308 lines
8.9 KiB
Python
308 lines
8.9 KiB
Python
""":mod:`wand.color` --- Colors
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.. versionadded:: 0.1.2
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"""
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import ctypes
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from .api import MagickPixelPacket, library
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from .compat import binary, text
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from .resource import Resource
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from .version import QUANTUM_DEPTH
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__all__ = 'Color', 'scale_quantum_to_int8'
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class Color(Resource):
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"""Color value.
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Unlike any other objects in Wand, its resource management can be
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implicit when it used outside of :keyword:`with` block. In these case,
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its resource are allocated for every operation which requires a resource
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and destroyed immediately. Of course it is inefficient when the
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operations are much, so to avoid it, you should use color objects
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inside of :keyword:`with` block explicitly e.g.::
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red_count = 0
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with Color('#f00') as red:
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with Image(filename='image.png') as img:
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for row in img:
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for col in row:
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if col == red:
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red_count += 1
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:param string: a color namel string e.g. ``'rgb(255, 255, 255)'``,
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``'#fff'``, ``'white'``. see `ImageMagick Color Names`_
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doc also
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:type string: :class:`basestring`
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.. versionchanged:: 0.3.0
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:class:`Color` objects become hashable.
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.. seealso::
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`ImageMagick Color Names`_
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The color can then be given as a color name (there is a limited
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but large set of these; see below) or it can be given as a set
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of numbers (in decimal or hexadecimal), each corresponding to
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a channel in an RGB or RGBA color model. HSL, HSLA, HSB, HSBA,
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CMYK, or CMYKA color models may also be specified. These topics
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are briefly described in the sections below.
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.. _ImageMagick Color Names: http://www.imagemagick.org/script/color.php
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.. describe:: == (other)
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Equality operator.
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:param other: a color another one
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:type color: :class:`Color`
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:returns: ``True`` only if two images equal.
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:rtype: :class:`bool`
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"""
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c_is_resource = library.IsPixelWand
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c_destroy_resource = library.DestroyPixelWand
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c_get_exception = library.PixelGetException
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c_clear_exception = library.PixelClearException
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__slots__ = 'raw', 'c_resource', 'allocated'
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def __init__(self, string=None, raw=None):
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if (string is None and raw is None or
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string is not None and raw is not None):
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raise TypeError('expected one argument')
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self.allocated = 0
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if raw is None:
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self.raw = ctypes.create_string_buffer(
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ctypes.sizeof(MagickPixelPacket)
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)
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with self:
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library.PixelSetColor(self.resource, binary(string))
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library.PixelGetMagickColor(self.resource, self.raw)
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else:
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self.raw = raw
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def __getinitargs__(self):
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return self.string, None
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def __enter__(self):
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if not self.allocated:
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with self.allocate():
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self.resource = library.NewPixelWand()
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library.PixelSetMagickColor(self.resource, self.raw)
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self.allocated += 1
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return Resource.__enter__(self)
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def __exit__(self, type, value, traceback):
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self.allocated -= 1
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if not self.allocated:
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Resource.__exit__(self, type, value, traceback)
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@property
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def string(self):
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"""(:class:`basestring`) The string representation of the color."""
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with self:
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color_string = library.PixelGetColorAsString(self.resource)
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return text(color_string.value)
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@property
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def normalized_string(self):
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"""(:class:`basestring`) The normalized string representation of
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the color. The same color is always represented to the same
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string.
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.. versionadded:: 0.3.0
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"""
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with self:
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string = library.PixelGetColorAsNormalizedString(self.resource)
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return text(string.value)
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@staticmethod
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def c_equals(a, b):
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"""Raw level version of equality test function for two pixels.
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:param a: a pointer to PixelWand to compare
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:type a: :class:`ctypes.c_void_p`
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:param b: a pointer to PixelWand to compare
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:type b: :class:`ctypes.c_void_p`
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:returns: ``True`` only if two pixels equal
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:rtype: :class:`bool`
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.. note::
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It's only for internal use. Don't use it directly.
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Use ``==`` operator of :class:`Color` instead.
