base 64 to Image

sig_to_img.rb

def signature_to_img(data, filename)
    return if data.blank?
    FileUtils.mkdir_p(File.dirname(filename))
    instructions = JSON.parse(data).map { |h| "line #{h['mx'].to_i},#{h['my'].to_i} #{h['lx'].to_i},#{h['ly'].to_i}" }.join(' ')
    Open3.popen3("convert -size 198x55 xc:transparent -stroke blue -draw @- #{filename}") do |input, output, error|
      input.puts instructions
    end
  end