Source code for picamera.color

# vim: set et sw=4 sts=4 fileencoding=utf-8:
#
# Python camera library for the Rasperry-Pi camera module
# Copyright (c) 2013-2017 Dave Jones <dave@waveform.org.uk>
#
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# modification, are permitted provided that the following conditions are met:
#
#     * Redistributions of source code must retain the above copyright
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#       names of its contributors may be used to endorse or promote products
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# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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from __future__ import (
    unicode_literals,
    print_function,
    division,
    absolute_import,
    )
# Make Py2's zip equivalent to Py3's
try:
    from itertools import izip as zip
except ImportError:
    pass

# Make Py2's str and range equivalent to Py3's
str = type('')


import colorsys
from math import pi, sqrt, atan2, degrees, radians, sin, cos, exp
from fractions import Fraction
from collections import namedtuple


# From the CSS Color Module Level 3 specification, section 4.3
# <http://www.w3.org/TR/css3-color/#svg-color>
NAMED_COLORS = {
    'aliceblue':             '#f0f8ff',
    'antiquewhite':          '#faebd7',
    'aqua':                  '#00ffff',
    'aquamarine':            '#7fffd4',
    'azure':                 '#f0ffff',
    'beige':                 '#f5f5dc',
    'bisque':                '#ffe4c4',
    'black':                 '#000000',
    'blanchedalmond':        '#ffebcd',
    'blue':                  '#0000ff',
    'blueviolet':            '#8a2be2',
    'brown':                 '#a52a2a',
    'burlywood':             '#deb887',
    'cadetblue':             '#5f9ea0',
    'chartreuse':            '#7fff00',
    'chocolate':             '#d2691e',
    'coral':                 '#ff7f50',
    'cornflowerblue':        '#6495ed',
    'cornsilk':              '#fff8dc',
    'crimson':               '#dc143c',
    'cyan':                  '#00ffff',
    'darkblue':              '#00008b',
    'darkcyan':              '#008b8b',
    'darkgoldenrod':         '#b8860b',
    'darkgray':              '#a9a9a9',
    'darkgreen':             '#006400',
    'darkgrey':              '#a9a9a9',
    'darkkhaki':             '#bdb76b',
    'darkmagenta':           '#8b008b',
    'darkolivegreen':        '#556b2f',
    'darkorange':            '#ff8c00',
    'darkorchid':            '#9932cc',
    'darkred':               '#8b0000',
    'darksalmon':            '#e9967a',
    'darkseagreen':          '#8fbc8f',
    'darkslateblue':         '#483d8b',
    'darkslategray':         '#2f4f4f',
    'darkslategrey':         '#2f4f4f',
    'darkturquoise':         '#00ced1',
    'darkviolet':            '#9400d3',
    'deeppink':              '#ff1493',
    'deepskyblue':           '#00bfff',
    'dimgray':               '#696969',
    'dimgrey':               '#696969',
    'dodgerblue':            '#1e90ff',
    'firebrick':             '#b22222',
    'floralwhite':           '#fffaf0',
    'forestgreen':           '#228b22',
    'fuchsia':               '#ff00ff',
    'gainsboro':             '#dcdcdc',
    'ghostwhite':            '#f8f8ff',
    'gold':                  '#ffd700',
    'goldenrod':             '#daa520',
    'gray':                  '#808080',
    'green':                 '#008000',
    'greenyellow':           '#adff2f',
    'grey':                  '#808080',
    'honeydew':              '#f0fff0',
    'hotpink':               '#ff69b4',
    'indianred':             '#cd5c5c',
    'indigo':                '#4b0082',
    'ivory':                 '#fffff0',
    'khaki':                 '#f0e68c',
    'lavender':              '#e6e6fa',
    'lavenderblush':         '#fff0f5',
    'lawngreen':             '#7cfc00',
    'lemonchiffon':          '#fffacd',
    'lightblue':             '#add8e6',
    'lightcoral':            '#f08080',
    'lightcyan':             '#e0ffff',
