# -*- coding: utf-8 -*-
# Author: Óscar Nájera
# License: 3-clause BSD
"""
Scrapers for embedding images
=============================
Collect images that have been produced by code blocks.
The only scrapers we support are Matplotlib and Mayavi, others should
live in modules that will support them (e.g., PyVista, Plotly).
"""
import os
import sys
from .utils import scale_image
__all__ = ['save_figures', 'figure_rst', 'ImagePathIterator', 'clean_modules',
'matplotlib_scraper', 'mayavi_scraper']
###############################################################################
# Scrapers
def _import_matplotlib():
"""Import matplotlib safely."""
# make sure that the Agg backend is set before importing any
# matplotlib
import matplotlib
matplotlib.use('agg')
matplotlib_backend = matplotlib.get_backend().lower()
if matplotlib_backend != 'agg':
raise ValueError(
"Sphinx-Gallery relies on the matplotlib 'agg' backend to "
"render figures and write them to files. You are "
"currently using the {} backend. Sphinx-Gallery will "
"terminate the build now, because changing backends is "
"not well supported by matplotlib. We advise you to move "
"sphinx_gallery imports before any matplotlib-dependent "
"import. Moving sphinx_gallery imports at the top of "
"your conf.py file should fix this issue"
.format(matplotlib_backend))
import matplotlib.pyplot as plt
return matplotlib, plt
# eventually it would be nice not to have to require MPL e.g. for PNG-based
# scrapers, but for now we need to do it to ensure we get Agg
_import_matplotlib()
[docs]def matplotlib_scraper(block, block_vars, gallery_conf, **kwargs):
"""Scrape Matplotlib images.
Parameters
----------
block : tuple
A tuple containing the (label, content, line_number) of the block.
block_vars : dict
Dict of block variables.
gallery_conf : dict
Contains the configuration of Sphinx-Gallery
**kwargs : dict
Additional keyword arguments to pass to
:meth:`~matplotlib.figure.Figure.savefig`, e.g. ``format='svg'``.
The ``format`` kwarg in particular is used to set the file extension
of the output file (currently only 'png', 'jpg', and 'svg' are
supported).
Returns
-------
rst : str
The ReSTructuredText that will be rendered to HTML containing
the images. This is often produced by :func:`figure_rst`.
"""
matplotlib, plt = _import_matplotlib()
image_path_iterator = block_vars['image_path_iterator']
image_paths = list()
for fig_num, image_path in zip(plt.get_fignums(), image_path_iterator):
if 'format' in kwargs:
image_path = '%s.%s' % (os.path.splitext(image_path)[0],
kwargs['format'])
# Set the fig_num figure as the current figure as we can't
# save a figure that's not the current figure.
fig = plt.figure(fig_num)
to_rgba = matplotlib.colors.colorConverter.to_rgba
# shallow copy should be fine here, just want to avoid changing
# "kwargs" for subsequent figures processed by the loop
these_kwargs = kwargs.copy()
for attr in ['facecolor', 'edgecolor']:
fig_attr = getattr(fig, 'get_' + attr)()
default_attr = matplotlib.rcParams['figure.' + attr]
if to_rgba(fig_attr) != to_rgba(default_attr) and \
attr not in kwargs:
these_kwargs[attr] = fig_attr
fig.savefig(image_path, **these_kwargs)
image_paths.append(image_path)
plt.close('all')
return figure_rst(image_paths, gallery_conf['src_dir'])
[docs]def mayavi_scraper(block, block_vars, gallery_conf):
"""Scrape Mayavi images.
Parameters
----------
block : tuple
A tuple containing the (label, content, line_number) of the block.
block_vars : dict
Dict of block variables.
gallery_conf : dict
Contains the configuration of Sphinx-Gallery
Returns
-------
rst : str
The ReSTructuredText that will be rendered to HTML containing
the images. This is often produced by :func:`figure_rst`.
"""
from mayavi import mlab
image_path_iterator = block_vars['image_path_iterator']
image_paths = list()
e = mlab.get_engine()
for scene, image_path in zip(e.scenes, image_path_iterator):
mlab.savefig(image_path, figure=scene)
# make sure the image is not too large
scale_image(image_path, image_path, 850, 999)
image_paths.append(image_path)
mlab.close(all=True)
return figure_rst(image_paths, gallery_conf['src_dir'])
_scraper_dict = dict(
matplotlib=matplotlib_scraper,
mayavi=mayavi_scraper,
)
[docs]class ImagePathIterator(object):
"""Iterate over image paths for a given example.
Parameters
----------
image_path : str
The template image path.
"""
def __init__(self, image_path):
self.image_path = image_path
self.paths = list()
self._stop = 1000000
def __len__(self):
"""Return the number of image paths used.
Returns
-------
n_paths : int
The number of paths.
"""
return len(self.paths)
def __iter__(self):
"""Iterate over paths.
Returns
-------
paths : iterable of str
This enables the use of this Python pattern::
>>> for epoch in epochs: # doctest: +SKIP
>>> print(epoch) # doctest: +SKIP
Where ``epoch`` is given by successive outputs of
:func:`mne.Epochs.next`.
"""
# we should really never have 1e6, let's prevent some user pain
for ii in range(self._stop):
yield self.next()
else:
raise RuntimeError('Generated over %s images' % (self._stop,))
def next(self):
return self.__next__()
def __next__(self):
# The +1 here is because we start image numbering at 1 in filenames
path = self.image_path.format(len(self) + 1)
self.paths.append(path)
return path
# For now, these are what we support
_KNOWN_IMG_EXTS = ('png', 'svg', 'jpg') # XXX add gif next
def _find_image_ext(path, number=None):
"""Find an image, tolerant of different file extensions."""
if number is not None:
path = path.format(number)
path = os.path.splitext(path)[0]
for ext in _KNOWN_IMG_EXTS:
this_path = '%s.%s' % (path, ext)
if os.path.isfile(this_path):
break
else:
ext = 'png'
return ('%s.%s' % (path, ext), ext)
# The following strings are used when we have several pictures: we use
# an html div tag that our CSS uses to turn the lists into horizontal
# lists.
HLIST_HEADER = """
.. rst-class:: sphx-glr-horizontal
"""
HLIST_IMAGE_TEMPLATE = """
*
.. image:: /%s
:class: sphx-glr-multi-img
"""
SINGLE_IMAGE = """
.. image:: /%s
:class: sphx-glr-single-img
"""
###############################################################################
# Module resetting
def _reset_matplotlib(gallery_conf, fname):
"""Reset matplotlib."""
_, plt = _import_matplotlib()
plt.rcdefaults()
def _reset_seaborn(gallery_conf, fname):
"""Reset seaborn."""
# Horrible code to 'unload' seaborn, so that it resets
# its default when is load
# Python does not support unloading of modules
# https://bugs.python.org/issue9072
for module in list(sys.modules.keys()):
if 'seaborn' in module:
del sys.modules[module]
_reset_dict = {
'matplotlib': _reset_matplotlib,
'seaborn': _reset_seaborn,
}
[docs]def clean_modules(gallery_conf, fname):
"""Remove, unload, or reset modules after running each example.
After a script is executed it can load a variety of settings that one
does not want to influence in other examples in the gallery.
Parameters
----------
gallery_conf : dict
The gallery configuration.
fname : str or None
The example being run. Will be None when this is called entering
a directory of examples to be built.
"""
for reset_module in gallery_conf['reset_modules']:
reset_module(gallery_conf, fname)