Module: Srcset

Defined in:
lib/jekyll-srcset-hook.rb

Class Method Summary collapse

Class Method Details

.modify_page_output ⇒ Object 



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# File 'lib/jekyll-srcset-hook.rb', line 56

def modify_page_output
  proc do |page|
    doc = Nokogiri.HTML5(page.content)
    elements = doc.xpath(".//body//img")
    # for some reason, need to remove last element as it is empty
    elements.pop

    elements.each do |image|
      next unless image[:src].start_with?(
        @config["url_endpoint"] || @config["pages"]["url_endpoint"]
      )

      original_image = image
      original_image = original_image.to_s.gsub!(">", " />")

      image =
        process_image(
          image,
          @config["transformations_widths"] ||
            @config["pages"]["transformations_widths"],
          @config["sizes"] || @config["pages"]["sizes"]
        )

      page.output.gsub!(original_image, image)
    end
  end
end

.modify_post_output ⇒ Object 



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# File 'lib/jekyll-srcset-hook.rb', line 29

def modify_post_output
  proc do |post|
    # posts are fragments (i.e. no DOCTYPE declaration/<html>...</html>)
    fragment = Nokogiri::HTML5.fragment(post.content)
    fragment
      .xpath(".//img")
      .each do |image|
        next unless image[:src].start_with?(
          @config["url_endpoint"] || @config["posts"]["url_endpoint"]
        )

        original_image = image
        original_image = original_image.to_s.gsub!(">", " />")

        image =
          process_image(
            image,
            @config["transformations_widths"] ||
              @config["posts"]["transformations_widths"],
            @config["sizes"] || @config["posts"]["sizes"]
          )

        post.output.gsub!(original_image, image)
      end
  end
end

.process_image(image, transformations, sizes) ⇒ Object 



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# File 'lib/jekyll-srcset-hook.rb', line 84

def process_image(image, transformations, sizes)
  srcset_value = ""
  transformations.each do |t_w|
    srcset_value += "#{image[:src]}#{t_w}, "
  end
  # remove the extra ", " at the end of srcset_value
  srcset_value.chomp!(", ")
  # add the attributes to the image
  image[:srcset] = srcset_value
  image[:sizes] = sizes
  image.to_s.gsub!(">", " />")
end

.set_config ⇒ Object 



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# File 'lib/jekyll-srcset-hook.rb', line 8

def set_config
  proc do |site|
    @config = site.config["jekyll-srcset-hook"]

    if @config.nil?
      Jekyll.logger.warn(
        "WARNING: jekyll-srcset configuration is not present in _config.yml"
      )
      next
    end

    unless @config["transformations_widths"].nil? && @config["sizes"].nil?
      Jekyll::Hooks.register(:posts, :post_render, &modify_post_output)
      Jekyll::Hooks.register(:pages, :post_render, &modify_page_output)
    end

    Jekyll::Hooks.register(:posts, :post_render, &modify_post_output) unless @config["posts"].nil?
    Jekyll::Hooks.register(:pages, :post_render, &modify_page_output) unless @config["pages"].nil?
  end
end