    'lightgoldenrodyellow':  '#fafad2',
    'lightgray':             '#d3d3d3',
    'lightgreen':            '#90ee90',
    'lightgrey':             '#d3d3d3',
    'lightpink':             '#ffb6c1',
    'lightsalmon':           '#ffa07a',
    'lightseagreen':         '#20b2aa',
    'lightskyblue':          '#87cefa',
    'lightslategray':        '#778899',
    'lightslategrey':        '#778899',
    'lightsteelblue':        '#b0c4de',
    'lightyellow':           '#ffffe0',
    'lime':                  '#00ff00',
    'limegreen':             '#32cd32',
    'linen':                 '#faf0e6',
    'magenta':               '#ff00ff',
    'maroon':                '#800000',
    'mediumaquamarine':      '#66cdaa',
    'mediumblue':            '#0000cd',
    'mediumorchid':          '#ba55d3',
    'mediumpurple':          '#9370db',
    'mediumseagreen':        '#3cb371',
    'mediumslateblue':       '#7b68ee',
    'mediumspringgreen':     '#00fa9a',
    'mediumturquoise':       '#48d1cc',
    'mediumvioletred':       '#c71585',
    'midnightblue':          '#191970',
    'mintcream':             '#f5fffa',
    'mistyrose':             '#ffe4e1',
    'moccasin':              '#ffe4b5',
    'navajowhite':           '#ffdead',
    'navy':                  '#000080',
    'oldlace':               '#fdf5e6',
    'olive':                 '#808000',
    'olivedrab':             '#6b8e23',
    'orange':                '#ffa500',
    'orangered':             '#ff4500',
    'orchid':                '#da70d6',
    'palegoldenrod':         '#eee8aa',
    'palegreen':             '#98fb98',
    'paleturquoise':         '#afeeee',
    'palevioletred':         '#db7093',
    'papayawhip':            '#ffefd5',
    'peachpuff':             '#ffdab9',
    'peru':                  '#cd853f',
    'pink':                  '#ffc0cb',
    'plum':                  '#dda0dd',
    'powderblue':            '#b0e0e6',
    'purple':                '#800080',
    'red':                   '#ff0000',
    'rosybrown':             '#bc8f8f',
    'royalblue':             '#4169e1',
    'saddlebrown':           '#8b4513',
    'salmon':                '#fa8072',
    'sandybrown':            '#f4a460',
    'seagreen':              '#2e8b57',
    'seashell':              '#fff5ee',
    'sienna':                '#a0522d',
    'silver':                '#c0c0c0',
    'skyblue':               '#87ceeb',
    'slateblue':             '#6a5acd',
    'slategray':             '#708090',
    'slategrey':             '#708090',
    'snow':                  '#fffafa',
    'springgreen':           '#00ff7f',
    'steelblue':             '#4682b4',
    'tan':                   '#d2b48c',
    'teal':                  '#008080',
    'thistle':               '#d8bfd8',
    'tomato':                '#ff6347',
    'turquoise':             '#40e0d0',
    'violet':                '#ee82ee',
    'wheat':                 '#f5deb3',
    'white':                 '#ffffff',
    'whitesmoke':            '#f5f5f5',
    'yellow':                '#ffff00',
    'yellowgreen':           '#9acd32',
    }


[docs]class Red(float): """ Represents the red component of a :class:`Color` for use in transformations. Instances of this class can be constructed directly with a float value, or by querying the :attr:`Color.red` attribute. Addition, subtraction, and multiplication are supported with :class:`Color` instances. For example:: >>> Color.from_rgb(0, 0, 0) + Red(0.5) <Color "#7f0000"> >>> Color('#f00') - Color('#900').red <Color "#660000"> >>> (Red(0.1) * Color('red')).red Red(0.1) """ def __repr__(self): return "Red(%s)" % self
[docs]class Green(float): """ Represents the green component of a :class:`Color` for use in transformations. Instances of this class can be constructed directly with a float value, or by querying the :attr:`Color.green` attribute. Addition, subtraction, and multiplication are supported with :class:`Color` instances. For example:: >>> Color(0, 0, 0) + Green(0.1) <Color "#001900"> >>> Color.from_yuv(1, -0.4, -0.6) - Green(1) <Color "#50002f"> >>> (Green(0.5) * Color('white')).rgb (Red(1.0), Green(0.5), Blue(1.0)) """ def __repr__(self): return "Green(%s)" % self
