ImageMode.py 1.6 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. # mode descriptor cache
  16. _modes = None
  17. class ModeDescriptor(object):
  18. """Wrapper for mode strings."""
  19. def __init__(self, mode, bands, basemode, basetype):
  20. self.mode = mode
  21. self.bands = bands
  22. self.basemode = basemode
  23. self.basetype = basetype
  24. def __str__(self):
  25. return self.mode
  26. def getmode(mode):
  27. """Gets a mode descriptor for the given mode."""
  28. global _modes
  29. if not _modes:
  30. # initialize mode cache
  31. from . import Image
  32. modes = {}
  33. # core modes
  34. for m, (basemode, basetype, bands) in Image._MODEINFO.items():
  35. modes[m] = ModeDescriptor(m, bands, basemode, basetype)
  36. # extra experimental modes
  37. modes["RGBa"] = ModeDescriptor("RGBa", ("R", "G", "B", "a"), "RGB", "L")
  38. modes["LA"] = ModeDescriptor("LA", ("L", "A"), "L", "L")
  39. modes["La"] = ModeDescriptor("La", ("L", "a"), "L", "L")
  40. modes["PA"] = ModeDescriptor("PA", ("P", "A"), "RGB", "L")
  41. # mapping modes
  42. for i16mode in (
  43. "I;16",
  44. "I;16S",
  45. "I;16L",
  46. "I;16LS",
  47. "I;16B",
  48. "I;16BS",
  49. "I;16N",
  50. "I;16NS",
  51. ):
  52. modes[i16mode] = ModeDescriptor(i16mode, ("I",), "L", "L")
  53. # set global mode cache atomically
  54. _modes = modes
  55. return _modes[mode]