def add_base_methods(object: typing.Any) -> typing.Any:
"""
This function / decorator adds methods to a given object.
These added methods are useful for:
- handling linkage (parent/child relationships),
- serialization (JSON)
- hashing
- implementing the "listener" design pattern
- etc
"""
def _to_json_serializable(to_convert=None):
"""
Convert this object to a representation that
can be serialized as JSON
"""
if isinstance(to_convert, dict):
return {
to_json_serializable(k): to_json_serializable(v)
for k, v in to_convert.items()
}
if isinstance(to_convert, list):
return [to_json_serializable(x) for x in to_convert]
if isinstance(to_convert, Decimal):
return float(to_convert)
if (isinstance(to_convert, HexadecimalString)
or isinstance(to_convert, String)
or isinstance(to_convert, Name)
or isinstance(to_convert, CanvasOperatorName)):
return str(to_convert)
return None
def to_json_serializable(self):
"""
This function converts this Object to something that can be JSON serialized
"""
return _to_json_serializable(self)
def image_hash_method(self):
"""
This function hashes Image objects
"""
w = self.width
h = self.height
pixels = [
self.getpixel((0, 0)),
self.getpixel((0, h - 1)),
self.getpixel((w - 1, 0)),
self.getpixel((w - 1, h - 1)),
]
hashcode = 1
for p in pixels:
if isinstance(p, typing.List) or isinstance(p, typing.Tuple):
hashcode += 32 * hashcode + sum(p)
else:
hashcode += 32 * hashcode + p
return hashcode
def deepcopy_mod(self, memodict={}):
"""
This function overrides the __deepcopy__ method
this was needed
"""
prev_function_ptr = self.__deepcopy__
self.__deepcopy__ = None
# copy
out = copy.deepcopy(self, memodict)
# restore
self.__deepcopy__ = prev_function_ptr
# add base methods
add_base_methods(out)
# return
return out
# get_parent
def get_parent(self):
"""
This function returns the parent Object of the current Object
"""
if "_parent" not in vars(self):
setattr(self, "_parent", None)
return self._parent
# set_parent
def set_parent(self, parent):
"""
This function sets the parent Object of the current Object
"""
if "_parent" not in vars(self):
setattr(self, "_parent", None)
self._parent = parent
return self
# get_root
def get_root(self):
"""
This function returns the root parent Object of the current Object
"""
e = self
while e.get_parent() is not None:
e = e.get_parent()
return e
# add_event_listener
def add_event_listener(self, event_listener: "EventListener"):
"""
This function adds an EventListener to this Object
"""
if "_event_listeners" not in vars(self):
setattr(self, "_event_listeners", [])
self._event_listeners.append(event_listener)
return self
# get_event_listener
def get_event_listeners(self) -> typing.List["EventListener"]:
"""
This function returns a typing.List[EventListener] for this Object
"""
if "_event_listeners" not in vars(self):
setattr(self, "_event_listeners", [])
return self._event_listeners
# _event_occurred
def _event_occurred(self, event: "Event"): # type: ignore [name-defined]
if "_event_listeners" not in vars(self):
setattr(self, "_event_listeners", [])
for l in self._event_listeners:
l._event_occurred(event)
if self.get_parent() is not None:
self.get_parent()._event_occurred(event)
return self
# set_reference
def set_reference(self, reference: "Reference"):
"""
This function sets the Reference for this Object, returning self
"""
if "_reference" not in vars(self):
setattr(self, "_reference", None)
assert (self._reference is None or reference is None
or self._reference.object_number == reference.object_number
or (self._reference.parent_stream_object_number
== reference.parent_stream_object_number
and self._reference.index_in_parent_stream
== reference.index_in_parent_stream))
self._reference = reference
return self
# get_reference
def get_reference(self) -> typing.Optional["Reference"]:
"""
This function returns the Reference for this Object or None if no Reference was set
"""
if "_reference" not in vars(self):
setattr(self, "_reference", None)
return self._reference
# set_can_be_referenced
def set_can_be_referenced(self, a_flag: bool):
"""
This function sets whether or not this Object can be referenced.
When an object can not be referenced, it is always embedded immediately in the PDF byte stream.
"""
if "_can_be_referenced" not in vars(self):
setattr(self, "_can_be_referenced", None)
self._can_be_referenced = a_flag
return self
# can_be_referenced
def can_be_referenced(self) -> bool:
"""
This function returns whether or not this Object can be referenced.
When an object can not be referenced, it is always embedded immediately in the PDF byte stream.
"""
if "_can_be_referenced" not in vars(self):
setattr(self, "_can_be_referenced", True)
return self._can_be_referenced
object.set_parent = types.MethodType(set_parent, object)
object.get_parent = types.MethodType(get_parent, object)
object.get_root = types.MethodType(get_root, object)
object.add_event_listener = types.MethodType(add_event_listener, object)
object.get_event_listeners = types.MethodType(get_event_listeners, object)
object._event_occurred = types.MethodType(_event_occurred, object)
object.set_reference = types.MethodType(set_reference, object)
object.get_reference = types.MethodType(get_reference, object)
object.set_can_be_referenced = types.MethodType(set_can_be_referenced,
object)
object.can_be_referenced = types.MethodType(can_be_referenced, object)
object.to_json_serializable = types.MethodType(to_json_serializable,
object)
if isinstance(object, Image):
object.__deepcopy__ = types.MethodType(deepcopy_mod, object)
object.__hash__ = types.MethodType(image_hash_method, object)
