DEP: PEP8 renaming (#905)

PdfReader: 
* getXmpMetadata / xmpMetadata ➔ xmp_metadata
* get_outlines ➔ _get_outlines (use outlines property instead)

Field attributes:
* additionalActions ➔ additional_actions
* defaultValue ➔ default_value
* mappingName ➔ mapping_name
* altName ➔ alternate_name
* fieldType ➔ field_type

StreamObject: 
* decodedSelf : decoded_self
* flateEncode  ➔ flate_encode

Other:

* Destination: getDestArray ➔ dest_array
* RectangleObject: ensureIsNumber ➔ _ensure_is_number
* TreeObject: addChild / removeChild  ➔ add_child / remove_child
* DecodedStreamObject: getData / setData  ➔ get_data / set_data

See #900

PyPDF2/_page.py

@@ -923,7 +923,7 @@ def compress_content_streams(self):
         if content is not None:
             if not isinstance(content, ContentStream):
                 content = ContentStream(content, self.pdf)
-            self[NameObject(PG.CONTENTS)] = content.flateEncode()
+            self[NameObject(PG.CONTENTS)] = content.flate_encode()
 
     def compressContentStreams(self):
         """

PyPDF2/_reader.py

@@ -389,7 +389,7 @@ def xmp_metadata(self):
         """
         try:
             self._override_encryption = True
-            return self.trailer[TK.ROOT].getXmpMetadata()
+            return self.trailer[TK.ROOT].xmp_metadata
         finally:
             self._override_encryption = False
 
@@ -729,9 +729,9 @@ def getNamedDestinations(self, tree=None, retval=None):
     @property
     def outlines(self):
         """Read-only property."""
-        return self.get_outlines()
+        return self._get_outlines()
 
-    def get_outlines(self, node=None, outlines=None):
+    def _get_outlines(self, node=None, outlines=None):
         """
         Retrieve the document outline present in the document.
 
@@ -768,7 +768,7 @@ def get_outlines(self, node=None, outlines=None):
             # check for sub-outlines
             if "/First" in node:
                 sub_outlines = []
-                self.get_outlines(node["/First"], sub_outlines)
+                self._get_outlines(node["/First"], sub_outlines)
                 if sub_outlines:
                     outlines.append(sub_outlines)
 
@@ -778,18 +778,33 @@ def get_outlines(self, node=None, outlines=None):
 
         return outlines
 
+    def get_outlines(self, node=None, outlines=None):
+        """
+        .. deprecated:: 1.28.0
+
+            Use the property :py:attr:`outlines` instead.
+        """
+        warnings.warn(
+            "get_outlines will be removed in PyPDF2 2.0.0. "
+            "Use the property :py:attr:`outlines` instead.",
+            PendingDeprecationWarning,
+            stacklevel=2,
+        )
+        return self._get_outlines(node, outlines)
+
     def getOutlines(self, node=None, outlines=None):
         """
         .. deprecated:: 1.28.0
 
-            Use :meth:`get_outlines` instead.
+            Use the property :py:attr:`outlines` instead.
         """
         warnings.warn(
-            "getOutlines will be removed in PyPDF2 2.0.0. Use get_outlines instead.",
+            "getOutlines will be removed in PyPDF2 2.0.0. "
+            "Use the property 'outlines' instead.",
             PendingDeprecationWarning,
             stacklevel=2,
         )
-        return self.get_outlines(node, outlines)
+        return self._get_outlines(node, outlines)
 
     def _get_page_number_by_indirect(self, indirect_ref):
         """Generate _pageId2Num"""
@@ -1073,7 +1088,7 @@ def _get_object_from_stream(self, indirect_reference):
         assert obj_stm["/Type"] == "/ObjStm"
         # /N is the number of indirect objects in the stream
         assert idx < obj_stm["/N"]
-        stream_data = BytesIO(b_(obj_stm.getData()))
+        stream_data = BytesIO(b_(obj_stm.get_data()))
         for i in range(obj_stm["/N"]):
             readNonWhitespace(stream_data)
             stream_data.seek(-1, 1)
@@ -1515,7 +1530,7 @@ def _read_pdf15_xref_stream(self, stream):
         xrefstream = read_object(stream, self)
         assert xrefstream["/Type"] == "/XRef"
         self.cache_indirect_object(generation, idnum, xrefstream)
-        stream_data = BytesIO(b_(xrefstream.getData()))
+        stream_data = BytesIO(b_(xrefstream.get_data()))
         # Index pairs specify the subsections in the dictionary. If
         # none create one subsection that spans everything.
         idx_pairs = xrefstream.get("/Index", [0, xrefstream.get("/Size")])

PyPDF2/_writer.py

@@ -966,7 +966,7 @@ def add_bookmark_destination(self, dest, parent=None):
             parent = outline_ref
 
         parent = parent.get_object()
-        parent.addChild(dest_ref, self)
+        parent.add_child(dest_ref, self)
 
         return dest_ref
 
@@ -1002,7 +1002,7 @@ def add_bookmark_dict(self, bookmark, parent=None):
             parent = outline_ref
 
         parent = parent.get_object()
-        parent.addChild(bookmark_ref, self)
+        parent.add_child(bookmark_ref, self)
 
         return bookmark_ref
 
@@ -1053,7 +1053,7 @@ def add_bookmark(
         dest = Destination(
             NameObject("/" + title + " bookmark"), page_ref, NameObject(fit), *zoom_args
         )
-        dest_array = dest.getDestArray()
+        dest_array = dest.dest_array
         action.update(
             {NameObject("/D"): dest_array, NameObject("/S"): NameObject("/GoTo")}
         )
@@ -1089,7 +1089,7 @@ def add_bookmark(
         bookmark_ref = self._add_object(bookmark)
 
         parent = parent.get_object()
-        parent.addChild(bookmark_ref, self)
+        parent.add_child(bookmark_ref, self)
 
         return bookmark_ref
 
@@ -1470,7 +1470,7 @@ def add_link(self, pagenum, pagedest, rect, border=None, fit="/Fit", *args):
         dest = Destination(
             NameObject("/LinkName"), page_dest, NameObject(fit), *zoom_args
         )  # TODO: create a better name for the link
-        dest_array = dest.getDestArray()
+        dest_array = dest.dest_array
 
         lnk = DictionaryObject()
         lnk.update(

PyPDF2/filters.py

@@ -553,7 +553,7 @@ def _xobj_to_image(x_object_obj):
     from PyPDF2.constants import GraphicsStateParameters as G
 
     size = (x_object_obj[IA.WIDTH], x_object_obj[IA.HEIGHT])
-    data = x_object_obj.getData()
+    data = x_object_obj.get_data()
     if x_object_obj[IA.COLOR_SPACE] == ColorSpaces.DEVICE_RGB:
         mode = "RGB"
     else:
@@ -564,7 +564,7 @@ def _xobj_to_image(x_object_obj):
             extension = ".png"
             img = Image.frombytes(mode, size, data)
             if G.S_MASK in x_object_obj:  # add alpha channel
-                alpha = Image.frombytes("L", size, x_object_obj[G.S_MASK].getData())
+                alpha = Image.frombytes("L", size, x_object_obj[G.S_MASK].get_data())
                 img.putalpha(alpha)
             img_byte_arr = io.BytesIO()
             img.save(img_byte_arr, format="PNG")