def setup(app):
    setup.app = app
    setup.config = app.config
    setup.confdir = app.confdir

    options = {'alt': directives.unchanged,
               'height': directives.length_or_unitless,
               'width': directives.length_or_percentage_or_unitless,
               'scale': directives.nonnegative_int,
               'align': _option_align,
               'class': directives.class_option,
               'include-source': _option_boolean,
               'format': _option_format,
               'context': directives.flag,
               'nofigs': directives.flag,
               'encoding': directives.encoding
               }

    app.add_directive('plot', plot_directive, True, (0, 2, False), **options)
    app.add_config_value('plot_pre_code', None, True)
    app.add_config_value('plot_include_source', False, True)
    app.add_config_value('plot_formats', ['png', 'hires.png', 'pdf'], True)
    app.add_config_value('plot_basedir', None, True)
    app.add_config_value('plot_html_show_formats', True, True)
    app.add_config_value('plot_rcparams', {}, True)
    app.add_config_value('plot_apply_rcparams', False, True)
    app.add_config_value('plot_working_directory', None, True)
    app.add_config_value('plot_template', None, True)

    app.connect('doctree-read', mark_plot_labels)