Added type hints

Tests/test_file_gif.py

@@ -53,6 +53,7 @@ def test_closed_file() -> None:
 
 def test_seek_after_close() -> None:
     im = Image.open("Tests/images/iss634.gif")
+    assert isinstance(im, GifImagePlugin.GifImageFile)
     im.load()
     im.close()
 
@@ -377,7 +378,8 @@ def test_save_netpbm_bmp_mode(tmp_path: Path) -> None:
         img = img.convert("RGB")
 
         tempfile = str(tmp_path / "temp.gif")
-        GifImagePlugin._save_netpbm(img, 0, tempfile)
+        b = BytesIO()
+        GifImagePlugin._save_netpbm(img, b, tempfile)
         with Image.open(tempfile) as reloaded:
             assert_image_similar(img, reloaded.convert("RGB"), 0)
 
@@ -388,7 +390,8 @@ def test_save_netpbm_l_mode(tmp_path: Path) -> None:
         img = img.convert("L")
 
         tempfile = str(tmp_path / "temp.gif")
-        GifImagePlugin._save_netpbm(img, 0, tempfile)
+        b = BytesIO()
+        GifImagePlugin._save_netpbm(img, b, tempfile)
         with Image.open(tempfile) as reloaded:
             assert_image_similar(img, reloaded.convert("L"), 0)
 
@@ -648,7 +651,7 @@ def test_dispose2_palette(tmp_path: Path) -> None:
             assert rgb_img.getpixel((50, 50)) == circle
 
             # Check that frame transparency wasn't added unnecessarily
-            assert img._frame_transparency is None
+            assert getattr(img, "_frame_transparency") is None
 
 
 def test_dispose2_diff(tmp_path: Path) -> None:

src/PIL/GifImagePlugin.py

@@ -29,9 +29,10 @@ import itertools
 import math
 import os
 import subprocess
+import sys
 from enum import IntEnum
 from functools import cached_property
-from typing import IO
+from typing import IO, TYPE_CHECKING, Any, List, Literal, NamedTuple, Union
 
 from . import (
     Image,
@@ -46,6 +47,9 @@ from ._binary import i16le as i16
 from ._binary import o8
 from ._binary import o16le as o16
 
+if TYPE_CHECKING:
+    from . import _imaging
+
 
 class LoadingStrategy(IntEnum):
     """.. versionadded:: 9.1.0"""
@@ -118,7 +122,7 @@ class GifImageFile(ImageFile.ImageFile):
         self._seek(0)  # get ready to read first frame
 
     @property
-    def n_frames(self):
+    def n_frames(self) -> int:
         if self._n_frames is None:
             current = self.tell()
             try:
@@ -163,11 +167,11 @@ class GifImageFile(ImageFile.ImageFile):
                 msg = "no more images in GIF file"
                 raise EOFError(msg) from e
 
-    def _seek(self, frame, update_image=True):
+    def _seek(self, frame: int, update_image: bool = True) -> None:
         if frame == 0:
             # rewind
             self.__offset = 0
-            self.dispose = None
+            self.dispose: _imaging.ImagingCore | None = None
             self.__frame = -1
             self._fp.seek(self.__rewind)
             self.disposal_method = 0
@@ -195,9 +199,9 @@ class GifImageFile(ImageFile.ImageFile):
             msg = "no more images in GIF file"
             raise EOFError(msg)
 
-        palette = None
+        palette: ImagePalette.ImagePalette | Literal[False] | None = None
 
-        info = {}
+        info: dict[str, Any] = {}
         frame_transparency = None
         interlace = None
         frame_dispose_extent = None
@@ -213,7 +217,7 @@ class GifImageFile(ImageFile.ImageFile):
                 #
                 s = self.fp.read(1)
                 block = self.data()
-                if s[0] == 249:
+                if s[0] == 249 and block is not None:
                     #
                     # graphic control extension
                     #
@@ -249,14 +253,14 @@ class GifImageFile(ImageFile.ImageFile):
                         info["comment"] = comment
                     s = None
                     continue
-                elif s[0] == 255 and frame == 0:
+                elif s[0] == 255 and frame == 0 and block is not None:
                     #
                     # application extension
                     #
                     info["extension"] = block, self.fp.tell()
                     if block[:11] == b"NETSCAPE2.0":
                         block = self.data()
-                        if len(block) >= 3 and block[0] == 1:
+                        if block and len(block) >= 3 and block[0] == 1:
                             self.info["loop"] = i16(block, 1)
                 while self.data():
                     pass
@@ -345,51 +349,52 @@ class GifImageFile(ImageFile.ImageFile):
             else:
                 return (color, color, color)
 
