Merge ccfc2524b8 into 7e4d8e2f55

Tests/test_file_ani.py

@@ -0,0 +1,171 @@
+from __future__ import annotations
+
+from io import BytesIO
+
+import pytest
+
+from PIL import Image
+
+
+def test_aero_busy() -> None:
+    with Image.open("Tests/images/ani/aero_busy.ani") as im:
+        assert im.size == (64, 64)
+        assert im.n_frames == 18
+
+        with Image.open("Tests/images/ani/aero_busy_0.png") as png:
+            assert png.tobytes() == im.tobytes()
+
+        im.seek(8)
+        with Image.open("Tests/images/ani/aero_busy_8.png") as png:
+            assert png.tobytes() == im.tobytes()
+
+        with pytest.raises(EOFError):
+            im.seek(-1)
+
+        with pytest.raises(EOFError):
+            im.seek(18)
+
+
+def test_posy_busy() -> None:
+    with Image.open("Tests/images/ani/posy_busy.ani") as im:
+        assert im.size == (96, 96)
+        assert im.n_frames == 77
+
+        with Image.open("Tests/images/ani/posy_busy_0.png") as png:
+            assert png.tobytes() == im.tobytes()
+
+        im.seek(24)
+        with Image.open("Tests/images/ani/posy_busy_24.png") as png:
+            assert png.tobytes() == im.tobytes()
+
+        with pytest.raises(EOFError):
+            im.seek(77)
+
+
+def test_stopwtch() -> None:
+    with Image.open("Tests/images/ani/stopwtch.ani") as im:
+        assert im.size == (32, 32)
+        assert im.n_frames == 8
+
+        assert im.info["seq"][0] == 0
+        assert im.info["seq"][2] == 0
+
+        for i, r in enumerate(im.info["rate"]):
+            if i == 1 or i == 2:
+                assert r == 16
+            else:
+                assert r == 8
+
+        with Image.open("Tests/images/ani/stopwtch_0.png") as png:
+            assert png.tobytes() == im.tobytes()
+
+        im.seek(5)
+        with Image.open("Tests/images/ani/stopwtch_5.png") as png:
+            assert png.tobytes() == im.tobytes()
+
+        with pytest.raises(EOFError):
+            im.seek(8)
+
+
+def test_save() -> None:
+    directory_path = "Tests/images/ani/"
+    filenames = [
+        "aero_busy_0.png",
+        "aero_busy_8.png",
+        "posy_busy_0.png",
+        "posy_busy_24.png",
+        "stopwtch_0.png",
+        "stopwtch_5.png",
+    ]
+
+    images = [Image.open(directory_path + filename) for filename in filenames]
+
+    with BytesIO() as output:
+        images[0].save(
+            output, append_images=[images[1]], seq=[0, 1], rate=[5, 10], format="ANI"
+        )
+
+        with Image.open(output, formats=["ANI"]) as im:
+            assert im.tobytes() == images[0].tobytes()
+            im.seek(1)
+            assert im.tobytes() == images[1].tobytes()
+            assert im.info["seq"] == [0, 1]
+            assert im.info["rate"] == [5, 10]
+
+    with BytesIO() as output:
+        images[2].save(
+            output,
+            append_images=[images[3]],
+            seq=[1, 0],
+            rate=[2, 2],
+            format="ANI",
+            sizes=[(96, 96)],
+        )
+
+        with Image.open(output, formats=["ANI"]) as im:
+            assert im.tobytes() == images[2].tobytes()
+            im.seek(1)
+            assert im.tobytes() == images[3].tobytes()
+            assert im.info["seq"] == [1, 0]
+            assert im.info["rate"] == [2, 2]
+
+    with BytesIO() as output:
+        images[4].save(
+            output, append_images=[images[5]], seq=[0, 1], rate=[3, 4], format="ANI"
+        )
+
+        with Image.open(output, formats=["ANI"]) as im:
+            assert im.tobytes() == images[4].tobytes()
+            im.seek(1)
+            assert im.tobytes() == images[5].tobytes()
+            assert im.info["seq"] == [0, 1]
+            assert im.info["rate"] == [3, 4]
+
+    with BytesIO() as output:
+        images[0].save(
+            output,
+            append_images=images[1:],
+            seq=[0, 2, 4, 1, 3, 5, 0, 1, 0, 1],
+            rate=[1, 2, 3, 1, 2, 3, 1, 2, 3, 4],
+            format="ANI",
+            sizes=[(32, 32)],
+        )
+
+        with Image.open(output, formats=["ANI"]) as im:
+            assert im.n_frames == 6
+            assert im.info["seq"] == [0, 2, 4, 1, 3, 5, 0, 1, 0, 1]
+            assert im.info["rate"] == [1, 2, 3, 1, 2, 3, 1, 2, 3, 4]
+            assert im.size == (32, 32)
+
+            im.seek(4)
+            assert im.tobytes() == images[4].tobytes()
+
+    with BytesIO() as output:
+        with pytest.raises(ValueError):
+            images[0].save(
+                output,
+                append_images=images[1:],
+                seq=[0, 1, 8, 1, 2],
+                rate=[1, 1, 1, 1, 1],
+                format="ANI",
+                sizes=[(32, 32)],
+            )
+
+        with pytest.raises(ValueError):
+            images[0].save(
+                output,
+                append_images=images[1:],
+                seq=[0, 1, 1, 1, 2],
+                rate=[1, 1, 1, 1],
+                format="ANI",
+                sizes=[(32, 32)],
+            )
+
+        with pytest.raises(ValueError):
+            images[0].save(
+                output,
+                append_images=images[1:],
+                rate=[1, 1, 1, 1],
+                format="ANI",
+                sizes=[(32, 32)],
+            )

