PDFPages Errors on savefig (missing encode) #9112
Description
With just a part of http://matplotlib.org/examples/pylab_examples/multipage_pdf.html
from matplotlib.backends.backend_pdf import PdfPages
import matplotlib.pyplot as plt
with PdfPages('multipage_pdf.pdf') as pdf:
plt.figure(figsize=(3, 3))
plt.plot(range(7), [3, 1, 4, 1, 5, 9, 2], 'r-o')
plt.title('Page One')
pdf.savefig() # saves the current figure into a pdf page
plt.close()Traceback
pdf.savefig()
File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_pdf.py", line 2462, in savefig
figure.savefig(self, format='pdf', **kwargs)
File "/usr/lib/python3/dist-packages/matplotlib/figure.py", line 1572, in savefig
self.canvas.print_figure(*args, **kwargs)
File "/usr/lib/python3/dist-packages/matplotlib/backend_bases.py", line 2245, in print_figure
**kwargs)
File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_cairo.py", line 483, in print_pdf
return self._save(fobj, 'pdf', *args, **kwargs)
File "/usr/lib/python3/dist-packages/matplotlib/backends/backend_cairo.py", line 516, in _save
surface = cairo.PDFSurface (fo, width_in_points, height_in_points)
File "/usr/lib/python3/dist-packages/cairocffi/surfaces.py", line 792, in __init__
_encode_filename(target), width_in_points, height_in_points)
File "/usr/lib/python3/dist-packages/cairocffi/surfaces.py", line 52, in _encode_filename
filename = filename.encode(sys.getfilesystemencoding())
AttributeError: 'PdfPages' object has no attribute 'encode'
The issue I see lies in Figure.savefig(self, *args, **kwargs) where Args get listed as:
Arguments:
*fname*:
A string containing a path to a filename, or a Python
file-like object, or possibly some backend-dependent object
such as :class:`~matplotlib.backends.backend_pdf.PdfPages`.
However the stack show above shows this "filename" passed down to cairosurfaces where it wants to encode the filename, which it can't do as it has a PDFPages object and not a filename.
I have been looking through the tests and we don't seem to try to save any tests for this. Maybe however this bug comes up only with the cairocffi.