This is an issue with fonts, you need to install a font that supports the characters you wish to display, and tell prawn
to use it.
prawn
version 0.12.0 comes with one font which will at least display something:
pdf = Prawn::Document.new
pdf.font "#{Prawn::BASEDIR}/data/fonts/gkai00mp.ttf"
pdf.text "не ну ни фига sebe"
send_data pdf.render
If you want it prettier, you need to find and use another font, and modify the pdf.font
line to use it.