svg_pathify turns svg basic shapes into <path> svg elements.
install
gem install svg_pathify
or in your Gemfile:
gem 'svg_pathify'
usage
require 'svg_pathify'
input = %Q{<polyline points="350,75 379,161 469,161 397,215
423,301 350,250 277,301 303,215
231,161 321,161" />}
output = SvgPathify.convert( input )
#=> '<path d="M350,75L379,161L469,161L397,215L423,301L350,250L277,301L303,215L231,161L321,161Z" />'