_plugins/ideal_image_slider.rb

# Jekyll Ideal Image Slider v1.2
# Description: Add image sliders to Jekyll with Ideal Image Slider
# Documentation: https://github.com/jekylltools/jekyll-ideal-image-slider#readme
# Source: https://github.com/jekylltools/jekyll-ideal-image-slider
#
# Syntax:
#
# {% slider height [bullets] [captions] %}
# {% endslider %}
#
# Example Input:
#
# {% slider 700 captions %}
#   ![alt text 1](image1.jpg)
#   [![alt text 2](image2.jpg)](/page/url)
#   [![alt text 3](image3.jpg)](http://example.com)
# {% endslider %}
#
# Example Output:
#
# <div id="slider">
#   <img src="image1.jpg" alt="alt text 1">
#   <a href="/page/url"><img src="image2.jpg" alt="alt text 2"></a>
#   <a href="http://example.com"><img src="image3.jpg" alt="alt text 3"></a>
# </div>

module Jekyll
  class SliderTag < Liquid::Block
    alias_method :render_block, :render
    @slider_bullets = nil
    @slider_captions = nil
    @slider_height = nil
    Bullets = /bullets/i
    Captions = /captions/i
    Height = /(auto|\d+:\d+)/i
    Height_Numeric = /(\d+)/i

    def initialize(name, markup, tokens)
      if markup =~ Height
        @slider_height = "\'#{$1}\'"
      elsif markup =~ Height_Numeric
        @slider_height = "#{$1}"
      else
        @slider_height = "\'auto\'"
      end
      if markup =~ Bullets
        @slider_bullets = "true"
      end
      if markup =~ Captions
        @slider_captions = "true"
      end
      super
    end

    def render(context)
      page = context.environments.first['page']
      page['iis_slider_active'] = true
      if @slider_height
        # generate slider id
        slider_id = "slider_" + ("a".."z").to_a.shuffle[0,5].join
        # call the default markdown renderer
        site = context.registers[:site]
        converter =
        if site.respond_to?(:find_converter_instance)
          site.find_converter_instance(Jekyll::Converters::Markdown)
        else
          site.getConverterImpl(Jekyll::Converters::Markdown)
        end
        # render the slider script
        slider_script = "<script>"
        slider_script += "var #{slider_id} = new IdealImageSlider.Slider({"
        slider_script += "selector:\'\##{slider_id}\',"
        slider_script += "height:#{@slider_height}"
        slider_script += "});"
        slider_script += "#{slider_id}.addBulletNav();" if @slider_bullets
        slider_script += "#{slider_id}.addCaptions();" if @slider_captions
        slider_script += "#{slider_id}.start();"
        slider_script += "</script>"
        slider_array = context.environments.first['site']['iis_slider_array']
        slider_array << slider_script
        context.environments.first['page']['iis_slider_scripts'] = slider_array
        # render the markdown, then remove all <p></p> tags from the html
        output = converter.convert(render_block(context)).gsub(/<\/?p>/, '')
        # render the slider
        slider = "<div class=\"iis-slider\" id=\"#{slider_id}\">#{output}</div>"
        slider
      else
        "Error processing input, expected syntax: {% slider height [captions] %}"
        puts "Error: incorrect slider syntax in " + page['path']
      end
    end
  end
end

Liquid::Template.register_tag('slider', Jekyll::SliderTag)