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Merge pull request #8317 from Yay295/tiff_exif_multistrip

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Fixed writing multiple StripOffsets to TIFF
This commit is contained in:
Andrew Murray 2024-09-25 18:38:19 +10:00 committed by GitHub
commit 3f24276bf2
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3 changed files with 30 additions and 4 deletions
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3
Tests/test_file_tiff.py
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@ -108,7 +108,8 @@ class TestFileTiff:
assert_image_equal_tofile(im, "Tests/images/hopper.tif")
with Image.open("Tests/images/hopper_bigtiff.tif") as im:
# multistrip support not yet implemented
# The data type of this file's StripOffsets tag is LONG8,
# which is not yet supported for offset data when saving multiple frames.
del im.tag_v2[273]
outfile = str(tmp_path / "temp.tif")

23
Tests/test_file_tiff_metadata.py
View File

@ -181,6 +181,29 @@ def test_change_stripbytecounts_tag_type(tmp_path: Path) -> None:
assert reloaded.tag_v2.tagtype[TiffImagePlugin.STRIPBYTECOUNTS] == TiffTags.LONG
def test_save_multiple_stripoffsets() -> None:
ifd = TiffImagePlugin.ImageFileDirectory_v2()
ifd[TiffImagePlugin.STRIPOFFSETS] = (123, 456)
assert ifd.tagtype[TiffImagePlugin.STRIPOFFSETS] == TiffTags.LONG
# all values are in little-endian
assert ifd.tobytes() == (
# number of tags == 1
b"\x01\x00"
# tag id (2 bytes), type (2 bytes), count (4 bytes), value (4 bytes)
# TiffImagePlugin.STRIPOFFSETS, TiffTags.LONG, 2, 18
# where STRIPOFFSETS is 273, LONG is 4
# and 18 is the offset of the tag data
b"\x11\x01\x04\x00\x02\x00\x00\x00\x12\x00\x00\x00"
# end of entries
b"\x00\x00\x00\x00"
# 26 is the total number of bytes output,
# the offset for any auxiliary strip data that will then be appended
# (123 + 26, 456 + 26) == (149, 482)
b"\x95\x00\x00\x00\xe2\x01\x00\x00"
)
def test_no_duplicate_50741_tag() -> None:
assert TAG_IDS["MakerNoteSafety"] == 50741
assert TAG_IDS["BestQualityScale"] == 50780

8
src/PIL/TiffImagePlugin.py
View File

@ -991,9 +991,11 @@ class ImageFileDirectory_v2(_IFDv2Base):
if stripoffsets is not None:
tag, typ, count, value, data = entries[stripoffsets]
if data:
msg = "multistrip support not yet implemented"
raise NotImplementedError(msg)
value = self._pack("L", self._unpack("L", value)[0] + offset)
size, handler = self._load_dispatch[typ]
values = [val + offset for val in handler(self, data, self.legacy_api)]
data = self._write_dispatch[typ](self, *values)
else:
value = self._pack("L", self._unpack("L", value)[0] + offset)
entries[stripoffsets] = tag, typ, count, value, data
# pass 2: write entries to file