matplotlib-users Mailing List for matplotlib

I've encountered a segmentation fault using the Agg backend when making 
and saving a png plot. The segmentation fault does not seem to occur 
under different backends (e.g. Cairo).
The sequence of commands amounts to making a plot, setting the limits of 
the plot, then saving the plot as a png using savefig. If the value of 
one of the points is too large, a segmentation fault is generated. 
Obviously the simple work-around is to not plot the out-of-bounds 
points, but the segmentation fault is probably not the desired behavior! 
Below is an example, which generates a segmentation fault on matplotlib 
versions 0.99.0 (run on OS X 10.5.8) and 0.98.5.2 (run on Fedora 11 and 
CentOS 5.3).
Can others reproduce this issue?
Thanks,
Mike Nicolls
import scipy
import matplotlib
matplotlib.use('Agg')
import pylab
if __name__ == '__main__':
 
 xdata,ydata = scipy.rand(2,10)
 xdata[3]=1.0e9 # comment out to avoid seg fault
 
 pylab.figure()
 pylab.plot(xdata,ydata,'k.')
 pylab.xlim((0.0,1.0))
 
 pylab.savefig('test.png')

Teemu Rinne wrote:
> from matplotlib import ft2font
> ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/2.5/ 
> lib/python
> 2.5/site-packages/matplotlib/ft2font.so, 2): Library not loaded: / 
> Users/jdhunter
> /devbuild/lib/libfreetype.6.dylib
> Am I missing something or is this 0.99.1 OSX package somehow broken?
I think it's broken -- it's looking for a libfreetype in the:
Users/jdhunter/devbuild/lib/
dir, which you're pretty unlikely to have!
John, did you mean to have only static lbs in your devbuild/lib dir, 
which I think would work?
-Chris
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On Wed, Sep 23, 2009 at 3:51 PM, Mark Bakker <ma...@gm...> wrote:
> Hello list,
> I recently started using Eclipse with Pydev. I like it a lot but have not
> been able to get interactive plotting going (which otherwise works fine).
>
> My file is simple:
>
> from pylab import *
>
> ion()
>
> plot([1,2,3])
>
>
>
You need to issue a show() here. Thus the plotting window will hang on the
screen until you close it.
Eclipse Platform
Version: 3.5.0
Build id: I20090611-1540
PyDev for Eclipse 1.5.0.1251989166
org.python.pydev.feature.feature.group
> When I run this form within Eclipse, I do see a graphing window open up but
> then it disappears again when it is done, before I can even look at it.
>
> Any suggestions on how to keep the graphing window open?
>
> Thanks,
>
> Mark
>
>
>
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-- 
Gökhan

Hello list,
I recently started using Eclipse with Pydev. I like it a lot but have not
been able to get interactive plotting going (which otherwise works fine).
My file is simple:
from pylab import *
ion()
plot([1,2,3])
When I run this form within Eclipse, I do see a graphing window open up but
then it disappears again when it is done, before I can even look at it.
Any suggestions on how to keep the graphing window open?
Thanks,
Mark

Hi,
I tried to install 0.99.1 [I installed 0.99 a few days ago. I hoped 
that with 0.99.1 I'd get rid of problems with using imshow with 
masked_array and set_bad(alpha=0.0)]:
Python 2.5.2 (r252:60911, Feb 22 2008, 07:57:53)
[GCC 4.0.1 (Apple Computer, Inc. build 5363)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
 >>> from pylab import *
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
 File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ 
python2.5/site-pac
kages/pylab.py", line 1, in <module>
 from matplotlib.pylab import *
 File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ 
python2.5/site-pac
kages/matplotlib/pylab.py", line 206, in <module>
 from matplotlib import mpl # pulls in most modules
 File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ 
python2.5/site-pac
kages/matplotlib/mpl.py", line 2, in <module>
 from matplotlib import axis
 File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ 
python2.5/site-pac
kages/matplotlib/axis.py", line 10, in <module>
 import matplotlib.font_manager as font_manager
 File "/Library/Frameworks/Python.framework/Versions/2.5/lib/ 
python2.5/site-pac
kages/matplotlib/font_manager.py", line 52, in <module>
 from matplotlib import ft2font
ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/2.5/ 
lib/python
2.5/site-packages/matplotlib/ft2font.so, 2): Library not loaded: / 
Users/jdhunter
/devbuild/lib/libfreetype.6.dylib
 Referenced from: /Library/Frameworks/Python.framework/Versions/2.5/ 
lib/python2
.5/site-packages/matplotlib/ft2font.so
 Reason: image not found
Am I missing something or is this 0.99.1 OSX package somehow broken?
Cheers,
Teemu Rinne
Dept Psychology
University of Helsinki