+        self.dispose = None
         self.dispose_extent = frame_dispose_extent
-        try:
+        if self.dispose_extent and self.disposal_method >= 2:
-            if self.disposal_method < 2:
+            try:
-                # do not dispose or none specified
+                if self.disposal_method == 2:
-                self.dispose = None
+                    # replace with background colour
-            elif self.disposal_method == 2:
-                # replace with background colour
 
-                # only dispose the extent in this frame
-                x0, y0, x1, y1 = self.dispose_extent
-                dispose_size = (x1 - x0, y1 - y0)
-
-                Image._decompression_bomb_check(dispose_size)
-
-                # by convention, attempt to use transparency first
-                dispose_mode = "P"
-                color = self.info.get("transparency", frame_transparency)
-                if color is not None:
-                    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"):
-                        dispose_mode = "RGB"
-                        color = _rgb(color)
-                self.dispose = Image.core.fill(dispose_mode, dispose_size, color)
-            else:
-                # replace with previous contents
-                if self.im is not None:
                     # only dispose the extent in this frame
-                    self.dispose = self._crop(self.im, self.dispose_extent)
-                elif frame_transparency is not None:
                     x0, y0, x1, y1 = self.dispose_extent
                     dispose_size = (x1 - x0, y1 - y0)
 
                     Image._decompression_bomb_check(dispose_size)
+
+                    # by convention, attempt to use transparency first
                     dispose_mode = "P"
-                    color = frame_transparency
+                    color = self.info.get("transparency", frame_transparency)
-                    if self.mode in ("RGB", "RGBA"):
+                    if color is not None:
-                        dispose_mode = "RGBA"
+                        if self.mode in ("RGB", "RGBA"):
-                        color = _rgb(frame_transparency) + (0,)
+                            dispose_mode = "RGBA"
+                            color = _rgb(color) + (0,)
+                    else:
+                        color = self.info.get("background", 0)
+                        if self.mode in ("RGB", "RGBA"):
+                            dispose_mode = "RGB"
+                            color = _rgb(color)
                     self.dispose = Image.core.fill(dispose_mode, dispose_size, color)
-        except AttributeError:
+                else:
-            pass
+                    # replace with previous contents
+                    if self.im is not None:
+                        # only dispose the extent in this frame
+                        self.dispose = self._crop(self.im, self.dispose_extent)
+                    elif frame_transparency is not None:
+                        x0, y0, x1, y1 = self.dispose_extent
+                        dispose_size = (x1 - x0, y1 - y0)
+
+                        Image._decompression_bomb_check(dispose_size)
+                        dispose_mode = "P"
+                        color = frame_transparency
+                        if self.mode in ("RGB", "RGBA"):
+                            dispose_mode = "RGBA"
+                            color = _rgb(frame_transparency) + (0,)
+                        self.dispose = Image.core.fill(
+                            dispose_mode, dispose_size, color
+                        )
+            except AttributeError:
+                pass
 
         if interlace is not None:
             transparency = -1
@@ -498,7 +503,12 @@ def _normalize_mode(im: Image.Image) -> Image.Image:
     return im.convert("L")
 
 
-def _normalize_palette(im, palette, info):
+_Palette = Union[bytes, bytearray, List[int], ImagePalette.ImagePalette]
+
+
+def _normalize_palette(
+    im: Image.Image, palette: _Palette | None, info: dict[str, Any]
+) -> Image.Image:
     """
     Normalizes the palette for image.
       - Sets the palette to the incoming palette, if provided.
@@ -526,8 +536,10 @@ def _normalize_palette(im, palette, info):
             source_palette = bytearray(i // 3 for i in range(768))
         im.palette = ImagePalette.ImagePalette("RGB", palette=source_palette)
 
