticks_on_window_or_on_axis_ > 0) //
         && (x_ticks_.major_value_labels_side_ > 0) ) // & x labels to top.
      { // Move top of plot window down to give space for x value labels.
        plot_top_ += x_ticks_.label_max_space_; // Move down.
      }
      else
      { // no labels on plot window (may be on mid-plot X-axis).
        // See also notes above on case where labels can overwrite axis.
      }
    } // x_ticks_. major_value_labels_side

    // Make space for any ticks.
    if(y_ticks_.left_ticks_on_)
    { // Start left of plot to right to give space for biggest of any external left ticks.
      plot_left_ += (std::max)(y_ticks_.major_tick_length_, y_ticks_.minor_tick_length_); // Avoid macro max trap!
    }
    if(x_ticks_.down_ticks_on_)
    { // Start bottom of plot higher to give space for any external down ticks.
      plot_bottom_ -= (std::max)(x_ticks_.major_tick_length_, x_ticks_.minor_tick_length_);// Avoid macro max trap!
    }

    if (x_axis_.axis_line_on_)
    { // Want an horizontal X-axis line, so check if range includes zero, so axes intersect,
      // and x_axis_ is svg coordinate of Y-axis (usually y = 0).
      // If not fix axis to bottom (or top) of the plot window.
      if ((x_axis_position_ == bottom) // All Y values definitely > zero.
        && !(x_ticks_.ticks_on_window_or_on_axis_ < 0) ) // & not already at bottom.
      { // y_min_ > 0 so X-axis will not intersect Y-axis, so use plot window.
        x_axis_.axis_ = plot_bottom_; // Put X-axis on bottom.
      }
      else if ((x_axis_position_ == top)  // All Y values definitely < zero.
        && !(x_ticks_.ticks_on_window_or_on_axis_ > 0) ) // & not already at top.
      { // // y_max_ < 0 so X-axis will not intersect Y-axis, so use plot window.
         x_axis_.axis_ = plot_top_; // Put X-axis on top.
      }
      else
      { // y_axis_position_ == y_intersects_x
        // Calculate below after transform is calculated.
      }
    } // if (use_x_axis_line_)

    if (y_axis_.axis_line_on_)
    { // Want a vertical Y-axis line,
      // For boxplot do not check if range includes zero, so axes intersect,
      // and y_axis_ is svg coordinate of X-axis (usually x = 0).
      // Instead fix axis to left (or right) of the plot window.
      if ((y_axis_position_ == left) // All X values definitely > zero.
         && !(y_ticks_.ticks_on_window_or_on_axis_ < 0) // & not already at left.
         )
      { // Y-axis will not intersect X -axis, so put Y-axis line on plot window.
        y_axis_.axis_ = plot_left_; // Y-axis to left,
        //plot_left_ += 2 * y_label_info_.font_size(); // with a space.
      }
      else if ((y_axis_position_ == right) // All X values definitely < zero.
        && !(y_ticks_.ticks_on_window_or_on_axis_ > 0) // & not already at right.
        )
      {
        y_axis_.axis_ = plot_right_; // Y-axis to right of plot window,
    }
    //else
    // for boxplot, Y-axis is always to right or left.
    //{
    //  x_axis_position_ = x_intersects_y;
    //  // Calculate below after transform is calculated.
    //}
    } // if (use_y_axis_line_)

    // plot window now calculated, so make some checks (might also check it fits into image?).
    if (plot_right_ <= plot_left_)
    {
      std::cout << "Plot window left " << plot_left_ << ", right " << plot_right_ << std::endl;
      throw std::runtime_error("Plot window right <= left!");
    }
    if (plot_top_ >= plot_bottom_)
    {
      std::cout << "Plot window top " << plot_top_ << ", bottom " << plot_bottom_ << std::endl;
      throw std::runtime_error("Plot window top >= bottom!");
    }

    // Calculate scale and shift factors for transform from Cartesian to plot.
    // SVG image is 0, 0 at top left,y increase *downwards*
    // Cartesian 0, 0 at bottom left, y increasing upwards.
    x_scale_ = (plot_right_ - plot_left_) / (x_axis_.max_ - x_axis_.min_);
    x_shift_ = plot_left_ - x_axis_.min_ * (plot_right_ - plot_left_) / (x_axis_.max_ - x_axis_.min_);
    y_scale_ = -(plot_bottom_ - plot_top_) / (y_axis_.max_ - y_axis_.min_);
    y_shift_ = plot_top_ - (y_axis_.max_ * (plot_top_ - plot_bottom_) / (y_axis_.max_ - y_axis_.min_));

    if (x_axis_.axis_line_on_)
    {
      if(x_axis_position_ == x_intersects_y)
      { // Y Range *does* include zero, so x_axis_ not yet calculated.
        double y(0.); // Use y = 0
        transform_y(y);
        x_axis_.axis_ = y; // svg Y coordinate of horizontal X-axis line.
      }
    }
    // For boxplot, Y axis is only ever left or right.
    //if (y_axis_.axis_line_on_)
    //{ // May need to calculate axes, if will intersect.
    //  if(y_axis_position_ == y_intersects_x)
    //  { // X Range *does* include zero, so y_axis_ not yet calculated.
    //    double x(0.);
    //    transform_x(x);
    //    y_axis_.axis_ = x; // SVG x coordinate of vertical Y-axis.
    //  }
    //}
    if (plot_window_on_)
    { // Draw plot window rectangle with border and/or background.
      image_.gs(detail::PLOT_WINDOW_BACKGROUND).push_back(
        new rect_element(plot_left_, plot_top_, (plot_right_ - plot_left_), plot_bottom_ - plot_top_));
    }
  } //  void calculate_plot_window()

  void draw_title()
  { //! Update title_info_ with position.
    title_info_.x(image_.x_size() / 2.); // Center of image.
    /*! \verbatim
      Assumes align = center_align.
      Note: center_align will ensure that will center correctly
      even if original string is long because contains Unicode like
      because the browser render engine does the centering.
      \endverbatim
    */
    double y = title_info_.textstyle().font_size() * text_margin_; // Leave a linespace above.
    title_info_.y(y); // Vertical position.
    image_.gs(boxplot::PLOT_TITLE).push_back(new text_element(title_info_));
  } // void draw_title()

  void draw_x_axis()
  { //! Draw the horizontal X-axis line.
    if (x_axis_.axis_line_on_)
    { // Want a X-axis line.
      if (x_axis_position_ == top)
      { // horizontal line at top of plot window.
         image_.gs(boxplot::X_AXIS).line(plot_left_, plot_top_, plot_right_, plot_top_);
      }
      else if (x_axis_position_ == bottom)
      {// horizontal line at bottom of plot window.
         image_.gs(boxplot::X_AXIS).line(plot_left_, plot_bottom_, plot_right_, plot_bottom_);
      }
      else
      { // horizontal line at y = 0
        double y(0.);
        transform_y(y);
        //x_axis_. = y;
         image_.gs(boxplot::X_AXIS).line(plot_left_, y, plot_right_, y);
      }
    }
    path_element& major_tick_path = image_.gs(boxplot::X_TICKS).path();
    for(size_t i = 0; i < series.size(); ++i)
    { // Draw a ticks for each series, evenly spaced along X axis.
      draw_x_major_tick(
        plot_left_ + (plot_right_- plot_left_) *
        ((double)(i + 1)) / (double)(series.size() + 1),
        major_tick_path, series[i].series_info_);
    }
  } // void draw_x_axis()

  void draw_y_axis()
  { //! Draw the vertical Y-axis line.
    if (y_axis_.axis_line_on_)
    { // Want a vertical Y-axis line, for boxplot only ever left or right.
      if (y_axis_position_ == left)
      { // Vertical line at left of plot window.
         image_.gs(boxplot::Y_AXIS).line(plot_left_, plot_bottom_, plot_left_, plot_top_);
      }
      else if (y_axis_position_ == right)
      {// Vertical line at right of plot window.
         image_.gs(boxplot::Y_AXIS).line(plot_right_, plot_bottom_, plot_right_, plot_top_);
      }
    }

    path_element& minor_tick_path = image_.gs(boxplot::Y_MINOR_TICKS).path();
    path_element& major_tick_path = image_.gs(boxplot::Y_MAJOR_TICKS).path();
    path_element& major_grid_path = image_.gs(boxplot::Y_MAJOR_GRID).path();
    path_element& minor_grid_path = image_.gs(boxplot::Y_MINOR_GRID).path();

