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issue #2959: support appending to existing PDFs
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@vashek
vashek committed Jan 18, 2018
1 parent b9ea737 commit 6207b44
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Showing 3 changed files with 746 additions and 124 deletions.
9 changes: 6 additions & 3 deletions src/PIL/Image.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1922,9 +1922,12 @@ def save(self, fp, format=None, **params):
save_handler = SAVE[format.upper()]

if open_fp:
# Open also for reading ("+"), because TIFF save_all
# writer needs to go back and edit the written data.
fp = builtins.open(filename, "w+b")
if params.get('append', False):
fp = builtins.open(filename, "r+b")
else:
# Open also for reading ("+"), because TIFF save_all
# writer needs to go back and edit the written data.
fp = builtins.open(filename, "w+b")

try:
save_handler(self, fp, filename)
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202 changes: 81 additions & 121 deletions src/PIL/PdfImagePlugin.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,11 +20,11 @@
# Image plugin for PDF images (output only).
##

from . import Image, ImageFile, ImageSequence
from . import Image, ImageFile, ImageSequence, pdfParser
from ._binary import i8
import io

__version__ = "0.4"
__version__ = "0.5"


#
Expand All @@ -37,19 +37,6 @@
# 4. page
# 5. page contents

def _obj(fp, obj, **dictionary):
fp.write("%d 0 obj\n" % obj)
if dictionary:
fp.write("<<\n")
for k, v in dictionary.items():
if v is not None:
fp.write("/%s %s\n" % (k, v))
fp.write(">>\n")


def _endobj(fp):
fp.write("endobj\n")


def _save_all(im, fp, filename):
_save(im, fp, filename, save_all=True)
Expand All @@ -60,13 +47,17 @@ def _save_all(im, fp, filename):

def _save(im, fp, filename, save_all=False):
resolution = im.encoderinfo.get("resolution", 72.0)
is_appending = im.encoderinfo.get("append", False)
if is_appending:
existing_pdf = pdfParser.PdfParser(f=fp, filename=filename)
fp.seek(0, io.SEEK_END)
else:
existing_pdf = pdfParser.PdfParser()

#
# make sure image data is available
im.load()

xref = [0]

class TextWriter(object):
def __init__(self, fp):
self.fp = fp
Expand All @@ -77,71 +68,32 @@ def __getattr__(self, name):
def write(self, value):
self.fp.write(value.encode('latin-1'))

fp = TextWriter(fp)

fp.write("%PDF-1.2\n")
fp.write("% created by PIL PDF driver " + __version__ + "\n")

# 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 = "/DeviceGray"
procset = "/ImageB" # grayscale
bits = 1
elif im.mode == "L":
filter = "/DCTDecode"
# params = "<< /Predictor 15 /Columns %d >>" % (width-2)
colorspace = "/DeviceGray"
procset = "/ImageB" # grayscale
elif im.mode == "P":
filter = "/ASCIIHexDecode"
colorspace = "[ /Indexed /DeviceRGB 255 <"
palette = im.im.getpalette("RGB")
for i in range(256):
r = i8(palette[i*3])
g = i8(palette[i*3+1])
b = i8(palette[i*3+2])
colorspace += "%02x%02x%02x " % (r, g, b)
colorspace += "> ]"
procset = "/ImageI" # indexed color
elif im.mode == "RGB":
filter = "/DCTDecode"
colorspace = "/DeviceRGB"
procset = "/ImageC" # color images
elif im.mode == "CMYK":
filter = "/DCTDecode"
colorspace = "/DeviceCMYK"
procset = "/ImageC" # color images
else:
raise ValueError("cannot save mode %s" % im.mode)
#fp = TextWriter(fp)

fp.write(b"%PDF-1.2\n")
fp.write(b"% created by PIL PDF driver " + __version__.encode("us-ascii") + b"\n")

#
# catalogue

xref.append(fp.tell())
_obj(
fp, 1,
Type="/Catalog",
Pages="2 0 R")
_endobj(fp)
catalog_ref = existing_pdf.next_object_id(fp.tell())
pages_ref = existing_pdf.next_object_id(0)
existing_pdf.write_obj(fp, catalog_ref,
Type=pdfParser.PdfName(b"Catalog"),
Pages=pages_ref)