+    used_palette_colors: list[int] | None
     if palette:
         used_palette_colors = []
+        assert source_palette is not None
         for i in range(0, len(source_palette), 3):
             source_color = tuple(source_palette[i : i + 3])
             index = im.palette.colors.get(source_color)
@@ -561,7 +573,7 @@ def _normalize_palette(im, palette, info):
 def _write_single_frame(
     im: Image.Image,
     fp: IO[bytes],
-    palette: bytes | bytearray | list[int] | ImagePalette.ImagePalette,
+    palette: _Palette | None,
 ) -> None:
     im_out = _normalize_mode(im)
     for k, v in im_out.info.items():
@@ -585,7 +597,7 @@ def _write_single_frame(
 
 def _getbbox(
     base_im: Image.Image, im_frame: Image.Image
-) -> tuple[Image.Image, tuple[int, int, int, int]]:
+) -> tuple[Image.Image, tuple[int, int, int, int] | None]:
     if _get_palette_bytes(im_frame) != _get_palette_bytes(base_im):
         im_frame = im_frame.convert("RGBA")
         base_im = base_im.convert("RGBA")
@@ -593,12 +605,20 @@ def _getbbox(
     return delta, delta.getbbox(alpha_only=False)
 
 
-def _write_multiple_frames(im, fp, palette):
+class _Frame(NamedTuple):
+    im: Image.Image
+    bbox: tuple[int, int, int, int] | None
+    encoderinfo: dict[str, Any]
+
+
+def _write_multiple_frames(
+    im: Image.Image, fp: IO[bytes], palette: _Palette | None
+) -> bool:
     duration = im.encoderinfo.get("duration")
     disposal = im.encoderinfo.get("disposal", im.info.get("disposal"))
 
-    im_frames = []
+    im_frames: list[_Frame] = []
-    previous_im = None
+    previous_im: Image.Image | None = None
     frame_count = 0
     background_im = None
     for imSequence in itertools.chain([im], im.encoderinfo.get("append_images", [])):
@@ -624,24 +644,22 @@ def _write_multiple_frames(im, fp, palette):
             frame_count += 1
 
             diff_frame = None
-            if im_frames:
+            if im_frames and previous_im:
                 # delta frame
                 delta, bbox = _getbbox(previous_im, im_frame)
                 if not bbox:
                     # This frame is identical to the previous frame
                     if encoderinfo.get("duration"):
-                        im_frames[-1]["encoderinfo"]["duration"] += encoderinfo[
+                        im_frames[-1].encoderinfo["duration"] += encoderinfo["duration"]
-                            "duration"
-                        ]
                     continue
-                if im_frames[-1]["encoderinfo"].get("disposal") == 2:
+                if im_frames[-1].encoderinfo.get("disposal") == 2:
                     if background_im is None:
                         color = im.encoderinfo.get(
                             "transparency", im.info.get("transparency", (0, 0, 0))
                         )
                         background = _get_background(im_frame, color)
                         background_im = Image.new("P", im_frame.size, background)
-                        background_im.putpalette(im_frames[0]["im"].palette)
+                        background_im.putpalette(im_frames[0].im.palette)
                     bbox = _getbbox(background_im, im_frame)[1]
                 elif encoderinfo.get("optimize") and im_frame.mode != "1":
                     if "transparency" not in encoderinfo:
@@ -687,31 +705,29 @@ def _write_multiple_frames(im, fp, palette):
             else:
                 bbox = None
             previous_im = im_frame
-            im_frames.append(
+            im_frames.append(_Frame(diff_frame or im_frame, bbox, encoderinfo))
-                {"im": diff_frame or im_frame, "bbox": bbox, "encoderinfo": encoderinfo}
-            )
 
     if len(im_frames) == 1:
         if "duration" in im.encoderinfo:
             # Since multiple frames will not be written, use the combined duration
-            im.encoderinfo["duration"] = im_frames[0]["encoderinfo"]["duration"]
+            im.encoderinfo["duration"] = im_frames[0].encoderinfo["duration"]
-        return
+        return False
 
     for frame_data in im_frames:
-        im_frame = frame_data["im"]
+        im_frame = frame_data.im
-        if not frame_data["bbox"]:
+        if not frame_data.bbox:
             # global header
-            for s in _get_global_header(im_frame, frame_data["encoderinfo"]):
+            for s in _get_global_header(im_frame, frame_data.encoderinfo):
                 fp.write(s)
             offset = (0, 0)
         else:
             # compress difference
             if not palette:
-                frame_data["encoderinfo"]["include_color_table"] = True
+                frame_data.encoderinfo["include_color_table"] = True
 
