def get_cached_content_stream(pdf, page_number: int) -> ContentStream:
key = (pdf.stream.name, page_number)
with _lock:
if key not in parsed_content_stream_data:
page = pdf.getPage(page_number)
originalContent = page.getContents()
assert originalContent is not None
parsed_content_stream_data[key] = PageObject._pushPopGS(
originalContent, pdf)
return parsed_content_stream_data[key]
def merge_page(pdf,
page_number: int,
page2,
page2transformation=None,
ctm=None,
expand=False):
"""
Merge the given page number of the given PDF with another page.
Note that the first PDF is assumed to be immutable, and its parsed content stream will
be cached *indefinitely* to ensure that future renders are extremely fast (at least,
as long as the other page, which we never cache, is relatively simple).
Note that most of this code was taken from `PyPDF2.pdf.PageObject`'s
`mergePage()` implementation.
"""
# 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.
page1 = pdf.getPage(page_number)
newResources = DictionaryObject()
rename = {}
originalResources = page1["/Resources"].getObject()
page2Resources = page2["/Resources"].getObject()
newAnnots = ArrayObject()
for page in (page1, page2):
if "/Annots" in page:
annots = page["/Annots"]
if isinstance(annots, ArrayObject):
for ref in annots:
newAnnots.append(ref)
for res in (
"/ExtGState",
"/Font",
"/XObject",
"/ColorSpace",
"/Pattern",
"/Shading",
"/Properties",
):
new, newrename = PageObject._mergeResources(originalResources,
page2Resources, res)
if new:
newResources[NameObject(res)] = new
rename.update(newrename)
# Combine /ProcSet sets.
newResources[NameObject("/ProcSet")] = ArrayObject(
frozenset(
originalResources.get("/ProcSet",
ArrayObject()).getObject()).union(
frozenset(
page2Resources.get(
"/ProcSet",
ArrayObject()).getObject())))
content_stream = get_cached_content_stream(pdf, page_number)
page2Content = page2.getContents()
if page2Content is not None:
if page2transformation is not None:
page2Content = page2transformation(page2Content)
page2Content = PageObject._contentStreamRename(page2Content, rename,
page1.pdf)
page2Content = PageObject._pushPopGS(page2Content, page1.pdf)
content_stream = append_to_content_stream(content_stream, page2Content)
# if expanding the page to fit a new page, calculate the new media box size
if expand:
corners1 = [
page1.mediaBox.getLowerLeft_x().as_numeric(),
page1.mediaBox.getLowerLeft_y().as_numeric(),
page1.mediaBox.getUpperRight_x().as_numeric(),
page1.mediaBox.getUpperRight_y().as_numeric(),
]
corners2 = [
page2.mediaBox.getLowerLeft_x().as_numeric(),
page2.mediaBox.getLowerLeft_y().as_numeric(),
page2.mediaBox.getUpperLeft_x().as_numeric(),
page2.mediaBox.getUpperLeft_y().as_numeric(),
page2.mediaBox.getUpperRight_x().as_numeric(),
page2.mediaBox.getUpperRight_y().as_numeric(),
page2.mediaBox.getLowerRight_x().as_numeric(),
page2.mediaBox.getLowerRight_y().as_numeric(),
]
if ctm is not None:
ctm = [float(x) for x in ctm]
new_x = [
ctm[0] * corners2[i] + ctm[2] * corners2[i + 1] + ctm[4]
for i in range(0, 8, 2)
]
new_y = [
ctm[1] * corners2[i] + ctm[3] * corners2[i + 1] + ctm[5]
for i in range(0, 8, 2)
]
else:
new_x = corners2[0:8:2]
new_y = corners2[1:8:2]
lowerleft = [min(new_x), min(new_y)]
upperright = [max(new_x), max(new_y)]
lowerleft = [
min(corners1[0], lowerleft[0]),
min(corners1[1], lowerleft[1])
]
upperright = [
max(corners1[2], upperright[0]),
max(corners1[3], upperright[1])
]
page1.mediaBox.setLowerLeft(lowerleft)
page1.mediaBox.setUpperRight(upperright)
new_page = PageObject.createBlankPage(page1.pdf)
new_page[NameObject("/Contents")] = content_stream
new_page[NameObject("/Resources")] = newResources
new_page[NameObject("/Annots")] = newAnnots
return new_page
def add_text(self, page_no, font, text_items, debug=False):
'''Adds text, given as a {string: coords} to the given page.'''
page = self.getPage(page_no)
newContentsArray = ArrayObject()
newContentsArray.append(PageObject._pushPopGS(page.getContents(), page.pdf))
addedContents = NovelContentStream(page.pdf)
addedContents.operations = self.text_to_operations(page, font, text_items, debug)
newContentsArray.append(addedContents)
newContents = ContentStream(newContentsArray, page.pdf).flateEncode()
page[NameObject('/Contents')] = newContents