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"""
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alpha = library.PixelGetAlpha
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return bool(library.IsPixelWandSimilar(a, b, 0) and
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alpha(a) == alpha(b))
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def __eq__(self, other):
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if not isinstance(other, Color):
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return False
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with self as this:
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with other:
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return self.c_equals(this.resource, other.resource)
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def __ne__(self, other):
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return not (self == other)
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def __hash__(self):
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if self.alpha:
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return hash(self.normalized_string)
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return hash(None)
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@property
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def red(self):
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"""(:class:`numbers.Real`) Red, from 0.0 to 1.0."""
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with self:
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return library.PixelGetRed(self.resource)
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@property
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def green(self):
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"""(:class:`numbers.Real`) Green, from 0.0 to 1.0."""
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with self:
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return library.PixelGetGreen(self.resource)
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@property
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def blue(self):
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"""(:class:`numbers.Real`) Blue, from 0.0 to 1.0."""
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with self:
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return library.PixelGetBlue(self.resource)
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@property
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def alpha(self):
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"""(:class:`numbers.Real`) Alpha value, from 0.0 to 1.0."""
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with self:
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return library.PixelGetAlpha(self.resource)
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@property
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def red_quantum(self):
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"""(:class:`numbers.Integral`) Red.
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Scale depends on :const:`~wand.version.QUANTUM_DEPTH`.
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.. versionadded:: 0.3.0
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"""
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with self:
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return library.PixelGetRedQuantum(self.resource)
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@property
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def green_quantum(self):
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"""(:class:`numbers.Integral`) Green.
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Scale depends on :const:`~wand.version.QUANTUM_DEPTH`.
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.. versionadded:: 0.3.0
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"""
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with self:
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return library.PixelGetGreenQuantum(self.resource)
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@property
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def blue_quantum(self):
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"""(:class:`numbers.Integral`) Blue.
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Scale depends on :const:`~wand.version.QUANTUM_DEPTH`.
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.. versionadded:: 0.3.0
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"""
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with self:
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return library.PixelGetBlueQuantum(self.resource)
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@property
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def alpha_quantum(self):
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"""(:class:`numbers.Integral`) Alpha value.
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Scale depends on :const:`~wand.version.QUANTUM_DEPTH`.
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.. versionadded:: 0.3.0
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"""
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with self:
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return library.PixelGetAlphaQuantum(self.resource)
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@property
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def red_int8(self):
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"""(:class:`numbers.Integral`) Red as 8bit integer which is a common
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style. From 0 to 255.
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.. versionadded:: 0.3.0
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"""
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return scale_quantum_to_int8(self.red_quantum)
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@property
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def green_int8(self):
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"""(:class:`numbers.Integral`) Green as 8bit integer which is
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a common style. From 0 to 255.
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.. versionadded:: 0.3.0
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"""
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return scale_quantum_to_int8(self.green_quantum)
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@property
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def blue_int8(self):
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"""(:class:`numbers.Integral`) Blue as 8bit integer which is
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a common style. From 0 to 255.
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.. versionadded:: 0.3.0
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"""
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return scale_quantum_to_int8(self.blue_quantum)
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@property
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def alpha_int8(self):
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"""(:class:`numbers.Integral`) Alpha value as 8bit integer which is
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a common style. From 0 to 255.
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.. versionadded:: 0.3.0
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"""
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return scale_quantum_to_int8(self.alpha_quantum)
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def __str__(self):
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return self.string
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def __repr__(self):
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c = type(self)
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return '{0}.{1}({2!r})'.format(c.__module__, c.__name__, self.string)
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def _repr_html_(self):
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html = """
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<span style="background-color:#{red:02X}{green:02X}{blue:02X};
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display:inline-block;
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line-height:1em;
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width:1em;"> </span>
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<strong>#{red:02X}{green:02X}{blue:02X}</strong>
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"""
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return html.format(red=self.red_int8,
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green=self.green_int8,
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blue=self.blue_int8)
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def scale_quantum_to_int8(quantum):
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"""Straightforward port of :c:func:`ScaleQuantumToChar()` inline
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function.
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:param quantum: quantum value
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:type quantum: :class:`numbers.Integral`
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:returns: 8bit integer of the given ``quantum`` value
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:rtype: :class:`numbers.Integral`
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.. versionadded:: 0.3.0
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"""
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if quantum <= 0:
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return 0
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table = {8: 1, 16: 257.0, 32: 16843009.0, 64: 72340172838076673.0}
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v = quantum / table[QUANTUM_DEPTH]
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if v >= 255:
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return 255
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return int(v + 0.5)
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