-            im_frame = im_frame.crop(frame_data["bbox"])
+            im_frame = im_frame.crop(frame_data.bbox)
-            offset = frame_data["bbox"][:2]
+            offset = frame_data.bbox[:2]
-        _write_frame_data(fp, im_frame, offset, frame_data["encoderinfo"])
+        _write_frame_data(fp, im_frame, offset, frame_data.encoderinfo)
     return True
 
 
@@ -748,7 +764,9 @@ def get_interlace(im: Image.Image) -> int:
     return interlace
 
 
-def _write_local_header(fp, im, offset, flags):
+def _write_local_header(
+    fp: IO[bytes], im: Image.Image, offset: tuple[int, int], flags: int
+) -> None:
     try:
         transparency = im.encoderinfo["transparency"]
     except KeyError:
@@ -849,7 +867,7 @@ def _save_netpbm(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
 _FORCE_OPTIMIZE = False
 
 
-def _get_optimize(im, info):
+def _get_optimize(im: Image.Image, info: dict[str, Any]) -> list[int] | None:
     """
     Palette optimization is a potentially expensive operation.
 
@@ -893,6 +911,7 @@ def _get_optimize(im, info):
                 and current_palette_size > 2
             ):
                 return used_palette_colors
+    return None
 
 
 def _get_color_table_size(palette_bytes: bytes) -> int:
@@ -933,7 +952,10 @@ def _get_palette_bytes(im: Image.Image) -> bytes:
     return im.palette.palette if im.palette else b""
 
 
-def _get_background(im, info_background):
+def _get_background(
+    im: Image.Image,
+    info_background: int | tuple[int, int, int] | tuple[int, int, int, int] | None,
+) -> int:
     background = 0
     if info_background:
         if isinstance(info_background, tuple):
@@ -956,7 +978,7 @@ def _get_background(im, info_background):
     return background
 
 
-def _get_global_header(im, info):
+def _get_global_header(im: Image.Image, info: dict[str, Any]) -> list[bytes]:
     """Return a list of strings representing a GIF header"""
 
     # Header Block
@@ -1018,7 +1040,12 @@ def _get_global_header(im, info):
     return header
 
 
-def _write_frame_data(fp, im_frame, offset, params):
+def _write_frame_data(
+    fp: IO[bytes],
+    im_frame: Image.Image,
+    offset: tuple[int, int],
+    params: dict[str, Any],
+) -> None:
     try:
         im_frame.encoderinfo = params
 
@@ -1038,7 +1065,9 @@ def _write_frame_data(fp, im_frame, offset, params):
 # Legacy GIF utilities
 
 
-def getheader(im, palette=None, info=None):
+def getheader(
+    im: Image.Image, palette: _Palette | None = None, info: dict[str, Any] | None = None
+) -> tuple[list[bytes], list[int] | None]:
     """
     Legacy Method to get Gif data from image.
 
@@ -1050,11 +1079,11 @@ def getheader(im, palette=None, info=None):
     :returns: tuple of(list of header items, optimized palette)
 
     """
-    used_palette_colors = _get_optimize(im, info)
-
     if info is None:
         info = {}
 
+    used_palette_colors = _get_optimize(im, info)
+
     if "background" not in info and "background" in im.info:
         info["background"] = im.info["background"]
 
@@ -1066,7 +1095,9 @@ def getheader(im, palette=None, info=None):
     return header, used_palette_colors
 
 
-def getdata(im, offset=(0, 0), **params):
+def getdata(
+    im: Image.Image, offset: tuple[int, int] = (0, 0), **params: Any
+) -> list[bytes]:
     """
     Legacy Method
 
