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Merge pull request #5588 from kmilos/patch-2

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Ensure TIFF RowsPerStrip is multiple of 8 for JPEG compression
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Andrew Murray 2021-07-18 18:17:25 +10:00 committed by GitHub
commit 7484bb08b4
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2 changed files with 6 additions and 2 deletions
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5
Tests/test_file_libtiff.py
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@ -968,10 +968,11 @@ class TestFileLibTiff(LibTiffTestCase):
assert str(e.value) == "-9"
TiffImagePlugin.READ_LIBTIFF = False
def test_save_multistrip(self, tmp_path):
@pytest.mark.parametrize("compression", ("tiff_adobe_deflate", "jpeg"))
def test_save_multistrip(self, compression, tmp_path):
im = hopper("RGB").resize((256, 256))
out = str(tmp_path / "temp.tif")
im.save(out, compression="tiff_adobe_deflate")
im.save(out, compression=compression)
with Image.open(out) as im:
# Assert that there are multiple strips

3
src/PIL/TiffImagePlugin.py
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@ -1577,6 +1577,9 @@ def _save(im, fp, filename):
# aim for 64 KB strips when using libtiff writer
if libtiff:
rows_per_strip = min((2 ** 16 + stride - 1) // 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])
else:
rows_per_strip = im.size[1]
strip_byte_counts = stride * rows_per_strip