def transform(
self,
object_to_transform: AnyPDFType,
context: Optional[WriteTransformerContext] = None,
):
"""
This method writes a Stream to a byte stream
"""
assert context is not None
assert context.destination is not None
assert isinstance(object_to_transform, Stream)
# avoid resolving objects twice
object_ref: typing.Optional[
Reference] = object_to_transform.get_reference(
) # type: ignore [attr-defined]
if object_ref is not None and object_ref in context.resolved_references:
assert object_ref is not None
assert object_ref.object_number is not None
logger.debug(
"skip writing object %d %d R (already resolved)" %
(object_ref.object_number, object_ref.generation_number or 0))
return
# start object if needed
started_object = False
if object_ref is not None:
assert object_ref.object_number is not None
if object_ref.object_number is not None and object_ref.byte_offset is None:
started_object = True
self.start_object(object_to_transform, context)
context.resolved_references.append(object_ref)
# build stream dictionary
stream_dictionary = Dictionary()
# objects to turn into reference
queue: typing.List[AnyPDFType] = []
for k, v in object_to_transform.items():
if k in ["Bytes", "DecodedBytes"]:
continue
if (isinstance(v, Dictionary) or isinstance(v, List)
or isinstance(v, Stream)
) and v.can_be_referenced(): # type: ignore [union-attr]
stream_dictionary[k] = self.get_reference(v, context)
queue.append(v)
else:
stream_dictionary[k] = v
# if self.compression_level == 0, remove \Filter
if context.compression_level == 0 and Name(
"Filter") in stream_dictionary:
stream_dictionary.pop(Name("Filter"))
# handle compression
if "DecodedBytes" in object_to_transform:
if context.compression_level == 0:
bts = object_to_transform["DecodedBytes"]
else:
bts = zlib.compress(object_to_transform["DecodedBytes"],
context.compression_level)
stream_dictionary[Name("Length")] = pDecimal(len(bts))
else:
assert "Bytes" in object_to_transform
bts = object_to_transform["Bytes"]
# write stream dictionary
self.get_root_transformer().transform(stream_dictionary, context)
# write "stream"
context.destination.write(bytes("stream\n", "latin1"))
# write bytes
context.destination.write(bts)
# write "endstream"
context.destination.write(bytes("\nendstream\n", "latin1"))
# end object if needed
if started_object:
self.end_object(object_to_transform, context)
for e in queue:
self.get_root_transformer().transform(e, context)
def transform(
self,
object_to_transform: AnyPDFType,
context: Optional[WriteTransformerContext] = None,
):
"""
This method writes a Dictionary to a byte stream
"""
assert isinstance(object_to_transform, Dictionary)
assert context is not None
assert context.destination is not None
assert context.destination
# avoid resolving objects twice
object_ref: typing.Optional[
Reference] = object_to_transform.get_reference(
) # type: ignore [attr-defined]
if object_ref is not None and object_ref in context.resolved_references:
assert object_ref is not None
assert object_ref.object_number is not None
logger.debug(
"skip writing object %d %d R (already resolved)" %
(object_ref.object_number, object_ref.generation_number or 0))
return
# output value
out_value = Dictionary()
# objects to turn into reference
queue: typing.List[AnyPDFType] = []
for k, v in object_to_transform.items():
if (isinstance(v, Dictionary) or isinstance(v, List)
or isinstance(v, Stream) or isinstance(v, Image)
or isinstance(v, Element)
) and v.can_be_referenced(): # type: ignore [union-attr]
out_value[k] = self.get_reference(v, context)
queue.append(v)
else:
out_value[k] = v
# start object if needed
started_object = False
if object_ref is not None:
assert object_ref.object_number is not None
if object_ref.object_number is not None and object_ref.byte_offset is None:
started_object = True
self.start_object(object_to_transform, context)
context.resolved_references.append(object_ref)
# write dictionary at current location
context.destination.write(bytes("<<", "latin1"))
N = len(out_value.items())
for i, (k, v) in enumerate(out_value.items()):
self.get_root_transformer().transform(k, context)
context.destination.write(bytes(" ", "latin1"))
self.get_root_transformer().transform(v, context)
if i != N - 1:
context.destination.write(bytes(" ", "latin1"))
context.destination.write(bytes(">>\n", "latin1"))
# end object if needed
if started_object:
self.end_object(object_to_transform, context)
for e in queue:
self.get_root_transformer().transform(e, context)
# return
return out_value