jekyll-figurify.rb

# frozen_string_literal: true

require 'jekyll'

module Jekyll
  module Generators
    # Our modifications to the markdown renderer to process images with figure captions
    # TODO: probably could be a hook post_read.
    class Figurify < Jekyll::Generator
      safe true

      def initialize(config)
        super
        @config = config['figurify'] ||= {}
      end

      def generate(site)
        site.pages
            .reject { |page| skip_layout? page.data['layout'] }
            .each { |page| figurify page, site }
        site.posts.docs
            .reject { |post| skip_layout? post.data['layout'] }
            .each { |post| figurify post, site }
      end

      private

      def insert_image(url, alt, style, dimensions, actual_path)
        # If it's a *local* SVG (we don't want to do this with remote SVGs, doesn't work right)
        if url =~ (/svg$/) && !actual_path.nil?
          fallback = ''
          if actual_path.nil?
            # External image, no fallback possible
            fallback = ''
          elsif File.exist?(actual_path.gsub(/svg$/, 'png'))
            fallback = "<img src=\"#{url.gsub(/svg$/, 'png')}\" alt=\"#{alt}\">"
          elsif File.exist?(actual_path.gsub(/svg$/, 'jpg'))
            fallback = "<img src=\"#{url.gsub(/svg$/, 'jpg')}\" alt=\"#{alt}\">"
          elsif File.exist?(actual_path.gsub(/svg$/, 'jpeg'))
            fallback = "<img src=\"#{url.gsub(/svg$/, 'jpeg')}\" alt=\"#{alt}\">"
          end

          %(
            <div style="overflow-x: auto">
            <object data="#{url}" #{style} type="image/svg+xml" alt="#{alt}">
              #{fallback}
              #{alt}
            </object>
            </div>
          )
        else
          %(
            <img src="#{url}"  alt="#{alt}" #{style} #{dimensions} loading="lazy">
          )
        end
      end

      def figurify(page, site)
        num_figure = 0
        return if page.content.nil?

        tuto_dir = File.dirname(page.path)
        page.content = page.content.gsub(/!\[([^\]]*)\]\((.+?)\s*(?:"(.*)")\)({:(.*)})?/) do
          alt = ::Regexp.last_match(1)
          url = ::Regexp.last_match(2)
          title = ::Regexp.last_match(3)
          style = ::Regexp.last_match(5)

          if skip_titles?(title) || (title.to_s.empty? && skip_empty?)
            Regexp.last_match
          else
            num_figure += 1

            alt.gsub!(/"/, '&quot;')
            if alt.strip.length.positive? && !(alt.end_with?('.') || alt.end_with?('!') || alt.end_with?('?'))
              alt = "#{alt}. "
            end

            dimensions, actual_path = Gtn::Images.html_image_dimensions(tuto_dir, url)
            prefix = figcaption_prefix(page, site)
            image = insert_image(url, alt, style, dimensions, actual_path)

            %(
              <figure id="figure-#{num_figure}" style="max-width: 90%;">
                #{image}
                <a target="_blank" href="#{url}" rel="noopener noreferrer"><small>Open image in new tab</small></a><br/><br/>
                <figcaption>
                  <span class="figcaption-prefix"><strong>#{prefix}#{num_figure}</strong>:</span> #{title}
                </figcaption>
              </figure>
            ).split("\n").map(&:strip).join
          end
        end

        page.content = page.content.gsub(/!\[([^\]]*)\]\((.+?)?\)({:(.*)})?/) do
          alt = ::Regexp.last_match(1)
          url = ::Regexp.last_match(2)
          style = ::Regexp.last_match(4)

          dimensions, _actual_path = Gtn::Images.html_image_dimensions(tuto_dir, url)

          alt.gsub!(/"/, '&quot;')
          if alt.strip.length.positive? && !(alt.end_with?('.') || alt.end_with?('!') || alt.end_with?('?'))
            alt = "#{alt}. "
          end

          %(
          <a href="#{url}" rel="noopener noreferrer">
            <img src="#{url}"  alt="#{alt}" #{style} #{dimensions} loading="lazy">
          </a>
          ).split("\n").map(&:strip).join
        end
      end

      def figcaption_prefix(page, site)
        fig = 'Figure'
        if page['lang']
          lang = page['lang']
          fig = site.data['lang'][lang]['figure']
        end
        @config['prefix'] || "#{fig} "
      end

      def skip_empty?
        @config['skip_empty'] || false
      end

      def skip_layout?(layout)
        to_skip = @config['skip_layouts'] || []

        true if to_skip.empty?

        to_skip.include?(layout)
      end

      def skip_titles?(title)
        to_skip = @config['skip_titles'] || []
        to_skip.include?(title)
      end
    end
  end
end