337 lines
13 KiB
Python
337 lines
13 KiB
Python
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"""Insert anchors, links, bookmarks and inputs in PDFs."""
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import hashlib
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import io
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from os.path import basename
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from urllib.parse import unquote, urlsplit
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import pydyf
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from .. import Attachment
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from ..logger import LOGGER
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from ..text.ffi import ffi, gobject, pango
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from ..text.fonts import get_font_description
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from ..urls import URLFetchingError
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def add_links(links_and_anchors, matrix, pdf, page, names, mark):
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"""Include hyperlinks in given PDF page."""
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links, anchors = links_and_anchors
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for link_type, link_target, rectangle, box in links:
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x1, y1 = matrix.transform_point(*rectangle[:2])
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x2, y2 = matrix.transform_point(*rectangle[2:])
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if link_type in ('internal', 'external'):
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box.link_annotation = pydyf.Dictionary({
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'Type': '/Annot',
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'Subtype': '/Link',
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'Rect': pydyf.Array([x1, y1, x2, y2]),
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'BS': pydyf.Dictionary({'W': 0}),
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})
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if mark:
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box.link_annotation['Contents'] = pydyf.String(link_target)
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if link_type == 'internal':
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box.link_annotation['Dest'] = pydyf.String(link_target)
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else:
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box.link_annotation['A'] = pydyf.Dictionary({
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'Type': '/Action',
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'S': '/URI',
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'URI': pydyf.String(link_target),
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})
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pdf.add_object(box.link_annotation)
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if 'Annots' not in page:
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page['Annots'] = pydyf.Array()
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page['Annots'].append(box.link_annotation.reference)
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for anchor in anchors:
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anchor_name, x, y = anchor
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x, y = matrix.transform_point(x, y)
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names.append([
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anchor_name, pydyf.Array([page.reference, '/XYZ', x, y, 0])])
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def add_outlines(pdf, bookmarks, parent=None):
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"""Include bookmark outlines in PDF."""
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count = len(bookmarks)
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outlines = []
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for title, (page, x, y), children, state in bookmarks:
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destination = pydyf.Array((pdf.page_references[page], '/XYZ', x, y, 0))
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outline = pydyf.Dictionary({
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'Title': pydyf.String(title), 'Dest': destination})
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pdf.add_object(outline)
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children_outlines, children_count = add_outlines(
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pdf, children, parent=outline)
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outline['Count'] = children_count
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if state == 'closed':
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outline['Count'] *= -1
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else:
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count += children_count
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if outlines:
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outline['Prev'] = outlines[-1].reference
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outlines[-1]['Next'] = outline.reference
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if children_outlines:
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outline['First'] = children_outlines[0].reference
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outline['Last'] = children_outlines[-1].reference
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if parent is not None:
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outline['Parent'] = parent.reference
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outlines.append(outline)
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if parent is None and outlines:
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outlines_dictionary = pydyf.Dictionary({
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'Count': count,
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'First': outlines[0].reference,
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'Last': outlines[-1].reference,
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})
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pdf.add_object(outlines_dictionary)
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for outline in outlines:
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outline['Parent'] = outlines_dictionary.reference
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pdf.catalog['Outlines'] = outlines_dictionary.reference
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return outlines, count
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def add_inputs(inputs, matrix, pdf, page, resources, stream, font_map,
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compress):
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"""Include form inputs in PDF."""
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if not inputs:
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return
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if 'Annots' not in page:
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page['Annots'] = pydyf.Array()
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if 'AcroForm' not in pdf.catalog:
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pdf.catalog['AcroForm'] = pydyf.Dictionary({
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'Fields': pydyf.Array(),
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'DR': resources.reference,
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'NeedAppearances': 'true',
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})
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page_reference = page['Contents'].split()[0]
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context = ffi.gc(
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pango.pango_font_map_create_context(font_map),
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gobject.g_object_unref)
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for i, (element, style, rectangle) in enumerate(inputs):
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rectangle = (
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*matrix.transform_point(*rectangle[:2]),
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*matrix.transform_point(*rectangle[2:]))
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input_type = element.attrib.get('type')
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default_name = f'unknown-{page_reference.decode()}-{i}'
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input_name = pydyf.String(element.attrib.get('name', default_name))
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# TODO: where does this 0.75 scale come from?
