460 lines
16 KiB
Python
460 lines
16 KiB
Python
from __future__ import division
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import os
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import types
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import logging
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import copy_reg
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import numpy as np
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from .table import Table
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from .utils import (text_in_bbox, get_table_index, get_score, count_empty,
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encode_list, get_text_objects, get_page_layout)
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__all__ = ['Stream']
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def _reduce_method(m):
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if m.im_self is None:
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return getattr, (m.im_class, m.im_func.func_name)
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else:
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return getattr, (m.im_self, m.im_func.func_name)
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copy_reg.pickle(types.MethodType, _reduce_method)
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def _text_bbox(t_bbox):
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"""Returns bounding box for the text present on a page.
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Parameters
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----------
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t_bbox : dict
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Dict with two keys 'horizontal' and 'vertical' with lists of
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LTTextLineHorizontals and LTTextLineVerticals respectively.
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Returns
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-------
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text_bbox : tuple
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Tuple of the form (x0, y0, x1, y1) in PDFMiner's coordinate
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space.
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"""
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xmin = min([t.x0 for direction in t_bbox for t in t_bbox[direction]])
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ymin = min([t.y0 for direction in t_bbox for t in t_bbox[direction]])
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xmax = max([t.x1 for direction in t_bbox for t in t_bbox[direction]])
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ymax = max([t.y1 for direction in t_bbox for t in t_bbox[direction]])
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text_bbox = (xmin, ymin, xmax, ymax)
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return text_bbox
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def _group_rows(text, ytol=2):
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"""Groups PDFMiner text objects into rows using their
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y-coordinates taking into account some tolerance ytol.
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Parameters
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----------
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text : list
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List of PDFMiner text objects.
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ytol : int
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Tolerance parameter.
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(optional, default: 2)
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Returns
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-------
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rows : list
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Two-dimensional list of text objects grouped into rows.
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"""
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row_y = 0
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rows = []
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temp = []
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for t in text:
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# is checking for upright necessary?
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# if t.get_text().strip() and all([obj.upright for obj in t._objs if
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# type(obj) is LTChar]):
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if t.get_text().strip():
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if not np.isclose(row_y, t.y0, atol=ytol):
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rows.append(sorted(temp, key=lambda t: t.x0))
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temp = []
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row_y = t.y0
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temp.append(t)
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rows.append(sorted(temp, key=lambda t: t.x0))
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__ = rows.pop(0) # hacky
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return rows
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def _merge_columns(l, mtol=0):
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"""Merges column boundaries if they overlap or lie within some
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tolerance mtol.
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Parameters
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----------
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l : list
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List of column coordinate tuples.
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mtol : int
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TODO
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(optional, default: 0)
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Returns
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-------
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merged : list
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List of merged column coordinate tuples.
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"""
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merged = []
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for higher in l:
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if not merged:
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merged.append(higher)
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else:
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lower = merged[-1]
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if mtol >= 0:
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if (higher[0] <= lower[1] or
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np.isclose(higher[0], lower[1], atol=mtol)):
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upper_bound = max(lower[1], higher[1])
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lower_bound = min(lower[0], higher[0])
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merged[-1] = (lower_bound, upper_bound)
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else:
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merged.append(higher)
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elif mtol < 0:
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if higher[0] <= lower[1]:
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if np.isclose(higher[0], lower[1], atol=abs(mtol)):
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merged.append(higher)
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else:
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upper_bound = max(lower[1], higher[1])
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lower_bound = min(lower[0], higher[0])
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merged[-1] = (lower_bound, upper_bound)
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else:
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merged.append(higher)
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return merged
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def _join_rows(rows_grouped, text_y_max, text_y_min):
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"""Makes row coordinates continuous.
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Parameters
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----------
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rows_grouped : list
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Two-dimensional list of text objects grouped into rows.
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text_y_max : int
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text_y_min : int
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Returns
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-------
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rows : list
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List of continuous row coordinate tuples.
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"""
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row_mids = [sum([(t.y0 + t.y1) / 2 for t in r]) / len(r)
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if len(r) > 0 else 0 for r in rows_grouped]
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rows = [(row_mids[i] + row_mids[i - 1]) / 2 for i in range(1, len(row_mids))]
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rows.insert(0, text_y_max)
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rows.append(text_y_min)
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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 rows
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def _join_columns(cols, text_x_min, text_x_max):
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"""Makes column coordinates continuous.
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Parameters
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----------
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cols : list
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List of column coordinate tuples.
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text_x_min : int
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text_y_max : int
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Returns
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-------
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cols : list
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Updated list of column coordinate tuples.
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"""
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cols = sorted(cols)
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cols = [(cols[i][0] + cols[i - 1][1]) / 2 for i in range(1, len(cols))]
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cols.insert(0, text_x_min)
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cols.append(text_x_max)
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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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return cols
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def _add_columns(cols, text, ytol):
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"""Adds columns to existing list by taking into account
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the text that lies outside the current column coordinates.
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Parameters
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----------
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cols : list
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List of column coordinate tuples.
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text : list
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List of PDFMiner text objects.
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ytol : int
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Tolerance parameter.
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Returns
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-------
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cols : list
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Updated list of column coordinate tuples.
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"""
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if text:
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text = _group_rows(text, ytol=ytol)
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elements = [len(r) for r in text]
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new_cols = [(t.x0, t.x1)
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for r in text if len(r) == max(elements) for t in r]
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cols.extend(_merge_columns(sorted(new_cols)))
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return cols
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class Stream:
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"""Stream looks for spaces between text elements to form a table.
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If you want to give columns, ncolumns, ytol or mtol for each table
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when specifying multiple table areas, make sure that their length
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is equal to the length of table_area. Mapping between them is based
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on index.
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Also, if you want to specify columns for the first table and
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ncolumns for the second table in a pdf having two tables, pass
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columns as ['x1,x2,x3,x4', ''] and ncolumns as [-1, 5].
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Parameters
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----------
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table_area : list
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List of strings of the form x1,y1,x2,y2 where
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(x1, y1) -> left-top and (x2, y2) -> right-bottom in PDFMiner's
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coordinate space, denoting table areas to analyze.
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(optional, default: None)
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columns : list
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List of strings where each string is comma-separated values of
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x-coordinates in PDFMiner's coordinate space.
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(optional, default: None)
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ncolumns : list
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List of ints specifying the number of columns in each table.
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(optional, default: None)
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headers : list
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List of strings where each string is a csv header for a table.
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(optional, default: None)
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ytol : list
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List of ints specifying the y-tolerance parameters.
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(optional, default: [2])
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mtol : list
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List of ints specifying the m-tolerance parameters.
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(optional, default: [0])
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margins : tuple
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PDFMiner margins. (char_margin, line_margin, word_margin)
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(optional, default: (1.0, 0.5, 0.1))
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split_text : bool
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Whether or not to split a text line if it spans across
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different cells.
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(optional, default: False)
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flag_size : bool
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Whether or not to highlight a substring using <s></s>
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if its size is different from rest of the string, useful for
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super and subscripts.
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(optional, default: True)
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debug : bool
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Set to True to generate a matplotlib plot of
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LTTextLineHorizontals in order to select table_area, columns.
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(optional, default: False)
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"""
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def __init__(self, table_area=None, columns=None, ncolumns=None,
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headers=None, ytol=[2], mtol=[0], margins=(1.0, 0.5, 0.1),
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split_text=False, flag_size=True, debug=False):
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self.method = 'stream'
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self.table_area = table_area
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self.columns = columns
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self.ncolumns = ncolumns
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self.ytol = ytol
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self.mtol = mtol
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self.headers = headers
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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.debug = debug
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def get_tables(self, pdfname):
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"""Expects a single page pdf as input with rotation corrected.
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Parameters
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---------
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pdfname : string
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Path to single page pdf file.
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Returns
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-------
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page : dict
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"""
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layout, dim = get_page_layout(pdfname, char_margin=self.char_margin,
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line_margin=self.line_margin, word_margin=self.word_margin)
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lttextlh = get_text_objects(layout, ltype="lh")
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lttextlv = get_text_objects(layout, ltype="lv")
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ltchar = get_text_objects(layout, ltype="char")
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width, height = dim
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bname, __ = os.path.splitext(pdfname)
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if not lttextlh:
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logging.warning("{0}: PDF has no text. It may be an image.".format(
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os.path.basename(bname)))
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return None
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if self.debug:
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self.debug_text = []
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self.debug_text.extend([(t.x0, t.y0, t.x1, t.y1) for t in lttextlh])
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self.debug_text.extend([(t.x0, t.y0, t.x1, t.y1) for t in lttextlv])
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if self.table_area is not None:
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if self.columns is not None:
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if len(self.table_area) != len(self.columns):
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raise ValueError("Length of columns should be equal to table_area.")
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if self.ncolumns is not None:
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if len(self.table_area) != len(self.ncolumns):
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raise ValueError("Length of ncolumns should be equal to table_area.")
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if self.headers is not None:
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if len(self.table_area) != len(self.headers):
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raise ValueError("Length of headers should be equal to table_area.")
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table_bbox = {}
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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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table_bbox[(x1, y2, x2, y1)] = None
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else:
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table_bbox = {(0, 0, width, height): None}
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if len(self.ytol) == 1 and self.ytol[0] == 2:
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self.ytol = self.ytol * len(table_bbox)
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if len(self.mtol) == 1 and self.mtol[0] == 0:
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self.mtol = self.mtol * len(table_bbox)
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page = {}
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tables = {}
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table_no = 0
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# sort tables based on y-coord
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for k in sorted(table_bbox.keys(), key=lambda x: x[1], reverse=True):
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# select elements which lie within table_bbox
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table_data = {}
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t_bbox = {}
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t_bbox['horizontal'] = text_in_bbox(k, lttextlh)
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t_bbox['vertical'] = text_in_bbox(k, lttextlv)
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char_bbox = text_in_bbox(k, ltchar)
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table_data['text_p'] = 100 * (1 - (len(char_bbox) / len(ltchar)))
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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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text_x_min, text_y_min, text_x_max, text_y_max = _text_bbox(t_bbox)
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rows_grouped = _group_rows(t_bbox['horizontal'], ytol=self.ytol[table_no])
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rows = _join_rows(rows_grouped, text_y_max, text_y_min)
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elements = [len(r) for r in rows_grouped]
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guess = False
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if self.columns is not None and self.columns[table_no] != "":
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# user has to input boundary columns too
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# take (0, width) by default
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# similar to else condition
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# len can't be 1
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cols = self.columns[table_no].split(',')
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cols = [float(c) for c in cols]
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cols.insert(0, text_x_min)
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cols.append(text_x_max)
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cols = [(cols[i], cols[i + 1]) for i in range(0, len(cols) - 1)]
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else:
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if self.ncolumns is not None and self.ncolumns[table_no] != -1:
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ncols = self.ncolumns[table_no]
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cols = [(t.x0, t.x1)
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for r in rows_grouped if len(r) == ncols for t in r]
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cols = _merge_columns(sorted(cols), mtol=self.mtol[table_no])
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if len(cols) != self.ncolumns[table_no]:
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logging.warning("{}: The number of columns after merge"
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" isn't the same as what you specified."
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" Change the value of mtol.".format(
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os.path.basename(bname)))
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cols = _join_columns(cols, text_x_min, text_x_max)
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else:
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guess = True
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ncols = max(set(elements), key=elements.count)
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len_non_mode = len(filter(lambda x: x != ncols, elements))
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if ncols == 1 and not self.debug:
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# no tables detected
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logging.warning("{}: Only one column was detected, the pdf"
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" may have no tables. Specify ncols if"
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" the pdf has tables.".format(
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os.path.basename(bname)))
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cols = [(t.x0, t.x1)
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for r in rows_grouped if len(r) == ncols for t in r]
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cols = _merge_columns(sorted(cols), mtol=self.mtol[table_no])
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inner_text = []
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for i in range(1, len(cols)):
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left = cols[i - 1][1]
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right = cols[i][0]
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inner_text.extend([t for direction in t_bbox
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for t in t_bbox[direction]
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if t.x0 > left and t.x1 < right])
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outer_text = [t for direction in t_bbox
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for t in t_bbox[direction]
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if t.x0 > cols[-1][1] or t.x1 < cols[0][0]]
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inner_text.extend(outer_text)
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cols = _add_columns(cols, inner_text, self.ytol[table_no])
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cols = _join_columns(cols, text_x_min, text_x_max)
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if self.headers is not None and self.headers[table_no] != [""]:
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self.headers[table_no] = self.headers[table_no].split(',')
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if len(self.headers[table_no]) != len(cols):
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logging.warning("Length of header ({0}) specified for table is not"
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" equal to the number of columns ({1}) detected.".format(
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len(self.headers[table_no]), len(cols)))
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while len(self.headers[table_no]) != len(cols):
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self.headers[table_no].append('')
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table = Table(cols, rows)
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table = table.set_all_edges()
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assignment_errors = []
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table_data['split_text'] = []
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table_data['superscript'] = []
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for direction in t_bbox:
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for t in 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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assignment_errors.append(error)
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if len(indices) > 1:
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table_data['split_text'].append(indices)
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for r_idx, c_idx, text in indices:
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if all(s in text for s in ['<s>', '</s>']):
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table_data['superscript'].append((r_idx, c_idx, text))
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table.cells[r_idx][c_idx].add_text(text)
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if guess:
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score = get_score([[66, assignment_errors], [34, [len_non_mode / len(elements)]]])
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else:
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score = get_score([[100, assignment_errors]])
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table_data['score'] = score
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ar = table.get_list()
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if self.headers is not None and self.headers[table_no] != ['']:
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ar.insert(0, self.headers[table_no])
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ar = encode_list(ar)
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table_data['data'] = ar
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empty_p, r_nempty_cells, c_nempty_cells = count_empty(ar)
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table_data['empty_p'] = empty_p
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table_data['r_nempty_cells'] = r_nempty_cells
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table_data['c_nempty_cells'] = c_nempty_cells
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table_data['nrows'] = len(ar)
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table_data['ncols'] = len(ar[0])
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tables['table-{0}'.format(table_no + 1)] = table_data
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table_no += 1
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page[os.path.basename(bname)] = tables
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return page |