[docs]class Blue(float): """ Represents the blue component of a :class:`Color` for use in transformations. Instances of this class can be constructed directly with a float value, or by querying the :attr:`Color.blue` attribute. Addition, subtraction, and multiplication are supported with :class:`Color` instances. For example:: >>> Color(0, 0, 0) + Blue(0.2) <Color "#000033"> >>> Color.from_hls(0.5, 0.5, 1.0) - Blue(1) <Color "#00fe00"> >>> Blue(0.9) * Color('white') <Color "#ffffe5"> """ def __repr__(self): return "Blue(%s)" % self
[docs]class Hue(float): """ Represents the hue of a :class:`Color` for use in transformations. Instances of this class can be constructed directly with a float value in the range [0.0, 1.0) representing an angle around the `HSL hue wheel`_. As this is a circular mapping, 0.0 and 1.0 effectively mean the same thing, i.e. out of range values will be normalized into the range [0.0, 1.0). The class can also be constructed with the keyword arguments ``deg`` or ``rad`` if you wish to specify the hue value in degrees or radians instead, respectively. Instances can also be constructed by querying the :attr:`Color.hue` attribute. Addition, subtraction, and multiplication are supported with :class:`Color` instances. For example:: >>> Color(1, 0, 0).hls (0.0, 0.5, 1.0) >>> (Color(1, 0, 0) + Hue(deg=180)).hls (0.5, 0.5, 1.0) Note that whilst multiplication by a :class:`Hue` doesn't make much sense, it is still supported. However, the circular nature of a hue value can lead to suprising effects. In particular, since 1.0 is equivalent to 0.0 the following may be observed:: >>> (Hue(1.0) * Color.from_hls(0.5, 0.5, 1.0)).hls (0.0, 0.5, 1.0) .. _HSL hue wheel: https://en.wikipedia.org/wiki/Hue """ def __new__(cls, n=None, deg=None, rad=None): if n is not None: return super(Hue, cls).__new__(cls, n % 1.0) elif deg is not None: return super(Hue, cls).__new__(cls, (deg / 360.0) % 1.0) elif rad is not None: return super(Hue, cls).__new__(cls, (rad / (2 * pi)) % 1.0) else: raise ValueError('You must specify a value, or deg or rad') def __repr__(self): return "Hue(deg=%s)" % self.deg @property def deg(self): return self * 360.0 @property def rad(self): return self * 2 * pi
[docs]class Lightness(float): """ Represents the lightness of a :class:`Color` for use in transformations. Instances of this class can be constructed directly with a float value, or by querying the :attr:`Color.lightness` attribute. Addition, subtraction, and multiplication are supported with :class:`Color` instances. For example:: >>> Color(0, 0, 0) + Lightness(0.1) <Color "#191919"> >>> Color.from_rgb_bytes(0x80, 0x80, 0) - Lightness(0.2) <Color "#191900"> >>> Lightness(0.9) * Color('wheat') <Color "#f0cd8d"> """ def __repr__(self): return "Lightness(%s)" % self
[docs]class Saturation(float): """ Represents the saturation of a :class:`Color` for use in transformations. Instances of this class can be constructed directly with a float value, or by querying the :attr:`Color.saturation` attribute. Addition, subtraction, and multiplication are supported with :class:`Color` instances. For example:: >>> Color(0.9, 0.9, 0.6) + Saturation(0.1) <Color "#ebeb92"> >>> Color('red') - Saturation(1) <Color "#7f7f7f"> >>> Saturation(0.5) * Color('wheat') <Color "#e4d9c3"> """ def __repr__(self): return "Lightness(%s)" % self
clamp_float = lambda v: max(0.0, min(1.0, v)) clamp_bytes = lambda v: max(0, min(255, v)) to_srgb = lambda c: 12.92 * c if c <= 0.0031308 else (1.055 * c ** (1/2.4) - 0.055) from_srgb = lambda c: c / 12.92 if c <= 0.04045 else ((c + 0.055) / 1.055) ** 2.4 D65 = (0.95047, 1.0, 1.08883) U = lambda x, y, z: 4 * x / (x + 15 * y + 3 * z) V = lambda x, y, z: 9 * y / (x + 15 * y + 3 * z) matrix_mult = lambda m, n: ( sum(mval * nval for mval, nval in zip(mrow, n)) for mrow in m )
