prawn:Prawn::Font::AFM.metrics_path
#!/usr/bin/env ruby require "prawn" p Prawn::Font::AFM.metrics_path
で、
[".", "/usr/lib/afm", "/usr/local/lib/afm", "/usr/openwin/lib/fonts/afm/", "/usr/local/ruby-1.8.7/lib/ruby/gems/1.8/gems/prawn-core-0.6.1/data/fonts/"]