Tests/test_file_cur.py

@@ -1,15 +1,16 @@
 from __future__ import annotations
 
+from io import BytesIO
+
 import pytest
 
 from PIL import CurImagePlugin, Image
 
-TEST_FILE = "Tests/images/deerstalker.cur"
 
-
-def test_sanity() -> None:
-    with Image.open(TEST_FILE) as im:
+def test_deerstalker() -> None:
+    with Image.open("Tests/images/cur/deerstalker.cur") as im:
         assert im.size == (32, 32)
+        assert im.info["hotspots"] == [(0, 0)]
         assert isinstance(im, CurImagePlugin.CurImageFile)
         # Check some pixel colors to ensure image is loaded properly
         assert im.getpixel((10, 1)) == (0, 0, 0, 0)
@@ -17,16 +18,118 @@ def test_sanity() -> None:
         assert im.getpixel((16, 16)) == (84, 87, 86, 255)
 
 
+def test_posy_link() -> None:
+    with Image.open("Tests/images/cur/posy_link.cur") as im:
+        assert im.size == (128, 128)
+        assert im.info["sizes"] == {(128, 128), (96, 96), (64, 64), (48, 48), (32, 32)}
+        assert im.info["hotspots"] == [(25, 7), (18, 5), (12, 3), (9, 2), (5, 1)]
+        # check some pixel colors
+        assert im.getpixel((0, 0)) == (0, 0, 0, 0)
+        assert im.getpixel((20, 20)) == (0, 0, 0, 255)
+        assert im.getpixel((40, 40)) == (255, 255, 255, 255)
+
+        im.size = (32, 32)
+        im.load()
+        assert im.getpixel((0, 0)) == (0, 0, 0, 0)
+        assert im.getpixel((10, 10)) == (191, 191, 191, 255)
+
+
+def test_stopwtch() -> None:
+    with Image.open("Tests/images/cur/stopwtch.cur") as im:
+        assert im.size == (32, 32)
+        assert im.info["hotspots"] == [(16, 19)]
+
+        assert im.getpixel((16, 16)) == (0, 0, 255, 255)
+        assert im.getpixel((8, 16)) == (255, 0, 0, 255)
+
+
+def test_win98_arrow() -> None:
+    with Image.open("Tests/images/cur/win98_arrow.cur") as im:
+        assert im.size == (32, 32)
+        assert im.info["hotspots"] == [(10, 10)]
+
+        assert im.getpixel((0, 0)) == (0, 0, 0, 0)
+        assert im.getpixel((16, 16)) == (0, 0, 0, 255)
+        assert im.getpixel((14, 19)) == (255, 255, 255, 255)
+
+
 def test_invalid_file() -> None:
-    invalid_file = "Tests/images/flower.jpg"
+    invalid_file = "Tests/images/cur/posy_link.png"
 
     with pytest.raises(SyntaxError):
         CurImagePlugin.CurImageFile(invalid_file)
 
-    no_cursors_file = "Tests/images/no_cursors.cur"
+    no_cursors_file = "Tests/images/cur/no_cursors.cur"
 
