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Merged
radarhere merged 1 commit into from
Oct 21, 2026
+27 −24
Merged

Do not set palette for non-P GIF images #10238

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8 changes: 5 additions & 3 deletions Tests/test_file_gif.py
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Original file line number Diff line number Diff line change
Expand Up @@ -113,6 +113,7 @@ def test_l_mode_transparency_after_rgb() -> None:
def test_palette_not_needed_for_second_frame() -> None:
with Image.open("Tests/images/palette_not_needed_for_second_frame.gif") as im:
im.seek(1)
assert im.palette is None
assert_image_similar(im, hopper("L").convert("RGB"), 8)


Expand All @@ -131,10 +132,12 @@ def test_strategy(monkeypatch: pytest.MonkeyPatch) -> None:
)
with Image.open("Tests/images/iss634.gif") as im:
assert im.mode == "RGB"
assert im.palette is None
assert_image_equal(im, expected_rgb_always)

with Image.open("Tests/images/chi.gif") as im:
assert im.mode == "RGBA"
assert im.palette is None
assert_image_equal(im, expected_rgb_always_rgba)

monkeypatch.setattr(
Expand Down Expand Up @@ -1375,16 +1378,15 @@ def test_palette_save_all_P(tmp_path: Path) -> None:
)

with Image.open(out) as im:
# Assert that the frames are correct, and each frame has the same palette
# Assert that the frames are correct
assert isinstance(im, GifImagePlugin.GifImageFile)
assert_image_equal(im.convert("RGB"), frames[0].convert("RGB"))
assert im.palette is not None
assert im.global_palette is not None
assert im.palette.palette == im.global_palette.palette

im.seek(1)
assert_image_equal(im.convert("RGB"), frames[1].convert("RGB"))
assert im.palette.palette == im.global_palette.palette
assert_image_equal(im, frames[1].convert("RGB"))


def test_palette_save_ImagePalette(tmp_path: Path) -> None:
Expand Down
43 changes: 22 additions & 21 deletions src/PIL/GifImagePlugin.py
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Original file line number Diff line number Diff line change
Expand Up @@ -123,7 +123,7 @@ def _open(self) -> None:
p = self.fp.read(3 << bits)
if self._is_palette_needed(p):
palette = ImagePalette.raw("RGB", p)
self.global_palette = self.palette = palette
self.global_palette = palette

self._fp = self.fp # FIXME: hack
self.__rewind = self.fp.tell()
Expand Down Expand Up @@ -319,22 +319,20 @@ def _seek(self, frame: int, update_image: bool = True) -> None:
self._frame_palette = palette if palette is not None else self.global_palette
self._frame_transparency = frame_transparency
if frame == 0:
self.palette = None
if self._frame_palette:
if LOADING_STRATEGY == LoadingStrategy.RGB_ALWAYS:
self._mode = "RGBA" if frame_transparency is not None else "RGB"
else:
self._mode = "P"
else:
self._mode = "L"
if palette:
self.palette = palette
elif self.global_palette:
from copy import copy

if palette:
self.palette = palette
elif self.global_palette:
from copy import copy

self.palette = copy(self.global_palette)
self.palette = copy(self.global_palette)
else:
self.palette = None
self._mode = "L"
elif self.mode == "P" and (
LOADING_STRATEGY != LoadingStrategy.RGB_AFTER_DIFFERENT_PALETTE_ONLY
or palette
Expand All @@ -347,6 +345,7 @@ def _seek(self, frame: int, update_image: bool = True) -> None:
else:
self._mode = "RGB"
self.im = self.im.convert("RGB", Image.Dither.FLOYDSTEINBERG)
self.palette = None

def _rgb(color: int) -> tuple[int, int, int]:
if self._frame_palette:
Expand Down Expand Up @@ -376,12 +375,12 @@ def _rgb(color: int) -> tuple[int, int, int]:
dispose_mode = "P"
color = self.info.get("transparency", frame_transparency)
if color is not None:
if self.mode in ("RGB", "RGBA"):
if self.mode in {"RGB", "RGBA"}:
dispose_mode = "RGBA"
color = _rgb(color) + (0,)
else:
color = self.info.get("background", 0)
if self.mode in ("RGB", "RGBA"):
if self.mode in {"RGB", "RGBA"}:
dispose_mode = "RGB"
color = _rgb(color)
self.dispose = Image.core.fill(dispose_mode, dispose_size, color)
Expand All @@ -397,7 +396,7 @@ def _rgb(color: int) -> tuple[int, int, int]:
Image._decompression_bomb_check(dispose_size)
dispose_mode = "P"
color = frame_transparency
if self.mode in ("RGB", "RGBA"):
if self.mode in {"RGB", "RGBA"}:
dispose_mode = "RGBA"
color = _rgb(frame_transparency) + (0,)
self.dispose = Image.core.fill(
Expand All @@ -412,7 +411,7 @@ def _rgb(color: int) -> tuple[int, int, int]:
if frame == 0:
if LOADING_STRATEGY != LoadingStrategy.RGB_ALWAYS:
self.info["transparency"] = frame_transparency
elif self.mode not in ("RGB", "RGBA"):
elif self.mode not in {"RGB", "RGBA"}:
transparency = frame_transparency
self.tile = [
ImageFile._Tile(
Expand All @@ -435,11 +434,13 @@ def load_prepare(self) -> None:
temp_mode = "P" if self._frame_palette else "L"
self._prev_im = None
if self.__frame == 0:
if self._frame_transparency is not None:
self.im = Image.core.fill(
temp_mode, self.size, self._frame_transparency
)
elif self.mode in ("RGB", "RGBA"):
self.im = Image.core.fill(
temp_mode, self.size, self._frame_transparency or 0
)
if temp_mode == "P":
assert self._frame_palette
self.im.putpalette("RGB", *self._frame_palette.getdata())
elif self.mode in {"RGB", "RGBA"}:
self._prev_im = self.im
if self._frame_palette:
self.im = Image.core.fill("P", self.size, self._frame_transparency or 0)
Expand Down Expand Up @@ -495,7 +496,7 @@ def load_end(self) -> None:

self.im = self._prev_im
self._mode = self.im.mode
if frame_im.mode in ("LA", "RGBA"):
if frame_im.mode in {"LA", "RGBA"}:
self.im.paste(frame_im, self.dispose_extent, frame_im)
else:
self.im.paste(frame_im, self.dispose_extent)
Expand Down Expand Up @@ -870,7 +871,7 @@ def _get_optimize(im: Image.Image, info: dict[str, Any]) -> list[int] | None:
:returns: list of indexes of palette entries in use, or None
"""
if (
im.mode in ("P", "L")
im.mode in {"L", "P"}
and info
and info.get("optimize")
and im.width != 0
Expand Down
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