sigilplugins/imagecrunch/PIL/PdfImagePlugin.py
2019-08-03 00:49:15 -07:00

227 lines
7.2 KiB
Python

#
# The Python Imaging Library.
# $Id$
#
# PDF (Acrobat) file handling
#
# History:
# 1996-07-16 fl Created
# 1997-01-18 fl Fixed header
# 2004-02-21 fl Fixes for 1/L/CMYK images, etc.
# 2004-02-24 fl Fixes for 1 and P images.
#
# Copyright (c) 1997-2004 by Secret Labs AB. All rights reserved.
# Copyright (c) 1996-1997 by Fredrik Lundh.
#
# See the README file for information on usage and redistribution.
#
##
# Image plugin for PDF images (output only).
##
from . import Image, ImageFile, ImageSequence, PdfParser
import io
__version__ = "0.5"
#
# --------------------------------------------------------------------
# object ids:
# 1. catalogue
# 2. pages
# 3. image
# 4. page
# 5. page contents
def _save_all(im, fp, filename):
_save(im, fp, filename, save_all=True)
##
# (Internal) Image save plugin for the PDF format.
def _save(im, fp, filename, save_all=False):
resolution = im.encoderinfo.get("resolution", 72.0)
is_appending = im.encoderinfo.get("append", False)
title = im.encoderinfo.get("title", None)
author = im.encoderinfo.get("author", None)
subject = im.encoderinfo.get("subject", None)
keywords = im.encoderinfo.get("keywords", None)
creator = im.encoderinfo.get("creator", None)
producer = im.encoderinfo.get("producer", None)
if is_appending:
existing_pdf = PdfParser.PdfParser(f=fp, filename=filename, mode="r+b")
else:
existing_pdf = PdfParser.PdfParser(f=fp, filename=filename, mode="w+b")
if title:
existing_pdf.info.Title = title
if author:
existing_pdf.info.Author = author
if subject:
existing_pdf.info.Subject = subject
if keywords:
existing_pdf.info.Keywords = keywords
if creator:
existing_pdf.info.Creator = creator
if producer:
existing_pdf.info.Producer = producer
#
# make sure image data is available
im.load()
existing_pdf.start_writing()
existing_pdf.write_header()
existing_pdf.write_comment("created by PIL PDF driver " + __version__)
#
# pages
ims = [im]
if save_all:
append_images = im.encoderinfo.get("append_images", [])
for append_im in append_images:
append_im.encoderinfo = im.encoderinfo.copy()
ims.append(append_im)
numberOfPages = 0
image_refs = []
page_refs = []
contents_refs = []
for im in ims:
im_numberOfPages = 1
if save_all:
try:
im_numberOfPages = im.n_frames
except AttributeError:
# Image format does not have n_frames. It is a single frame image
pass
numberOfPages += im_numberOfPages
for i in range(im_numberOfPages):
image_refs.append(existing_pdf.next_object_id(0))
page_refs.append(existing_pdf.next_object_id(0))
contents_refs.append(existing_pdf.next_object_id(0))
existing_pdf.pages.append(page_refs[-1])
#
# catalog and list of pages
existing_pdf.write_catalog()
pageNumber = 0
for imSequence in ims:
im_pages = ImageSequence.Iterator(imSequence) if save_all else [imSequence]
for im in im_pages:
# FIXME: Should replace ASCIIHexDecode with RunLengthDecode (packbits)
# or LZWDecode (tiff/lzw compression). Note that PDF 1.2 also supports
# Flatedecode (zip compression).
bits = 8
params = None
if im.mode == "1":
filter = "ASCIIHexDecode"
colorspace = PdfParser.PdfName("DeviceGray")
procset = "ImageB" # grayscale
bits = 1
elif im.mode == "L":
filter = "DCTDecode"
# params = "<< /Predictor 15 /Columns %d >>" % (width-2)
colorspace = PdfParser.PdfName("DeviceGray")
procset = "ImageB" # grayscale
elif im.mode == "P":
filter = "ASCIIHexDecode"
palette = im.im.getpalette("RGB")
colorspace = [PdfParser.PdfName("Indexed"), PdfParser.PdfName("DeviceRGB"), 255, PdfParser.PdfBinary(palette)]
procset = "ImageI" # indexed color
elif im.mode == "RGB":
filter = "DCTDecode"
colorspace = PdfParser.PdfName("DeviceRGB")
procset = "ImageC" # color images
elif im.mode == "CMYK":
filter = "DCTDecode"
colorspace = PdfParser.PdfName("DeviceCMYK")
procset = "ImageC" # color images
else:
raise ValueError("cannot save mode %s" % im.mode)
#
# image
op = io.BytesIO()
if filter == "ASCIIHexDecode":
if bits == 1:
# FIXME: the hex encoder doesn't support packed 1-bit
# images; do things the hard way...
data = im.tobytes("raw", "1")
im = Image.new("L", (len(data), 1), None)
im.putdata(data)
ImageFile._save(im, op, [("hex", (0, 0)+im.size, 0, im.mode)])
elif filter == "DCTDecode":
Image.SAVE["JPEG"](im, op, filename)
elif filter == "FlateDecode":
ImageFile._save(im, op, [("zip", (0, 0)+im.size, 0, im.mode)])
elif filter == "RunLengthDecode":
ImageFile._save(im, op, [("packbits", (0, 0)+im.size, 0, im.mode)])
else:
raise ValueError("unsupported PDF filter (%s)" % filter)
#
# Get image characteristics
width, height = im.size
existing_pdf.write_obj(image_refs[pageNumber], stream=op.getvalue(),
Type=PdfParser.PdfName("XObject"),
Subtype=PdfParser.PdfName("Image"),
Width=width, # * 72.0 / resolution,
Height=height, # * 72.0 / resolution,
Filter=PdfParser.PdfName(filter),
BitsPerComponent=bits,
DecodeParams=params,
ColorSpace=colorspace)
#
# page
existing_pdf.write_page(page_refs[pageNumber],
Resources=PdfParser.PdfDict(
ProcSet=[PdfParser.PdfName("PDF"), PdfParser.PdfName(procset)],
XObject=PdfParser.PdfDict(image=image_refs[pageNumber])),
MediaBox=[0, 0, int(width * 72.0 / resolution), int(height * 72.0 / resolution)],
Contents=contents_refs[pageNumber]
)
#
# page contents
page_contents = PdfParser.make_bytes(
"q %d 0 0 %d 0 0 cm /image Do Q\n" % (
int(width * 72.0 / resolution),
int(height * 72.0 / resolution)))
existing_pdf.write_obj(contents_refs[pageNumber], stream=page_contents)
pageNumber += 1
#
# trailer
existing_pdf.write_xref_and_trailer()
if hasattr(fp, "flush"):
fp.flush()
existing_pdf.close()
#
# --------------------------------------------------------------------
Image.register_save("PDF", _save)
Image.register_save_all("PDF", _save_all)
Image.register_extension("PDF", ".pdf")
Image.register_mime("PDF", "application/pdf")