@@ -1083,12 +1114,23 @@ def getdata(im, offset=(0, 0), **params):
     :returns: List of bytes containing GIF encoded frame data
 
     """
+    from io import BytesIO
 
-    class Collector:
+    class Collector(BytesIO):
         data = []
 
-        def write(self, data: bytes) -> None:
+        if sys.version_info >= (3, 12):
-            self.data.append(data)
+            from collections.abc import Buffer
+
+            def write(self, data: Buffer) -> int:
+                self.data.append(data)
+                return len(data)
+
+        else:
+
+            def write(self, data: Any) -> int:
+                self.data.append(data)
+                return len(data)
 
     im.load()  # make sure raster data is available
 

src/PIL/Image.py

@@ -41,7 +41,7 @@ import warnings
 from collections.abc import Callable, MutableMapping
 from enum import IntEnum
 from types import ModuleType
-from typing import IO, TYPE_CHECKING, Any, Literal, Protocol, Sequence, cast
+from typing import IO, TYPE_CHECKING, Any, Literal, Protocol, Sequence, Tuple, cast
 
 # VERSION was removed in Pillow 6.0.0.
 # PILLOW_VERSION was removed in Pillow 9.0.0.
@@ -1367,7 +1367,7 @@ class Image:
         """
         return ImageMode.getmode(self.mode).bands
 
-    def getbbox(self, *, alpha_only: bool = True) -> tuple[int, int, int, int]:
+    def getbbox(self, *, alpha_only: bool = True) -> tuple[int, int, int, int] | None:
         """
         Calculates the bounding box of the non-zero regions in the
         image.
@@ -3029,12 +3029,18 @@ def new(
         color = ImageColor.getcolor(color, mode)
 
     im = Image()
-    if mode == "P" and isinstance(color, (list, tuple)) and len(color) in [3, 4]:
+    if (
-        # RGB or RGBA value for a P image
+        mode == "P"
-        from . import ImagePalette
+        and isinstance(color, (list, tuple))
+        and all(isinstance(i, int) for i in color)
+    ):
+        color_ints: tuple[int, ...] = cast(Tuple[int, ...], tuple(color))
+        if len(color_ints) == 3 or len(color_ints) == 4:
+            # RGB or RGBA value for a P image
+            from . import ImagePalette
 
-        im.palette = ImagePalette.ImagePalette()
+            im.palette = ImagePalette.ImagePalette()
-        color = im.palette.getcolor(color)
+            color = im.palette.getcolor(color_ints)
     return im._new(core.fill(mode, size, color))
 
 

src/PIL/ImageOps.py

@@ -497,7 +497,7 @@ def expand(
     color = _color(fill, image.mode)
     if image.palette:
         palette = ImagePalette.ImagePalette(palette=image.getpalette())
-        if isinstance(color, tuple):
+        if isinstance(color, tuple) and (len(color) == 3 or len(color) == 4):
             color = palette.getcolor(color)
     else:
         palette = None

src/PIL/ImagePalette.py

@@ -18,10 +18,13 @@
 from __future__ import annotations
 
 import array
-from typing import IO, Sequence
+from typing import IO, TYPE_CHECKING, Sequence
 
 from . import GimpGradientFile, GimpPaletteFile, ImageColor, PaletteFile
 
+if TYPE_CHECKING:
+    from . import Image
+
 
 class ImagePalette:
     """
@@ -128,7 +131,11 @@ class ImagePalette:
                 raise ValueError(msg) from e
         return index
 
-    def getcolor(self, color, image=None) -> int:
+    def getcolor(
+        self,
+        color: tuple[int, int, int] | tuple[int, int, int, int],
+        image: Image.Image | None = None,
+    ) -> int:
         """Given an rgb tuple, allocate palette entry.
 
         .. warning:: This method is experimental.
@@ -163,7 +170,7 @@ class ImagePalette:
                 self.dirty = 1
                 return index
         else:
-            msg = f"unknown color specifier: {repr(color)}"
+            msg = f"unknown color specifier: {repr(color)}"  # type: ignore[unreachable]
             raise ValueError(msg)
 
     def save(self, fp: str | IO[str]) -> None: