middleman-gnuplot

This extension to the Middleman framework provides helper functions to generate plots using gnuplot.

Add the gem to your Gemfile:

gem 'middleman-gnuplot', :path => "path-to/middleman-gnuplot"

Update your gem list:

$ bundle install

Modify the config.rb of your project as follows:

activate :gnuplot do |opts|
  opts.gp_tmpdir = 'tmp' # path, where plots are stored before copied to build dir
  opts.gp_outdir = 'img' # directory holding plot files with build dir
  opts.gp_format = 'png' # determines output format (currently supports png and pdf)
end

If not specified, the plots will be generated with random filenames, which are 6 characters long. This setting can be overridden in config.rb to e.g. 8 using the following line:

set :gp_rndfilelength, 8

All functions return the output filename of the plot, which can be used as argument for the image_tag helper function.

The middleman-gnuplot extension provides the following helper methods:

• plot_functions ([{:expression, :style, :color}], filename, plot title): Plot simple expressions, which can be defined as single hash or array thereof. The function returns a filename, which can be used as argument for the image_tag helper. expression can hold terms that can be interpreted by gnuplot, e.g. sin(x) or similar. style: lines, points, etc. color takes an RGB color definition in hex format. filenamedefines the output filename. If nil, a random filename is generated and returned by the function.

  image_tag plot_functions([{:expression => "sin(x)",
                            :style => "lines",
                            :color => "#4575B4"},
                           {:expression => "tan(x)",
                            :color => "#D73027"}],
                            "filename",
                            "Plot Title")

• plot_script(script, filename, title): This helper can be used to generate a plot with a gnuplot script. script should contain the path to the gnuplot script. filename defines the output filename. If nil, a random filename is generated and returned by the function. The title parameter can be used to define a plot title.

  image_tag plot_script("path_to_gnuplot_script", "filename", "Plot Title")

• plot_data(data, series, filename, title): Plots data points from a given array data directly. The data series can be specified as hashes within the array series. Allowed fields are :x, :y, :title and :style (lines, points, linespoints, ...). The default style is lines. filename defines the output filename. If nil, a random filename is generated and returned by the function. The title parameter can be used to define a plot title.

  image_tag plot_data([[1,2,1],[2,5,3],[3,3,1],[4,1,5]], 
                      [{:x => 1, 
                        :y => 2, 
                        :title => "Series 1"},
                       {:x => 1, 
                        :y => 3, 
                        :title => "Series 2", 
                        :style => "points"}], 
                        "filename", "Plot Title"

The build summary of middleman lists plot files that were generated in previous runs as being removed from the build directory. Nevertheless, the plots generated in the current run are moved to the build directory after the middleman sitemap is evaluated and therefore do not show up in this list.

Feel free to contact me, if you have a better solution for this issue!

1. Fork it ( http://github.com/hermanndetz/middleman-gnuplot/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request