[docs]class Color(namedtuple('Color', ('red', 'green', 'blue'))): """ The Color class is a tuple which represents a color as red, green, and blue components. The class has a flexible constructor which allows you to create an instance from a variety of color systems including `RGB`_, `Y'UV`_, `Y'IQ`_, `HLS`_, and `HSV`_. There are also explicit constructors for each of these systems to allow you to force the use of a system in your code. For example, an instance of :class:`Color` can be constructed in any of the following ways:: >>> Color('#f00') <Color "#ff0000"> >>> Color('green') <Color "#008000"> >>> Color(0, 0, 1) <Color "#0000ff"> >>> Color(hue=0, saturation=1, value=0.5) <Color "#7f0000"> >>> Color(y=0.4, u=-0.05, v=0.615) <Color "#ff0f4c"> The specific forms that the default constructor will accept are enumerated below: .. tabularcolumns:: |p{40mm}|p{100mm}| +------------------------------+------------------------------------------+ | Style | Description | +==============================+==========================================+ | Single positional parameter | Equivalent to calling | | | :meth:`Color.from_string`. | +------------------------------+------------------------------------------+ | Three positional parameters | Equivalent to calling | | | :meth:`Color.from_rgb` if all three | | | parameters are between 0.0 and 1.0, or | | | :meth:`Color.from_rgb_bytes` otherwise. | +------------------------------+ | | Three named parameters: | | | *r*, *g*, *b* | | +------------------------------+ | | Three named parameters: | | | *red*, *green*, *blue* | | +------------------------------+------------------------------------------+ | Three named parameters: | Equivalent to calling | | *y*, *u*, *v* | :meth:`Color.from_yuv` if *y* is between | | | 0.0 and 1.0, *u* is between -0.436 and | | | 0.436, and *v* is between -0.615 and | | | 0.615, or :meth:`Color.from_yuv_bytes` | | | otherwise. | +------------------------------+------------------------------------------+ | Three named parameters: | Equivalent to calling | | *y*, *i*, *q* | :meth:`Color.from_yiq`. | +------------------------------+------------------------------------------+ | Three named parameters: | Equivalent to calling | | *h*, *l*, *s* | :meth:`Color.from_hls`. | +------------------------------+ | | Three named parameters: | | | *hue*, *lightness*, | | | *saturation* | | +------------------------------+------------------------------------------+ | Three named parameters: | Equivalent to calling | | *h*, *s*, *v* | :meth:`Color.from_hsv` | +------------------------------+ | | Three named parameters: | | | *hue*, *saturation*, *value* | | +------------------------------+------------------------------------------+ | Three named parameters: | Equivalent to calling | | *x*, *y*, *z* | :meth:`Color.from_cie_xyz` | +------------------------------+------------------------------------------+ | Three named parameters: | Equivalent to calling | | *l*, *a*, *b* | :meth:`Color.from_cie_lab` | +------------------------------+------------------------------------------+ | Three named parameters: | Equivalent to calling | | *l*, *u*, *v* | :meth:`Color.from_cie_luv` | +------------------------------+------------------------------------------+ If the constructor parameters do not conform to any of the variants in the table above, a :exc:`ValueError` will be thrown. Internally, the color is *always* represented as 3 float values corresponding to the red, green, and blue components of the color. These values take a value from 0.0 to 1.0 (least to full intensity). The class provides several attributes which can be used to convert one color system into another:: >>> Color('#f00').hls (0.0, 0.5, 1.0) >>> Color.from_string('green').hue Hue(deg=120.0) >>> Color.from_rgb_bytes(0, 0, 255).yuv (0.114, 0.435912, -0.099978) As :class:`Color` derives from tuple, instances are immutable. While this provides the advantage that they can be used as keys in a dict, it does mean that colors themselves cannot be directly manipulated (e.g. by reducing the red