Fix for unreadable ghostscript font

I'm using the ruby Scruffy gem to create some graphs. It relies on RMagick to render the text and create the pngs. When I run my ruby script I get this error.

sh: gs: command not found
sh: gs: com开发者_Python百科mand not found
/Users/natebird/.rvm/gems/ree-1.8.7-2011.03/gems/scruffy-0.2.6/lib/scruffy/rasterizers/rmagick_rasterizer.rb:15:in `from_blob': unable to read font `/usr/local/share/ghostscript/fonts/n019003l.pfb' @ error/annotate.c/RenderFreetype/1128: `(null)' (Magick::ImageMagickError)
    from /Users/natebird/.rvm/gems/ree-1.8.7-2011.03/gems/scruffy-0.2.6/lib/scruffy/rasterizers/rmagick_rasterizer.rb:15:in `rasterize'
    from /Users/natebird/.rvm/gems/ree-1.8.7-2011.03/gems/scruffy-0.2.6/lib/scruffy/graph.rb:164:in `render'
    from autobench_grapher.rb:61:in `generate_graph'
    from autobench_grapher.rb:30:in `run'
    from autobench_grapher.rb:15:in `run'
    from autobench_grapher.rb:91

---

You need to install ghostscript (see: gs: command not found). How you do this depends on what platform you are on.