Source code for vsutil.types

Enums and related functions.
__all__ = ['Dither', 'Range', 'EXPR_VARS', 'resolve_enum']

# this file only depends on the stdlib and should stay that way
from enum import Enum
from typing import Any, Callable, Optional, Type, TypeVar, Union

E = TypeVar('E', bound=Enum)

class _NoSubmoduleRepr:
    def __repr__(self):
        """Removes submodule name from standard repr, helpful since we re-export everything at the top-level."""
        return '<%s.%s.%s: %r>' % (self.__module__.split('.')[0], self.__class__.__name__,, self.value)

[docs]class Dither(_NoSubmoduleRepr, str, Enum): """ Enum for `zimg_dither_type_e`. """ NONE = 'none' """Round to nearest.""" ORDERED = 'ordered' """Bayer patterned dither.""" RANDOM = 'random' """Pseudo-random noise of magnitude 0.5.""" ERROR_DIFFUSION = 'error_diffusion' """Floyd-Steinberg error diffusion."""
[docs]class Range(_NoSubmoduleRepr, int, Enum): """ Enum for `zimg_pixel_range_e`. """ LIMITED = 0 """Studio (TV) legal range, 16-235 in 8 bits.""" FULL = 1 """Full (PC) dynamic range, 0-255 in 8 bits."""
EXPR_VARS: str = 'xyzabcdefghijklmnopqrstuvw' """ This constant contains a list of all variables that can appear inside an expr-string ordered by assignment. So the first clip will have the name *EXPR_VARS[0]*, the second one will have the name *EXPR_VARS[1]*, and so on. This can be used to automatically generate expr-strings. """ def _readable_enums(enum: Type[Enum]) -> str: """ Returns a list of all possible values in `enum`. Since VapourSynth imported enums don't carry the correct module name, use a special case for them. """ if 'importlib' in enum.__module__: return ', '.join([f'<vapoursynth.{}: {i.value}>' for i in enum]) else: return ', '.join([repr(i) for i in enum])
[docs]def resolve_enum(enum: Type[E], value: Any, var_name: str, fn: Optional[Callable] = None) -> Union[E, None]: """ Attempts to evaluate `value` in `enum` if value is not ``None``, otherwise returns ``None``. >>> def my_fn(family: Optional[int]): ... return resolve_enum(vs.ColorFamily, family, 'family', my_fn) >>> my_fn(None) None >>> my_fn(3) <ColorFamily.YUV: 3> >>> my_fn(9) ValueError: my_fn: family must be in <vapoursynth.UNDEFINED: 0>, <vapoursynth.GRAY: 1>, ... :param enum: Enumeration, i.e. ``vapoursynth.ColorFamily``. :param value: Value to check. Can be ``None``. :param var_name: User-provided parameter name that needs to be checked. :param fn: Function that should be causing the exception (used for error message only). :return: The enum member or ``None``. """ if value is None: return None try: return enum(value) except ValueError: raise ValueError(f"{fn.__name__ + ': ' if fn else ''}{var_name} must be in {_readable_enums(enum)}.") from None