Ruby script to draw a graph by gnuplot.(Ex.3)

gnuplot_3.rb

#! /usr/local/bin/ruby
#-----------------------------------------------
# Ruby script to draw a graph by gnuplot.(Ex.3)
#-----------------------------------------------
require 'gnuplot'

Gnuplot.open do |gp|
  Gnuplot::SPlot.new(gp) do |plot|
    plot.terminal "png enhanced font 'IPA P ゴシック' fontscale 1.2"
    plot.output   "gnuplot_3.png"
    plot.set      "object 1 rect from screen 0,0 to screen 1,1 fc rgb '#D0D0E0' fillstyle solid 1.0 behind"
    plot.title    "作成例３"
    plot.xrange   "[-10:10]"
    plot.yrange   "[-10:10]"
    plot.xlabel   "x"
    plot.ylabel   "y"
    plot.zlabel   "z"
    plot.pm3d
    plot.grid

    plot.data << Gnuplot::DataSet.new("sin(x)*cos(y)") do |ds|
      ds.with      = "lines"
      ds.linecolor = 6
    end
  end
end