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Save 1 mode PDF using CCITTFaxDecode filter #6470

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merged 2 commits into from Aug 7, 2022
Merged

Save 1 mode PDF using CCITTFaxDecode filter #6470

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f5b27f9
Save 1 mode PDF using CCITTFaxDecode filter
radarhere Aug 1, 2022
2b14d83
Added strip_size as TIFF encoder argument
radarhere Aug 1, 2022
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12 changes: 8 additions & 4 deletions Tests/test_file_libtiff.py
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Expand Up @@ -1011,14 +1011,18 @@ def test_save_multistrip(self, compression, tmp_path):
# Assert that there are multiple strips
assert len(im.tag_v2[STRIPOFFSETS]) > 1

def test_save_single_strip(self, tmp_path):
@pytest.mark.parametrize("argument", (True, False))
def test_save_single_strip(self, argument, tmp_path):
im = hopper("RGB").resize((256, 256))
out = str(tmp_path / "temp.tif")

TiffImagePlugin.STRIP_SIZE = 2**18
if not argument:
TiffImagePlugin.STRIP_SIZE = 2**18
try:

im.save(out, compression="tiff_adobe_deflate")
arguments = {"compression": "tiff_adobe_deflate"}
if argument:
arguments["strip_size"] = 2**18
im.save(out, **arguments)

with Image.open(out) as im:
assert len(im.tag_v2[STRIPOFFSETS]) == 1
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13 changes: 8 additions & 5 deletions src/PIL/PdfImagePlugin.py
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Expand Up @@ -25,7 +25,7 @@
import os
import time

from . import Image, ImageFile, ImageSequence, PdfParser, TiffImagePlugin, __version__
from . import Image, ImageFile, ImageSequence, PdfParser, __version__

#
# --------------------------------------------------------------------
Expand Down Expand Up @@ -181,10 +181,13 @@ def _save(im, fp, filename, save_all=False):
if filter == "ASCIIHexDecode":
ImageFile._save(im, op, [("hex", (0, 0) + im.size, 0, im.mode)])
elif filter == "CCITTFaxDecode":
original_strip_size = TiffImagePlugin.STRIP_SIZE
TiffImagePlugin.STRIP_SIZE = math.ceil(im.width / 8) * im.height
im.save(op, "TIFF", compression="group4")
TiffImagePlugin.STRIP_SIZE = original_strip_size
im.save(
op,
"TIFF",
compression="group4",
# use a single strip
strip_size=math.ceil(im.width / 8) * im.height,
)
elif filter == "DCTDecode":
Image.SAVE["JPEG"](im, op, filename)
elif filter == "FlateDecode":
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3 changes: 2 additions & 1 deletion src/PIL/TiffImagePlugin.py
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Expand Up @@ -1684,7 +1684,8 @@ def _save(im, fp, filename):
stride = len(bits) * ((im.size[0] * bits[0] + 7) // 8)
# aim for given strip size (64 KB by default) when using libtiff writer
if libtiff:
rows_per_strip = 1 if stride == 0 else min(STRIP_SIZE // stride, im.size[1])
im_strip_size = encoderinfo.get("strip_size", STRIP_SIZE)
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Rather than updating STRIP_SIZE and needing to reset it afterwards, I've added "strip_size" as a TIFF encoder argument.

rows_per_strip = 1 if stride == 0 else min(im_strip_size // stride, im.size[1])
# JPEG encoder expects multiple of 8 rows
if compression == "jpeg":
rows_per_strip = min(((rows_per_strip + 7) // 8) * 8, im.size[1])
Expand Down