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:
    1. surface = cairo.PSSurface ("", width, height)
    2. 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)
Cover image from Data-Driven Security
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1 Comment Slopegraphs In Python – colors, fonts & alignment

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