matplotlib-users Mailing List for matplotlib

Hey all,

Anyone know what has changed from Maplotlib 1.0.x to 1.1.x that might cause
a PyQt4 application to segfault?

Here is the code I'm working on:
https://github.com/sunpy/sunpy/blob/master/doc/examples/rgb_composite/rgb_composite.py

It works fine with earlier versions of Matplotlib (0.99 and 1.0.x) but when
I try and run the demo with Matplotlib 1.1 I get a segfault.

Any ideas?

Thanks,
Keith

Benjamin Root <ben.root@...> writes:


> You might need to do a complete rebuild of your mpl trunk.  I would guess that 
> you originally built mpl when you had the older version of libpng.  When you 
> updated the library, that wouldn't trigger a relink of _png.so whenever you 
> rebuilt the trunk.  Wipe out the _png.so file and rebuild.Ben Root

OK. it's fixed now. It was probably all my fault, as I changed the way I
installed matplotlib. Before I was using the "python setupegg.py develop"
alternative and today I did "python setup.py install" (blame command line
completion). 
Thanks for your help.

Jorge

On Tue, Mar 6, 2012 at 12:26 PM, Jorge Scandaliaris
<jor...@ya...>wrote:

> Benjamin Root <ben.root@...> writes:
>
>
> >
> > Strange.  Could you include the entire sphinx output as well as any logs
> > that the build produced?Ben Root
> >
>
> Somehow I assumed that matplotlib itself was OK, but I just discovered
> something new:
>
> In [1]: import matplotlib.mathtext
> ---------------------------------------------------------------------------
> ImportError                               Traceback (most recent call last)
> /home/jscandal/<ipython-input-1-06d3562c96cd> in <module>()
> ----> 1 import matplotlib.mathtext
>
> /home/jscandal/sw/matplotlib/matplotlib.git/lib/matplotlib/mathtext.py in
> <module>()
>     59
>     60 import matplotlib.colors as mcolors
> ---> 61 import matplotlib._png as _png
>     62 ####################
>     63
>
> ImportError: libpng14.so.14: cannot open shared object file: No such
> file or directory
>
> Looking .../lib/matplotlib there are a few .so file and one is _png.so
> (shipped by matplotlib) which seem to require libpng14:
>
> $ ldd _png.so
>        linux-vdso.so.1 =>  (0x00007fffd3bff000)
>        libpng14.so.14 => not found
>        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007fad573ff000)
>        libpython2.7.so.1.0 => /usr/lib/libpython2.7.so.1.0
> (0x00007fad5703f000)
>        libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007fad56e29000)
>        libpthread.so.0 => /lib/libpthread.so.0 (0x00007fad56c0d000)
>        libc.so.6 => /lib/libc.so.6 (0x00007fad5686b000)
>        libm.so.6 => /lib/libm.so.6 (0x00007fad56577000)
>        /lib/ld-linux-x86-64.so.2 (0x00007fad57964000)
>        libdl.so.2 => /lib/libdl.so.2 (0x00007fad56373000)
>        libutil.so.1 => /lib/libutil.so.
>
>
> Does that give you any clue?
>
> Thanks,
>
> Jorge
>
>
You might need to do a complete rebuild of your mpl trunk.  I would guess
that you originally built mpl when you had the older version of libpng.
When you updated the library, that wouldn't trigger a relink of _png.so
whenever you rebuilt the trunk.  Wipe out the _png.so file and rebuild.

Ben Root

Benjamin Root <ben.root@...> writes:


> 
> Strange.  Could you include the entire sphinx output as well as any logs 
> that the build produced?Ben Root
> 

Somehow I assumed that matplotlib itself was OK, but I just discovered 
something new:

In [1]: import matplotlib.mathtext
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
/home/jscandal/<ipython-input-1-06d3562c96cd> in <module>()
----> 1 import matplotlib.mathtext

/home/jscandal/sw/matplotlib/matplotlib.git/lib/matplotlib/mathtext.py in 
<module>()
     59 
     60 import matplotlib.colors as mcolors
---> 61 import matplotlib._png as _png
     62 ####################
     63 

ImportError: libpng14.so.14: cannot open shared object file: No such 
file or directory

Looking .../lib/matplotlib there are a few .so file and one is _png.so 
(shipped by matplotlib) which seem to require libpng14:

$ ldd _png.so
        linux-vdso.so.1 =>  (0x00007fffd3bff000)
        libpng14.so.14 => not found
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007fad573ff000)
        libpython2.7.so.1.0 => /usr/lib/libpython2.7.so.1.0 
(0x00007fad5703f000)
        libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007fad56e29000)
        libpthread.so.0 => /lib/libpthread.so.0 (0x00007fad56c0d000)
        libc.so.6 => /lib/libc.so.6 (0x00007fad5686b000)
        libm.so.6 => /lib/libm.so.6 (0x00007fad56577000)
        /lib/ld-linux-x86-64.so.2 (0x00007fad57964000)
        libdl.so.2 => /lib/libdl.so.2 (0x00007fad56373000)
        libutil.so.1 => /lib/libutil.so.