#
# pages
ims = [im]
if save_all:
append_images = im.encoderinfo.get("append_images", [])
for append_im in append_images:
if append_im.mode != im.mode:
append_im = append_im.convert(im.mode)
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:
Expand All @@ -151,38 +103,71 @@ def write(self, value):
# Image format does not have n_frames. It is a single frame image
pass
numberOfPages += im_numberOfPages
pages = [str(pageNumber*3+4)+" 0 R"
for pageNumber in range(0, 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])

xref.append(fp.tell())
_obj(
fp, 2,
Type="/Pages",
Count=len(pages),
Kids="["+"\n".join(pages)+"]")
_endobj(fp)
existing_pdf.write_obj(fp, pages_ref,
Type=pdfParser.PdfName("Pages"),
Count=len(existing_pdf.pages),
Kids=existing_pdf.pages)

pageNumber = 0
for imSequence in ims:
for im in ImageSequence.Iterator(imSequence):
# 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 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":
elif filter == "DCTDecode":
Image.SAVE["JPEG"](im, op, filename)
elif filter == "/FlateDecode":
elif filter == "FlateDecode":
ImageFile._save(im, op, [("zip", (0, 0)+im.size, 0, im.mode)])
elif filter == "/RunLengthDecode":
elif filter == "RunLengthDecode":
ImageFile._save(im, op, [("packbits", (0, 0)+im.size, 0, im.mode)])
else:
raise ValueError("unsupported PDF filter (%s)" % filter)
Expand All @@ -192,41 +177,28 @@ def write(self, value):

width, height = im.size

xref.append(fp.tell())
_obj(
fp, pageNumber*3+3,
Type="/XObject",
Subtype="/Image",
existing_pdf.write_obj(fp, image_refs[pageNumber], stream=op.getvalue(),
Type=pdfParser.PdfName("XObject"),
Subtype=pdfParser.PdfName("Image"),
Width=width, # * 72.0 / resolution,
Height=height, # * 72.0 / resolution,
Length=len(op.getvalue()),
Filter=filter,
Filter=pdfParser.PdfName(filter),
BitsPerComponent=bits,
DecodeParams=params,
ColorSpace=colorspace)

fp.write("stream\n")
fp.fp.write(op.getvalue())
fp.write("\nendstream\n")

_endobj(fp)

#
# page

xref.append(fp.tell())
_obj(fp, pageNumber*3+4)
fp.write(
"<<\n/Type /Page\n/Parent 2 0 R\n"
"/Resources <<\n/ProcSet [ /PDF %s ]\n"
"/XObject << /image %d 0 R >>\n>>\n"
"/MediaBox [ 0 0 %d %d ]\n/Contents %d 0 R\n>>\n" % (
procset,
pageNumber*3+3,
int(width * 72.0 / resolution),
int(height * 72.0 / resolution),
pageNumber*3+5))
_endobj(fp)
existing_pdf.write_obj(fp, page_refs[pageNumber],
Type=pdfParser.PdfName("Page"),
Parent=pages_ref,
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
Expand All @@ -238,25 +210,13 @@ def write(self, value):
int(width * 72.0 / resolution),
int(height * 72.0 / resolution)))

xref.append(fp.tell())
_obj(fp, pageNumber*3+5, Length=len(op.fp.getvalue()))

fp.write("stream\n")
fp.fp.write(op.fp.getvalue())
fp.write("\nendstream\n")

_endobj(fp)
existing_pdf.write_obj(fp, contents_refs[pageNumber], stream=op.fp.getvalue())

pageNumber += 1

#
# trailer
startxref = fp.tell()
fp.write("xref\n0 %d\n0000000000 65535 f \n" % len(xref))
for x in xref[1:]:
fp.write("%010d 00000 n \n" % x)
fp.write("trailer\n<<\n/Size %d\n/Root 1 0 R\n>>\n" % len(xref))
fp.write("startxref\n%d\n%%%%EOF\n" % startxref)
existing_pdf.write_xref_and_trailer(fp, catalog_ref)
if hasattr(fp, "flush"):
fp.flush()

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