ImageMagick helper to import custom fonts from Ruby

imagemagick_font_tool.rb

# ImageMagick helper to import custom fonts from Ruby instead of imagick_type_gen python script
# Designed for OSX/Heroku

# Usage:
#   desc 'Init custom fonts'
#   task fonts: :environment do
#     ImagemagickFontTool.export_type_xml(nil, '/app') # For Heroku
#     if Rails.env.development?
#       home_type_config = File.expand_path '~/.magick/myapp-type.xml' # Need to register this manually in ~/.magick/type.xml
#       ImagemagickFontTool.export_type_xml home_type_config
#     end
#   end

class ImagemagickFontTool
  FONT_EXTENSIONS = %w(ttf otf)

  def self.export_type_xml(target_xml_path = nil, override_font_path = nil)
    fonts_folder_path = Rails.root.join('db/fonts')

    font_files = Dir["#{fonts_folder_path}/**/*"].select do |path|
      File.file?(path) && FONT_EXTENSIONS.include?(File.extname(path)[1..-1])
    end

    builder = Nokogiri::XML::Builder.new do |xml|
      xml.typemap do
        font_files.each do |ttf_file|
          ttf = TTFunk::File.open(ttf_file)
          format = File.extname(ttf_file)[1..-1]
          attrs = {
            format: format,
            name: ttf.name.postscript_name,
            glyphs: ttf_file
          }
          if format == 'ttf'
            family = ttf.name.font_family[0..1]
            name = ttf.name.font_name[0..1]
            subfamily = ttf.name.font_subfamily[0..1]

            attrs[:name] = name.first
            attrs[:family] = family.first


            # full_name = name.last || name.first
            # attrs[:name] = name.first
            # attrs[:fullname] = full_name unless full_name == attrs[:name]
            # attrs[:family] = family.first unless family.first == attrs[:name]

            # style = subfamily.first.downcase
            # attrs[:style] = style if %w(bold italic regular).any?{|s| style.include?(s) }
          end
          if override_font_path
            attrs[:glyphs] = File.join(override_font_path, File.basename(ttf_file))
          end
          xml.type attrs #.map{|k,v| [k, v.to_s] }.to_h
        end
      end
    end

    target_xml_path ||= Rails.root.join('.magick', 'type.xml')
    File.open(target_xml_path, 'w'){|f| f.write builder.to_xml}
    target_xml_path
  end

end