ImageMode.py 2.3 KB

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  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. #
  15. from __future__ import annotations
  16. import sys
  17. from functools import lru_cache
  18. from typing import NamedTuple
  19. class ModeDescriptor(NamedTuple):
  20. """Wrapper for mode strings."""
  21. mode: str
  22. bands: tuple[str, ...]
  23. basemode: str
  24. basetype: str
  25. typestr: str
  26. def __str__(self) -> str:
  27. return self.mode
  28. @lru_cache
  29. def getmode(mode: str) -> ModeDescriptor:
  30. """Gets a mode descriptor for the given mode."""
  31. endian = "<" if sys.byteorder == "little" else ">"
  32. modes = {
  33. # core modes
  34. # Bits need to be extended to bytes
  35. "1": ("L", "L", ("1",), "|b1"),
  36. "L": ("L", "L", ("L",), "|u1"),
  37. "I": ("L", "I", ("I",), f"{endian}i4"),
  38. "F": ("L", "F", ("F",), f"{endian}f4"),
  39. "P": ("P", "L", ("P",), "|u1"),
  40. "RGB": ("RGB", "L", ("R", "G", "B"), "|u1"),
  41. "RGBX": ("RGB", "L", ("R", "G", "B", "X"), "|u1"),
  42. "RGBA": ("RGB", "L", ("R", "G", "B", "A"), "|u1"),
  43. "CMYK": ("RGB", "L", ("C", "M", "Y", "K"), "|u1"),
  44. "YCbCr": ("RGB", "L", ("Y", "Cb", "Cr"), "|u1"),
  45. # UNDONE - unsigned |u1i1i1
  46. "LAB": ("RGB", "L", ("L", "A", "B"), "|u1"),
  47. "HSV": ("RGB", "L", ("H", "S", "V"), "|u1"),
  48. # extra experimental modes
  49. "RGBa": ("RGB", "L", ("R", "G", "B", "a"), "|u1"),
  50. "LA": ("L", "L", ("L", "A"), "|u1"),
  51. "La": ("L", "L", ("L", "a"), "|u1"),
  52. "PA": ("RGB", "L", ("P", "A"), "|u1"),
  53. }
  54. if mode in modes:
  55. base_mode, base_type, bands, type_str = modes[mode]
  56. return ModeDescriptor(mode, bands, base_mode, base_type, type_str)
  57. mapping_modes = {
  58. # I;16 == I;16L, and I;32 == I;32L
  59. "I;16": "<u2",
  60. "I;16S": "<i2",
  61. "I;16L": "<u2",
  62. "I;16LS": "<i2",
  63. "I;16B": ">u2",
  64. "I;16BS": ">i2",
  65. "I;16N": f"{endian}u2",
  66. "I;16NS": f"{endian}i2",
  67. "I;32": "<u4",
  68. "I;32B": ">u4",
  69. "I;32L": "<u4",
  70. "I;32S": "<i4",
  71. "I;32BS": ">i4",
  72. "I;32LS": "<i4",
  73. }
  74. type_str = mapping_modes[mode]
  75. return ModeDescriptor(mode, ("I",), "L", "L", type_str)