Hi,
pickers work great to make matplotlib plots more interactive/general user
friendly.
On the subject of the legend_picker.py example, I was wondering if it was
possible to combine both a legend picker and a line picker in the same plot.
>From what I gather they will both use the same onpick event callback. 
So my question is : How do I discriminate between a pick on the legend from
a pick on a line ? The event.artist is a line2D in both cases. 
 
John Hunter-4 wrote:
> 
> On Mon, Aug 3, 2009 at 11:38 PM, Gökhan Sever<gok...@gm...>
> wrote:
>> Hello,
>>
>> I was wondering if it is possible to hide some data on figures using a
>> say
>> right click option to any of the legend entry and make it temporarily
>> hidden/visible to better analyse the rest of the data?
>>
>> Check this screenshot for example:
>>
>> http://img25.imageshack.us/img25/9427/datahiding.png
>>
>> The red data clutters the rest of the figure, and I would like to be able
>> to
>> hide it temporarily so that I can investigate the other two relations
>> more
>> easily.
>>
>> Any ideas? or alternative solutions?
> 
> It's a nice idea, and should be doable with the pick interface we have
> for all mpl artists. Unfortunately, there were a few problems in the
> legend implementation which blocked the pick events from hitting the
> proxy lines they contained. I just made a few changes to mpl svn HEAD
> to support this, and added a new example.
> 
> examples/event_handling/legend_picking.py
> 
> which I'll include below. JJ could you review the changes to legend.py?
> 
> Instructions for checking out svn are at::
> 
> 
> http://matplotlib.sourceforge.net/faq/installing_faq.html#install-from-svn
> 
> Here is the example:
> 
> """
> Enable picking on the legend to toggle the legended line on and off
> """
> import numpy as np
> import matplotlib.pyplot as plt
> 
> t = np.arange(0.0, 0.2, 0.1)
> y1 = 2*np.sin(2*np.pi*t)
> y2 = 4*np.sin(2*np.pi*2*t)
> 
> fig = plt.figure()
> ax = fig.add_subplot(111)
> 
> line1, = ax.plot(t, y1, lw=2, color='red', label='1 hz')
> line2, = ax.plot(t, y2, lw=2, color='blue', label='2 hz')
> 
> leg = ax.legend(loc='upper left', fancybox=True, shadow=True)
> leg.get_frame().set_alpha(0.4)
> 
> 
> lines = [line1, line2]
> lined = dict()
> for legline, realine in zip(leg.get_lines(), lines):
> legline.set_picker(5) # 5 pts tolerance
> lined[legline] = realine
> 
> def onpick(event):
> legline = event.artist
> realline = lined[legline]
> vis = realline.get_visible()
> realline.set_visible(not vis)
> fig.canvas.draw()
> 
> fig.canvas.mpl_connect('pick_event', onpick)
> 
> plt.show()
> 
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View this message in context: http://www.nabble.com/Hiding-data-via-legend-tp24802219p25531267.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

Hi,
I have the same problem as Andrew Kelly
I did the example code below (from coords_demo.py) to reproduce the bug :
#!/usr/bin/env python
"""
An example of how to interact with the plotting canvas by connecting
to move and click events
"""
import sys
from pylab import *
t = arange(0.0, 1.0, 0.01)
s = sin(2*pi*t)
ax = subplot(111)
ax.set_xscale('log')
#ax.plot(t,s)
ax.axhline(0.5, 0, 1)
def on_move(event):
 # get the x and y pixel coords
 x, y = event.x, event.y
 
 if event.inaxes:
 ax = event.inaxes # the axes instance
 print 'data coords', event.xdata, event.ydata
 lst = ax.hitlist(event)
 
def on_click(event):
 # get the x and y coords, flip y from top to bottom
 x, y = event.x, event.y
 if event.button==1:
 if event.inaxes is not None:
 print 'data coords', event.xdata, event.ydata
binding_id = connect('motion_notify_event', on_move)
connect('button_press_event', on_click)
if "test_disconnect" in sys.argv:
 print "disconnecting console coordinate printout..."
 disconnect(binding_id)
show()
Regards,
Cédrick