Slopegraphs In Python – colors, fonts & alignment

On the heels of last evening’s release of Slopegraphs in Python post comes some minor tweaks:

• Complete alignment control of labels & and values
• Colors (for background, lines, labels & values) — I picked a random pattern from Adobe's Kuler
• A font change (to prove width calculations work)

…and a new example slopegraph:

As promised, the latest revisions are in github.

Some notes for aspiring Python/Cairo hackers:

• RGB colors are 0-1 in Cairo, so divide your 0-255 values by 255 to get the corresponding Cairo value and make sure you're doing float arithmetic in Python
• It turns out simple Cairo font rendering (ie. non-Pango) does not interpret well in Illustrator from a Cairo PDF surface, so if you do plan on post-processing the slopegraphs, use a postscript/EPS surface:

  surface = cairo.PSSurface ("slopegraph.ps", width, height)
  surface.set_eps(True)

  (I'll be incorporating an output option as this gets closer to 1.0)
• If you do plan on using this at all, grab the Bitstream Vera Serif font (link goes to FontSquirrel, but you can find it almost everywhere as it's free)