component). However, several auxilliary classes in the module provide the ability to perform simple transformations of colors via operators which produce a new :class:`Color` instance. For example:: >>> Color('red') - Red(0.5) <Color "#7f0000"> >>> Color('green') + Red(0.5) <Color "#7f8000"> >>> Color.from_hls(0.5, 0.5, 1.0) <Color "#00feff"> >>> Color.from_hls(0.5, 0.5, 1.0) * Lightness(0.8) <Color "#00cbcc"> >>> (Color.from_hls(0.5, 0.5, 1.0) * Lightness(0.8)).hls (0.5, 0.4, 1.0) From the last example above one can see that even attributes not directly stored by the color (such as lightness) can be manipulated in this fashion. In this case a :class:`Color` instance is constructed from HLS (hue, lightness, saturation) values with a lightness of 0.5. This is multiplied by a :class:`Lightness` instance with a value of 0.8 which constructs a new :class:`Color` with the same hue and saturation, but a lightness of 0.5 * 0.8 = 0.4. If an instance is converted to a string (with :func:`str`) it will return a string containing the 7-character HTML code for the color (e.g. "#ff0000" for red). As can be seen in the examples above, a similar representation is returned for :func:`repr`. .. _RGB: https://en.wikipedia.org/wiki/RGB_color_space .. _Y'UV: https://en.wikipedia.org/wiki/YUV .. _Y'IQ: https://en.wikipedia.org/wiki/YIQ .. _HLS: https://en.wikipedia.org/wiki/HSL_and_HSV .. _HSV: https://en.wikipedia.org/wiki/HSL_and_HSV """ def __new__(cls, *args, **kwargs): def from_rgb(r, g, b): if 0.0 <= r <= 1.0 and 0.0 <= g <= 1.0 and 0.0 <= b <= 1.0: return cls.from_rgb(r, g, b) else: return cls.from_rgb_bytes(r, g, b) def from_yuv(y, u, v): if 0.0 <= y <= 1.0 and -0.436 <= u <= 0.436 and -0.615 <= v <= 0.615: return cls.from_yuv(y, u, v) else: return cls.from_yuv_bytes(y, u, v) if kwargs: try: return { frozenset('rgb'): from_rgb, frozenset('yuv'): from_yuv, frozenset('yiq'): cls.from_yiq, frozenset('hls'): cls.from_hls, frozenset('hsv'): cls.from_hsv, frozenset('xyz'): cls.from_cie_xyz, frozenset('lab'): cls.from_cie_lab, frozenset('luv'): cls.from_cie_luv, frozenset(('red', 'green', 'blue')): lambda red, green, blue: from_rgb(red, green, blue), frozenset(('hue', 'lightness', 'saturation')): lambda hue, lightness, saturation: cls.from_hls(hue, lightness, saturation), frozenset(('hue', 'saturation', 'value')): lambda hue, saturation, value: cls.from_hsv(hue, saturation, value), }[frozenset(kwargs.keys())](**kwargs) except KeyError: pass else: if len(args) == 1: return cls.from_string(args[0]) elif len(args) == 3: return from_rgb(*args) raise ValueError('Unable to construct Color from provided arguments')
[docs] @classmethod def from_string(cls, s): """ Construct a :class:`Color` from a 4 or 7 character CSS-like representation (e.g. "#f00" or "#ff0000" for red), or from one of the named colors (e.g. "green" or "wheat") from the `CSS standard`_. Any other string format will result in a :exc:`ValueError`. .. _CSS standard: http://www.w3.org/TR/css3-color/#svg-color """ if isinstance(s, bytes): s = s.decode('ascii') if s.startswith('#'): if len(s) == 7: return cls.from_rgb_bytes( int(s[1:3], base=16), int(s[3:5], base=16), int(s[5:7], base=16) ) elif len(s) == 4: return cls.from_rgb_bytes( int(s[1:2], base=16) * 0x11, int(s[2:3], base=16) * 0x11, int(s[3:4], base=16) * 0x11 ) raise ValueError('Unrecognized color format "%s"' % s) try: return cls.from_string(NAMED_COLORS[s.lower()]) except KeyError: raise ValueError('Unrecognized color name "%s"' % s)
[docs] @classmethod def from_rgb(cls, r, g, b): """ Construct a :class:`Color` from three `RGB`_ float values between 0.0 and 1.0. """ return super(Color, cls).__new__(cls, r, g, b)
[docs] @classmethod def from_rgb_565(cls, n): """ Construct a :class:`Color` from an unsigned 16-bit integer number in RGB565 format. """ r = (n & 0xF800) / 0xF800 g = (n & 0x07E0) / 0x07E0 b = (n & 0x001F) / 0x001F return super(Color, cls).__new__(cls, r, g, b)
