I've run into a case where the rendering in a line plot is incomplete
and some lines are not drawn at all. I submitted a question to
matplotlib-users with the same subject. Eric Firing responded that
this is a manifestation of the "infamous path simplification" bug,
which should be fixed in svn. However, the script below shows the
same problem for me using the current svn on CentOS-5 with python 2.6.
For my purposes setting path.simplify to False is fine but Eric
requested that I provide an example, so here it is:
import numpy
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
y = numpy.array([
4., 2., 2., 3., 3., 2., 2., 6., 6., 5., 5., 4., 4.,
7., 7., 2., 2., 4., 4., 2., 2., 2., 2., 4., 4., 4.,
4., 4., 4., 7., 7., 3., 3., 5., 5., 4., 4., 5., 5.,
4., 4., 7., 7., 6., 6., 2., 2., 2., 2., 5., 5., 4.,
4., 4., 4., 6., 6., 3., 3., 4., 4., 3., 3., 2., 2.,
3., 3., 4., 4., 4., 4., 4., 4., 6., 6., 5., 5., 4.,
4., 7., 7., 3., 3., 4., 4., 4., 4., 5., 5., 4., 4.,
7., 7., 3., 3., 4., 4., 4., 4., 6., 6., 4., 4., 4.,
4., 4., 4., 2., 2., 5., 5., 6., 6., 3., 3., 5., 5.,
4., 4., 0., 0., 5., 5., 1., 1., 4., 4., 5., 5., 4.])
plt.figure(figsize=(7,4))
plt.plot(y)
plt.savefig('test.png')
plt.xlim(-12000, 8274)
plt.savefig('test_panned.png')
- Tom
Thanks. I can confirm this with today's SVN. I'm looking into the cause.
Mike
On 04/25/2010 07:11 PM, Tom Aldcroft wrote:
> import numpy
> import matplotlib
> matplotlib.use('Agg')
> import matplotlib.pyplot as plt
>
> y = numpy.array([
> 4., 2., 2., 3., 3., 2., 2., 6., 6., 5., 5., 4., 4.,
> 7., 7., 2., 2., 4., 4., 2., 2., 2., 2., 4., 4., 4.,
> 4., 4., 4., 7., 7., 3., 3., 5., 5., 4., 4., 5., 5.,
> 4., 4., 7., 7., 6., 6., 2., 2., 2., 2., 5., 5., 4.,
> 4., 4., 4., 6., 6., 3., 3., 4., 4., 3., 3., 2., 2.,
> 3., 3., 4., 4., 4., 4., 4., 4., 6., 6., 5., 5., 4.,
> 4., 7., 7., 3., 3., 4., 4., 4., 4., 5., 5., 4., 4.,
> 7., 7., 3., 3., 4., 4., 4., 4., 6., 6., 4., 4., 4.,
> 4., 4., 4., 2., 2., 5., 5., 6., 6., 3., 3., 5., 5.,
> 4., 4., 0., 0., 5., 5., 1., 1., 4., 4., 5., 5., 4.])
>
> plt.figure(figsize=(7,4))
> plt.plot(y)
> plt.savefig('test.png')
>
> plt.xlim(-12000, 8274)
> plt.savefig('test_panned.png')
>
I think this is due to improper use of the path.simplify_threshold value
in the simplification code. It should have been squared since it's used
in a 2-dimensional euclidean distance calculation.
I have made the change to SVN r8280 and updated a few of the unit tests
that are now more accurate than they used to be. As a workaround (if
you're not running from SVN and don't want to rebuild), you can set the
rcParam path.simplify_threshold to 0.01, rather than 0.1.
Mike
Michael Droettboom wrote:
> Thanks. I can confirm this with today's SVN. I'm looking into the cause.
>
> Mike
>
> On 04/25/2010 07:11 PM, Tom Aldcroft wrote:
>
>> import numpy
>> import matplotlib
>> matplotlib.use('Agg')
>> import matplotlib.pyplot as plt
>>
>> y = numpy.array([
>> 4., 2., 2., 3., 3., 2., 2., 6., 6., 5., 5., 4., 4.,
>> 7., 7., 2., 2., 4., 4., 2., 2., 2., 2., 4., 4., 4.,
>> 4., 4., 4., 7., 7., 3., 3., 5., 5., 4., 4., 5., 5.,
>> 4., 4., 7., 7., 6., 6., 2., 2., 2., 2., 5., 5., 4.,
>> 4., 4., 4., 6., 6., 3., 3., 4., 4., 3., 3., 2., 2.,
>> 3., 3., 4., 4., 4., 4., 4., 4., 6., 6., 5., 5., 4.,
>> 4., 7., 7., 3., 3., 4., 4., 4., 4., 5., 5., 4., 4.,
>> 7., 7., 3., 3., 4., 4., 4., 4., 6., 6., 4., 4., 4.,
>> 4., 4., 4., 2., 2., 5., 5., 6., 6., 3., 3., 5., 5.,
>> 4., 4., 0., 0., 5., 5., 1., 1., 4., 4., 5., 5., 4.])
>>
>> plt.figure(figsize=(7,4))
>> plt.plot(y)
>> plt.savefig('test.png')
>>
>> plt.xlim(-12000, 8274)
>> plt.savefig('test_panned.png')
>>
>>
>
>
> ------------------------------------------------------------------------------
> _______________________________________________
> Matplotlib-devel mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
>
--
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA