257 lines
9.4 KiB
Python
257 lines
9.4 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 subprocess
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from .imgproc import (adaptive_threshold, find_lines, find_table_contours,
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find_table_joints)
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from .table import Table
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from .utils import (scale_to_pdf, scale_to_image, segments_bbox, text_bbox,
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get_rotation, merge_close_values, get_row_index,
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get_column_index, get_score, reduce_index, outline,
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fill_spanning, count_empty, encode_list, get_page_layout,
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get_text_objects)
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__all__ = ['Lattice']
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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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class Lattice:
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"""Lattice algorithm
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Makes use of pdf geometry by processing its image, to make a table
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and fills text objects in table cells.
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Parameters
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----------
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pdfobject : camelot.pdf.Pdf
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fill : string
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Fill data in horizontal and/or vertical spanning
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cells. (optional, default: None) {None, 'h', 'v', 'hv'}
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scale : int
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Scaling factor. Large scaling factor leads to smaller lines
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being detected. (optional, default: 15)
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mtol : int
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Tolerance to account for when merging lines which are
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very close. (optional, default: 2)
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invert : bool
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Invert pdf image to make sure that lines are in foreground.
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(optional, default: False)
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debug : string
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Debug by visualizing pdf geometry.
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(optional, default: None) {'contour', 'line', 'joint', 'table'}
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Attributes
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----------
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tables : dict
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Dictionary with page number as key and list of tables on that
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page as value.
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"""
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def __init__(self, table_area=None, fill=None, mtol=[2], scale=15,
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invert=False, margins=(1.0, 0.5, 0.1), debug=None):
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self.method = 'lattice'
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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.scale = scale
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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.debug = debug
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def get_tables(self, pdfname):
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"""Returns all tables found in given pdf.
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Returns
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-------
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tables : dict
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Dictionary with page number as key and list of tables on that
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page as value.
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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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ltchar = get_text_objects(layout, LTType="char")
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lttextlh = get_text_objects(layout, LTType="lh")
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lttextlv = get_text_objects(layout, LTType="lv")
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width, height = dim
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bname, __ = os.path.splitext(pdfname)
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if not ltchar:
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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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imagename = ''.join([bname, '.png'])
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gs_call = [
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"-q", "-sDEVICE=png16m", "-o", imagename, "-r600", pdfname
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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)
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img, threshold = adaptive_threshold(imagename, invert=self.invert)
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pdf_x = width
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pdf_y = height
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img_x = img.shape[1]
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img_y = img.shape[0]
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sc_x_image = img_x / float(pdf_x)
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sc_y_image = img_y / float(pdf_y)
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sc_x_pdf = pdf_x / float(img_x)
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sc_y_pdf = pdf_y / float(img_y)
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factors_image = (sc_x_image, sc_y_image, pdf_y)
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factors_pdf = (sc_x_pdf, sc_y_pdf, img_y)
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vmask, v_segments = find_lines(threshold, direction='vertical',
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scale=self.scale)
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hmask, h_segments = find_lines(threshold, direction='horizontal',
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scale=self.scale)
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if self.table_area is not None:
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if self.fill is not None:
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if len(self.table_area) != len(self.fill):
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raise ValueError("message")
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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 = int(x1)
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y1 = int(y1)
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x2 = int(x2)
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y2 = int(y2)
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x1, y1, x2, y2 = scale_to_image((x1, y1, x2, y2), factors_image)
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areas.append((x1, y1, abs(x2 - x1), abs(y2 - y1)))
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table_bbox = find_table_joints(areas, vmask, hmask)
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else:
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contours = find_table_contours(vmask, hmask)
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table_bbox = find_table_joints(contours, vmask, hmask)
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if len(self.mtol) == 1 and self.mtol[0] == 2:
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self.mtol = self.mtol * len(table_bbox)
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if self.debug:
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self.debug_images = (img, table_bbox)
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table_bbox, v_segments, h_segments = scale_to_pdf(table_bbox, v_segments,
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h_segments, factors_pdf)
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if self.debug:
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self.debug_segments = (v_segments, h_segments)
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self.debug_tables = []
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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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v_s, h_s = segments_bbox(k, v_segments, h_segments)
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char_bbox = text_bbox(k, ltchar)
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lh_bbox = text_bbox(k, lttextlh)
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lv_bbox = text_bbox(k, lttextlv)
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table_data['text_p'] = 100 * (1 - (len(char_bbox) / len(ltchar)))
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table_rotation = get_rotation(char_bbox, lh_bbox, lv_bbox)
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cols, rows = zip(*table_bbox[k])
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cols, rows = list(cols), list(rows)
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cols.extend([k[0], k[2]])
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rows.extend([k[1], k[3]])
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# sort horizontal and vertical segments
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cols = merge_close_values(sorted(cols), mtol=self.mtol[table_no])
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rows = merge_close_values(
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sorted(rows, reverse=True), mtol=self.mtol[table_no])
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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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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)
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nouse = table.nocont_ / (len(v_s) + len(h_s))
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table_data['line_p'] = 100 * (1 - nouse)
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# set spanning cells to True
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table = table.set_spanning()
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# set table border edges to True
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table = outline(table)
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if self.debug:
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self.debug_tables.append(table)
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rerror = []
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cerror = []
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for t in char_bbox:
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try:
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r_idx, rass_error = get_row_index(t, rows)
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except TypeError:
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# couldn't assign LTChar to any cell
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continue
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try:
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c_idx, cass_error = get_column_index(t, cols)
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except TypeError:
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# couldn't assign LTChar to any cell
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continue
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rerror.append(rass_error)
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cerror.append(cass_error)
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r_idx, c_idx = reduce_index(table, table_rotation, r_idx, c_idx)
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table.cells[r_idx][c_idx].add_object(t)
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for i in range(len(table.cells)):
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for j in range(len(table.cells[i])):
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t_bbox = table.cells[i][j].get_objects()
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try:
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cell_rotation = get_rotation(t_bbox)
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except ZeroDivisionError:
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cell_rotation = ''
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pass
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# fill text after sorting it
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if cell_rotation == '':
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t_bbox.sort(key=lambda x: (-x.y0, x.x0))
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elif cell_rotation == 'left':
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t_bbox.sort(key=lambda x: (x.x0, x.y0))
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elif cell_rotation == 'right':
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t_bbox.sort(key=lambda x: (-x.x0, -x.y0))
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table.cells[i][j].add_text(''.join([t.get_text()
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for t in t_bbox]))
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score = get_score([[50, rerror], [50, cerror]])
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table_data['score'] = score
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if self.fill is not None:
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table = fill_spanning(table, fill=self.fill[table_no])
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ar = table.get_list()
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if table_rotation == 'left':
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ar = zip(*ar[::-1])
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elif table_rotation == 'right':
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ar = zip(*ar[::1])
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ar.reverse()
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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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if self.debug:
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return None
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return page |