-    cur = CurImagePlugin.CurImageFile(TEST_FILE)
+    cur = CurImagePlugin.CurImageFile("Tests/images/cur/deerstalker.cur")
     cur.fp.close()
     with open(no_cursors_file, "rb") as cur.fp:
         with pytest.raises(TypeError):
             cur._open()
+
+
+def test_save_win98_arrow() -> None:
+    with Image.open("Tests/images/cur/win98_arrow.png") as im:
+        # save the data
+        with BytesIO() as output:
+            im.save(
+                output,
+                format="CUR",
+                sizes=[(32, 32)],
+                hotspots=[(10, 10)],
+                bitmap_format="bmp",
+            )
+
+            with Image.open(output) as reloaded:
+                assert im.tobytes() == reloaded.tobytes()
+
+        with BytesIO() as output:
+            im.save(output, format="CUR")
+
+            # check default save params
+            with Image.open(output) as reloaded:
+                assert reloaded.size == (32, 32)
+                assert reloaded.info["sizes"] == {(32, 32), (24, 24), (16, 16)}
+                assert reloaded.info["hotspots"] == [(0, 0), (0, 0), (0, 0)]
+
+
+def test_save_posy_link() -> None:
+    sizes = [(128, 128), (96, 96), (64, 64), (48, 48), (32, 32)]
+    hotspots = [(25, 7), (18, 5), (12, 3), (9, 2), (5, 1)]
+
+    with Image.open("Tests/images/cur/posy_link.png") as im:
+        # save the data
+        with BytesIO() as output:
+            im.save(
+                output,
+                sizes=sizes,
+                hotspots=hotspots,
+                format="CUR",
+                bitmap_format="bmp",
+            )
+
+            # make sure saved output is readable
+            # and sizes/hotspots are correct
+            with Image.open(output, formats=["CUR"]) as reloaded:
+                assert (128, 128) == reloaded.size
+                assert set(sizes) == reloaded.info["sizes"]
+
+        with BytesIO() as output:
+            im.save(output, sizes=sizes[3:], hotspots=hotspots[3:], format="CUR")
+
+            # make sure saved output is readable
+            # and sizes/hotspots are correct
+            with Image.open(output, formats=["CUR"]) as reloaded:
+                assert (48, 48) == reloaded.size
+                assert set(sizes[3:]) == reloaded.info["sizes"]
+
+            # make sure error is thrown when size and hotspot len's
+            # don't match
+            with pytest.raises(ValueError):
+                im.save(
+                    output,
+                    sizes=sizes[2:],
+                    hotspots=hotspots[3:],
+                    format="CUR",
+                    bitmap_format="bmp",
+                )

