examples/axis/log.py

   1 # Certainly logarithmic axes are supported in PyX. By playing with
   2 # partitioners and texters, you can easily change the base.
   3 #
   4 # It is left as an exercise to the reader to create a automatic
   5 # partitioner for logarithmic axes with base 2.
   6
   7 import math
   8 from pyx import *
   9 from pyx.graph import axis
  10
  11 p = path.curve(0, 0, 3, 0, 1, 4, 4, 4)
  12
  13 log2parter = axis.parter.log([axis.parter.preexp([axis.tick.rational(1)], 4),
  14                               axis.parter.preexp([axis.tick.rational(1)], 2)])
  15 log2texter = axis.texter.exponential(nomantissaexp=r"{2^{%s}}",
  16                                      mantissamax=axis.tick.rational(2))
  17
  18 c = canvas.canvas()
  19 c.insert(axis.pathaxis(p, axis.log(min=1, max=1024)))
  20 c.insert(axis.pathaxis(p.transformed(trafo.translate(4, 0)),
  21                        axis.log(min=1, max=1024, parter=log2parter)))
  22 c.insert(axis.pathaxis(p.transformed(trafo.translate(8, 0)),
  23                        axis.log(min=1, max=1024, parter=log2parter,
  24                                 texter=log2texter)))
  25 c.writeEPSfile("log")