def __init__(self, contents, media_box, resources=None):
resources = resources or generic.DictionaryObject()
if isinstance(contents, list):
if not all(map(instance_test(generic.IndirectObject), contents)):
raise PdfWriteError(
'Contents array must consist of indirect references'
)
if not isinstance(contents, generic.ArrayObject):
contents = generic.ArrayObject(contents)
elif not isinstance(contents, generic.IndirectObject):
raise PdfWriteError(
'Contents must be either an indirect reference or an array'
)
if len(media_box) != 4:
raise ValueError('Media box must consist of 4 coordinates.')
super().__init__({
pdf_name('/Type'): pdf_name('/Page'),
pdf_name('/MediaBox'): generic.ArrayObject(
map(generic.NumberObject, media_box)
),
pdf_name('/Resources'): resources,
pdf_name('/Contents'): contents
})
def add_object(self, obj, obj_stream: Optional[ObjectStream] = None,
idnum=None) -> generic.IndirectObject:
"""
Add a new object to this writer.
:param obj:
The object to add.
:param obj_stream:
An object stream to add the object to.
:param idnum:
Manually specify the object ID of the object to be added.
This is only allowed for object IDs that have previously been
allocated using :meth:`allocate_placeholder`.
:return:
A :class:`~.generic.IndirectObject` instance referring to
the object just added.
"""
if idnum is not None:
if idnum not in self._allocated_placeholders:
raise PdfWriteError(
"Manually specifying idnum is only allowed for "
"references previously allocated using "
"allocate_placeholder()."
)
preallocated = True
else:
preallocated = False
idnum = self._lastobj_id + 1
if obj_stream is None:
self.objects[(0, idnum)] = obj
elif obj_stream in self.object_streams:
obj_stream.add_object(idnum, obj)
self.objs_in_streams[idnum] = obj
else:
raise PdfWriteError(
f'Stream {repr(obj_stream)} is unknown to this PDF writer.'
)
if preallocated:
self._allocated_placeholders.remove(idnum)
else:
self._lastobj_id += 1
return generic.IndirectObject(idnum, 0, self)
def prepare_object_stream(self, compress=True):
"""Prepare and return a new :class:`.ObjectStream` object.
:param compress:
Indicates whether the resulting object stream should be compressed.
:return:
An :class:`.ObjectStream` object.
"""
if not self.stream_xrefs: # pragma: no cover
raise PdfWriteError(
'Object streams require Xref streams to be enabled.')
stream = ObjectStream(compress=compress)
self.object_streams.append(stream)
return stream
def append_signature_field(pdf_out: BasePdfFileWriter,
sig_field_spec: SigFieldSpec):
"""
Append signature fields to a PDF file.
:param pdf_out:
Incremental writer to house the objects.
:param sig_field_spec:
A :class:`.SigFieldSpec` object describing the signature field
to add.
"""
root = pdf_out.root
page_ref = pdf_out.find_page_for_modification(sig_field_spec.on_page)[0]
# use default appearance
field_created, sig_field_ref = _prepare_sig_field(
sig_field_spec.sig_field_name, root, update_writer=pdf_out,
existing_fields_only=False, lock_sig_flags=False,
box=sig_field_spec.box, include_on_page=page_ref,
combine_annotation=sig_field_spec.combine_annotation
)
if not field_created:
raise PdfWriteError(
'Signature field with name %s already exists.'
% sig_field_spec.sig_field_name
)
sig_field = sig_field_ref.get_object()
if sig_field_spec.seed_value_dict is not None:
# /SV must be an indirect reference as per the spec
sv_ref = pdf_out.add_object(
sig_field_spec.seed_value_dict.as_pdf_object()
)
sig_field[pdf_name('/SV')] = sv_ref
lock = sig_field_spec.format_lock_dictionary()
if lock is not None:
sig_field[pdf_name('/Lock')] = pdf_out.add_object(lock)