python-pillow/Pillow
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Allow for different palette entry sizes when correcting offset

Browse Source
This commit is contained in:
Andrew Murray 2026-03-19 10:38:28 +11:00
parent 93de6a78d8
commit 735d02584b
2 changed files with 14 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
Tests/test_file_bmp.py
View File

@ -238,13 +238,21 @@ def test_unsupported_bmp_bitfields_layout() -> None:
Image.open(fp)
def test_offset() -> None:
@pytest.mark.parametrize(
"offset, path",
(
(26, "pal8os2.bmp"),
(54, "pal8.bmp"),
),
)
def test_offset(offset: int, path: str) -> None:
image_path = "Tests/images/bmp/g/" + path
# Exclude the palette size from the pixel data offset
with open("Tests/images/bmp/g/pal8.bmp", "rb") as fp:
with open(image_path, "rb") as fp:
data = fp.read()
data = data[:10] + o32(54) + data[14:]
data = data[:10] + o32(offset) + data[14:]
with Image.open(io.BytesIO(data)) as im:
assert_image_equal_tofile(im, "Tests/images/bmp/g/pal8.bmp")
assert_image_equal_tofile(im, image_path)
def test_use_raw_alpha(monkeypatch: pytest.MonkeyPatch) -> None:

4
src/PIL/BmpImagePlugin.py
View File

@ -181,9 +181,10 @@ class BmpImageFile(ImageFile.ImageFile):
assert isinstance(file_info["bits"], int)
if not file_info.get("colors", 0):
file_info["colors"] = 1 << file_info["bits"]
assert isinstance(file_info["palette_padding"], int)
assert isinstance(file_info["colors"], int)
if offset == 14 + file_info["header_size"] and file_info["bits"] <= 8:
offset += 4 * file_info["colors"]
offset += file_info["palette_padding"] * file_info["colors"]
# ---------------------- Check bit depth for unusual unsupported values
self._mode, raw_mode = BIT2MODE.get(file_info["bits"], ("", ""))
@ -262,7 +263,6 @@ class BmpImageFile(ImageFile.ImageFile):
msg = f"Unsupported BMP Palette size ({file_info['colors']})"
raise OSError(msg)
else:
assert isinstance(file_info["palette_padding"], int)
padding = file_info["palette_padding"]
palette = read(padding * file_info["colors"])
grayscale = True