examples/graphs/step.py

   1 from pyx import *
   2
   3 def step(x, a):
   4     if a > 0:
   5         return x
   6
   7 c = canvas.canvas()
   8 g = c.insert(graph.graphxy(width = 10))
   9 df = data.datafile("step.dat")
  10 df.addcolumn("y1a=step(y1, y1-0.02)", context=locals())
  11 df.addcolumn("y1b=step(y1, 0.02-y1)", context=locals())
  12 df.addcolumn("y2a=step(y2, x-1)", context=locals())
  13 df.addcolumn("y2b=step(y2, 1-x)", context=locals())
  14 g.plot(graph.data(df, x=1, y="y1a"), graph.line(color.rgb.red))
  15 g.plot(graph.data(df, x=1, y="y1b"), graph.line(color.rgb.blue))
  16 g.plot(graph.data(df, x=1, y="y2a"), graph.line(color.rgb.red))
  17 g.plot(graph.data(df, x=1, y="y2b"), graph.line(color.rgb.blue))
  18 c.writetofile("step")
  19