codekingpro/portable-devtools

1#
2# The Python Imaging Library.
3# $Id$
4#
5# sequence support classes
6#
7# history:
8# 1997-02-20 fl     Created
9#
10# Copyright (c) 1997 by Secret Labs AB.
11# Copyright (c) 1997 by Fredrik Lundh.
12#
13# See the README file for information on usage and redistribution.
14#
15
16##
17from __future__ import annotations
18
19from . import Image
20
21TYPE_CHECKING = False
22if TYPE_CHECKING:
23    from collections.abc import Callable
24
25
26class Iterator:
27    """
28    This class implements an iterator object that can be used to loop
29    over an image sequence.
30
31    You can use the ``[]`` operator to access elements by index. This operator
32    will raise an :py:exc:`IndexError` if you try to access a nonexistent
33    frame.
34
35    :param im: An image object.
36    """
37
38    def __init__(self, im: Image.Image) -> None:
39        if not hasattr(im, "seek"):
40            msg = "im must have seek method"
41            raise AttributeError(msg)
42        self.im = im
43        self.position = getattr(self.im, "_min_frame", 0)
44
45    def __getitem__(self, ix: int) -> Image.Image:
46        try:
47            self.im.seek(ix)
48            return self.im
49        except EOFError as e:
50            msg = "end of sequence"
51            raise IndexError(msg) from e
52
53    def __iter__(self) -> Iterator:
54        return self
55
56    def __next__(self) -> Image.Image:
57        try:
58            self.im.seek(self.position)
59            self.position += 1
60            return self.im
61        except EOFError as e:
62            msg = "end of sequence"
63            raise StopIteration(msg) from e
64
65
66def all_frames(
67    im: Image.Image | list[Image.Image],
68    func: Callable[[Image.Image], Image.Image] | None = None,
69) -> list[Image.Image]:
70    """
71    Applies a given function to all frames in an image or a list of images.
72    The frames are returned as a list of separate images.
73
74    :param im: An image, or a list of images.
75    :param func: The function to apply to all of the image frames.
76    :returns: A list of images.
77    """
78    if not isinstance(im, list):
79        im = [im]
80
81    ims = []
82    for imSequence in im:
83        current = imSequence.tell()
84
85        ims += [im_frame.copy() for im_frame in Iterator(imSequence)]
86
87        imSequence.seek(current)
88    return [func(im) for im in ims] if func else ims
89