src/PIL/AniImagePlugin.py

@@ -0,0 +1,445 @@
+from __future__ import annotations
+
+import struct
+from io import BytesIO
+from typing import IO, Any
+
+from PIL import BmpImagePlugin, CurImagePlugin, Image, ImageFile
+from PIL._binary import i32le as i32
+from PIL._binary import o8
+from PIL._binary import o16le as o16
+from PIL._binary import o32le as o32
+
+
+def _accept(prefix: bytes) -> bool:
+    return prefix.startswith(b"RIFF")
+
+
+def _save_frame(im: Image.Image, fp: BytesIO, info: dict[str, Any]) -> None:
+    fp.write(b"\0\0\2\0")
+    bmp = True
+    s = info.get(
+        "sizes",
+        [(16, 16), (24, 24), (32, 32), (48, 48), (64, 64), (128, 128), (256, 256)],
+    )
+    h = info.get("hotspots", [(0, 0) for _ in range(len(s))])
+
+    if len(h) != len(s):
+        msg = "Number of hotspots must be equal to number of cursor sizes"
+        raise ValueError(msg)
+
+    # sort and remove duplicate sizes
+    sizes, hotspots = [], []
+    for size, hotspot in sorted(zip(s, h), key=lambda x: x[0]):
+        if size not in sizes:
+            sizes.append(size)
+            hotspots.append(hotspot)
+
+    frames = []
+    width, height = im.size
+    for size in sorted(set(sizes)):
+        if size[0] > width or size[1] > height or size[0] > 256 or size[1] > 256:
+            continue
+
+        # TODO: invent a more convenient method for proportional scalings
+        frame = im.copy()
+        frame.thumbnail(size, Image.Resampling.LANCZOS, reducing_gap=None)
+        frames.append(frame)
+
+    fp.write(o16(len(frames)))  # idCount(2)
+    offset = fp.tell() + len(frames) * 16
+    for hotspot, frame in zip(hotspots, frames):
+        width, height = frame.size
+        # 0 means 256
+        fp.write(o8(width if width < 256 else 0))  # bWidth(1)
+        fp.write(o8(height if height < 256 else 0))  # bHeight(1)
+
+        bits, colors = BmpImagePlugin.SAVE[frame.mode][1:] if bmp else (32, 0)
+        fp.write(o8(colors))  # bColorCount(1)
+        fp.write(b"\0")  # bReserved(1)
+        fp.write(o16(hotspot[0]))  # x_hotspot(2)
+        fp.write(o16(hotspot[1]))  # y_hotspot(2)
+
+        image_io = BytesIO()
+        if bmp:
+            if bits != 32:
+                and_mask = Image.new("1", size)
+                ImageFile._save(
+                    and_mask,
+                    image_io,
+                    [ImageFile._Tile("raw", (0, 0) + size, 0, ("1", 0, -1))],
+                )
+            else:
+                frame.alpha = True
+
+            frame.save(image_io, "dib")
+        else:
+            frame.save(image_io, "png")
+        image_io.seek(0)
+        image_bytes = image_io.read()
+        if bmp:
+            image_bytes = image_bytes[:8] + o32(height * 2) + image_bytes[12:]
+
+        bytes_len = len(image_bytes)
+        fp.write(o32(bytes_len))  # dwBytesInRes(4)
+        fp.write(o32(offset))  # dwImageOffset(4)
+        current = fp.tell()
+        fp.seek(offset)
+        fp.write(image_bytes)
+        offset = offset + bytes_len
+        fp.seek(current)
+
+
+def _write_single_frame(im: Image.Image, fp: IO[bytes]) -> None:
+    fp.write(b"anih")
+    anih = o32(36) + o32(36) + (o32(1) * 2) + (o32(0) * 4) + o32(60) + o32(1)
+    fp.write(anih)
+
+    fp.write(b"LIST" + o32(0))
+    list_offset = fp.tell()
+    fp.write(b"fram")
+
+    fp.write(b"icon" + o32(0))
+    icon_offset = fp.tell()
+    with BytesIO(b"") as icon_fp:
+        _save_frame(im, icon_fp, im.encoderinfo)
+        icon_fp.seek(0)
+        icon_data = icon_fp.read()
+
+    fp.write(icon_data)
+    fram_end = fp.tell()
+
+    fp.seek(icon_offset - 4)
+    icon_size = fram_end - icon_offset
+    fp.write(o32(icon_size))
+
+    fp.seek(list_offset - 4)
+    list_size = fram_end - list_offset
+    fp.write(o32(list_size))
+
+    fp.seek(fram_end)
+
+
+def _write_multiple_frames(im: Image.Image, fp: IO[bytes]) -> None:
+    anih_offset = fp.tell()
+    fp.write(b"anih" + o32(36))
+    fp.write(o32(0) * 9)
+
+    fp.write(b"LIST" + o32(0))
+    list_offset = fp.tell()
+    fp.write(b"fram")
+
+    frames = [im]
+    frames.extend(im.encoderinfo.get("append_images", []))
+    for frame in frames:
+        fp.write(b"icon" + o32(0))
+        icon_offset = fp.tell()
+        with BytesIO(b"") as icon_fp:
+            _save_frame(frame, icon_fp, im.encoderinfo)
+            icon_fp.seek(0)
+            icon_data = icon_fp.read()
+
+        fp.write(icon_data)
+        fram_end = fp.tell()
+
+        fp.seek(icon_offset - 4)
+        icon_size = fram_end - icon_offset
