304 lines
8.6 KiB
Python
304 lines
8.6 KiB
Python
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#
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# The Python Imaging Library.
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# $Id$
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#
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# PDF (Acrobat) file handling
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#
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# History:
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# 1996-07-16 fl Created
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# 1997-01-18 fl Fixed header
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# 2004-02-21 fl Fixes for 1/L/CMYK images, etc.
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# 2004-02-24 fl Fixes for 1 and P images.
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#
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# Copyright (c) 1997-2004 by Secret Labs AB. All rights reserved.
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# Copyright (c) 1996-1997 by Fredrik Lundh.
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#
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# See the README file for information on usage and redistribution.
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#
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##
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# Image plugin for PDF images (output only).
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##
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from __future__ import annotations
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import io
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import math
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import os
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import time
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from . import Image, ImageFile, ImageSequence, PdfParser, __version__, features
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#
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# --------------------------------------------------------------------
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# object ids:
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# 1. catalogue
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# 2. pages
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# 3. image
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# 4. page
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# 5. page contents
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def _save_all(im, fp, filename):
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_save(im, fp, filename, save_all=True)
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##
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# (Internal) Image save plugin for the PDF format.
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def _write_image(im, filename, existing_pdf, image_refs):
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# FIXME: Should replace ASCIIHexDecode with RunLengthDecode
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# (packbits) or LZWDecode (tiff/lzw compression). Note that
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# PDF 1.2 also supports Flatedecode (zip compression).
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params = None
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decode = None
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#
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# Get image characteristics
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width, height = im.size
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dict_obj = {"BitsPerComponent": 8}
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if im.mode == "1":
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if features.check("libtiff"):
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filter = "CCITTFaxDecode"
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dict_obj["BitsPerComponent"] = 1
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params = PdfParser.PdfArray(
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[
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PdfParser.PdfDict(
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{
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"K": -1,
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"BlackIs1": True,
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"Columns": width,
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"Rows": height,
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}
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)
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]
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)
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else:
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filter = "DCTDecode"
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dict_obj["ColorSpace"] = PdfParser.PdfName("DeviceGray")
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procset = "ImageB" # grayscale
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elif im.mode == "L":
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filter = "DCTDecode"
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# params = f"<< /Predictor 15 /Columns {width-2} >>"
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dict_obj["ColorSpace"] = PdfParser.PdfName("DeviceGray")
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procset = "ImageB" # grayscale
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elif im.mode == "LA":
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filter = "JPXDecode"
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# params = f"<< /Predictor 15 /Columns {width-2} >>"
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procset = "ImageB" # grayscale
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dict_obj["SMaskInData"] = 1
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elif im.mode == "P":
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filter = "ASCIIHexDecode"
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palette = im.getpalette()
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dict_obj["ColorSpace"] = [
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PdfParser.PdfName("Indexed"),
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PdfParser.PdfName("DeviceRGB"),
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len(palette) // 3 - 1,
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PdfParser.PdfBinary(palette),
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]
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procset = "ImageI" # indexed color
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if "transparency" in im.info:
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smask = im.convert("LA").getchannel("A")
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smask.encoderinfo = {}
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image_ref = _write_image(smask, filename, existing_pdf, image_refs)[0]
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dict_obj["SMask"] = image_ref
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elif im.mode == "RGB":
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filter = "DCTDecode"
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dict_obj["ColorSpace"] = PdfParser.PdfName("DeviceRGB")
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procset = "ImageC" # color images
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elif im.mode == "RGBA":
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filter = "JPXDecode"
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procset = "ImageC" # color images
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dict_obj["SMaskInData"] = 1
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elif im.mode == "CMYK":
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filter = "DCTDecode"
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dict_obj["ColorSpace"] = PdfParser.PdfName("DeviceCMYK")
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procset = "ImageC" # color images
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decode = [1, 0, 1, 0, 1, 0, 1, 0]
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else:
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msg = f"cannot save mode {im.mode}"
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raise ValueError(msg)
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#
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# image
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op = io.BytesIO()
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if filter == "ASCIIHexDecode":
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ImageFile._save(im, op, [("hex", (0, 0) + im.size, 0, im.mode)])
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elif filter == "CCITTFaxDecode":
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im.save(
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op,
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"TIFF",
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compression="group4",
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# use a single strip
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strip_size=math.ceil(width / 8) * height,
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)
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elif filter == "DCTDecode":
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Image.SAVE["JPEG"](im, op, filename)
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elif filter == "JPXDecode":
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del dict_obj["BitsPerComponent"]
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Image.SAVE["JPEG2000"](im, op, filename)
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else:
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msg = f"unsupported PDF filter ({filter})"
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raise ValueError(msg)