Does that give you any clue?

Thanks,

Jorge

Hi:

I am getting an error when I save a figure as PDF with a particular
configuration and when I use a greek latex leter (say $\alpha$) as a
ylabel. The following code illustrates the problem.

###############################################
import matplotlib.pyplot as plt
import matplotlib as mpl

params = {
    'text.usetex' : True,
    'font.family': 'serif',
    'font.serif' : ['Times'],
    }
mpl.rcParams.update(params)

plt.figure()
plt.plot([1,2,3])
plt.ylabel(r'$\alpha$')
plt.savefig('f1.pdf')
###############################################

When I run it I get

Traceback (most recent call last):
  File "multipage_pdf.py", line 14, in <module>
    plt.savefig('f1.pdf')
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/pyplot.py",
line 472, in savefig
    return fig.savefig(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/figure.py",
line 1173, in savefig
    self.canvas.print_figure(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/backend_bases.py",
line 2027, in print_figure
    **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/backend_bases.py",
line 1799, in print_pdf
    return pdf.print_pdf(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_pdf.py",
line 2187, in print_pdf
    file.close()
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_pdf.py",
line 470, in close
    self.writeFonts()
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_pdf.py",
line 557, in writeFonts
    fonts[Fx] = self.embedTeXFont(filename, self.dviFontInfo[filename])
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_pdf.py",
line 622, in embedTeXFont
    t1font = t1font.transform(fontinfo.effects)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/type1font.py",
line 301, in transform
    buffer.write(value)
TypeError: unicode argument expected, got 'str'


Note that with any of the following variations the code works as expected:

- If I use plt.ylabel(r'$x_2$') instead of plt.ylabel(r'$\alpha$).
- If I save as PNG instead of PDF.
- Use the default configuration (comment the mpl.rcParams.update(params) line).

I am using MPL verion 1.2.x (built from commit 396a6446).

Am I doing something wrong? Any idea how to solve it?

Alejandro.

Benjamin Root <ben.root@...> writes:

> 
> Strange.  Could you include the entire sphinx output as well as any logs that
the build produced?Ben Root
> 

Well, all the output available was what I posted. I don't see any log file in
the build directory. I added the -P option to sphinx-build, the output is below.
I'll keep looking here, maybe there is a problem in my setup

$ sphinx-build -P -b html -d build/doctrees . build/html
Running Sphinx v1.1.2
Exception occurred while building, starting debugger:
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/sphinx/cmdline.py", line 188, in main
    warningiserror, tags)
  File "/usr/lib/python2.7/site-packages/sphinx/application.py", line 114, in
__init__
    self.setup_extension(extension)
  File "/usr/lib/python2.7/site-packages/sphinx/application.py", line 250, in
setup_extension
    err)
ExtensionError: Could not import extension matplotlib.sphinxext.mathmpl
(exception: libpng14.so.14: cannot open shared object file: No such file or
directory)
> /usr/lib/python2.7/site-packages/sphinx/application.py(250)setup_extension()
-> err)
(Pdb) q

Jorge

On Tue, Mar 6, 2012 at 9:27 AM, Jorge Scandaliaris
<jor...@ya...>wrote:

> Hi, I updated mpl to trunk today and I received the followin error when
> trying
> to build the documentation:
>
> $ python2 make.py html
> Running Sphinx v1.1.2
>
> Extension error:
> Could not import extension matplotlib.sphinxext.mathmpl (exception:
> libpng14.so.14: cannot open shared object file: No such file or directory)
> Building HTML failed.
>
> My distribution uses libpng 1.58, so it's no surprise there's no libpng14.
> Matplotlib itself detected the libpng version OK and built correctly. Any
> ideas?
>
> Thanks,
>
> Jorge
>
>
Strange.  Could you include the entire sphinx output as well as any logs
that the build produced?

Ben Root

Hi, I updated mpl to trunk today and I received the followin error when trying
to build the documentation:

$ python2 make.py html
Running Sphinx v1.1.2

Extension error:
Could not import extension matplotlib.sphinxext.mathmpl (exception:
libpng14.so.14: cannot open shared object file: No such file or directory)
Building HTML failed.

My distribution uses libpng 1.58, so it's no surprise there's no libpng14.
Matplotlib itself detected the libpng version OK and built correctly. Any ideas?

Thanks,

Jorge

Hi all,

I'm trying to make a simple bush a button plot something using
matplotlib and pyside, and noticed that one cannot use directly
FigureCanvas as the Widget, it has to be added to another QWidget
instead. I consider this a bug, but first thought of writing to the
mailing list to check it. The code example is here:

http://stackoverflow.com/questions/9500661/connecting-pyside-with-matplotlib-using-qtdesigner-using-pushbutton-to-draw/9571834#9571834

Although someone answered saying that now the widget that I promoted
is _the_ canvas that I have to draw, and not the canvas inside. Is
there anything more clear on that?

Thanks!