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font_size = style['font_size'] * 0.75
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field_stream = pydyf.Stream(compress=compress)
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field_stream.set_color_rgb(*style['color'][:3])
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if input_type == 'checkbox':
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# Checkboxes
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width = rectangle[2] - rectangle[0]
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height = rectangle[1] - rectangle[3]
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checked_stream = pydyf.Stream(extra={
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'Resources': resources.reference,
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'Type': '/XObject',
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'Subtype': '/Form',
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'BBox': pydyf.Array((0, 0, width, height)),
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}, compress=compress)
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checked_stream.push_state()
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checked_stream.begin_text()
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checked_stream.set_color_rgb(*style['color'][:3])
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checked_stream.set_font_size('ZaDb', font_size)
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# Center (let’s assume that Dingbat’s check has a 0.8em size)
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x = (width - font_size * 0.8) / 2
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y = (height - font_size * 0.8) / 2
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checked_stream.move_text_to(x, y)
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checked_stream.show_text_string('4')
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checked_stream.end_text()
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checked_stream.pop_state()
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pdf.add_object(checked_stream)
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checked = 'checked' in element.attrib
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field_stream.set_font_size('ZaDb', font_size)
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field = pydyf.Dictionary({
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'Type': '/Annot',
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'Subtype': '/Widget',
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'Rect': pydyf.Array(rectangle),
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'FT': '/Btn',
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'P': page.reference,
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'T': pydyf.String(input_name),
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'V': '/Yes' if checked else '/Off',
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'AP': pydyf.Dictionary({'N': pydyf.Dictionary({
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'Yes': checked_stream.reference,
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})}),
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'AS': '/Yes' if checked else '/Off',
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'DA': pydyf.String(b' '.join(field_stream.stream)),
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})
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else:
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# Text, password, textarea, files, and unknown
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font_description = get_font_description(style)
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font = pango.pango_font_map_load_font(
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font_map, context, font_description)
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font = stream.add_font(font)
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font.used_in_forms = True
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field_stream.set_font_size(font.hash, font_size)
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value = (
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element.text if element.tag == 'textarea'
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else element.attrib.get('value', ''))
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field = pydyf.Dictionary({
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'Type': '/Annot',
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'Subtype': '/Widget',
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'Rect': pydyf.Array(rectangle),
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'FT': '/Tx',
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'P': page.reference,
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'T': pydyf.String(input_name),
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'V': pydyf.String(value),
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'DA': pydyf.String(b' '.join(field_stream.stream)),
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})
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if element.tag == 'textarea':
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field['Ff'] = 2 ** (13 - 1)
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elif input_type == 'password':
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field['Ff'] = 2 ** (14 - 1)
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elif input_type == 'file':
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field['Ff'] = 2 ** (21 - 1)
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pdf.add_object(field)
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page['Annots'].append(field.reference)
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pdf.catalog['AcroForm']['Fields'].append(field.reference)
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def add_annotations(links, matrix, document, pdf, page, annot_files, compress):
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"""Include annotations in PDF."""
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# TODO: splitting a link into multiple independent rectangular
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# annotations works well for pure links, but rather mediocre for
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# other annotations and fails completely for transformed (CSS) or
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# complex link shapes (area). It would be better to use /AP for all
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# links and coalesce link shapes that originate from the same HTML
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# link. This would give a feeling similiar to what browsers do with
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# links that span multiple lines.
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for link_type, annot_target, rectangle, _ in links:
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if link_type != 'attachment':
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continue
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if annot_target not in annot_files:
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# A single link can be split in multiple regions. We don't want
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# to embed a file multiple times of course, so keep a reference
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# to every embedded URL and reuse the object number.
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# TODO: Use the title attribute as description. The comment
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# above about multiple regions won't always be correct, because
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# two links might have the same href, but different titles.