+        fp.write(o32(icon_size))
+
+        fp.seek(fram_end)
+
+    fp.seek(list_offset - 4)
+    list_size = fram_end - list_offset
+    fp.write(o32(list_size))
+
+    fp.seek(fram_end)
+
+    seq = im.encoderinfo.get("seq", [])
+    if seq:
+        fp.write(b"seq " + o32(0))
+        seq_offset = fp.tell()
+        for i in seq:
+            if i >= len(frames):
+                msg = "Sequence index out of animation frame bounds"
+                raise ValueError(msg)
+
+            fp.write(o32(i))
+
+        fram_end = fp.tell()
+        fp.seek(seq_offset - 4)
+        seq_size = fram_end - seq_offset
+        fp.write(o32(seq_size))
+
+        fp.seek(fram_end)
+
+    rate = im.encoderinfo.get("rate", [])
+    if rate:
+        fp.write(b"rate" + o32(0))
+        rate_offset = fp.tell()
+
+        if seq:
+            if len(rate) != len(seq):
+                msg = "Length of rate must match length of sequence"
+                raise ValueError(msg)
+        else:
+            if len(rate) != len(frames):
+                msg = "Length of rate must match number of frames"
+                raise ValueError(msg)
+
+        for r in rate:
+            fp.write(o32(r))
+
+        fram_end = fp.tell()
+        fp.seek(rate_offset - 4)
+        rate_size = fram_end - rate_offset
+        fp.write(o32(rate_size))
+
+        fp.seek(fram_end)
+
+    display_rate = im.encoderinfo.get("display_rate", 2)
+    n_frames = len(frames)
+    n_steps = len(seq) if seq else n_frames
+    flag = 1 if not seq else 3
+
+    fram_end = fp.tell()
+
+    fp.seek(anih_offset)
+    fp.write(b"anih")
+    anih = (
+        o32(36)
+        + o32(36)
+        + o32(n_frames)
+        + o32(n_steps)
+        + (o32(0) * 4)
+        + o32(display_rate)
+        + o32(flag)
+    )
+    fp.write(anih)
+
+    fp.seek(fram_end)
+
+
+def _write_info(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
+    fp.write(b"LIST" + o32(0))
+    list_offset = fp.tell()
+
+    inam = im.encoderinfo.get("inam", filename)
+    iart = im.encoderinfo.get("iart", "Pillow")
+
+    if isinstance(inam, str):
+        inam = inam.encode()
+    if not isinstance(inam, bytes):
+        msg = "'inam' argument must be either a string or bytes"
+        raise TypeError(msg)
+
+    if isinstance(iart, str):
+        iart = iart.encode()
+    if not isinstance(iart, bytes):
+        msg = "'iart' argument must be either a string or bytes"
+        raise TypeError(msg)
+
+    fp.write(b"INFO")
+    fp.write(b"INAM" + o32(0))
+    inam_offset = fp.tell()
+
+    fp.write(inam + b"\x00")
+    inam_size = fp.tell() - inam_offset
+
+    fp.write(b"IART" + o32(0))
+    iart_offset = fp.tell()
+
+    fp.write(iart + b"\x00")
+    iart_size = fp.tell() - iart_offset
+
+    info_end = fp.tell()
+
+    fp.seek(iart_offset - 4)
+    fp.write(o32(iart_size))
+
+    fp.seek(inam_offset - 4)
+    fp.write(o32(inam_size))
+
+    fp.seek(list_offset - 4)
+    list_size = info_end - list_offset
+    fp.write(o32(list_size))
+
+    fp.seek(info_end)
+
+
+def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
+    fp.write(b"RIFF\x00\x00\x00\x00")
+    riff_offset = fp.tell()
+
+    fp.write(b"ACON")
+    _write_info(im, fp, filename)
+
+    frames = im.encoderinfo.get("append_images", [])
+    if frames:
+        _write_multiple_frames(im, fp)
+    else:
+        _write_single_frame(im, fp)
+
+    riff_end = fp.tell()
+    fp.seek(riff_offset - 4)
+    riff_size = riff_end - riff_offset
+    fp.write(o32(riff_size))
+
+    fp.seek(riff_end)
+
+
+class AniFile:
+    def __init__(self, fp: BytesIO) -> None:
+        if not _accept(fp.read(4)):
+            SyntaxError("Not an ANI file")
+
+        self.image_data = []
+
+        self.buf = fp
+        self.rate = None
+        self.seq = None
+        self.anih = None
+
+        size, fformat = struct.unpack("<I4s", fp.read(8))
+
+        self.riff = {"size": size, "fformat": fformat}
+
+        chunkOffset = fp.tell()
+        while chunkOffset < self.riff["size"]:
+            fp.seek(chunkOffset)
+            chunk, size = struct.unpack("<4sI", fp.read(8))
+            chunkOffset = chunkOffset + size + 8
+
+            if chunk == b"anih":
+                s = fp.read(36)
+                self.anih = {
+                    "size": i32(s),  # Data structure size (in bytes)
+                    "nFrames": i32(s, 4),  # Number of frames
+                    "nSteps": i32(s, 8),  # Number of frames before repeat
+                    "iWidth": i32(s, 12),  # Width of frame (in pixels)
+                    "iHeight": i32(s, 16),  # Height of frame (in pixels)
+                    "iBitCount": i32(s, 20),  # Number of bits per pixel
+                    "nPlanes": i32(s, 24),  # Number of color planes
+                    # Default frame display rate (1/60th sec)
+                    "iDispRate": i32(s, 28),
+                    "bfAttributes": i32(s, 32),  # ANI attribute bit flags
+                }
+
+            if chunk == b"seq ":
+                s = fp.read(size)
+                self.seq = [i32(s, i * 4) for i in range(size // 4)]
+
+            if chunk == b"rate":
+                s = fp.read(size)
+                self.rate = [i32(s, i * 4) for i in range(size // 4)]
+
+            if chunk == b"LIST":
+                listtype = struct.unpack("<4s", fp.read(4))[0]
+                if listtype != b"fram":
+                    continue
+
+                listOffset = 0
+                while listOffset < size - 8:
+                    _, lSize = struct.unpack("<4sI", fp.read(8))
+                    self.image_data.append({"offset": fp.tell(), "size": lSize})
+
+                    fp.read(lSize)
+                    listOffset = listOffset + lSize + 8
+
+        if self.anih is None:
+            msg = "not an ANI file"
+            raise SyntaxError(msg)
+
+        if self.seq is None:
+            self.seq = list(range(self.anih["nFrames"]))
+
+        if self.rate is None:
+            self.rate = [self.anih["iDispRate"] for i in range(self.anih["nFrames"])]
+
+    def frame(self, frame: int) -> CurImagePlugin.CurImageFile:
+        assert self.anih is not None
+        if frame > self.anih["nFrames"]:
+            msg = "Frame index out of animation bounds"
+            raise EOFError(msg)
+
+        offset, size = self.image_data[frame].values()
+        self.buf.seek(offset)
+        data = self.buf.read(size)
+
+        return CurImagePlugin.CurImageFile(BytesIO(data))
+
+    def sizes(self) -> list[int]:
+        return [data["size"] for data in self.image_data]
+
+    def hotspots(self) -> None:
+        pass
+
+
+class AniImageFile(ImageFile.ImageFile):
+    """
+    PIL read-only image support for Microsoft Windows .ani files.
+
+    By default the largest resolution image and first frame in the file will
+    be loaded.
+
+    The info dictionary has four keys:
+        'seq': the sequence of the frames used for animation.
+        'rate': the rate (in 1/60th of a second) for each frame in the sequence.
+        'frames': the number of frames in the file.
+        'sizes': a list of the sizes available for the current frame.
+        'hotspots': a list of the cursor hotspots for a given frame.
+
+    Saving is similar to GIF. Arguments for encoding are:
+        'sizes': The sizes of the cursor (used for scaling by windows).
+        'hotspots': The hotspot for each size, with (0, 0) being the top left.
+        'append_images': The frames for animation. Please note that the sizes and
+        hotspots are shared across each frame.
+        'seq': The sequence of frames, zero indexed.
+        'rate': The rate for each frame in the seq. Must be the same length as seq or
+        equal to the number of frames if seq is not passed.
+    """
+
+    format = "ANI"
+    format_description = "Windows Animated Cursor"
+
+    def _open(self) -> None:
+        self.ani = AniFile(self.fp)
+        self.info["seq"] = self.ani.seq
+        self.info["rate"] = self.ani.rate
+
+        assert self.ani.anih is not None
+        self.n_frames = self.ani.anih["nFrames"]
+
+        self.frame = 0
+        self.seek(0)
+        self.load()
+        self.size = self.im.size
+
+    @property
+    def size(self) -> tuple[int, int]:
+        return self._size
+
+    @size.setter
+    def size(self, value: tuple[int, int]) -> None:
+        if value not in self.info["sizes"]:
+            msg = "This is not one of the allowed sizes of this image"
+            raise ValueError(msg)
+        self._size = value
+
+    def load(self) -> Image.core.PixelAccess | None:
+        im = self.ani.frame(self.frame)
+        self.info["sizes"] = im.info["sizes"]
+        self.info["hotspots"] = im.info["hotspots"]
+        self.im = im.im
+        self._mode = im.mode
+        return Image.Image.load(self)
+
+    def seek(self, frame: int) -> None:
+        if not self._seek_check(frame):
+            return
+
+        self.frame = frame
+
+
+Image.register_open(AniImageFile.format, AniImageFile, _accept)
+Image.register_extension(AniImageFile.format, ".ani")
+Image.register_save(AniImageFile.format, _save)