    // y_minor_jump is the interval between minor ticks.
    double y_minor_jump = y_ticks_.major_interval_ / ((double)(y_ticks_.num_minor_ticks_ + 1.) );

    // Draw the ticks on the positive side.
    for(double y = 0; y <= y_axis_.max_; y += y_ticks_.major_interval_)
    {
      for(double j = y + y_minor_jump;
        j < (y + y_ticks_.major_interval_) * (1. - 2 * std::numeric_limits<double>::epsilon());
        j += y_minor_jump)
      {
        draw_y_minor_tick(j, minor_tick_path, minor_grid_path);
      }
      draw_y_major_tick(y, major_tick_path, major_grid_path);
    }

    // Draw the ticks on the negative side.
    for(double y = 0; y >= y_axis_.min_; y -= y_ticks_.major_interval_)
    {
      // draw minor ticks
      for(double j = y;
        j > y - y_ticks_.major_interval_;
        j -= y_ticks_.major_interval_ / (y_ticks_.num_minor_ticks_ + 1.))
      {
        draw_y_minor_tick(j, minor_tick_path, minor_grid_path);
      }
      draw_y_major_tick(y, major_tick_path, major_grid_path);
    }
  } // void draw_y_axis()

  void draw_x_major_tick(double i, path_element& tick_path, text_element& series_info)
  { //! Draw X axis major tick, and optional boxplot label.
    double x_left = i;
    double y_top = plot_bottom_; // Top of tick.
    if (x_ticks_.up_ticks_on_)
    { //
      y_top -= (std::max)(x_ticks_.major_tick_length_, x_ticks_.minor_tick_length_);
    }
    double y_bottom = plot_bottom_;
    if (x_ticks_.down_ticks_on_)
    { // Move down for tick.
      y_bottom += (std::max)(x_ticks_.major_tick_length_, x_ticks_.minor_tick_length_);
    }
    tick_path.M(x_left, y_top).L(x_left, y_bottom); // leaving current position at bottom or tick.
    if(x_axis_.label_on_) //    use_x_major_labels)
    {
      series_info.x(x_left); // Horizontal position.
      double y = y_bottom + series_info.textstyle().font_size() * (text_margin_ * 0.7); // Leave a linespace above.
      series_info.y(y); // Vertical position.
      image_.gs(boxplot::VALUE_LABELS).push_back(new text_element(series_info));
    }
  } // void draw_x_major_tick

   void draw_y_major_tick(double value, path_element& tick_path, path_element& grid_path)
  { //! Draw a Y axis major tick, tick value labels & horizontal grid.
    double y(value); // for tick and/or grid.
    transform_y(y); // Cartesian to SVG coordinates.
    if((y < plot_top_ - 0.01) || (y > plot_bottom_ + 0.01))
      // Allow a bit extra to allow for round-off errors.
    { // tick value is way outside plot window, so nothing to do.
      return;
    }
    double x_left(0.); // Left end of tick.
    double x_right(image_.y_size()); // Right end of tick.
    if(y_ticks_.major_grid_on_ == true)
    { // Draw horizontal major Y grid line.
      if(!plot_window_on_ == true)
      {
        if(y_ticks_.major_value_labels_side_ < 0) // left
        { // Start further right to give space for y axis value label.
          y -= y_ticks_value_label_style_.font_size() * text_margin_;
        }

        if(y_ticks_.left_ticks_on_ == true)
        { // And similarly space for left ticks.
          y -= y_ticks_.major_tick_length_;
        }
      }
      else
      { // plot_window_on_ to use full width of plot window.
        x_left = plot_left_ + plot_window_border_.border_width_; // Don't write over either border.
        x_right = plot_right_ - plot_window_border_.border_width_;
      }
      grid_path.M(x_left, y).L(x_right, y); // Horizontal grid line.
   } // y_major_grid_on

    // Draw major ticks & tick value label, if necessary.
    double y_tick_length = y_ticks_.major_tick_length_;
    if (y_ticks_.ticks_on_window_or_on_axis_ < 0)
    { // Start ticks on the plot window border left.
      x_left = plot_left_; // x_left = left,
      x_right = plot_left_; //  x_right = right.
    }
    else if (y_ticks_.ticks_on_window_or_on_axis_ > 0)
    { // Start ticks on the plot window border right.
      x_left = plot_right_;
      x_right = plot_right_;
    }
    else // y_ticks_.ticks_on_window_or_on_axis_== 0
    { // Internal style ticks on vertical Y-axis.
      x_left = y_axis_.axis_; // Y-axis line.
      x_right = y_axis_.axis_;
    }
    if(y_ticks_.left_ticks_on_)
    {
      x_left -= y_tick_length; // left
    }
    if (y_ticks_.right_ticks_on_)
    {
      x_right += y_tick_length; // right.
    }
    tick_path.M(x_left, y).L(x_right, y); // Draw the major tick.
    // leaving x_left at the left most end of any tick,
    // and x_right at the rightmost end of any tick.
    // These may be on the axis line: y is the vertical tick position.

    if(y_ticks_.major_value_labels_side_ != 0)
    { // Label the tick with a value, for example "sin(x)"
      // (more likely to be a text string for boxplot, where 2D will be numeric tick value label).
      std::stringstream label;
      label.precision(y_ticks_.value_precision_);
      label.flags(y_ticks_.value_ioflags_); // set ALL IOflags.
      label << value; // Example: label.str() == "20" or "0.25" or "1.2e+015"
       if (y_ticks_.strip_e0s_)
      { // Remove unecessary e, +, leadings 0s.
        std::string v = strip_e0s(label.str());
        label.str(v);
      }

