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"""WordprocessingML Package class and related objects."""
from __future__ import annotations
from typing import IO, cast
from docx.image.image import Image
from docx.opc.constants import RELATIONSHIP_TYPE as RT
from docx.opc.package import OpcPackage
from docx.opc.packuri import PackURI
from docx.parts.image import ImagePart
from docx.shared import lazyproperty
class Package(OpcPackage):
"""Customizations specific to a WordprocessingML package."""
def after_unmarshal(self):
"""Called by loading code after all parts and relationships have been loaded.
This method affords the opportunity for any required post-processing.
"""
self._gather_image_parts()
def get_or_add_image_part(self, image_descriptor: str | IO[bytes]) -> ImagePart:
"""Return |ImagePart| containing image specified by `image_descriptor`.
The image-part is newly created if a matching one is not already present in the
collection.
"""
return self.image_parts.get_or_add_image_part(image_descriptor)
@lazyproperty
def image_parts(self) -> ImageParts:
"""|ImageParts| collection object for this package."""
return ImageParts()
def _gather_image_parts(self):
"""Load the image part collection with all the image parts in package."""
for rel in self.iter_rels():
if rel.is_external:
continue
if rel.reltype != RT.IMAGE:
continue
if rel.target_part in self.image_parts:
continue
self.image_parts.append(cast("ImagePart", rel.target_part))
class ImageParts:
"""Collection of |ImagePart| objects corresponding to images in the package."""
def __init__(self):
self._image_parts: list[ImagePart] = []
def __contains__(self, item: object):
return self._image_parts.__contains__(item)
def __iter__(self):
return self._image_parts.__iter__()
def __len__(self):
return self._image_parts.__len__()
def append(self, item: ImagePart):
self._image_parts.append(item)
def get_or_add_image_part(self, image_descriptor: str | IO[bytes]) -> ImagePart:
"""Return |ImagePart| object containing image identified by `image_descriptor`.
The image-part is newly created if a matching one is not present in the
collection.
"""
image = Image.from_file(image_descriptor)
matching_image_part = self._get_by_sha1(image.sha1)
if matching_image_part is not None:
return matching_image_part
return self._add_image_part(image)
def _add_image_part(self, image: Image):
"""Return |ImagePart| instance newly created from `image` and appended to the collection."""
partname = self._next_image_partname(image.ext)
image_part = ImagePart.from_image(image, partname)
self.append(image_part)
return image_part
def _get_by_sha1(self, sha1: str) -> ImagePart | None:
"""Return the image part in this collection having a SHA1 hash matching `sha1`,
or |None| if not found."""
for image_part in self._image_parts:
if image_part.sha1 == sha1:
return image_part
return None
def _next_image_partname(self, ext: str) -> PackURI:
"""The next available image partname, starting from ``/word/media/image1.{ext}``
where unused numbers are reused.
The partname is unique by number, without regard to the extension. `ext` does
not include the leading period.
"""
def image_partname(n: int) -> PackURI:
return PackURI("/word/media/image%d.%s" % (n, ext))
used_numbers = [image_part.partname.idx for image_part in self]
for n in range(1, len(self) + 1):
if n not in used_numbers:
return image_partname(n)
return image_partname(len(self) + 1)
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