The Gtk2SVG gem now has its own SVG DOM

require 'gtk2svg' 


s =<<SVG
<svg width="400" height="110">
   <line x1="0" y1="0" x2="200" y2="200" style="stroke:rgb(255,0,0);stroke-width:2" />
</svg>
SVG

app = Gtk2SVG::Main.new s
line = app.doc.root.element 'line'
sleep 1
line.x1 = 55
app.refresh