240 lines
9.2 KiB
Python
240 lines
9.2 KiB
Python
from __future__ import division
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import os
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import copy
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import logging
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import subprocess
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import numpy as np
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import pandas as pd
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from .base import BaseParser
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from ..core import Table
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from ..utils import (scale_image, scale_pdf, segments_in_bbox, text_in_bbox,
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merge_close_values, get_table_index, compute_accuracy,
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count_empty_strings, encode_, setup_logging)
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from ..image_processing import (adaptive_threshold, find_lines,
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find_table_contours, find_table_joints)
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logger = setup_logging(__name__)
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class Lattice(BaseParser):
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"""
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"""
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def __init__(self, table_area=None, fill=None, mtol=2, jtol=2,
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blocksize=15, threshold_constant=-2, scale=15, iterations=0,
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invert=False, margins=(1.0, 0.5, 0.1), split_text=False,
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flag_size=True, shift_text=['l', 't'], debug=None):
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self.table_area = table_area
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self.fill = fill
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self.mtol = mtol
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self.jtol = jtol
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self.blocksize = blocksize
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self.threshold_constant = threshold_constant
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self.scale = scale
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self.iterations = iterations
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self.invert = invert
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self.char_margin, self.line_margin, self.word_margin = margins
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self.split_text = split_text
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self.flag_size = flag_size
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self.shift_text = shift_text
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self.debug = debug
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@staticmethod
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def _reduce_index(t, idx, shift_text):
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indices = []
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for r_idx, c_idx, text in idx:
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for d in shift_text:
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if d == 'l':
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if t.cells[r_idx][c_idx].hspan:
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while not t.cells[r_idx][c_idx].left:
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c_idx -= 1
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if d == 'r':
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if t.cells[r_idx][c_idx].hspan:
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while not t.cells[r_idx][c_idx].right:
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c_idx += 1
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if d == 't':
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if t.cells[r_idx][c_idx].vspan:
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while not t.cells[r_idx][c_idx].top:
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r_idx -= 1
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if d == 'b':
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if t.cells[r_idx][c_idx].vspan:
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while not t.cells[r_idx][c_idx].bottom:
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r_idx += 1
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indices.append((r_idx, c_idx, text))
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return indices
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@staticmethod
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def _fill_spanning(t, fill=None):
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for f in fill:
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if f == "h":
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for i in range(len(t.cells)):
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for j in range(len(t.cells[i])):
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if t.cells[i][j].text.strip() == '':
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if t.cells[i][j].hspan and not t.cells[i][j].left:
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t.cells[i][j].text = t.cells[i][j - 1].text
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elif f == "v":
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for i in range(len(t.cells)):
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for j in range(len(t.cells[i])):
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if t.cells[i][j].text.strip() == '':
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if t.cells[i][j].vspan and not t.cells[i][j].top:
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t.cells[i][j].text = t.cells[i - 1][j].text
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return t
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def _generate_image(self):
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self.imagename = ''.join([self.rootname, '.png'])
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gs_call = [
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"-q", "-sDEVICE=png16m", "-o", self.imagename, "-r600", self.filename
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]
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if "ghostscript" in subprocess.check_output(["gs", "-version"]).lower():
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gs_call.insert(0, "gs")
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else:
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gs_call.insert(0, "gsc")
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subprocess.call(gs_call, stdout=open(os.devnull, 'w'),
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stderr=subprocess.STDOUT)
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def _generate_table_bbox(self):
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self.image, self.threshold = adaptive_threshold(self.imagename, invert=self.invert,
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blocksize=self.blocksize, c=self.threshold_constant)
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image_width = self.image.shape[1]
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image_height = self.image.shape[0]
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image_width_scaler = image_width / float(self.pdf_width)
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image_height_scaler = image_height / float(self.pdf_height)
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pdf_width_scaler = self.pdf_width / float(image_width)
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pdf_height_scaler = self.pdf_height / float(image_height)
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image_scalers = (image_width_scaler, image_height_scaler, self.pdf_height)
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pdf_scalers = (pdf_width_scaler, pdf_height_scaler, image_height)
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vertical_mask, vertical_segments = find_lines(self.threshold,
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direction='vertical', scale=self.scale, iterations=self.iterations)
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horizontal_mask, horizontal_segments = find_lines(self.threshold,
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direction='horizontal', scale=self.scale, iterations=self.iterations)
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if self.table_area is not None:
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areas = []
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for area in self.table_area:
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x1, y1, x2, y2 = area.split(",")
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x1 = float(x1)
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y1 = float(y1)
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x2 = float(x2)
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y2 = float(y2)
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x1, y1, x2, y2 = scale_pdf((x1, y1, x2, y2), image_scalers)
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areas.append((x1, y1, abs(x2 - x1), abs(y2 - y1)))
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table_bbox = find_table_joints(areas, vertical_mask, horizontal_mask)
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else:
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contours = find_table_contours(vertical_mask, horizontal_mask)
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table_bbox = find_table_joints(contours, vertical_mask, horizontal_mask)
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self.table_bbox_unscaled = copy.deepcopy(table_bbox)
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self.table_bbox, self.vertical_segments, self.horizontal_segments = scale_image(
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table_bbox, vertical_segments, horizontal_segments, pdf_scalers)
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def _generate_columns_and_rows(self, table_idx, tk):
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# select elements which lie within table_bbox
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t_bbox = {}
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v_s, h_s = segments_in_bbox(
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tk, self.vertical_segments, self.horizontal_segments)
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t_bbox['horizontal'] = text_in_bbox(tk, self.horizontal_text)
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t_bbox['vertical'] = text_in_bbox(tk, self.vertical_text)
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self.t_bbox = t_bbox
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for direction in t_bbox:
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t_bbox[direction].sort(key=lambda x: (-x.y0, x.x0))
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cols, rows = zip(*self.table_bbox[tk])
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cols, rows = list(cols), list(rows)
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cols.extend([tk[0], tk[2]])
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rows.extend([tk[1], tk[3]])
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# sort horizontal and vertical segments
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cols = merge_close_values(sorted(cols), mtol=self.mtol)
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rows = merge_close_values(sorted(rows, reverse=True), mtol=self.mtol)
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# make grid using x and y coord of shortlisted rows and cols
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cols = [(cols[i], cols[i + 1])
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for i in range(0, len(cols) - 1)]
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rows = [(rows[i], rows[i + 1])
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for i in range(0, len(rows) - 1)]
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return cols, rows, v_s, h_s
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def _generate_table(self, table_idx, cols, rows, **kwargs):
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v_s = kwargs.get('v_s')
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h_s = kwargs.get('h_s')
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if v_s is None or h_s is None:
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raise ValueError('No segments found on {}'.format(self.rootname))
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table = Table(cols, rows)
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# set table edges to True using ver+hor lines
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table = table.set_edges(v_s, h_s, jtol=self.jtol)
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# set spanning cells to True
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table = table.set_span()
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# set table border edges to True
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table = table.set_border()
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pos_errors = []
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for direction in self.t_bbox:
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for t in self.t_bbox[direction]:
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indices, error = get_table_index(
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table, t, direction, split_text=self.split_text,
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flag_size=self.flag_size)
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if indices[:2] != (-1, -1):
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pos_errors.append(error)
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indices = Lattice._reduce_index(table, indices, shift_text=self.shift_text)
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for r_idx, c_idx, text in indices:
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table.cells[r_idx][c_idx].text = text
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accuracy = compute_accuracy([[100, pos_errors]])
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if self.fill is not None:
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table = Lattice._fill_spanning(table, fill=self.fill)
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data = table.data
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data = encode_(data)
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table.df = pd.DataFrame(data)
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table.shape = table.df.shape
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whitespace, __, __ = count_empty_strings(data)
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table.accuracy = accuracy
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table.whitespace = whitespace
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table.order = table_idx + 1
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table.page = int(os.path.basename(self.rootname).replace('page-', ''))
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return table
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def extract_tables(self, filename):
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"""
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Parameters
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----------
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filename
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Returns
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-------
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"""
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logger.info('Processing {}'.format(os.path.basename(filename)))
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self._generate_layout(filename)
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if not self.horizontal_text:
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logger.info("No tables found on {}".format(
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os.path.basename(self.rootname)))
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return [], self.g
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self._generate_image()
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self._generate_table_bbox()
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_tables = []
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# sort tables based on y-coord
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for table_idx, tk in enumerate(sorted(self.table_bbox.keys(),
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key=lambda x: x[1], reverse=True)):
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cols, rows, v_s, h_s = self._generate_columns_and_rows(table_idx, tk)
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table = self._generate_table(table_idx, cols, rows, v_s=v_s, h_s=h_s)
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_tables.append(table)
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if self.debug:
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self.g.images = (self.image, self.table_bbox_unscaled)
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self.g.segments = (self.vertical_segments, self.horizontal_segments)
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self.g.tables = _tables
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return _tables, self.g |