[docs] @classmethod def from_rgb_bytes(cls, r, g, b): """ Construct a :class:`Color` from three `RGB`_ byte values between 0 and 255. """ return super(Color, cls).__new__(cls, r / 255.0, g / 255.0, b / 255.0)
[docs] @classmethod def from_yuv(cls, y, u, v): """ Construct a :class:`Color` from three `Y'UV`_ float values. The Y value may be between 0.0 and 1.0. U may be between -0.436 and 0.436, while V may be between -0.615 and 0.615. """ return super(Color, cls).__new__( cls, clamp_float(y + 1.14 * v), clamp_float(y - 0.395 * u - 0.581 * v), clamp_float(y + 2.033 * u), )
[docs] @classmethod def from_yuv_bytes(cls, y, u, v): """ Construct a :class:`Color` from three `Y'UV`_ byte values between 0 and 255. The U and V values are biased by 128 to prevent negative values as is typical in video applications. The Y value is biased by 16 for the same purpose. """ c = y - 16 d = u - 128 e = v - 128 return cls.from_rgb_bytes( clamp_bytes((298 * c + 409 * e + 128) >> 8), clamp_bytes((298 * c - 100 * d - 208 * e + 128) >> 8), clamp_bytes((298 * c + 516 * d + 128) >> 8), )
[docs] @classmethod def from_yiq(cls, y, i, q): """ Construct a :class:`Color` from three `Y'IQ`_ float values. Y' can be between 0.0 and 1.0, while I and Q can be between -1.0 and 1.0. """ return super(Color, cls).__new__(cls, *colorsys.yiq_to_rgb(y, i, q))
[docs] @classmethod def from_hls(cls, h, l, s): """ Construct a :class:`Color` from `HLS`_ (hue, lightness, saturation) floats between 0.0 and 1.0. """ return super(Color, cls).__new__(cls, *colorsys.hls_to_rgb(h, l, s))
[docs] @classmethod def from_hsv(cls, h, s, v): """ Construct a :class:`Color` from `HSV`_ (hue, saturation, value) floats between 0.0 and 1.0. """ return super(Color, cls).__new__(cls, *colorsys.hsv_to_rgb(h, s, v))
[docs] @classmethod def from_cie_xyz(cls, x, y, z): """ Construct a :class:`Color` from (X, Y, Z) float values representing a color in the `CIE 1931 color space`_. The conversion assumes the sRGB working space with reference white D65. .. _CIE 1931 color space: https://en.wikipedia.org/wiki/CIE_1931_color_space """ m = matrix_mult( (( 3.2404542, -1.5371385, -0.4985314), (-0.9692660, 1.8760108, 0.0415560), ( 0.0556434, -0.2040259, 1.0572252), ), (x, y, z, )) return super(Color, cls).__new__(cls, *(to_srgb(c) for c in m))
[docs] @classmethod def from_cie_lab(cls, l, a, b): """ Construct a :class:`Color` from (L*, a*, b*) float values representing a color in the `CIE Lab color space`_. The conversion assumes the sRGB working space with reference white D65. .. _CIE Lab color space: https://en.wikipedia.org/wiki/Lab_color_space """ theta = Fraction(6, 29) fy = (l + 16) / 116 fx = fy + a / 500 fz = fy - b / 200 xyz = ( n ** 3 if n > theta else 3 * theta ** 2 * (n - Fraction(4, 29)) for n in (fx, fy, fz) ) return cls.from_cie_xyz(*(n * m for n, m in zip(xyz, D65)))
[docs] @classmethod def from_cie_luv(cls, l, u, v): """ Construct a :class:`Color` from (L*, u*, v*) float values representing a color in the `CIE Luv color space`_. The conversion assumes the sRGB working space with reference white D65. .. _CIE Luv color space: https://en.wikipedia.org/wiki/CIELUV """ uw = U(*D65) vw = V(*D65) u_p = u / (13 * l) + uw v_p = v / (13 * l) + vw y = D65[1] * (l * Fraction(3, 29) ** 3 if l <= 8 else ((l + 16) / 116) ** 3) x = y * (9 * u_p) / (4 * v_p) z = y * (12 - 3 * u_p - 20 * v_p) / (4 * v_p) return cls.from_cie_xyz(x, y, z)
def __add__(self, other): if isinstance(other, Red): return Color(clamp_float(self.red + other), self.green, self.blue) elif isinstance(other, Green): return Color(self.red, clamp_float(self.green + other), self.blue) elif isinstance(other, Blue): return Color(self.red, self.green, clamp_float(self.blue + other)) elif isinstance(other, Hue): h, l, s = self.hls return Color.from_hls((h + other) % 1.0, l, s) elif isinstance(other, Lightness): h, l, s = self.hls return Color.from_hls(h, clamp_float(l + other), s) elif isinstance(other, Saturation): h, l, s = self.hls return Color.from_hls(h, l, clamp_float(s + other)) return NotImplemented def __radd__(self, other): # Addition is commutative if isinstance(other, (Red, Green, Blue, Hue, Lightness, Saturation)): return self.