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stream = op.getvalue()
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if filter == "CCITTFaxDecode":
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stream = stream[8:]
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filter = PdfParser.PdfArray([PdfParser.PdfName(filter)])
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else:
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filter = PdfParser.PdfName(filter)
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image_ref = image_refs.pop(0)
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existing_pdf.write_obj(
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image_ref,
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stream=stream,
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Type=PdfParser.PdfName("XObject"),
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Subtype=PdfParser.PdfName("Image"),
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Width=width, # * 72.0 / x_resolution,
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Height=height, # * 72.0 / y_resolution,
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Filter=filter,
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Decode=decode,
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DecodeParms=params,
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**dict_obj,
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)
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return image_ref, procset
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def _save(im, fp, filename, save_all=False):
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is_appending = im.encoderinfo.get("append", False)
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if is_appending:
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existing_pdf = PdfParser.PdfParser(f=fp, filename=filename, mode="r+b")
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else:
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existing_pdf = PdfParser.PdfParser(f=fp, filename=filename, mode="w+b")
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dpi = im.encoderinfo.get("dpi")
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if dpi:
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x_resolution = dpi[0]
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y_resolution = dpi[1]
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else:
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x_resolution = y_resolution = im.encoderinfo.get("resolution", 72.0)
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info = {
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"title": (
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None if is_appending else os.path.splitext(os.path.basename(filename))[0]
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),
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"author": None,
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"subject": None,
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"keywords": None,
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"creator": None,
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"producer": None,
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"creationDate": None if is_appending else time.gmtime(),
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"modDate": None if is_appending else time.gmtime(),
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}
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for k, default in info.items():
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v = im.encoderinfo.get(k) if k in im.encoderinfo else default
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if v:
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existing_pdf.info[k[0].upper() + k[1:]] = v
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#
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# make sure image data is available
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im.load()
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existing_pdf.start_writing()
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existing_pdf.write_header()
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existing_pdf.write_comment(f"created by Pillow {__version__} PDF driver")
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#
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# pages
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ims = [im]
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if save_all:
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append_images = im.encoderinfo.get("append_images", [])
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for append_im in append_images:
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append_im.encoderinfo = im.encoderinfo.copy()
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ims.append(append_im)
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number_of_pages = 0
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image_refs = []
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page_refs = []
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contents_refs = []
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for im in ims:
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im_number_of_pages = 1
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if save_all:
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try:
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im_number_of_pages = im.n_frames
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except AttributeError:
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# Image format does not have n_frames.
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# It is a single frame image
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pass
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number_of_pages += im_number_of_pages
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for i in range(im_number_of_pages):
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image_refs.append(existing_pdf.next_object_id(0))
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if im.mode == "P" and "transparency" in im.info:
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image_refs.append(existing_pdf.next_object_id(0))
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page_refs.append(existing_pdf.next_object_id(0))
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contents_refs.append(existing_pdf.next_object_id(0))
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existing_pdf.pages.append(page_refs[-1])
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#
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# catalog and list of pages
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existing_pdf.write_catalog()
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page_number = 0
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for im_sequence in ims:
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im_pages = ImageSequence.Iterator(im_sequence) if save_all else [im_sequence]
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for im in im_pages:
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image_ref, procset = _write_image(im, filename, existing_pdf, image_refs)
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#
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# page
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existing_pdf.write_page(
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page_refs[page_number],
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Resources=PdfParser.PdfDict(
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ProcSet=[PdfParser.PdfName("PDF"), PdfParser.PdfName(procset)],
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XObject=PdfParser.PdfDict(image=image_ref),
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),
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MediaBox=[
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0,
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0,
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im.width * 72.0 / x_resolution,
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im.height * 72.0 / y_resolution,
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],
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Contents=contents_refs[page_number],
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)
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#
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# page contents
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page_contents = b"q %f 0 0 %f 0 0 cm /image Do Q\n" % (
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im.width * 72.0 / x_resolution,
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im.height * 72.0 / y_resolution,
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)
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existing_pdf.write_obj(contents_refs[page_number], stream=page_contents)
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page_number += 1
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#
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# trailer
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existing_pdf.write_xref_and_trailer()
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if hasattr(fp, "flush"):
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fp.flush()
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existing_pdf.close()
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#
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# --------------------------------------------------------------------
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Image.register_save("PDF", _save)
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Image.register_save_all("PDF", _save_all)
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Image.register_extension("PDF", ".pdf")
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Image.register_mime("PDF", "application/pdf")
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