Aluode/PerceptionLabPortable

1#
2# The Python Imaging Library.
3# $Id$
4#
5# standard mode descriptors
6#
7# History:
8# 2006-03-20 fl   Added
9#
10# Copyright (c) 2006 by Secret Labs AB.
11# Copyright (c) 2006 by Fredrik Lundh.
12#
13# See the README file for information on usage and redistribution.
14#
15from __future__ import annotations
16
17import sys
18from functools import lru_cache
19from typing import NamedTuple
20
21
22class ModeDescriptor(NamedTuple):
23    """Wrapper for mode strings."""
24
25    mode: str
26    bands: tuple[str, ...]
27    basemode: str
28    basetype: str
29    typestr: str
30
31    def __str__(self) -> str:
32        return self.mode
33
34
35@lru_cache
36def getmode(mode: str) -> ModeDescriptor:
37    """Gets a mode descriptor for the given mode."""
38    endian = "<" if sys.byteorder == "little" else ">"
39
40    modes = {
41        # core modes
42        # Bits need to be extended to bytes
43        "1": ("L", "L", ("1",), "|b1"),
44        "L": ("L", "L", ("L",), "|u1"),
45        "I": ("L", "I", ("I",), f"{endian}i4"),
46        "F": ("L", "F", ("F",), f"{endian}f4"),
47        "P": ("P", "L", ("P",), "|u1"),
48        "RGB": ("RGB", "L", ("R", "G", "B"), "|u1"),
49        "RGBX": ("RGB", "L", ("R", "G", "B", "X"), "|u1"),
50        "RGBA": ("RGB", "L", ("R", "G", "B", "A"), "|u1"),
51        "CMYK": ("RGB", "L", ("C", "M", "Y", "K"), "|u1"),
52        "YCbCr": ("RGB", "L", ("Y", "Cb", "Cr"), "|u1"),
53        # UNDONE - unsigned |u1i1i1
54        "LAB": ("RGB", "L", ("L", "A", "B"), "|u1"),
55        "HSV": ("RGB", "L", ("H", "S", "V"), "|u1"),
56        # extra experimental modes
57        "RGBa": ("RGB", "L", ("R", "G", "B", "a"), "|u1"),
58        "LA": ("L", "L", ("L", "A"), "|u1"),
59        "La": ("L", "L", ("L", "a"), "|u1"),
60        "PA": ("RGB", "L", ("P", "A"), "|u1"),
61    }
62    if mode in modes:
63        base_mode, base_type, bands, type_str = modes[mode]
64        return ModeDescriptor(mode, bands, base_mode, base_type, type_str)
65
66    mapping_modes = {
67        # I;16 == I;16L, and I;32 == I;32L
68        "I;16": "<u2",
69        "I;16S": "<i2",
70        "I;16L": "<u2",
71        "I;16LS": "<i2",
72        "I;16B": ">u2",
73        "I;16BS": ">i2",
74        "I;16N": f"{endian}u2",
75        "I;16NS": f"{endian}i2",
76        "I;32": "<u4",
77        "I;32B": ">u4",
78        "I;32L": "<u4",
79        "I;32S": "<i4",
80        "I;32BS": ">i4",
81        "I;32LS": "<i4",
82    }
83
84    type_str = mapping_modes[mode]
85    return ModeDescriptor(mode, ("I",), "L", "L", type_str)
86