__add__(other) return NotImplemented def __sub__(self, other): if isinstance(other, Red): return Color(clamp_float(self.red - other), self.green, self.blue) elif isinstance(other, Green): return Color(self.red, clamp_float(self.green - other), self.blue) elif isinstance(other, Blue): return Color(self.red, self.green, clamp_float(self.blue - other)) elif isinstance(other, Hue): h, l, s = self.hls return Color.from_hls((h - other) % 1.0, l, s) elif isinstance(other, Lightness): h, l, s = self.hls return Color.from_hls(h, clamp_float(l - other), s) elif isinstance(other, Saturation): h, l, s = self.hls return Color.from_hls(h, l, clamp_float(s - other)) return NotImplemented def __rsub__(self, other): if isinstance(other, Red): return Color(clamp_float(other - self.red), self.green, self.blue) elif isinstance(other, Green): return Color(self.red, clamp_float(other - self.green), self.blue) elif isinstance(other, Blue): return Color(self.red, self.green, clamp_float(other - self.blue)) elif isinstance(other, Hue): h, l, s = self.hls return Color.from_hls((other - h) % 1.0, l, s) elif isinstance(other, Lightness): h, l, s = self.hls return Color.from_hls(h, clamp_float(other - l), s) elif isinstance(other, Saturation): h, l, s = self.hls return Color.from_hls(h, l, clamp_float(other - s)) return NotImplemented def __mul__(self, other): if isinstance(other, Red): return Color(clamp_float(self.red * other), self.green, self.blue) elif isinstance(other, Green): return Color(self.red, clamp_float(self.green * other), self.blue) elif isinstance(other, Blue): return Color(self.red, self.green, clamp_float(self.blue * other)) elif isinstance(other, Hue): h, l, s = self.hls return Color.from_hls((h * other) % 1.0, l, s) elif isinstance(other, Lightness): h, l, s = self.hls return Color.from_hls(h, clamp_float(l * other), s) elif isinstance(other, Saturation): h, l, s = self.hls return Color.from_hls(h, l, clamp_float(s * other)) return NotImplemented def __rmul__(self, other): # Multiplication is commutative if isinstance(other, (Red, Green, Blue, Hue, Lightness, Saturation)): return self.__mul__(other) def __str__(self): return '#%02x%02x%02x' % self.rgb_bytes def __repr__(self): return '<Color "%s">' % str(self) @property def rgb(self): """ Returns a 3-tuple of (red, green, blue) float values (between 0.0 and 1.0). """ return (self.red, self.green, self.blue) @property def rgb_565(self): """ Returns an unsigned 16-bit integer number representing the color in the RGB565 encoding. """ return ( (int(self.red * 0xF800) & 0xF800) | (int(self.green * 0x07E0) & 0x07E0) | (int(self.blue * 0x001F) & 0x001F)) @property def rgb_bytes(self): """ Returns a 3-tuple of (red, green, blue) byte values. """ return ( int(self.red * 255), int(self.green * 255), int(self.blue * 255), ) @property def yuv(self): """ Returns a 3-tuple of (y, u, v) float values; y values can be between 0.0 and 1.0, u values are between -0.436 and 0.436, and v values are between -0.615 and 0.615. """ r, g, b = self.rgb y = 0.299 * r + 0.587 * g + 0.114 * b return ( y, 0.492 * (b - y), 0.877 * (r - y), ) @property def yuv_bytes(self): """ Returns a 3-tuple of (y, u, v) byte values. Y values are biased by 16 in the result to prevent negatives. U and V values are biased by 128 for the same purpose. """ r, g, b = self.rgb_bytes return ( (( 66 * r + 129 * g + 25 * b + 128) >> 8) + 16, ((-38 * r - 73 * g + 112 * b + 128) >> 8) + 128, ((112 * r - 94 * g - 18 * b + 128) >> 8) + 128, ) @property def yiq(self): """ Returns a 3-tuple of (y, i, q) float values; y values can be between 0.0 and 1.0, whilst i and q values can be between -1.0 and 1.0. """ return colorsys.rgb_to_yiq(self.red, self.green, self.blue) @property def cie_xyz(self): """ Returns a 3-tuple of (X, Y, Z) float values representing the color in the `CIE 1931 color space`_. The conversion assumes the sRGB working space, with reference white D65. .. _CIE 1931 color space: