SVG Glyph Helpers

svg_glyph.rb

# app/lib/svg_glyph.rb

class SvgGlyph

  CURRENT_COLOR = '#383838'
  GLYPH_NS      = 'glyphs'
  GLYPH_PATH    = "app/assets/images/#{GLYPH_NS}"

  def self.h
    ActionController::Base.helpers
  end

  def self.optimize(tag, filename, options={})
    svg_file = Rails.root.join(GLYPH_PATH, "#{filename}.svg")

    return h.content_tag(:svg, h.content_tag(:text, "#{filename}.svg Not Found")) if !File.exist?(svg_file)

    css_class  = options.delete(:class)
    glyph_name = filename.split('/').last
    document   = Nokogiri::XML(File.open(svg_file))

    document.remove_namespaces!

    if tag.to_s == 'svg'
      document.root[:class]        = ['glyph', glyph_name, css_class].compact.join(' ')
      document.root['aria-hidden'] = true
    elsif tag.to_s == 'symbol'
      document.root.name = 'symbol'
      document.root[:id] = [filename.split('/').last, options.delete(:id)].compact.join('--')
    end

    document.to_html.gsub(CURRENT_COLOR, 'currentColor')
                    .gsub("#{GLYPH_NS}/", '')
                    .strip!
  end

end

svg_glyph_helper.rb

# app/helpers/svg_glyph_helper.rb
# Usage
#   * Add the glyph sheet: `= glyph_sheet`
#   * Reference an icon: `= glyph('#icon-id')`

module SvgGlyphHelper

  def glyph(glyph, options={})
    text            = options.delete(:text)
    options[:class] = ['glyph', glyph.delete('#'), options.delete(:class)]

    if glyph.match(/^\#/)
      capture do
        concat content_tag(:span, options) {
          concat content_tag(:svg, class: 'glyph__img') { content_tag(:use, nil, 'xlink:href'=>glyph) }
        }
        concat content_tag(:span, text, class: 'glyph__text') if text
      end
    else
      SvgGlyph.optimize(:svg, glyph, options).html_safe
    end
  end

  def glyph_sheet
    content_tag(:svg, id: 'glyphs', style: 'display:none', 'aria-hidden'=>true) do
      Dir.glob(Rails.root.join(SvgGlyph::GLYPH_PATH, '*.svg')).each do |glyph|
        concat SvgGlyph.optimize(:symbol, glyph.split('/').last.gsub('.svg', ''), {}).html_safe
      end
    end
  end

end