      double x = 0; // Where to start writing from, at end of left or right tick, if any.
      // = 0 is only to avoid unitialised warning.
      align_style alignment = align_style::center_align;
      // Adjustments to provide space from end of tick before or after writing label.
      if (y_ticks_.label_rotation_ == horizontal)
      {  // Just shift up to center value digits on tick.
        if (y_ticks_.major_value_labels_side_ < 0)
        { // labels to left, so start a little to left of x_left.
          y += y_ticks_value_label_style_.font_size() * 0.2;
          x = x_left - y_ticks_value_label_style_.font_size() * 0.5;
          alignment = align_style::right_align;
        }
        else if(y_ticks_.major_value_labels_side_ > 0)
        { // labels to right, so start a little to right of x_right.
         y += y_ticks_value_label_style_.font_size() * 0.2;
         x = x_right + y_ticks_value_label_style_.font_size() * 0.5;
          alignment = align_style::left_align;
        }
      }
      else if (y_ticks_.label_rotation_ == upsidedown)
       {  // Just shift up to center value digits on tick.
        if (y_ticks_.major_value_labels_side_ < 0)
        { // labels to left, so start a little to left of x_left.
          y -= y_ticks_value_label_style_.font_size() * 0.1;
          x = x_left - y_ticks_value_label_style_.font_size() * 0.5;
          alignment = align_style::left_align;
        }
        else if(y_ticks_.major_value_labels_side_ > 0)
        { // labels to right, so start a little to right of x_right.
          y -= y_ticks_value_label_style_.font_size() * 0.1;
          x = x_right + y_ticks_value_label_style_.font_size() * 0.5;
          alignment = align_style::right_align;
        }
      }
      else if (y_ticks_.label_rotation_ == uphill)
      { // Assume some 45 slope, so need about sqrt(2) less space.
        if (y_ticks_.major_value_labels_side_ < 0)
        { // labels to left, so start a little to left of x_left.
          y -= y_ticks_value_label_style_.font_size() * 0.2;
          x = x_left - y_ticks_value_label_style_.font_size() * 0.2;
          // Seems to need a bit more space for right than left if rotated.
          alignment = align_style::right_align;
        }
        else if(y_ticks_.major_value_labels_side_ > 0)
        { // labels to right, so start a little to right of x_right.
          y += y_ticks_value_label_style_.font_size() * 0.2;
          x = x_right + y_ticks_value_label_style_.font_size() * 0.7;
          alignment = align_style::left_align;
        }
      }
      else if (y_ticks_.label_rotation_ == downhill)
      { // Assume some 45 slope, so need about sqrt(2) less space.
        if (y_ticks_.major_value_labels_side_ < 0)
        { // labels to left, so start a little to left of x_left.
          y += y_ticks_value_label_style_.font_size() * 0.3;
          x = x_left - y_ticks_value_label_style_.font_size() * 0.7;
          // Seems to need a bit more space for right than left if rotated.
          alignment = align_style::right_align;
        }
        else if(y_ticks_.major_value_labels_side_ > 0)
        { // labels to right, so start a little to right of x_right.
          y -= y_ticks_value_label_style_.font_size() * 0.3;
          x = x_right + y_ticks_value_label_style_.font_size() * 0.1;
          alignment = align_style::left_align;
        }
      }
      else if (y_ticks_.label_rotation_ == upward)
      { // Tick value label straight up vertically on Y-axis.
        y -= y_ticks_value_label_style_.font_size() * 0.1;
        if (y_ticks_.major_value_labels_side_ < 0)
        { // labels to left, so start a little to left of x_left.
          x = x_left - y_ticks_value_label_style_.font_size() * 0.7;
          // Seems to need a bit more space for right than left if rotated.
          alignment = align_style::center_align;
        }
        else if(y_ticks_.major_value_labels_side_ > 0)
        { // labels to right, so start a little to right of x_right.
          x = x_right + y_ticks_value_label_style_.font_size() * 1.5;
          alignment = align_style::center_align;
        }
      }
      else if (y_ticks_.label_rotation_ == downward)
      { // Tick value label straight down vertically on Y-axis.
        y -= y_ticks_value_label_style_.font_size() * 0.1;
        if (y_ticks_.major_value_labels_side_ < 0)
        { // labels to left, so start a little to left of x_left.
          x = x_left - y_ticks_value_label_style_.font_size() * 1.2;
          // Seems to need a bit more space for right than left if rotated.
          alignment = align_style::center_align;
        }
        else if(y_ticks_.major_value_labels_side_ > 0)
        { // labels to right, so start a little to right of x_right.
          x = x_right + y_ticks_value_label_style_.font_size() * 0.7;
          alignment = align_style::center_align;
        }
      }
      else
      { // Others not yet implemented.
        return; // Without any value label.
     } // All rotations.
    if (x <= 0)
    { // Sanity checks on svg coordinate.
      throw std::runtime_error("Y-tick X value wrong!");
    }
    if (y <= 0)
    { // Sanity checks on svg coordinate.
      throw std::runtime_error("Y-tick Y value wrong!");
    }
    if(y_ticks_.ticks_on_window_or_on_axis_ != 0)
      { // External to plot window style left or right.
        // Always want all values including "0", if labeling external to plot window.
        // y_ticks_.ticks_on_window_or_on_axis_ == true != 0
        image_.gs(boxplot::VALUE_LABELS).text(
          x,
          y,
          label.str(), y_ticks_value_label_style_, alignment, y_ticks_.label_rotation_);
      }
      else
      { // ! y_ticks_.y_ticks_on_plot_window_ == 0 'Internal' - value labels either side of vertical Y-axis.
        if ((value != 0) && y_axis_.axis_line_on_)
        { // Avoid a zero ON the Y-axis if it would be cut through by any horizontal X-axis line.
          image_.gs(boxplot::VALUE_LABELS).text(
            x,
            y,
            label.str(),
            y_ticks_value_label_style_,
            alignment,
            y_ticks_.label_rotation_);
        }
      } // either on plot window or 'on axis'.
    } // want value label on tick
  } // draw_y_major_tick

  void draw_y_minor_tick(double value, path_element& tick_path, path_element& grid_path)
  { //! Draw a Y-axis minor tick and optional grid.
    double x_left(0.); // Start on vertical Y axis line.
    double x_right(image_.y_size()); // right edge of image.
    double y(value); // Tick position and value label,
    transform_y(y); // convert to svg.

    if(y_ticks_.minor_grid_on_)
    { // Draw the minor grid, if wanted.
      if(!plot_window_on_)
      {
        if(x_axis_.label_on_)
        {
          x_left += y_ticks_value_label_style_.font_size() * text_margin_;
          x_right -= y_ticks_value_label_style_.font_size() * text_margin_;
        }
      }
      else
      { // plot_window_on_
        x_left = plot_left_ + plot_window_border_.border_width_;
        x_right = plot_right_ - plot_window_border_.border_width_; // Ensure just *inside* window?
      }
      if((y >= plot_top_) && (y <= plot_bottom_) && (x_left >= plot_left_) && (x_right <= plot_right_) )
      { // Make sure that we are drawing inside the allowed plot window.
        // Note comparisons are 'upside-down' - y is increasing downwards!
        grid_path.M(x_left, y).L(x_right, y); // Draw grid line.
      }
      else
      {
        // Just ignore outside plot window
      }
    } // y_minor_grid

    // Draw y minor ticks.
    if(y_ticks_.ticks_on_window_or_on_axis_ < 0)
    { // Put y minor ticks on the plot window border left.
      x_left = plot_left_;
      x_right = plot_left_;
    }
    else if (y_ticks_.ticks_on_window_or_on_axis_ > 0)
    { // Put y minor ticks on the plot window border left.
      x_left = plot_right_;
      x_right = plot_right_;
    }
    else
    { // Internal style, y_ticks_.ticks_on_window_or_on_axis_ == 0
      x_left = y_axis_.axis_; // On the Y-axis line itself.
      x_right = y_axis_.axis_;
    }
    if(y_ticks_.left_ticks_on_)
    {
      x_left -= y_ticks_.minor_tick_length_;
    }
    if(y_ticks_.right_ticks_on_)
    {
      x_right += y_ticks_.minor_tick_length_;
    }
    //if((x_left >= plot_left_) && (x_right <= plot_right_) && (y <= plot_bottom_) && (y >= plot_top_))
    // but can never be inside if left tick!
    if((y <= plot_bottom_) && (y >= plot_top_))
    { // Make sure that we are drawing inside of the allowed plot window.
      tick_path.M(x_left, y).L(x_right, y); // Draw the tick.
    }
    else
    {// Do nothing?  warn?
#ifdef BOOST_SVG_DIAGNOSTICS
      std::cout << "y minor tick at " << y << ", from  " << x_left << " to " << x_right << ", is OUTside window bottom " << plot_bottom_ << " to top " << plot_top_ << std::endl;
#endif
    }
  } // void draw_y_minor_tick

  void draw_x_axis_label()
  { //! Draw an axis label (and optional units) for example "length (km)".
    // X-label color is set in constructor thus:
    // image_.gs(detail::PLOT_X_LABEL).style().stroke_color(black);
    // and changed using x_label_color(color);

    std::string label = x_label_info_.text(); // x_axis_ label, and optional units.
    if (x_axis_.label_units_on_ && (x_units_info_.text() != ""))
    { // Append the units, if any, user providing brackets () if required.
      label += x_units_info_.text();
    }

    double y = plot_bottom_;
    y += x_ticks_.value_label_style_.font_size() * 2.; // Shift down to suit ticks?
    if (x_ticks_.ticks_on_window_or_on_axis_ < 0) // bottom == -1
    { // Ticks & value labels below X-axis.
      if (x_ticks_.major_value_labels_side_ < 0) // - is bottom.
      { // Shift down to allow for any value labels.
        y += x_ticks_.label_max_space_;
      }
      if (x_ticks_.down_ticks_on_)
      { // Shift down for biggest of any ticks.
        y += (std::max)(x_ticks_.minor_tick_length_, x_ticks_.major_tick_length_);
      }
    }

    image_.gs(boxplot::X_LABEL).push_back(new text_element(
      ( // x position relative to the x-axis which is middle of plot window.
      plot_right_ + plot_left_) / 2,  // x coordinate - middle.
      y, // Down from plot window.
      label,
      x_label_info_.textstyle(),
      align_style::center_align, horizontal)
      );
  } // void draw_x_axis_label()

  void draw_y_axis_label()
  { //! Draw vertical y_axis label, and optional y units.
    // Y-label color is set in constructor thus:
    // image_.gs(boxplot::Y_LABEL).style().fill_color(black);
    // and changed using y_label_color(color);

    std::string label = y_label_info_.text();
    if (y_axis_.label_units_on_ && (y_units_info_.text() != ""))
    { // Append the units, user must provide any enclosing ()s, if wanted.
      label += y_units_info_.text() ;
    }

    double x = plot_left_;
    x -= y_axis_label_style_.font_size() * 0.7; // Shift left to suit.
    if (y_ticks_.ticks_on_window_or_on_axis_ < 0)
    { // Ticks & value labels to left of Y-axis.
      if (y_ticks_.down_ticks_on_)
      { // Shift left for biggest of any ticks.
        x -= (std::max)(y_ticks_.minor_tick_length_, y_ticks_.major_tick_length_);
      }
      if (y_ticks_.major_value_labels_side_ < 0)
      { // Shift left to allow for any value labels.
        x -= y_ticks_.label_max_space_;
      }
    }

    image_.gs(boxplot::Y_LABEL).push_back(new
      text_element(x,
      (plot_bottom_ + plot_top_) / 2., // center on the plot window.
      label, // "Y-Axis" for example.
      y_axis_label_style_,
      align_style::center_align, // One might want it to left or right_align?
      upward)); // Y label must be drawn vertically.

