gallery/path/sierpinski.py

   1 # Sierpinski triangle
   2 # contributed by Gerhard Schmid
   3
   4 from math import sqrt
   5 from pyx import *
   6
   7 # triangle geometry
   8 l = 10
   9 h = 0.5 * sqrt(3) * l
  10
  11 # base triangle path
  12 p = path.path(path.moveto(0, 0),
  13               path.lineto(l, 0),
  14               path.lineto(0.5 * l, h),
  15               path.closepath())
  16
  17 for i in range(6):
  18     # path is scaled down ...
  19     p = p.transformed(trafo.scale(0.5))
  20     # ... and three times plotted (translated accordingly)
  21     p += ( p.transformed(trafo.translate(0.5 * l, 0)) +
  22            p.transformed(trafo.translate(0.25 * l, 0.5 * h)))
  23
  24 c = canvas.canvas()
  25 c.stroke(p, [style.linewidth.Thin])
  26 c.writeEPSfile("sierpinski")
  27 c.writePDFfile("sierpinski")