example.rb

require 'open-uri'
require 'prawn'
require 'prawn/measurement_extensions'
require 'mongo'
require_relative 'logging'

class HealthMarkRenderer
  include Singleton, Logging

  def render_health_mark(pdf, health_mark_object, health_marks)
    # Get the binding's ACTUAL value from the product data
    bound_attribute = health_mark_object['binding']

    # There is no data in the product that will render this item, so ignore it
    return if bound_attribute.nil?

    # Check that the data is an ID reference
    return unless bound_attribute.is_a?(String)

    health_mark = health_marks.find { |health_mark| health_mark['_id'].to_s == bound_attribute }

    # Don't render anything, as it requires data
    return if health_mark['countryCode'].nil? || health_mark['establishmentCode'].nil?

    x_position = health_mark_object['settings']['x'].to_f
    y_position = health_mark_object['settings']['y'].to_f
    rt = health_mark_object['settings']['rt'].to_f
    width = health_mark_object['settings']['width'].to_f
    height = health_mark_object['settings']['height'].to_f

    pdf.rotate(-rt, :origin => [x_position + (width / 2.0), -(y_position + (height / 2.0))]) do
      # Work out the current ratio of width to height
      aspect_ratio = width / height

      # Check the proportions of this control match
      # the expected (they probably wont!)
      if aspect_ratio > 2
        # The control is too SHORT
        new_width = height * 2
        # Adjust the X value to compensate
        x_position += (width - new_width) / 2
        # Save the new width
        width = new_width
      elsif aspect_ratio < 2
        # The control is too WIDE
        new_height = width / 2
        # Adjust the Y value to compensate
        y_position += (height - new_height) / 2
        # Save the new height
        height = new_height
      end

      pdf.translate(x_position, -y_position) do
        # Draw the outlines
        pdf.stroke do
          pdf.ellipse([width / 2.0, -height / 2.0], width / 2.0, height / 2.0)
        end

        # Set the font size at the maximum allowed
        pdf.font_size 100

        pdf.formatted_text_box(
            [
                text: "#{health_mark['countryCode']}\n#{health_mark['establishmentCode']}\nEC",
                styles: [:bold],
                color: '#000000'
            ],
            at: [width / 10.0, -height / 10.0],
            width: (width / 10.0) * 8,
            height: (height / 10.0) * 8,
            overflow: :shrink_to_fit,
            align: :center,
            valign: :center,
            # Allow the font to go all the way down to the unreadable 1pt setting.
            min_font_size: 1,
            disable_wrap_by_char: true
        )
      end
    end
  end
end