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Switched to saving 1-bit PDFs with DCTDecode #5430

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Merged
hugovk merged 1 commit into from
Apr 25, 2021
Merged

Switched to saving 1-bit PDFs with DCTDecode #5430

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3 changes: 2 additions & 1 deletion Tests/test_file_pdf.py
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Original file line number Diff line number Diff line change
Expand Up @@ -42,7 +42,8 @@ def test_monochrome(tmp_path):
mode = "1"

# Act / Assert
helper_save_as_pdf(tmp_path, mode)
outfile = helper_save_as_pdf(tmp_path, mode)
assert os.path.getsize(outfile) < 15000


def test_greyscale(tmp_path):
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8 changes: 1 addition & 7 deletions src/PIL/PdfImagePlugin.py
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Expand Up @@ -124,7 +124,7 @@ def _save(im, fp, filename, save_all=False):
decode = None

if im.mode == "1":
filter = "ASCIIHexDecode"
filter = "DCTDecode"
colorspace = PdfParser.PdfName("DeviceGray")
procset = "ImageB" # grayscale
bits = 1
Expand Down Expand Up @@ -161,12 +161,6 @@ def _save(im, fp, filename, save_all=False):
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", im.size)
im.putdata(data)
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@radarhere radarhere Apr 22, 2021

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This code is now unused, so I have removed it.

ImageFile._save(im, op, [("hex", (0, 0) + im.size, 0, im.mode)])
elif filter == "DCTDecode":
Image.SAVE["JPEG"](im, op, filename)
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