  } // draw_y_axis_label

  void draw_box(double q1, double q3, // Quartiles.
  double x, double width,
  const svg_style& box_styl)
  { //! Draw the box border and any fill color.
    g_element& g_ptr = image_.gs(boxplot::MEDIAN).add_g_element();

    g_ptr.style().stroke_color(box_styl.stroke_color())
      .stroke_width(box_styl.stroke_width())
      .fill_color(box_styl.fill_color());
    transform_y(q1);
    transform_y(q3);
    double half_width = width/2;
    g_ptr.rect(x - half_width, q3, width, q1 - q3);
    g_ptr.clip_id(plot_window_clip_); // Clip elements.
  } //  void draw_box

  void draw_median(double median, double x_offset, double box_width,
    const svg_style& median_style, const value_style& values_style)
  { //! Draw the median of the data series line within the box,
    //! and optionally the median value.
    double median_y = median;
    transform_y(median_y); // SVG coordinate of median line.
    g_element& g_ptr = image_.gs(boxplot::MEDIAN).add_g_element();
    g_ptr.style().stroke_color(median_style.stroke_color())
      .stroke_width(median_style.stroke_width());

    double half_width = box_width / 2;
    g_ptr.line(x_offset - half_width, median_y, x_offset + half_width, median_y);
    //  void draw_plot_point_value(double x, double y, g_element& g_ptr, value_style& val_style, plot_point_style& point_style, double value)
    if (median_values_on_)
    { // Show the value of the median too.
      g_element& g_ptr_median = image_.gs(boxplot::DATA_VALUE_LABELS).add_g_element();
      draw_plot_point_value(x_offset + half_width, median_y, g_ptr_median, const_cast<value_style&>(values_style), mild_outlier_, median);
      // Share the mild_outlier point style?
      g_ptr_median.clip_id(plot_window_clip_);
      // TODO this doesn't have the desired effect???
    }
    // Clip elements.
    g_ptr.clip_id(plot_window_clip_);
  } // void draw_median

  void draw_whiskers(double min, double max, double length, double x,
    const svg_style& min_whisker, const svg_style& max_whisker,
    const svg_style& axis_whisker)
  { //! Draw the whiskers for the boxplot.
    // Set up document structure for whiskers:
    g_element& g_whisk_ptr = image_.gs(boxplot::WHISKER).add_g_element();

    // Set colors for min and max whiskers.
    g_whisk_ptr.add_g_element().style()
      .stroke_color(min_whisker.stroke_color())
      .fill_color(min_whisker.fill_color())
      .stroke_width(min_whisker.stroke_width());

    g_whisk_ptr.add_g_element().style()
      .stroke_color(max_whisker.stroke_color())
      .fill_color(max_whisker.fill_color())
      .stroke_width(max_whisker.stroke_width());

    // Set axis structure and colors.
    g_element& g_axis_ptr = image_.gs(boxplot::BOX_AXIS).add_g_element();

    g_axis_ptr.style()
      .stroke_color(axis_whisker.stroke_color())
      .fill_color(axis_whisker.fill_color())
      .stroke_width(axis_whisker.stroke_width());

    transform_y(min);
    transform_y(max);

    double half_length = length / 2.;
    g_whisk_ptr.gs(0).line(x - half_length, min, x + half_length, min);
    g_whisk_ptr.gs(1).line(x - half_length, max, x + half_length, max);
    g_axis_ptr.line(x, min, x, max);

    // Clip elements.
    g_axis_ptr.clip_id(plot_window_clip_);
    g_whisk_ptr.clip_id(plot_window_clip_);
  } // void draw_whiskers()

  void draw_outliers(double x, const std::vector<double>& outliers,
    const std::vector<double>& extreme_outliers,
    const plot_point_style& mild_style, const plot_point_style& extreme_style,
    const value_style& values_style)
  { //! Draw any outliers, both mild and extreme.
    // Draw marker points for any mild and/or extreme outliers.
    g_element& g_mild_ptr = image_.gs(boxplot::MILD_OUTLIERS).add_g_element();
    g_mild_ptr.style().fill_color(mild_style.fill_color_)
      .stroke_color(mild_style.stroke_color_);

//  void draw_plot_point_value(double x, double y, g_element& g_ptr, value_style& sty, double value)
//  void draw_plot_point(double x, double y, g_element& g_ptr,  plot_point_style& sty)
//  using boost::svg::detail::axis_plot_frame<Derived>::draw_plot_point in axis_plot_frame.hpp.

    std::vector<double>::const_iterator i;
    double y;
    for(i = outliers.begin(); i != outliers.end(); ++i)
    { // Mild outliers.
      double value = *i;  // Save in case want to display value.
      if ((value <= y_axis_.max_) && (value >= y_axis_.min_))
      { // Inside plot window so want to show.
        y = value;
        transform_y(y); // to SVG.
        draw_plot_point(x, y, g_mild_ptr, const_cast<plot_point_style&>(mild_style), unc<false>(0), unc<false>(0)); // Kludge!
        if (outlier_values_on_)
        { // Show the value of the data point too.
          draw_plot_point_value(x, y, image_.gs(boxplot::DATA_VALUE_LABELS).add_g_element(), const_cast<value_style&>(values_style), mild_outlier_, value);
        }
        // Label the (outlier) data point with a name here?
      } // In window OK.
    }
    g_element& g_ext_ptr = image_.gs(boxplot::EXTREME_OUTLIERS).add_g_element();
    g_ext_ptr.style().fill_color(extreme_style.fill_color_)
      .stroke_color(extreme_style.stroke_color_);

    for(i = extreme_outliers.begin(); i != extreme_outliers.end(); ++i)
    { // Extreme outliers.
      double value = *i; // Save in case want to display value.
      if ((value <= y_axis_.max_) && (value >= y_axis_.min_))
      { // Inside plot window so want to show.
        y = value;
        transform_y(y); // to SVG.
        draw_plot_point(x, y, g_ext_ptr, const_cast<plot_point_style&>(extreme_style), 0, 0); // Kludge!
        if (extreme_outlier_values_on_) // This isn't a series setting - but might be.
        { // Show the value of the data point too.
          draw_plot_point_value(x, y, image_.gs(boxplot::DATA_VALUE_LABELS).add_g_element(), const_cast<value_style&>(values_style), ext_outlier_, value);
        }
      } // in window.
    }

    // Clip elements to prevent any ouliers outside the plot window being shown.
    // But actually it may chop them in half!
    g_mild_ptr.clip_id(plot_window_clip_);
    g_ext_ptr.clip_id(plot_window_clip_);
  } // void draw_outliers

  void draw_boxplot(svg_boxplot_series& a_series, double x_offset)
  { //! Draw a whole boxplot, box, median line, axis whiskers, and outliers.