src/PIL/BmpImagePlugin.py

@@ -244,9 +244,7 @@ class BmpImageFile(ImageFile.ImageFile):
                 msg = "Unsupported BMP bitfields layout"
                 raise OSError(msg)
         elif file_info["compression"] == self.COMPRESSIONS["RAW"]:
-            if file_info["bits"] == 32 and (
-                header == 22 or USE_RAW_ALPHA  # 32-bit .cur offset
-            ):
+            if file_info["bits"] == 32 and (USE_RAW_ALPHA or hasattr(self, "alpha")):
                 raw_mode, self._mode = "BGRA", "RGBA"
         elif file_info["compression"] in (
             self.COMPRESSIONS["RLE8"],

src/PIL/CurImagePlugin.py

@@ -17,59 +17,221 @@
 #
 from __future__ import annotations
 
-from . import BmpImagePlugin, Image, ImageFile
+from io import BytesIO
+from typing import IO, NamedTuple
+
+from . import BmpImagePlugin, IcoImagePlugin, Image, ImageFile
 from ._binary import i16le as i16
 from ._binary import i32le as i32
+from ._binary import o8
+from ._binary import o16le as o16
+from ._binary import o32le as o32
 
 #
 # --------------------------------------------------------------------
 
+_MAGIC = b"\x00\x00\x02\x00"
+
+
+def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
+    fp.write(_MAGIC)
+    bmp = im.encoderinfo.get("bitmap_format", "") == "bmp"
+    s = im.encoderinfo.get(
+        "sizes",
+        [(16, 16), (24, 24), (32, 32), (48, 48), (64, 64), (128, 128), (256, 256)],
+    )
+    h = im.encoderinfo.get("hotspots", [(0, 0) for i in range(len(s))])
+
+    if len(h) != len(s):
+        msg = "Number of hotspots must be equal to number of cursor sizes"
+        raise ValueError(msg)
+
+    # sort and remove duplicate sizes
+    sizes, hotspots = [], []
+    for size, hotspot in sorted(zip(s, h), key=lambda x: x[0]):
+        if size not in sizes:
+            sizes.append(size)
+            hotspots.append(hotspot)
+
+    frames = []
+    width, height = im.size
+    for size in sizes:
+        if size[0] > width or size[1] > height or size[0] > 256 or size[1] > 256:
+            continue
+
+        # TODO: invent a more convenient method for proportional scalings
+        frame = im.copy()
+        frame.thumbnail(size, Image.Resampling.LANCZOS, reducing_gap=None)
+        frames.append(frame)
+
+    fp.write(o16(len(frames)))  # idCount(2)
+    offset = fp.tell() + len(frames) * 16
+    for hotspot, frame in zip(hotspots, frames):
+        width, height = frame.size
+        # 0 means 256
+        fp.write(o8(width if width < 256 else 0))  # bWidth(1)
+        fp.write(o8(height if height < 256 else 0))  # bHeight(1)
+
+        bits, colors = BmpImagePlugin.SAVE[frame.mode][1:] if bmp else (32, 0)
+        fp.write(o8(colors))  # bColorCount(1)
+        fp.write(b"\0")  # bReserved(1)
+        fp.write(o16(hotspot[0]))  # x_hotspot(2)
+        fp.write(o16(hotspot[1]))  # y_hotspot(2)
+
+        image_io = BytesIO()
+        if bmp:
+            if bits != 32:
+                and_mask = Image.new("1", size)
+                ImageFile._save(
+                    and_mask,
+                    image_io,
+                    [ImageFile._Tile("raw", (0, 0) + size, 0, ("1", 0, -1))],
+                )
+            else:
+                frame.alpha = True
+
+            frame.save(image_io, "dib")
+        else:
+            frame.save(image_io, "png")
+        image_io.seek(0)
+        image_bytes = image_io.read()
+        if bmp:
+            image_bytes = image_bytes[:8] + o32(height * 2) + image_bytes[12:]
+
+        bytes_len = len(image_bytes)
+        fp.write(o32(bytes_len))  # dwBytesInRes(4)
+        fp.write(o32(offset))  # dwImageOffset(4)
+        current = fp.tell()
+        fp.seek(offset)
+        fp.write(image_bytes)
+        offset = offset + bytes_len
+        fp.seek(current)
+
 
 def _accept(prefix: bytes) -> bool:
-    return prefix.startswith(b"\0\0\2\0")
+    return prefix.startswith(_MAGIC)
+
+
+class IconHeader(NamedTuple):
+    width: int
+    height: int
+    nb_color: int
+    reserved: int
+    bpp: int
+    x_hotspot: int
+    y_hotspot: int
+    size: int
+    offset: int
+    dim: tuple[int, int]
+    square: int
 
 
 ##
 # Image plugin for Windows Cursor files.
+class CurFile(IcoImagePlugin.IcoFile):
+    def __init__(self, buf: IO[bytes]) -> None:
+        """
+        Parse image from file-like object containing cur file data
+        """
 
