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I just installed matplotlib 1.4.2 via pip, and executing the file
matplotlib-1.4.2/examples/pylab_examples/tex_demo.py from the source
tarball gives the same error:

Traceback (most recent call last):
  File "matplotlib-1.4.2/examples/pylab_examples/tex_demo.py", line 29,
in <module>
    plt.savefig('tex_demo')
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/pyplot.py",
line 577, in savefig
    res = fig.savefig(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/figure.py",
line 1470, in savefig
    self.canvas.print_figure(*args, **kwargs)
  File
"/usr/local/lib/python2.7/dist-packages/matplotlib/backend_bases.py",
line 2194, in print_figure
    **kwargs)
  File
"/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_gtk3agg.py", line 97, in print_png
    return agg.print_png(filename, *args, **kwargs)
  File
"/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_agg.py", line 521, in print_png
    FigureCanvasAgg.draw(self)
  File
"/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_agg.py", line 469, in draw
    self.figure.draw(self.renderer)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/artist.py",
line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/figure.py",
line 1079, in draw
    func(*args)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/artist.py",
line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File
"/usr/local/lib/python2.7/dist-packages/matplotlib/axes/_base.py", line
2092, in draw
    a.draw(renderer)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/artist.py",
line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/axis.py", line
1128, in draw
    self.label.draw(renderer)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/artist.py",
line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/matplotlib/text.py", line
581, in draw
    self._fontproperties, angle, mtext=mtext)
  File
"/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_agg.py", line 259, in draw_tex
    self._renderer.draw_text_image(Z, x, y, angle, gc)
OverflowError: cannot convert float infinity to integer

System information
Linux mwlaptop 3.16.0-24-generic #32-Ubuntu SMP Tue Oct 28 13:07:32 UTC
2014 x86_64 x86_64 x86_64 GNU/Linux

Would it make sense to at least emit a warning when a mask is encountered.
There are very few places in matplotlib where masked arrays are not allowed
(I think histograms is the other spot, but I can't remember for sure).

On Sun, Nov 2, 2014 at 11:10 AM, Ian Thomas <ian...@gm...> wrote:

> On 1 November 2014 18:20, Hartmut Kaiser <har...@gm...> wrote:
>
>> Thanks Ian! Your detailed answer is much appreciated.
>>
>> As you might have already guessed, we have quite some problems creating
>> clean geometries from the generated contour data. I have tried to put
>> together one (reasonably) small test case illustrating at least one of our
>> issues. I apologize for the lengthy code attached.
>>
>> The two attached figures demonstrate what we see. Matplotlib.png
>> (generated by the library) does not really look ok. Also, the attached
>> shape.png shows that there are a lot of geometries generated which are
>> self-intersecting (highlighted in dark blue), and we already skip polygons
>> with less than 3 points. BTW, there are many polygons stacked with the same
>> geometries.
>>
>> Anything we can do about this?
>>
>> Thanks!
>> Regards Hartmut
>>
>
> Hartmut,
>
> You are using masked arrays where you shouldn't, again.  The documentation
> for tricontour states that it expects z to be an array, it doesn't say
> masked array.  If you pass it a masked array, it will ignore the mask.
> Hence you have a number of triangles that include a vertex with a z-value
> of -99999; when contoured these are going to give you lots of thin polygons
> that you don't want.
>
> You need to stop using masked arrays where they are not expected.  Your
> triangulation should only contain triangles for which you have valid data
> at all three vertices.  So either remove invalid triangles from your 'ele'
> array before creating the triangulation, or set a mask on the triangulation
> once it has been created, e.g.
>
>     point_mask_indices = numpy.where(z.mask)
>     tri_mask = numpy.any(numpy.in1d(ele, point_mask_indices).reshape(-1,
> 3), axis=1)
>     triang.set_mask(tri_mask)
>
> Ian
>
>
> ------------------------------------------------------------------------------
>
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
>

On 1 November 2014 18:20, Hartmut Kaiser <har...@gm...> wrote:

> Thanks Ian! Your detailed answer is much appreciated.
>
> As you might have already guessed, we have quite some problems creating
> clean geometries from the generated contour data. I have tried to put
> together one (reasonably) small test case illustrating at least one of our
> issues. I apologize for the lengthy code attached.
>
> The two attached figures demonstrate what we see. Matplotlib.png
> (generated by the library) does not really look ok. Also, the attached
> shape.png shows that there are a lot of geometries generated which are
> self-intersecting (highlighted in dark blue), and we already skip polygons
> with less than 3 points. BTW, there are many polygons stacked with the same
> geometries.
>
> Anything we can do about this?
>
> Thanks!
> Regards Hartmut
>

Hartmut,

You are using masked arrays where you shouldn't, again.  The documentation
for tricontour states that it expects z to be an array, it doesn't say
masked array.  If you pass it a masked array, it will ignore the mask.
Hence you have a number of triangles that include a vertex with a z-value
of -99999; when contoured these are going to give you lots of thin polygons
that you don't want.

You need to stop using masked arrays where they are not expected.  Your
triangulation should only contain triangles for which you have valid data
at all three vertices.  So either remove invalid triangles from your 'ele'
array before creating the triangulation, or set a mask on the triangulation
once it has been created, e.g.

    point_mask_indices = numpy.where(z.mask)
    tri_mask = numpy.any(numpy.in1d(ele, point_mask_indices).reshape(-1,
3), axis=1)
    triang.set_mask(tri_mask)

Ian

Well, the methodology is sufficient and efficient, I'm OK with that :)

Thanks for these additional information.

Regards,
Le 2 nov. 2014 09:34, "Scott Lasley" <sl...@sp...> a écrit :

> I wish I could say that it was because of a deep understanding of the
> inner workings of matplotlib or a rock solid grasp of python 3's bytes vs
> strings, but it wasn't.   fig.savefig threw the "TypeError: string argument
> expected, got 'bytes'" exception, so I figured BytesIO might work better
> with the binary png data than StringIO, and it did.  Your image URI
> included base64 encoding I added the base64 code and fiddled with decoding
> to get it to produce ASCII.  iPython is great for this sort of playing
> around with snippets of code.
>
> btw, if you are not aware of the pros and cons of using data uri's to
> embed images take a look at this Wikipedia page for some helpful information
> http://en.wikipedia.org/wiki/Data_URI_scheme
>
> Apologies if you were expecting a more detailed answer,
> Scott
>
>
> On Nov 1, 2014, at 4:37 PM, Julien Hillairet <jul...@gm...>
> wrote:
>
> > Indeed, it works also for me with Python 3.3.5.
> >
> > Could you explain the changes you made and the reasons behind the
> byte/string encoding ?
> >
> > Best regards,
> >
> > 2014-11-01 17:21 GMT+01:00 Scott Lasley <sl...@sp...>:
> > This works for me with python 3.4.2
> >
> > import matplotlib.pyplot as plt
> > from io import BytesIO
> > import base64
> >
> > fig = plt.figure()
> > ax = fig.add_subplot(111)
> > ax.plot([1,2,3])
> >
> > sio = BytesIO()
> >
> > fig.savefig(sio, format="png")
> >
> > html = """<html><body>
> > <img src="data:image/png;base64,{}"/>
> > </body></html>""".format(base64.encodebytes(sio.getvalue()).decode())
> >
> >
> > For python 2.7.8 change html =""" to
> >
> > html = """<html><body>
> > <img src="data:image/png;base64,%s"/>
> > </body></html>""" % base64.encodestring(sio.getvalue())
> >
> > Best regards,
> > Scott
> >
> >
> > On Nov 1, 2014, at 7:37 AM, Julien Hillairet <jul...@gm...>
> wrote:
> >
> > > Dear all,
> > > I'm trying to write a html page content in which a png figure is
> generated by matplotlib, with Python3.
> > > However, the following piece of code does not work with
> matplotlib/Python3 (while it should work with Python2). The error is the
> following on
> > > TypeError: string argument expected, got 'bytes'
> > > when on fig.savefig(sio, format="png")
> > > Could someone explain me how to do it ?
> > > Best regards,
> > > Julien
> > >
> > > --------------------------------------------
> > >
> > > import matplotlib.pyplot as plt
> > >
> > > from io import StringIO
> > > fig = plt.figure()
> > > ax = fig.add_subplot(111)
> > > ax.plot([1,2,3])
> > >
> > > sio = StringIO()
> > >
> > > fig.savefig(sio, format="png")
> > >
> > > html = """<html><body>
> > > ...a bunch of text and html here...
> > > <img src="data:image/png;base64,%s"/>
> > > ...more text and html...
> > > </body></html>""" % sio.getvalue().strip()
> > >
> > >
> ------------------------------------------------------------------------------
>
>

I wish I could say that it was because of a deep understanding of the inner workings of matplotlib or a rock solid grasp of python 3's bytes vs strings, but it wasn't.   fig.savefig threw the "TypeError: string argument expected, got 'bytes'" exception, so I figured BytesIO might work better with the binary png data than StringIO, and it did.  Your image URI included base64 encoding I added the base64 code and fiddled with decoding to get it to produce ASCII.  iPython is great for this sort of playing around with snippets of code.

btw, if you are not aware of the pros and cons of using data uri's to embed images take a look at this Wikipedia page for some helpful information
http://en.wikipedia.org/wiki/Data_URI_scheme

Apologies if you were expecting a more detailed answer,
Scott


On Nov 1, 2014, at 4:37 PM, Julien Hillairet <jul...@gm...> wrote:

> Indeed, it works also for me with Python 3.3.5. 
> 
> Could you explain the changes you made and the reasons behind the byte/string encoding ? 
> 
> Best regards,
> 
> 2014-11-01 17:21 GMT+01:00 Scott Lasley <sl...@sp...>:
> This works for me with python 3.4.2
> 
> import matplotlib.pyplot as plt
> from io import BytesIO
> import base64
> 
> fig = plt.figure()
> ax = fig.add_subplot(111)
> ax.plot([1,2,3])
> 
> sio = BytesIO()
> 
> fig.savefig(sio, format="png")
> 
> html = """<html><body>
> <img src="data:image/png;base64,{}"/>
> </body></html>""".format(base64.encodebytes(sio.getvalue()).decode())
> 
> 
> For python 2.7.8 change html =""" to
> 
> html = """<html><body>
> <img src="data:image/png;base64,%s"/>
> </body></html>""" % base64.encodestring(sio.getvalue())
> 
> Best regards,
> Scott
> 
> 
> On Nov 1, 2014, at 7:37 AM, Julien Hillairet <jul...@gm...> wrote:
> 
> > Dear all,
> > I'm trying to write a html page content in which a png figure is generated by matplotlib, with Python3.
> > However, the following piece of code does not work with matplotlib/Python3 (while it should work with Python2). The error is the following on
> > TypeError: string argument expected, got 'bytes'
> > when on fig.savefig(sio, format="png")
> > Could someone explain me how to do it ?
> > Best regards,
> > Julien
> >
> > --------------------------------------------
> >
> > import matplotlib.pyplot as plt
> >
> > from io import StringIO
> > fig = plt.figure()
> > ax = fig.add_subplot(111)
> > ax.plot([1,2,3])
> >
> > sio = StringIO()
> >
> > fig.savefig(sio, format="png")
> >
> > html = """<html><body>
> > ...a bunch of text and html here...
> > <img src="data:image/png;base64,%s"/>
> > ...more text and html...
> > </body></html>""" % sio.getvalue().strip()
> >
> > ------------------------------------------------------------------------------

How can I save a matplotlib figure with text as a postscript image and that
the text will be saved as text. Currently when I save the image as
postscript all the text in the image ( xlabel, ylabel etc.. ) is saved as
path and not as text.. Is it possible to save it as text?

If I use the following code ( use latex)

matplotlib.rcParams["text.usetex"] = True
and save the image as postscript the text is saved as text.. But I do not
want to use latex.. Is it possible without latex?


Thanks


Question also on stackoverflow
http://stackoverflow.com/questions/26649266/matplotlib-save-image-as-postscript-when-xlabel-is-saved-as-text-and-not-path



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