    // const here causes trouble
    // Need to calculate quartiles here to permit custom plot quartile definition.
    a_series.calculate_quantiles();

    draw_whiskers(a_series.whisker_min_, a_series.whisker_max_,
      a_series.whisker_length_, x_offset,
      a_series.min_whisker_style_, a_series.max_whisker_style_,
      a_series.axis_style_);

    draw_box(a_series.q1_, a_series.q3_, x_offset, a_series.box_width_,
      a_series.box_style_);

    draw_median(a_series.median_, x_offset,
      a_series.box_width_ - a_series.box_style_.stroke_width(),
      a_series.median_style_, a_series.values_style_);

    draw_outliers(x_offset, a_series.outliers_, a_series.extreme_outliers_,
      a_series.mild_outlier_, a_series.ext_outlier_, a_series.values_style_);
  } // void draw_boxplot

  void update_image()
  { //! Update the entire SVG image.
    clear_all();

    // Draw image background & border, if any.
    image_.gs(boxplot::PLOT_BACKGROUND).push_back(
      new rect_element(0, 0, image_.x_size(), image_.y_size()) );

    draw_title();
    calculate_plot_window();

    // Define the clip path for the plot window.
    // We don't want to allow too much overlap of the plot window lines,
    // so allow for the border.

    double margin = plot_window_border_.border_width_ * 5.; // Or more?
    // This controls how much points can overlap the plot window.
    // Might also make margin relative to data value font size and/or data marker size?
    image_.clip_path(rect_element(plot_left_ - margin, // margin left
      plot_top_ - margin, // margin above top
      plot_right_ - plot_left_ + margin, // increased lengths for rect (not x, y)
      plot_bottom_ - plot_top_ + margin),
      plot_window_clip_); // clip id

    draw_x_axis(); // Must do X-axis first.
    draw_y_axis();

    if(x_axis_.label_on_)
    {
      draw_x_axis_label();
    }
    if(y_axis_.label_on_)
    {
      draw_y_axis_label();
    }
    for(unsigned int i=0; i < series.size(); ++i)
    { // Draw box'n'whiskers for each data series.
      draw_boxplot(series[i],
        plot_left_ + (plot_right_ - plot_left_) * ((double)(i + 1)) / (double)(series.size() + 1));
      // Spaced evenly across the plot window width.
      // Actually this leaves rather lot of space at the outside compared to spacing in middle?
    }
  } // void update_image()

  //! \endcond

  // Seems not to be used?
  //svg& get_svg()
  //{
  //  update_image();
  //  return image_;
  //}

  // svg_boxplot& load_stylesheet(const std::string& file);  // Removed pending reimplementation of stylesheets.

  // Declarations of user svg_boxplot functions.

  svg_boxplot& write(const std::string& file); //! Write SVG boxplot to file.
  svg_boxplot& write(std::ostream& s_out); //! Write SVG boxplot to ostream.
  svg_boxplot& title_on(bool cmd); //! true if to include title in plot.
  svg_boxplot& x_label_on(bool cmd);
  svg_boxplot& median_values_on(bool cmd);
  bool median_values_on();
  svg_boxplot& outlier_values_on(bool cmd);
  bool outlier_values_on();
  svg_boxplot& extreme_outlier_values_on(bool cmd);
  bool extreme_outlier_values_on();
  svg_boxplot& y_label_on(bool cmd);
  svg_boxplot& y_major_labels_on(int cmd);
  svg_boxplot& x_major_labels_on(int cmd);
  svg_boxplot& y_major_tick_color(const svg_color& col);
  svg_boxplot& x_tick_color(const svg_color& col);
  svg_boxplot& y_minor_tick_color(const svg_color& col);
  svg_boxplot& title_color(const svg_color& col);
  svg_boxplot& background_color(const svg_color& col);
  svg_boxplot& background_border_color(const svg_color& col);
  svg_boxplot& plot_background_color(const svg_color& col);
  svg_boxplot& plot_border_color(const svg_color& col);
  svg_boxplot& y_range(double min_y, double max_y);
  std::pair<double, double> y_range();
  svg_boxplot& y_label(const std::string& str);
  svg_boxplot& size(unsigned int x, unsigned int y);
  svg_boxplot& y_label_font_size(unsigned int size);
  svg_boxplot& y_label_color(const svg_color& col);
  svg_boxplot& title(const std::string& str);
  svg_boxplot& title_size(unsigned int size);
  svg_boxplot& x_label(const std::string& str);
  svg_boxplot& x_label_size(unsigned int size);
  svg_boxplot& x_label_color(const svg_color& col);
  svg_boxplot& y_major_interval(double inter);
  svg_boxplot& x_tick_length(unsigned int length);
  svg_boxplot& y_major_tick_length(unsigned int length);

  svg_boxplot& y_minor_tick_length(unsigned int length);
  svg_boxplot& y_num_minor_ticks(unsigned int num);
  svg_boxplot& x_tick_width(unsigned int width);
  svg_boxplot& y_major_tick_width(unsigned int width);
  svg_boxplot& y_minor_tick_width(unsigned int width);
  unsigned int x_size();
  unsigned int y_size();
  std::string title(); // title assigned to boxplot.
  bool x_label_on();
  int x_major_labels();
  // get color information
  svg_color title_color(); // Color of title text.
  svg_color background_color(); // Fill color of whole image background.
  svg_color background_border_color(); // Color of image border.
  svg_color plot_background_color();
  svg_color plot_border_color();
  svg_color x_label_color();
  svg_color x_tick_color();
  double x_tick_length();
  double x_major_tick_width();
  std::string x_label_text();
  std::string y_label_text();

  // svg_boxplot Member Functions to control all box and whisker settings.
  // (Note there are an identically names set of functions for svg_boxplot_series).

  svg_boxplot& whisker_length(double width); // Set length of whiskers.
  double whisker_length(); // \return length of whiskers.
  svg_boxplot& box_width(double width); // Width of the actual box (not the border).
  double box_width(); // \return Width of the box (not the border).
  svg_boxplot& x_axis_position(int pos); //<! Position of the horizontal X-axis line (on the border).
  double x_axis_position(); // Position of the horizontal X-axis line (on the border).
  svg_boxplot& y_axis_position(int pos); // Position of the vertical Y-axis line (on the border).
  double y_axis_position(); // Position of the vertical Y-axis line (on the border).
  svg_boxplot& box_fill(const svg_color& color); // Color of box fill, not border.
  svg_color box_fill(); // Color of box fill, not border.
  svg_boxplot& box_border(const svg_color& color); // Color of border (not fill) to box.
  svg_color box_border(); // Color of border (not fill) to box.
  svg_boxplot& median_color(const svg_color& color); // Color of median line in box.
  svg_color median_color(); // Color of median line in box.
  svg_boxplot& median_width(double l); // Width of median line in box.
  double median_width(); //  Width of median line in box.
  svg_boxplot& axis_color(const svg_color& color); // Set color of vertical whisker axis line in box.
  svg_color axis_color(); // \return Color of vertical whisker axis line in box.
  svg_boxplot& axis_width(double l); //< Width of vertical whisker axis line in box.
  double axis_width(); //  Width of vertical whisker axis line in box.

  svg_boxplot& outlier_style(plot_point_style& os); // Set style of points used to mark outliers.
  plot_point_style& outlier_style(); // \return style of points used to mark outliers.
  svg_boxplot& outlier_color(const svg_color& color); // Set Color of outlier marker.
  svg_color outlier_color(); // \return Color of outlier marker.
  svg_boxplot& outlier_fill(const svg_color& color); // Set Fill color of outlier marker.
  svg_color outlier_fill(); // \return Fill color of outlier marker.
  svg_boxplot& extreme_outlier_color(const svg_color& color); // Color of extreme outlier marker.
  svg_color extreme_outlier_color(); // \return  Color of extreme outlier marker.
  svg_boxplot& extreme_outlier_fill(const svg_color& color); // Fill color of extreme outlier marker.
  svg_color extreme_outlier_fill(); // \return  Fill color of extreme outlier marker.

  svg_boxplot& outlier_shape(point_shape shape); // Shape of outlier marker.
  point_shape outlier_shape(); // \return  Shape of outlier marker.

  svg_boxplot& outlier_size(int size); // Set size of outlier marker.
  int outlier_size(); // Size of outlier marker.

  svg_boxplot& extreme_outlier_shape(point_shape shape); // Shape of extreme outlier marker.
  point_shape extreme_outlier_shape(); // \return  Shape of extreme outlier marker.

  svg_boxplot& extreme_outlier_size(int size); // Size of extreme outlier marker.
  int extreme_outlier_size(); // \return  Size of extreme outlier marker.

  svg_boxplot& quartile_definition(int def); // H&F quartile definition.
  int quartile_definition(); // \return  H&F quartile definition.

  bool y_autoscale(); // \return @c true if to use @c y_autoscaled values.
  svg_boxplot& y_autoscale(bool b); // \return Set @c true if to use @c y_autoscaled values.

  svg_boxplot& y_autoscale(double min, double max); // Autoscale using two doubles.

  svg_boxplot& y_autoscale(std::pair<double, double> p); // Autoscale using min and max pair of doubles.

  /*
    Autoscale using iterators into container (allowing only a part of container values to be used).
    \tparam T an STL container: @c array, @c vector ...
  */
  template <class T>
  svg_boxplot& y_autoscale(const T& begin, const T& end);
  // explicit svg_boxplot::y_autoscale causes C2442 here, but omitting svg_boxplot:: is OK????

  /*
    Autoscale using @b whole container.
    \tparam T an STL container: @c array, @c vector ...
  */
  template <class T>
  svg_boxplot& y_autoscale(const T& container); // Autoscale using whole container.

  // Plot member functions to add a Data Series Boxplot.

  // Use overloaded functions to provide access to boxplot's non-static members values.
  // Version with NO default values.

  /*! \brief Add a data series (the whole container) to boxplot.

  \tparam T STL Container type holding data series.

  \param container STL Container holding data series values to boxplot (must be convertible to double).
  \param title Title of data series.
  \param bw Box width.
  \param bs Box_style
  \param ms Median marker style.
  \param as Axis style.
  \param wl Whisker length.
  \param minws Min whisker style.
  \param maxws Max whisker style.
  \param os Mild outlier style.
  \param extos Extreme outlier style.
  \param q_def Quartile definition H&F \#.
  \param vs Style for data values.
  \param ss Series style - for series title.

  @b Example:

  \code
  myboxplot.plot(myvalues);
  \endcode

  */
  template <class T>
  svg_boxplot_series& plot(
    const T& container, // STL Container holding data series.
    const std::string& title, // Title of data series.
    double bw, // Box width.
    svg_style bs, // box_style.
    svg_style ms, // median marker style.
    svg_style as, // axis style.
    double wl, // whisker length.
    svg_style minws, // min whisker style.
    svg_style maxws, // max whisker style.
    plot_point_style os, // mild outlier style.
    plot_point_style extos, // extreme outlier style.
    int q_def, // Quartile definition H&F \#.
    value_style vs,  // style for data values.
    text_style ss // series style - for series title.
    )
  {
    series.push_back(
      svg_boxplot_series(
        boost::make_transform_iterator(container.begin(), detail::double_1d_convert()),
        boost::make_transform_iterator(container.end(), detail::double_1d_convert()),
        title, bw, bs, ms, as,
        wl, minws, maxws,
        os, extos, q_def, vs, ss
        )
        // Get all styles etc from parent boxplot.
      );
      return series[series.size() - 1]; // Number of data series added so far.
  } // svg_boxplot_series& plot(const T& container, const std::string& title )

  /*! Add a container of data series to boxplot.\n
    Plot version copying box'n'whiskers parameters from parent boxplot.
    \tparam T data series value type (must be convertible to @c double).
    \param container A container of data series to boxplot.
    \param title Title for boxplot. (Warning given if the default "" is used.)
    \return Reference to data series just added.
  */
  template <class T> // \tparam T data series value type (must be convertible to double).
  svg_boxplot_series& plot(const T& container, // Add a container of data series to boxplot.
    const std::string& title = "") // Warning given if this default is used.
  { // plot version copying box'n'whiskers parameters from parent boxplot.
    if (title.size() == 0)
    {
      std::cout << "Data series has no title!" << std::endl;
    }
    series.push_back( // Add a new data series for a boxplot.
      svg_boxplot_series(
        boost::make_transform_iterator(container.begin(), detail::double_1d_convert()),
        boost::make_transform_iterator(container.end(), detail::double_1d_convert()),
        title, box_width_, box_style_, median_style_, axis_style_,
        whisker_length_, min_whisker_style_, max_whisker_style_,
        mild_outlier_, ext_outlier_, quartile_definition_, values_style_, series_style_
        )
        // Get all styles etc from parent boxplot.
      );
      return series[series.size() - 1]; // Reference to data series just added.
  } // svg_boxplot_series& plot(const T& container, const std::string& title)

}; // class svg_boxplot

// Definitions to match declarations above for separate file.

  //svg_boxplot& svg_boxplot::load_stylesheet(const std::string& file)
  //{ // removed until new implementation supports stylesheets.
  //  image.load_stylesheet(file);
  //  return *this;
  //}

  svg_boxplot& svg_boxplot::write(const std::string& file)
  { //! Write SVG image to file.
    std::string filename(file); // Copy to avoid problems with const if need to append.
    if (filename.find(".svg") == std::string::npos)
    { // No file type suffix, so provide the default .svg.
      filename.append(".svg");
    }
    std::ofstream fout(filename.c_str());
    if(fout.fail())
    {
      throw std::runtime_error("Unable to open "+ filename);
    }

    image_.image_filename(filename);
    // Note filename for optional output as comment in the .svg file.
    svg_boxplot::write(fout); // Use the ostream version.
    return *this;
  } // svg_boxplot& write(const std::string& file)

  svg_boxplot& svg_boxplot::write(std::ostream& s_out)
  { //! Write SVG image to ostream.
    // This ostream version used by filename version.
    update_image();
    image_.write(s_out);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::title_on(bool cmd)
  { //! Set true to show whole boxplot title.
    title_on_ = cmd;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::x_label_on(bool cmd)
  { //! Set true if X axis name or label, for example: "length of thing".
      x_axis_.label_on_ = cmd;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_label_on(bool cmd)
  { //! Set true if Y axis name or label, for example: "width of thing".
      y_axis_.label_on_ = cmd;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_major_labels_on(int cmd)
  { //! Set direction of Y major labels.
    //! < 0 means to left (default), 0 (false) means none, > 0 means to right.
    y_ticks_.major_value_labels_side_ = cmd;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::x_major_labels_on(int cmd)
  { /*! Set direction of X major labels.\n
        0 means to down (default), 0 (false) means none, > 0 means to top.
    */
    x_ticks_.major_value_labels_side_ = cmd;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::median_values_on(bool cmd)
  { //! Set @c true to show median value(s).
    median_values_on_ = cmd;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::outlier_values_on(bool cmd)
  { //! Set @c true to show mild outlier values.
    outlier_values_on_ = cmd;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }
  svg_boxplot& svg_boxplot::extreme_outlier_values_on(bool cmd)
  {//! Set @c true to show extreme outlier values.
    extreme_outlier_values_on_ = cmd;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  bool svg_boxplot::median_values_on()
  { //! \return @c true if to show median value(s).
    return outlier_values_on_;
  }

  bool svg_boxplot::outlier_values_on()
  { //! \return @c true if to show mild outlier value(s).
    return outlier_values_on_;
  }

  bool svg_boxplot::extreme_outlier_values_on()
  { //! \return @c true if to show extreme outlier value(s).
    return extreme_outlier_values_on_;
  }

  svg_boxplot& svg_boxplot::y_major_tick_color(const svg_color& col)
  { //! Set Y major ticks color.
    image_.gs(boxplot::Y_MAJOR_TICKS).style().stroke_color(col);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::x_tick_color(const svg_color& col)
  { //! \return Y major ticks color.
    image_.gs(boxplot::X_TICKS).style().stroke_color(col);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_minor_tick_color(const svg_color& col)
  {  //! Set Y minor ticks color.
    image_.gs(detail::PLOT_Y_MINOR_TICKS).style().stroke_color(col);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::title_color(const svg_color& col)
  { //! Set boxplot title color.
    image_.gs(boxplot::PLOT_TITLE).style().stroke_color(col);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::background_color(const svg_color& col)
  { //! Set SVG image background color.
    // "imageBackground"
    image_.gs(boxplot::PLOT_BACKGROUND).style().fill_color(col);
    return *this;
  }

