Histogram libraries for ruby using gnuplot gem

hist_gp.rb

# -*- coding: utf-8 -*-

# hist_gp.rb
#
# Author: Rintaro Okamura
#
# Description:
#   Histogram libraries for ruby using gnuplot gem
#

require 'gnuplot'

module HistGnuplot
  class Hist
    def initialize

    end
  end

  # 2D histogram
  class Hist2D
    attr_accessor :xdata, :ydata,
      :title, :xlabel, :ylabel, :cblabel,
      :binres_x, :binres_y,
      :interval_x, :interval_y,
      :dx, :dy, :x, :y, 
      :max_x, :max_y,
      :min_x, :min_y,
      :logscale

    def initialize(xdata, ydata, bin_x=100, bin_y=100)

      @binres_x = bin_x
      @binres_y = bin_y

      @xdata = xdata
      @ydata = ydata

      @max_x = xdata.max.to_f
      @min_x = xdata.min.to_f
      @max_y = ydata.max.to_f
      @min_y = ydata.min.to_f

      @max_x = 999.0 if @max_x.infinite?
      @max_y = 999.0 if @max_y.infinite?
      @min_x = -999.0 if @min_x.infinite?
      @min_y = -999.0 if @min_y.infinite?

      @logscale = false
    end

    def plot(outfilepath='none')
      @interval_x = ((@max_x - @min_x).to_f / @binres_x).to_f
      @interval_y = ((@max_y - @min_y).to_f / @binres_y).to_f

      @dx = @interval_x / 2.0
      @dy = @interval_y / 2.0

      @x = []
      @y = []

      @binres_x.times do |i|
        @x.push(@min_x + @interval_x * (i + 1).to_f - @dx)
      end
      @binres_y.times do |i|
        @y.push(@min_y + @interval_y * (i + 1).to_f - @dy)
      end

      hist = Array.new(@binres_x).map{Array.new(@binres_y, 0)}
      @binres_x.times do |ix|
        insidebin_x_index = @xdata.each_with_index.select {|a|
          a[0] >= (@x[ix]) and a[0] < (@x[ix] + @interval_x)
        }.map{|a| a[1]}
        @binres_y.times do |iy|
          insidebin_y_index = @ydata.each_with_index.select {|a|
            a[0] >= (@y[iy]) and a[0] < (@y[iy] + @interval_y)
          }.map{|a| a[1]}
          hist[ix][iy] = (insidebin_x_index & insidebin_y_index).length
        end
      end

      Gnuplot.open do |gp|
        SPlot.new(gp) do |plot|
          case outfilepath
          when /^none$/
            plot.terminal 'x11'
          when /\.tex$/
            plot.terminal "tikz"
            plot.output File.expand_path(outfilepath)
          when /\.pdf$/
            plot.terminal "pdf"
            plot.output File.expand_path(outfilepath)
          when /\.png$/
            plot.terminal "pngcairo"
            plot.output File.expand_path(outfilepath)
          else
            STDERR.puts "Error: unknown filetype"
            exit
          end

          plot.title @title

          plot.xlabel @xlabel
          plot.ylabel @ylabel
          plot.cblabel @cblabel

          plot.set "datafile missing \"Infinity\""

          plot.set "key off"

          plot.set "view map"
          plot.set "size square"

          plot.xrange "[#{@min_x}:#{@max_x}]"
          plot.yrange "[#{@min_y}:#{@max_y}]"

          if @logscale 
            plot.cbrange "[1:#{hist.flatten.max}]"
            plot.set "logscale cb"
          else
            plot.cbrange "[0:#{hist.flatten.max}]"
          end

          plot.set "palette defined ( 0 '#000090', 1 '#000fff', 2 '#0090ff', 3 '#0fffee', 4 '#90ff70', 5 '#ffee00', 6 '#ff7000', 7 '#ee0000', 8 '#7f0000')"

          plot.data <<
          Gnuplot::DataSet.new([@x, @y, hist]) do |ds|
            ds.with = 'image pixels'
          end
        end
      end
    end
  end
end


private

# https://github.com/rdp/ruby_gnuplot/blob/master/lib/gnuplot.rb#L358
class SPlot < Gnuplot::Plot

  def initialize (io = nil, cmd = "splot")
    @cmd = cmd
    @settings = []
    @arbitrary_lines = []
    @data = []
    @styles = []
    yield self if block_given?
    $stderr.puts "writing this to gnuplot:\n" + to_gsplot + "\n" if $VERBOSE

    if io
      io << to_gsplot
      io << store_datasets
    end
  end

  def to_gsplot (io = "")
    @settings.each do |setting|
      io << setting.map(&:to_s).join(" ") << "\n"
    end
    @styles.each{|s| io << s.to_s << "\n"}
    @arbitrary_lines.each{|line| io << line << "\n" }

    io
  end

  def store_datasets (io = "")
    if @data.size > 0
      io << @cmd << " " << @data.collect { |e| e.plot_args }.join(", ")
      io << "\n"

      v = @data.collect { |ds| ds.to_gsplot }
      io << v.compact.join("e\n")
    end
  end
end

class Array
  def to_gsplot
    f = ""

    if ( self[0].kind_of? Array ) then
      x = self[0]
      y = self[1]
      d = self[2]

      x.each_with_index do |xv, i|
        y.each_with_index do |yv, j|
          f << [ xv, yv, d[i][j] ].join(" ") << "\n"
        end
        f << "\n"
      end
    elsif ( self[0].kind_of? Numeric ) then
      self.length.times do |i| f << "#{self[i]}\n" end
    else
      self[0].zip( *self[1..-1] ).to_gsplot
    end

    f
  end
end