Class: Mathjax_Renderer::Renderer

Inherits:
Object
  • Object
show all
Includes:
Capybara::DSL
Defined in:
lib/mathjax_renderer/renderer.rb

Instance Method Summary collapse

Constructor Details

#initialize(mathml, image_base_url = nil, options = {}) ⇒ Renderer

Returns a new instance of Renderer.



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# File 'lib/mathjax_renderer/renderer.rb', line 9

def initialize(mathml, image_base_url = nil, options = {})
  @mathml = mathml
  @image_base_url = image_base_url
  @options = {min_width: 0, extra_style:'', padding:0}.merge options
end

Instance Method Details

#html ⇒ Object 



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# File 'lib/mathjax_renderer/renderer.rb', line 80

def html
  return cached(params_hash) if cached? params_hash

  render! if @html.nil?

  @html
end

#image_name ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/mathjax_renderer/renderer.rb', line 15

def image_name
  raise ArgumentError if @image_base_url.nil?
  render! unless File.exist?(image_path)
  _image_name
end

#render! ⇒ Object 



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# File 'lib/mathjax_renderer/renderer.rb', line 21

def render!
  server = RendererServer.new
  server.ensure_started!

  added_margin = [@options[:padding],@options[:min_width]].max

  url = server.add_content(@mathml, added_margin, @options[:extra_style])

  Headless.ly do

    Capybara.register_driver :chrome do |app|
      Capybara::Selenium::Driver.new(app, :browser => :chrome)
    end

    Capybara.default_driver = :chrome
    Capybara.app_host = "http://localhost:#{server.port}"

    visit url

    def mathjax_ready?(page)
      html = Nokogiri::HTML(page.html)
      !html.css('.MathJax').empty? && html.css('.MathJax_Processing').empty? && html.css('.MathJax_Processed').empty?
    end

    sleep 0.1 until mathjax_ready?(page)

    unless @image_base_url.nil?
      require 'chunky_png'
      driver = page.driver

      require 'fileutils'
      FileUtils.mkpath @image_base_url

      driver.save_screenshot(image_path)

      el= page.find('.MathJax .math').native

      image = ChunkyPNG::Image.from_file(image_path)

      correction = [(@options[:min_width] -(el.size.width + 2 * @options[:padding])) / 2,0].max

      x = el.location.x + 1 - @options[:padding]-correction
      y = el.location.y + 1 - @options[:padding]
      width = [el.size.width + 2 * @options[:padding],@options[:min_width]].max
      height = el.size.height+ 2 * @options[:padding]

      image.crop!(x, y, width, height)
      image.save(image_path)
    end
    result = Nokogiri::HTML(page.html).css('.MathJax')[0]

    put_cache!(params_hash,result)

    page.driver.quit

    @html = result
  end
end