-
-class CurImageFile(BmpImagePlugin.BmpImageFile):
-    format = "CUR"
-    format_description = "Windows Cursor"
-
-    def _open(self) -> None:
-        offset = self.fp.tell()
-
-        # check magic
-        s = self.fp.read(6)
+        # check if CUR
+        s = buf.read(6)
         if not _accept(s):
             msg = "not a CUR file"
             raise SyntaxError(msg)
 
-        # pick the largest cursor in the file
-        m = b""
-        for i in range(i16(s, 4)):
-            s = self.fp.read(16)
-            if not m:
-                m = s
-            elif s[0] > m[0] and s[1] > m[1]:
-                m = s
-        if not m:
+        self.buf = buf
+        self.entry = []
+
+        # Number of items in file
+        self.nb_items = i16(s, 4)
+
+        # Get headers for each item
+        for _ in range(self.nb_items):
+            s = buf.read(16)
+
+            # See Wikipedia
+            width = s[0] or 256
+            height = s[1] or 256
+
+            size = i32(s, 8)
+            square = width * height
+
+            # TODO: This needs further investigation. Cursor files do not really
+            # specify their bpp like ICO's as those bits are used for the y_hotspot.
+            # For now, bpp is calculated by subtracting the AND mask (equal to number
+            # of pixels * 1bpp) and dividing by the number of pixels. This seems
+            # to work well so far.
+            BITMAP_INFO_HEADER_SIZE = 40
+            bpp_without_and = ((size - BITMAP_INFO_HEADER_SIZE) * 8) // square
+            if bpp_without_and != 32:
+                bpp = ((size - BITMAP_INFO_HEADER_SIZE) * 8 - square) // square
+            else:
+                bpp = bpp_without_and
+
+            icon_header = IconHeader(
+                width=width,
+                height=height,
+                nb_color=s[2],  # No. of colors in image (0 if >=8bpp)
+                reserved=s[3],
+                bpp=bpp,
+                x_hotspot=i16(s, 4),
+                y_hotspot=i16(s, 6),
+                size=size,
+                offset=i32(s, 12),
+                dim=(width, height),
+                square=square,
+            )
+
+            self.entry.append(icon_header)
+
+        self.entry = sorted(self.entry, key=lambda x: x.square, reverse=True)
+
+    def hotspots(self) -> list[tuple[int, int]]:
+        return [(h.x_hotspot, h.y_hotspot) for h in self.entry]
+
+
+class CurImageFile(IcoImagePlugin.IcoImageFile):
+    """
+    PIL read-only image support for Microsoft Windows .cur files.
+
+    By default the largest resolution image in the file will be loaded. This
+    can be changed by altering the 'size' attribute before calling 'load'.
+
+    The info dictionary has a key 'sizes' that is a list of the sizes available
+    in the icon file. It also contains key 'hotspots' that is a list of the
+    cursor hotspots.
+
+    Handles classic, XP and Vista icon formats.
+
+    When saving, PNG compression is used. Support for this was only added in
+    Windows Vista. If you are unable to view the icon in Windows, convert the
+    image to "RGBA" mode before saving. This is an extension of the IcoImagePlugin.
+
+    Raises:
+        ValueError: The number of sizes and hotspots do not match.
+        SyntaxError: The file is not a cursor file.
+        TypeError: There are no cursors contained withing the file.
+    """
+
+    format = "CUR"
+    format_description = "Windows Cursor"
+
+    def _open(self) -> None:
+        self.ico = CurFile(self.fp)
+        self.info["sizes"] = self.ico.sizes()
+        self.info["hotspots"] = self.ico.hotspots()
+        if len(self.ico.entry) > 0:
+            self.size = self.ico.entry[0].dim
+        else:
             msg = "No cursors were found"
             raise TypeError(msg)
-
-        # load as bitmap
-        self._bitmap(i32(m, 12) + offset)
-
-        # patch up the bitmap height
-        self._size = self.size[0], self.size[1] // 2
-        d, e, o, a = self.tile[0]
-        self.tile[0] = ImageFile._Tile(d, (0, 0) + self.size, o, a)
+        self.load()
 
 
 #
 # --------------------------------------------------------------------
 
 Image.register_open(CurImageFile.format, CurImageFile, _accept)
-
+Image.register_save(CurImageFile.format, _save)
 Image.register_extension(CurImageFile.format, ".cur")

src/PIL/__init__.py

@@ -25,6 +25,7 @@ del _version
 
 
 _plugins = [
+    "AniImagePlugin",
     "AvifImagePlugin",
     "BlpImagePlugin",
     "BmpImagePlugin",