camelot-py/camelot/pdf.py

226 lines
8.8 KiB
Python

import os
import shutil
import tempfile
import itertools
import multiprocessing as mp
import cv2
from PyPDF2 import PdfFileReader, PdfFileWriter
__all__ = ['Pdf']
def _parse_page_numbers(pagenos):
"""Converts list of dicts to list of ints.
Parameters
----------
pagenos : list
List of dicts representing page ranges. A dict must have only
two keys named 'start' and 'end' having int as their value.
Returns
-------
page_numbers : list
List of int page numbers.
"""
page_numbers = []
for p in pagenos:
page_numbers.extend(range(p['start'], p['end'] + 1))
page_numbers = sorted(set(page_numbers))
return page_numbers
class Pdf:
"""Pdf manager.
Handles all operations like temp directory creation, splitting file
into single page pdfs, running extraction using multiple processes
and removing the temp directory.
Parameters
----------
extractor : object
camelot.stream.Stream or camelot.lattice.Lattice extractor
object.
pdfname : string
Path to pdf file.
pagenos : list
List of dicts representing page ranges. A dict must have only
two keys named 'start' and 'end' having int as their value.
(optional, default: [{'start': 1, 'end': 1}])
parallel : bool
Whether or not to run using multiple processes.
(optional, default: False)
clean : bool
Whether or not to remove the temp directory.
(optional, default: False)
"""
def __init__(self, extractor, pdfname, pagenos=[{'start': 1, 'end': 1}],
parallel=False, clean=False):
self.extractor = extractor
self.pdfname = pdfname
if not self.pdfname.endswith('.pdf'):
raise TypeError("Only PDF format is supported right now.")
self.pagenos = _parse_page_numbers(pagenos)
self.parallel = parallel
self.cpu_count = mp.cpu_count()
self.pool = mp.Pool(processes=self.cpu_count)
self.clean = clean
self.temp = tempfile.mkdtemp()
def split(self):
"""Splits file into single page pdfs.
"""
infile = PdfFileReader(open(self.pdfname, 'rb'), strict=False)
for p in self.pagenos:
page = infile.getPage(p - 1)
outfile = PdfFileWriter()
outfile.addPage(page)
with open(os.path.join(self.temp, 'page-{0}.pdf'.format(p)), 'wb') as f:
outfile.write(f)
def extract(self):
"""Runs table extraction by calling extractor.get_tables
on all single page pdfs.
"""
self.split()
pages = [os.path.join(self.temp, 'page-{0}.pdf'.format(p))
for p in self.pagenos]
if self.parallel:
tables = self.pool.map(self.extractor.get_tables, pages)
tables = {k: v for d in tables if d is not None for k, v in d.items()}
else:
tables = {}
if self.extractor.debug:
if self.extractor.method == 'stream':
self.debug = self.extractor.debug
self.debug_text = []
elif self.extractor.method == 'lattice':
self.debug = self.extractor.debug
self.debug_images = []
self.debug_segments = []
self.debug_tables = []
for p in pages:
table = self.extractor.get_tables(p)
if table is not None:
tables.update(table)
if self.extractor.debug:
if self.extractor.method == 'stream':
self.debug_text.append(self.extractor.debug_text)
elif self.extractor.method == 'lattice':
self.debug_images.append(self.extractor.debug_images)
self.debug_segments.append(self.extractor.debug_segments)
self.debug_tables.append(self.extractor.debug_tables)
if self.clean:
self.remove_tempdir()
return tables
def remove_tempdir(self):
"""Removes temporary directory that was created to save single
page pdfs and their images.
"""
shutil.rmtree(self.temp)
def debug_plot(self):
"""Generates a matplotlib plot based on the selected extractor
debug option.
"""
import matplotlib.pyplot as plt
import matplotlib.patches as patches
if self.debug is True:
try:
for text in self.debug_text:
fig = plt.figure()
ax = fig.add_subplot(111, aspect='equal')
xs, ys = [], []
for t in text:
xs.extend([t[0], t[1]])
ys.extend([t[2], t[3]])
ax.add_patch(
patches.Rectangle(
(t[0], t[1]),
t[2] - t[0],
t[3] - t[1]
)
)
ax.set_xlim(min(xs) - 10, max(xs) + 10)
ax.set_ylim(min(ys) - 10, max(ys) + 10)
plt.show()
except AttributeError:
raise ValueError("This option only be used with Stream.")
elif self.debug == 'contour':
try:
for img, table_bbox in self.debug_images:
for t in table_bbox.keys():
cv2.rectangle(img, (t[0], t[1]),
(t[2], t[3]), (255, 0, 0), 3)
plt.imshow(img)
plt.show()
except AttributeError:
raise ValueError("This option only be used with Lattice.")
elif self.debug == 'joint':
try:
for img, table_bbox in self.debug_images:
x_coord = []
y_coord = []
for k in table_bbox.keys():
for coord in table_bbox[k]:
x_coord.append(coord[0])
y_coord.append(coord[1])
max_x, max_y = max(x_coord), max(y_coord)
plt.plot(x_coord, y_coord, 'ro')
plt.axis([0, max_x + 100, max_y + 100, 0])
plt.imshow(img)
plt.show()
except AttributeError:
raise ValueError("This option only be used with Lattice.")
elif self.debug == 'line':
try:
for v_s, h_s in self.debug_segments:
for v in v_s:
plt.plot([v[0], v[2]], [v[1], v[3]])
for h in h_s:
plt.plot([h[0], h[2]], [h[1], h[3]])
plt.show()
except AttributeError:
raise ValueError("This option only be used with Lattice.")
elif self.debug == 'table':
try:
for tables in self.debug_tables:
for table in tables:
for r in range(len(table.rows)):
for c in range(len(table.cols)):
if table.cells[r][c].left:
plt.plot([table.cells[r][c].lb[0],
table.cells[r][c].lt[0]],
[table.cells[r][c].lb[1],
table.cells[r][c].lt[1]])
if table.cells[r][c].right:
plt.plot([table.cells[r][c].rb[0],
table.cells[r][c].rt[0]],
[table.cells[r][c].rb[1],
table.cells[r][c].rt[1]])
if table.cells[r][c].top:
plt.plot([table.cells[r][c].lt[0],
table.cells[r][c].rt[0]],
[table.cells[r][c].lt[1],
table.cells[r][c].rt[1]])
if table.cells[r][c].bottom:
plt.plot([table.cells[r][c].lb[0],
table.cells[r][c].rb[0]],
[table.cells[r][c].lb[1],
table.cells[r][c].rb[1]])
plt.show()
except AttributeError:
raise ValueError("This option only be used with Lattice.")
else:
raise UserWarning("This method can only be called after"
" debug has been specified.")