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MAINT: Increase readability of _merge_page #3291

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MAINT: Increase readability of _merge_page #3291

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90e9d87
MAINT: Increase readability of _merge_page
j-t-1 May 21, 2025
ad6e02a
MAINT: Increase readability of _merge_page
j-t-1 May 21, 2025
7387f0b
MAINT: Increase readability of _merge_page
j-t-1 May 21, 2025
17afa32
MAINT: Increase readability of _merge_page
j-t-1 May 22, 2025
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74 changes: 37 additions & 37 deletions pypdf/_page.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1122,9 +1122,6 @@ def _merge_page(
over: bool = True,
expand: bool = False,
) -> None:
# First we work on merging the resource dictionaries. This allows us
# to find out what symbols in the content streams we might need to
# rename.
try:
assert isinstance(self.indirect_reference, IndirectObject)
if hasattr(
Expand All @@ -1136,47 +1133,43 @@ def _merge_page(
except (AssertionError, AttributeError):
pass

new_resources = DictionaryObject()
rename = {}
# First we work on merging the resource dictionaries. This allows us
# to find out what symbols in the content streams we might need to
# rename.
try:
original_resources = cast(DictionaryObject, self[PG.RESOURCES].get_object())
except KeyError:
original_resources = DictionaryObject()
try:
page2resources = cast(DictionaryObject, page2[PG.RESOURCES].get_object())
page2_resources = cast(DictionaryObject, page2[PG.RESOURCES].get_object())
except KeyError:
page2resources = DictionaryObject()
new_annots = ArrayObject()

for page in (self, page2):
if PG.ANNOTS in page:
annots = page[PG.ANNOTS]
if isinstance(annots, ArrayObject):
new_annots.extend(annots)
page2_resources = DictionaryObject()

new_resources = DictionaryObject()
rename = {}
for res in (
RES.EXT_G_STATE,
RES.FONT,
RES.XOBJECT,
RES.COLOR_SPACE,
RES.PATTERN,
RES.SHADING,
RES.XOBJECT,
RES.FONT,
RES.PROPERTIES,
):
new, newrename = self._merge_resources(
original_resources, page2resources, res
new, new_rename = self._merge_resources(
original_resources, page2_resources, res
)
if new:
new_resources[NameObject(res)] = new
rename.update(newrename)
rename.update(new_rename)

# Combine /ProcSet sets, making sure there's a consistent order
# Combine /ProcSet sets, making sure there is a consistent order
new_resources[NameObject(RES.PROC_SET)] = ArrayObject(
sorted(
set(
original_resources.get(RES.PROC_SET, ArrayObject()).get_object()
).union(
set(page2resources.get(RES.PROC_SET, ArrayObject()).get_object())
set(page2_resources.get(RES.PROC_SET, ArrayObject()).get_object())
)
)
)
Expand All @@ -1187,10 +1180,10 @@ def _merge_page(
original_content.isolate_graphics_state()
new_content_array.append(original_content)

page2content = page2.get_contents()
if page2content is not None:
page2_content = page2.get_contents()
if page2_content is not None:
rect = getattr(page2, MERGE_CROP_BOX)
page2content.operations.insert(
page2_content.operations.insert(
0,
(
map(
Expand All @@ -1205,25 +1198,32 @@ def _merge_page(
b"re",
),
)
page2content.operations.insert(1, ([], b"W"))
page2content.operations.insert(2, ([], b"n"))
page2_content.operations.insert(1, ([], b"W"))
page2_content.operations.insert(2, ([], b"n"))
if page2transformation is not None:
page2content = page2transformation(page2content)
page2content = PageObject._content_stream_rename(
page2content, rename, self.pdf
page2_content = page2transformation(page2_content)
page2_content = PageObject._content_stream_rename(
page2_content, rename, self.pdf
)
page2content.isolate_graphics_state()
page2_content.isolate_graphics_state()
if over:
new_content_array.append(page2content)
new_content_array.append(page2_content)
else:
new_content_array.insert(0, page2content)
new_content_array.insert(0, page2_content)

# if expanding the page to fit a new page, calculate the new media box size
if expand:
self._expand_mediabox(page2, ctm)

self.replace_contents(ContentStream(new_content_array, self.pdf))
self[NameObject(PG.RESOURCES)] = new_resources
self.replace_contents(ContentStream(new_content_array, self.pdf))

new_annots = ArrayObject()
for page in (self, page2):
if PG.ANNOTS in page:
annots = page[PG.ANNOTS]
if isinstance(annots, ArrayObject):
new_annots.extend(annots)
self[NameObject(PG.ANNOTS)] = new_annots

def _merge_page_writer(
Expand All @@ -1240,7 +1240,6 @@ def _merge_page_writer(
assert isinstance(self.indirect_reference, IndirectObject)
pdf = self.indirect_reference.pdf

rename = {}
if PG.RESOURCES not in self:
self[NameObject(PG.RESOURCES)] = DictionaryObject()
original_resources = cast(DictionaryObject, self[PG.RESOURCES].get_object())
Expand All @@ -1249,13 +1248,14 @@ def _merge_page_writer(
else:
page2resources = cast(DictionaryObject, page2[PG.RESOURCES].get_object())

rename = {}
for res in (
RES.EXT_G_STATE,
RES.FONT,
RES.XOBJECT,
RES.COLOR_SPACE,
RES.PATTERN,
RES.SHADING,
RES.XOBJECT,
RES.FONT,
RES.PROPERTIES,
):
if res in page2resources:
Expand All @@ -1265,7 +1265,7 @@ def _merge_page_writer(
original_resources, page2resources, res, False
)
rename.update(newrename)
# Combine /ProcSet sets.
# Combine /ProcSet sets
if RES.PROC_SET in page2resources:
if RES.PROC_SET not in original_resources:
original_resources[NameObject(RES.PROC_SET)] = ArrayObject()
Expand Down
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