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annot_files[annot_target] = write_pdf_attachment(
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pdf, (annot_target, None), document.url_fetcher, compress)
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annot_file = annot_files[annot_target]
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if annot_file is None:
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continue
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rectangle = (
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*matrix.transform_point(*rectangle[:2]),
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*matrix.transform_point(*rectangle[2:]))
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stream = pydyf.Stream([], {
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'Type': '/XObject',
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'Subtype': '/Form',
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'BBox': pydyf.Array(rectangle),
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}, compress)
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pdf.add_object(stream)
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annot = pydyf.Dictionary({
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'Type': '/Annot',
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'Rect': pydyf.Array(rectangle),
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'Subtype': '/FileAttachment',
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'T': pydyf.String(),
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'FS': annot_file.reference,
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'AP': pydyf.Dictionary({'N': stream.reference}),
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'AS': '/N',
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})
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pdf.add_object(annot)
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if 'Annots' not in page:
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page['Annots'] = pydyf.Array()
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page['Annots'].append(annot.reference)
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def write_pdf_attachment(pdf, attachment, url_fetcher, compress):
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"""Write an attachment to the PDF stream."""
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# Attachments from document links like <link> or <a> can only be URLs.
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# They're passed in as tuples
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url = ''
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if isinstance(attachment, tuple):
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url, description = attachment
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attachment = Attachment(
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url=url, url_fetcher=url_fetcher, description=description)
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elif not isinstance(attachment, Attachment):
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attachment = Attachment(guess=attachment, url_fetcher=url_fetcher)
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try:
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with attachment.source as (source_type, source, url, _):
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if isinstance(source, bytes):
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source = io.BytesIO(source)
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uncompressed_length = 0
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stream = b''
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md5 = hashlib.md5()
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for data in iter(lambda: source.read(4096), b''):
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uncompressed_length += len(data)
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md5.update(data)
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stream += data
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file_extra = pydyf.Dictionary({
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'Type': '/EmbeddedFile',
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'Params': pydyf.Dictionary({
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'CheckSum': f'<{md5.hexdigest()}>',
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'Size': uncompressed_length,
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})
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})
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file_stream = pydyf.Stream([stream], file_extra, compress=compress)
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pdf.add_object(file_stream)
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except URLFetchingError as exception:
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LOGGER.error('Failed to load attachment: %s', exception)
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return
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# TODO: Use the result object from a URL fetch operation to provide more
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# details on the possible filename.
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if url and urlsplit(url).path:
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filename = basename(unquote(urlsplit(url).path))
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else:
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filename = 'attachment.bin'
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attachment = pydyf.Dictionary({
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'Type': '/Filespec',
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'F': pydyf.String(),
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'UF': pydyf.String(filename),
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'EF': pydyf.Dictionary({'F': file_stream.reference}),
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'Desc': pydyf.String(attachment.description or ''),
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})
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pdf.add_object(attachment)
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return attachment
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def resolve_links(pages):
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"""Resolve internal hyperlinks.
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Links to a missing anchor are removed with a warning.
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If multiple anchors have the same name, the first one is used.
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:returns:
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A generator yielding lists (one per page) like :attr:`Page.links`,
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except that ``target`` for internal hyperlinks is
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``(page_number, x, y)`` instead of an anchor name.
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The page number is a 0-based index into the :attr:`pages` list,
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and ``x, y`` are in CSS pixels from the top-left of the page.
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"""
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anchors = set()
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paged_anchors = []
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for i, page in enumerate(pages):
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paged_anchors.append([])
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for anchor_name, (point_x, point_y) in page.anchors.items():
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if anchor_name not in anchors:
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paged_anchors[-1].append((anchor_name, point_x, point_y))
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anchors.add(anchor_name)
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for page in pages:
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page_links = []
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for link in page.links:
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link_type, anchor_name, _, _ = link
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if link_type == 'internal':
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if anchor_name not in anchors:
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LOGGER.error(
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'No anchor #%s for internal URI reference',
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anchor_name)
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else:
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page_links.append(link)
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else:
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# External link
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page_links.append(link)
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yield page_links, paged_anchors.pop(0)
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