  svg_boxplot& svg_boxplot::background_border_color(const svg_color& col)
  { //! Set SVG image background border color.
    image_.gs(boxplot::PLOT_BACKGROUND).style().stroke_color(col);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::plot_background_color(const svg_color& col)
  { //! Set plot window background color.
    // Plot Window "plotBackground"
    image_.gs(boxplot::PLOT_WINDOW_BACKGROUND).style().fill_color(col);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::plot_border_color(const svg_color& col)
  { //! Set plot window border color.
    // Plot window "plotBackground"
    image_.gs(boxplot::PLOT_WINDOW_BACKGROUND).style().stroke_color(col);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_range(double min_y, double max_y)
  { //! Set range of Y values for Y axis (and do not use autoscale).
    if (!boost::math::isfinite(min_y))
    {
      throw std::runtime_error("Y range: min not finite!");
    }
    if (!boost::math::isfinite(max_y))
    {
      throw std::runtime_error("Y range: max not finite!");
    }
    if(max_y <= min_y)
    { // max <= min.
      throw std::runtime_error("Y range: y max <= y min!");
    }
    if((max_y - min_y) < std::numeric_limits<double>::epsilon() * 1000)
    { // Range too small to display.
      throw std::runtime_error("Y range too small!" );
    }
    y_axis_.min_ = min_y;
    y_axis_.max_ = max_y;
    y_autoscale_ = false;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  } // svg_boxplot& y_range(double y1, double y2)

  std::pair<double, double> svg_boxplot::y_range()
  { //! Set y_range using a pair of doubles (and do not use autoscale).
    std::pair<double, double> r;
    r.first = y_axis_.min_;
    r.second = y_axis_.max_;
    y_autoscale_ = false;
    return r;
  } //   std::pair<double, double> svg_boxplot::y_range()

  svg_boxplot& svg_boxplot::y_label(const std::string& str)
  { //! Set Y axis label.
    y_label_info_.text(str);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::size(unsigned int x, unsigned int y)
  { //! Set SVG image width (x) and height (y).
    image_.size(x, y);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_label_font_size(unsigned int size)
  { //! Set font size for Y axis label.
     y_axis_label_style_.font_size(size);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_label_color(const svg_color& col)
  { //! Set font color for Y axis label.
    image_.gs(boxplot::Y_LABEL).style().fill_color(col);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::title(const std::string& str)
  { //! Set title text for plot.
    title_info_.text(str);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }
  svg_boxplot& svg_boxplot::title_size(unsigned int size)
  { //! Set font size for title text.
    y_label_info_.textstyle().font_size(size);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::x_axis_position(int pos)
  {  /*! Set position of the horizontal X-axis line (on the border).\n
      But controlled by the intersection with Y-axis,
      so this only changes the default position from bottom to top,
      but will be changed if X-axis intersects the Y-axis
      (that is, if Y-axis includes zero).
     */
     x_axis_position_ = pos; // top or bottom
    return *this;  //! \return Reference to svg_boxplot to make chainable.
  }

  double svg_boxplot::x_axis_position()
  {  //! \return position of the horizontal X-axis line (on the border).
    return x_axis_position_; // top or bottom
  }

  svg_boxplot& svg_boxplot::y_axis_position(int pos)
  { /*! Set position of the vertical Y-axis line (on the border).
      But controlled by the intersection with X-axis,
      so this only changes the default position from bottom to top,
      but will be changed if X-axis intersects the X-axis
      (that is if X-axis includes zero).
    */
     y_axis_position_ = pos; // left or right
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  double svg_boxplot::y_axis_position()
  { //! \return Position of the vertical Y-axis line (on the border).
    return y_axis_position_; // left or right
  }

  svg_boxplot& svg_boxplot::x_label(const std::string& str)
  { //! Set label for X axis (can also append optional units).
    //! \see x_label_units_on and \see x_label_units
    x_label_info_.text(str);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::x_label_size(unsigned int size)
  { //! Set the font size for the X axis label.
    x_label_info_.textstyle().font_size(size);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::x_label_color(const svg_color& col)
  { //! Set the font color for the X axis label.
    image_.gs(boxplot::X_LABEL).style().fill_color(col);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_major_interval(double inter)
  { //! Set the interval between major ticks on the Y axis.
    y_ticks_.major_interval_ = inter;
    return *this;
  }

  svg_boxplot& svg_boxplot::x_tick_length(unsigned int length)
  { //! Set the length of major ticks on the X axis.
    x_ticks_.major_tick_length_ = length;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_major_tick_length(unsigned int length)
  { //! Set the length of major ticks on the Y axis.
    y_ticks_.major_tick_length_ = length;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_minor_tick_length(unsigned int length)
  { //! Set the length of minor ticks on the Y axis.
    y_ticks_.minor_tick_length_ = length;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_num_minor_ticks(unsigned int num)
  { //! Set the number of minor ticks between major ticks on the Y axis.
    //! For example, 1 gives alternating major and minor ticks,\n
    //! 4 is more useful giving major ticks at 1, 5, 10, 15...\n
    //! 9 gives major ticks at 10, 20, 30...
    y_ticks_.num_minor_ticks_ = num;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::x_tick_width(unsigned int width)
  { //! Set the width of major ticks on the X axis.
    image_.gs(boxplot::X_TICKS).style().stroke_width(width);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_major_tick_width(unsigned int width)
  { //! Set the width of major ticks on the Y axis.
    image_.gs(boxplot::Y_MAJOR_TICKS).style().stroke_width(width);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_boxplot& svg_boxplot::y_minor_tick_width(unsigned int width)
  { //! Set the width of minor ticks on the Y axis.
    image_.gs(boxplot::Y_MINOR_TICKS).style().stroke_width(width);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  unsigned int svg_boxplot::x_size()
  { //! \return width of the SVG image.
    return image_.x_size();
  }

  unsigned int svg_boxplot::y_size()
  { //! \return height of the SVG image.
    return image_.x_size();
  }

  std::string svg_boxplot::title()
  { //! \return title of the plot.
    return title_info_.text();
  }

  bool svg_boxplot::x_label_on()
  { //! \return label for the X axis.
    return x_axis_.label_on_;
  }

  int svg_boxplot::x_major_labels()
  { //! \return which side of the X axis for labels.
    return y_ticks_.major_value_labels_side_;
  }

  svg_color svg_boxplot::title_color()
  { //! \return color of the title.
    return image_.gs(boxplot::PLOT_TITLE).style().fill_color();
  }

  svg_color svg_boxplot::background_color()
  { //! \return Color of the background for the SVG image.
    return image_.gs(boxplot::PLOT_BACKGROUND).style().fill_color();
  }

  svg_color svg_boxplot::background_border_color()
  { //! \return Color of the border of the background for the SVG image.
    return image_.gs(boxplot::PLOT_BACKGROUND).style().stroke_color();
  }

  svg_color svg_boxplot::plot_background_color()
  { //! \return Color of the background for the plot.
    return image_.gs(boxplot::PLOT_WINDOW_BACKGROUND).style().fill_color();
  }

  svg_color svg_boxplot::plot_border_color()
  { //! \return Color of the border of the background for the plot.
    return image_.gs(boxplot::PLOT_WINDOW_BACKGROUND).style().stroke_color();
  }

  svg_color svg_boxplot::x_label_color()
  { //! \return Color of the X axis label.
    return image_.gs(boxplot::X_LABEL).style().fill_color();
  }

  svg_color svg_boxplot::x_tick_color()
  { //! \return Color of ticks on the X axis.
    return image_.gs(boxplot::X_TICKS).style().stroke_color();
  }

  double svg_boxplot::x_tick_length()
  { //! \return Length of major ticks on the X axis.
    return x_ticks_.major_tick_length_;
  }

  double svg_boxplot::x_major_tick_width()
  { //! \return Width of major ticks on the X axis.
    return image_.gs(boxplot::X_TICKS).style().stroke_width();
  }

  std::string svg_boxplot::x_label_text()
  { //! \return Text of label for X axis.
    return x_label_info_.text();
  }

  std::string svg_boxplot::y_label_text()
  { //! \return  Text of label for Y axis.
    return y_label_info_.text();
  }

  svg_boxplot& svg_boxplot::whisker_length(double length)
  { //! Set the length of the whisker.
    whisker_length_ = length;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  /*! Get whisker length (width of the box, not the margin).
  */
  double svg_boxplot::whisker_length()
  { // width of the box, not the margin.
    return whisker_length_; //!< \return Length of whisker.
  }

  svg_boxplot& svg_boxplot::box_width(double width)
  { //! Set width of the box.
    //! (Width of the box, not the border).
    box_width_ = width;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  double svg_boxplot::box_width()
  { //! \return width of the box. (Width of the box, not the border).
    return box_width_;
  }

  svg_boxplot& svg_boxplot::box_fill(const svg_color& color)
  { //! Set color of box fill (not border).
    box_style_.fill_color(color);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_color svg_boxplot::box_fill()
  { //! \return Color of box fill (not border).
    return box_style_.fill_color();
  }

