import logging
import traitlets as traits
from nbconvert.preprocessors import Preprocessor
from nbformat.notebooknode import NotebookNode
[docs]class LatexCaptions(Preprocessor):
""" a preprocessor to
1. find cells with a ipub.caption meta-tag,
extract the caption and label to a dict and remove the cell
2. find cells with the found labels and replace their captions
"""
add_prefix = traits.Bool(False, help="add float type/number prefix to caption (from caption_prefix tag)").tag(
config=True)
[docs] def preprocess(self, nb, resources):
logging.info('extracting caption cells')
# extract captions
final_cells = []
captions = {}
for cell in nb.cells:
if hasattr(cell.metadata, 'ipub'):
if hasattr(cell.metadata.ipub.get('equation', False), 'get'):
if hasattr(cell.metadata.ipub.equation.get('environment', False), 'startswith'):
if cell.metadata.ipub.equation.environment.startswith('breqn'):
if "ipub" not in nb.metadata:
nb.metadata["ipub"] = NotebookNode({'enable_breqn': True})
else:
nb.metadata.ipub['enable_breqn'] = True
if hasattr(cell.metadata.ipub, 'caption'):
if cell.cell_type == 'markdown':
capt = cell.source.split(r'\n')[0]
captions[cell.metadata.ipub.caption] = capt
continue
elif cell.cell_type == 'code':
if not cell.outputs:
pass
elif "text/latex" in cell.outputs[0].get('data', {}):
capt = cell.outputs[0].data["text/latex"].split(r'\n')[0]
captions[cell.metadata.ipub.caption] = capt
continue
elif "text/plain" in cell.outputs[0].get('data', {}):
capt = cell.outputs[0].data["text/plain"].split(r'\n')[0]
captions[cell.metadata.ipub.caption] = capt
continue
final_cells.append(cell)
nb.cells = final_cells
# replace captions
for cell in nb.cells:
if hasattr(cell.metadata, 'ipub'):
for key in cell.metadata.ipub:
if hasattr(cell.metadata.ipub[key], 'label'):
if cell.metadata.ipub[key]['label'] in captions:
logging.debug('replacing caption for: {}'.format(cell.metadata.ipub[key]['label']))
cell.metadata.ipub[key]['caption'] = captions[cell.metadata.ipub[key]['label']]
# add float type/number prefix to caption, if required
if self.add_prefix:
if hasattr(cell.metadata.ipub[key], 'caption'):
if hasattr(cell.metadata.ipub[key], 'caption_prefix'):
newcaption = cell.metadata.ipub[key].caption_prefix + cell.metadata.ipub[key].caption
cell.metadata.ipub[key].caption = newcaption
return nb, resources