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Use I;16 mode for 9-bit JPEG 2000 images #7900

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Merged
radarhere merged 6 commits into from
Mar 25, 2024
Merged

Use I;16 mode for 9-bit JPEG 2000 images #7900

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ce060a8
Fix 9-bit JPEG 2000 images not using I;16
scaramallion Mar 24, 2024
901c13c
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Mar 24, 2024
1f182ce
Fix parsing the J2K header
scaramallion Mar 25, 2024
0f49eaf
Simplified code
radarhere Mar 25, 2024
7ca9bdd
Update Tests/test_file_jpeg2k.py
scaramallion Mar 25, 2024
144959b
Merge pull request #2 from radarhere/dev-j2k-precision
scaramallion Mar 25, 2024
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Binary file added Tests/images/9bit.j2k
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7 changes: 7 additions & 0 deletions Tests/test_file_jpeg2k.py
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Original file line number Diff line number Diff line change
Expand Up @@ -446,3 +446,10 @@ def test_plt_marker() -> None:
hdr = out.read(2)
length = _binary.i16be(hdr)
out.seek(length - 2, os.SEEK_CUR)


def test_9bit():
# Test 9-bit images are decoded to I;16
with Image.open("Tests/images/9bit.j2k") as im:
assert im.mode == "I;16"
assert im.size == (128, 128)
4 changes: 2 additions & 2 deletions src/PIL/Jpeg2KImagePlugin.py
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Original file line number Diff line number Diff line change
Expand Up @@ -110,11 +110,11 @@ def _parse_codestream(fp):
xrsiz = [None] * csiz
yrsiz = [None] * csiz
for i in range(csiz):
ssiz[i], xrsiz[i], yrsiz[i] = struct.unpack_from(">BBB", siz, 36 + 3 * i)
ssiz[i], xrsiz[i], yrsiz[i] = struct.unpack_from(">BBB", siz, 38 + 3 * i)

size = (xsiz - xosiz, ysiz - yosiz)
if csiz == 1:
if (yrsiz[0] & 0x7F) > 8:
if (ssiz[0] & 0x7F) + 1 > 8:
mode = "I;16"
else:
mode = "L"
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