  svg_boxplot& svg_boxplot::box_border(const svg_color& color)
  { //! Set color of box border.
    box_style_.stroke_color(color);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_color svg_boxplot::box_border()
  { //! \return Color of box border.
    return box_style_.stroke_color();
  }

  svg_boxplot& svg_boxplot::median_color(const svg_color& color)
  { //! Set color of median line in box.
    median_style_.stroke_color(color);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_color svg_boxplot::median_color()
  { //! \return color of median line in box.
    return median_style_.stroke_color();
  }

  svg_boxplot& svg_boxplot::median_width(double width)
  { //! Set width of the box (not the border).
    median_style_.stroke_width(width);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  double svg_boxplot::median_width()
  { //! \return width of the box (not the border).
    return median_style_.stroke_width();
  }

  svg_boxplot& svg_boxplot::axis_color(const svg_color& color)
  { //! Set color of vertical whisker axis line in box.
    axis_style_.stroke_color(color);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_color svg_boxplot::axis_color()
  { //! \return Color of vertical whisker axis line in box.
    return axis_style_.stroke_color();
  }

  svg_boxplot& svg_boxplot::axis_width(double width)
  { //! Set width of the box, not the border.
    median_style_.stroke_width(width);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  double svg_boxplot::axis_width()
  { //! \return Width of the box, not the border.
    return median_style_.stroke_width();
  }

  svg_boxplot& svg_boxplot::outlier_color(const svg_color& color)
  { //! Set color of outlier.
    mild_outlier_.stroke_color(color);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_color svg_boxplot::outlier_color()
  { //! \return Color of mild outlier.
    return mild_outlier_.stroke_color();
  }

  svg_boxplot& svg_boxplot::outlier_fill(const svg_color& color)
  { //! Set color of mild outlier fill.
    mild_outlier_.fill_color(color);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_color svg_boxplot::outlier_fill()
  { //! \return Color of outlier fill.
    return mild_outlier_.fill_color();
  }

  svg_boxplot& svg_boxplot::extreme_outlier_color(const svg_color& color)
  { //! Color of extreme outlier.
    ext_outlier_.stroke_color(color);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  svg_color svg_boxplot::extreme_outlier_color()
  { //! \return Color of extreme outlier.
    return ext_outlier_.stroke_color();
  }

  svg_boxplot& svg_boxplot::extreme_outlier_fill(const svg_color& color)
  { //! Set color of extreme outlier fill.
    ext_outlier_.fill_color(color);
    return *this;  //! \return Reference to svg_boxplot to make chainable.
  }

  svg_color svg_boxplot::extreme_outlier_fill()
  { //! \return Color of extreme outlier fill.
    return ext_outlier_.fill_color();
  }

  svg_boxplot& svg_boxplot::outlier_shape(point_shape shape)
  { //! Set shape of outlier marker.
    mild_outlier_.shape_ = shape;
    return *this;  //! \return Reference to svg_boxplot to make chainable.
  }

  point_shape svg_boxplot::outlier_shape()
  { //! \return Outlier marker shape.
    return mild_outlier_.shape_;
  }

  svg_boxplot& svg_boxplot::extreme_outlier_shape(point_shape shape)
  { //! Set shape of extreme outlier marker.
    ext_outlier_.shape_ = shape;
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  point_shape svg_boxplot::extreme_outlier_shape()
  { //! \return Shape of extreme outlier marker.
    return ext_outlier_.shape_ ;
  }

  svg_boxplot&  svg_boxplot::outlier_size(int size)
  { //! Set size of outlier marker.
    mild_outlier_.size(size);
    return *this;  //! \return Reference to svg_boxplot to make chainable.
  }

  int svg_boxplot::outlier_size()
  { //! \return Size of outlier marker.
    return mild_outlier_.size();
  }

  svg_boxplot&  svg_boxplot::outlier_style(plot_point_style& os)
  { //! Set outlier style.
    mild_outlier_ = os;
    return *this;  //! \return Reference to svg_boxplot to make chainable.
  }

  plot_point_style& svg_boxplot::outlier_style()
  {
    return mild_outlier_; //!< \return Outlier_style.
  }

  svg_boxplot& svg_boxplot::extreme_outlier_size(int size)
  { //! Set size of extreme outlier marker.
    ext_outlier_.size(size);
    return *this; //! \return Reference to svg_boxplot to make chainable.
  }

  int svg_boxplot::extreme_outlier_size()
  { //! \return Size of extreme outlier marker.
    return ext_outlier_.size();
  }

  svg_boxplot& svg_boxplot::quartile_definition(int def)
  { //! Set definition of quartile.
    quartile_definition_ = def;
    return *this; //! \return Reference to @c svg_boxplot to make chainable.
  }

  int svg_boxplot::quartile_definition()
  { //! \return Definition \# of quartile.
    return quartile_definition_;
  }

  bool svg_boxplot::y_autoscale()
  { //! \return @c true if Y-axis to use autoscaling.
    return y_autoscale_;
  }

  svg_boxplot& svg_boxplot::y_autoscale(bool b)
  { /*! Set @c true if Y axis is to use autoscale.
      \return Reference to @c svg_boxplot to make chainable.
    */
    y_autoscale_ = b;
    return *this; //  Reference to @c svg_boxplot to make chainable.
  }

  /*!
    Autoscale Y-axis using minimum and maximum provided as two doubles.
  */
  svg_boxplot& svg_boxplot::y_autoscale(double min, double max)
  {
    scale_axis(min, max, // double min and double max.
    &y_auto_min_value_, &y_auto_max_value_, &y_auto_tick_interval_, &y_auto_ticks_,
    autoscale_check_limits_, autoscale_plusminus_,
    y_include_zero_, y_tight_, y_min_ticks_, y_steps_);
    y_autoscale_ = true;  // Change (from default @c false) to use provided values.
    return *this;  //! \return Reference to @c svg_boxplot to make chainable.
  }

  /*! Set Y min & max values (as a std::pair) to use for autoscaling Y-axis.
  */
  svg_boxplot& svg_boxplot::y_autoscale(std::pair<double, double> p)
  {
    scale_axis(p.first, p.second, // double min and max from pair.
    &y_auto_min_value_, &y_auto_max_value_, &y_auto_tick_interval_, &y_auto_ticks_,
    autoscale_check_limits_, autoscale_plusminus_,
    y_include_zero_, y_tight_, y_min_ticks_, y_steps_);
    y_autoscale_ = true;  // Change (from default false) to use calculated values.
    return *this;  //! \return Reference to @c svg_boxplot to make chainable.
  } // autoscale(pair<double, double> p)

  /*!
    Autoscale using iterators into a container
    (allowing only a part of container values to be used to calculate minimum and maximum Y-axis).
    \tparam T an STL container: @c array, @c vector ...
    \param begin First element to use to calculate autoscaled values.
    \param end Last element to use to calculate autoscaled values.
  */
  template <class T>
  svg_boxplot& svg_boxplot::y_autoscale(const T& begin, const T& end)
  {
    scale_axis(begin, end,
    &y_auto_min_value_, &y_auto_max_value_, &y_auto_tick_interval_, &y_auto_ticks_,
    autoscale_check_limits_, autoscale_plusminus_,
    y_include_zero_, y_tight_, y_min_ticks_, y_steps_);
    y_autoscale_ = true; // Change (from default false) to use calculated values.
    return *this;  //! \return Reference to @c svg_boxplot to make chainable.
  } // y_autoscale(const T& begin, const T& end)

  /*!
    Autoscale using a whole container to calculate minimum and maximum autoscaled Y-axis values.
    \tparam T an STL container: @c array, @c vector ...
  */
  template <class T>
  svg_boxplot& svg_boxplot::y_autoscale(const T& container) // Whole data series.
  {
    scale_axis(container.begin(), container.end(), // All the container.
    &y_auto_min_value_, &y_auto_max_value_, &y_auto_tick_interval_, &y_auto_ticks_,
    autoscale_check_limits_, autoscale_plusminus_,
    y_include_zero_, y_tight_, y_min_ticks_, y_steps_);
    y_autoscale_ = true;  // Change (from default false) to use calculated values.
    return *this; //! \return Reference to @c svg_boxplot to make chainable.
  } // y_autoscale(const T& container)

} // namespace svg
} // namespace boost
#endif // BOOST_SVG_SVG_BOXPLOT_HPP