Hi,

When I attempt to plot small-scale features with the PS backend, it

seems that there's a granularity at which things cannot be further

specified. I cannot remember encoutering this before, although I can't

be sure it's not an old phenomenon. Anyhow, the following script

illustrates the issue. With the PS backend, zooming in on the output

shows the points spread significantly away from their locations that

would be expected.

import matplotlib

matplotlib.use('PS')

import pylab

import numpy

x=numpy.linspace(-100,100,2000)

x+=0.001*numpy.random.rand(len(x))

y=numpy.sin(x/30.0)

y+=0.001*numpy.random.rand(len(x))

pylab.plot(x,y,'.',ms=0.1)

pylab.savefig('dots_dynamic_range')

With the Agg and PDF backends, this does not occur. I'm attaching a few

example images which hopefully make the issue clear. (These have all

seen a little bit of processing to reduce the file sizes.)