https://en.wikipedia.org/wiki/CIE_1931_color_space """ return tuple(matrix_mult( ((0.4124564, 0.3575761, 0.1804375), (0.2126729, 0.7151522, 0.0721750), (0.0193339, 0.1191920, 0.9503041), ), (from_srgb(self.red), from_srgb(self.green), from_srgb(self.blue) ) )) @property def cie_lab(self): """ Returns a 3-tuple of (L*, a*, b*) float values representing the color in the `CIE Lab color space`_ with the `D65 standard illuminant`_. .. _CIE Lab color space: https://en.wikipedia.org/wiki/Lab_color_space .. _D65 standard illuminant: https://en.wikipedia.org/wiki/Illuminant_D65 """ K = Fraction(1, 3) * Fraction(29, 6) ** 2 e = Fraction(6, 29) ** 3 x, y, z = (n / m for n, m in zip(self.cie_xyz, D65)) fx, fy, fz = ( n ** Fraction(1, 3) if n > e else K * n + Fraction(4, 29) for n in (x, y, z) ) return (116 * fy - 16, 500 * (fx - fy), 200 * (fy - fz)) @property def cie_luv(self): """ Returns a 3-tuple of (L*, u*, v*) float values representing the color in the `CIE Luv color space`_ with the `D65 standard illuminant`_. .. _CIE Luv color space: https://en.wikipedia.org/wiki/CIELUV """ K = Fraction(29, 3) ** 3 e = Fraction(6, 29) ** 3 XYZ = self.cie_xyz yr = XYZ[1] / D65[1] L = 116 * yr ** Fraction(1, 3) - 16 if yr > e else K * yr u = 13 * L * (U(*XYZ) - U(*D65)) v = 13 * L * (V(*XYZ) - V(*D65)) return (L, u, v) @property def hls(self): """ Returns a 3-tuple of (hue, lightness, saturation) float values (between 0.0 and 1.0). """ return colorsys.rgb_to_hls(self.red, self.green, self.blue) @property def hsv(self): """ Returns a 3-tuple of (hue, saturation, value) float values (between 0.0 and 1.0). """ return colorsys.rgb_to_hsv(self.red, self.green, self.blue) @property def red(self): """ Returns the red component of the color as a :class:`Red` instance which can be used in operations with other :class:`Color` instances. """ # super() calls needed here to avoid recursion return Red(super(Color, self).red) @property def green(self): """ Returns the green component of the color as a :class:`Green` instance which can be used in operations with other :class:`Color` instances. """ return Green(super(Color, self).green) @property def blue(self): """ Returns the blue component of the color as a :class:`Blue` instance which can be used in operations with other :class:`Color` instances. """ return Blue(super(Color, self).blue) @property def hue(self): """ Returns the hue of the color as a :class:`Hue` instance which can be used in operations with other :class:`Color` instances. """ return Hue(self.hls[0]) @property def lightness(self): """ Returns the lightness of the color as a :class:`Lightness` instance which can be used in operations with other :class:`Color` instances. """ return Lightness(self.hls[1]) @property def saturation(self): """ Returns the saturation of the color as a :class:`Saturation` instance which can be used in operations with other :class:`Color` instances. """ return Saturation(self.hls[2])
[docs] def difference(self, other, method='euclid'): """ Determines the difference between this color and *other* using the specified *method*. The *method* is specified as a string, and the following methods are valid: * 'euclid' - This is the default method. Calculate the `Euclidian distance`_. This is by far the fastest method, but also the least accurate in terms of human perception. * 'cie1976' - Use the `CIE 1976`_ formula for calculating the difference between two colors in CIE Lab space. * 'cie1994g' - Use the `CIE 1994`_ formula with the "graphic arts" bias for calculating the difference. * 'cie1994t' - Use the `CIE 1994`_ forumula with the "textiles" bias for calculating the difference. * 'cie2000' - Use the `CIEDE 2000`_ formula for calculating the difference. Note that the Euclidian distance will be significantly different to the other calculations; effectively this just measures the distance between the two colors by treating them as coordinates in a three dimensional Euclidian space. All other methods are means of calculating a `Delta E`_ value in which 2.3 is considered a `just-noticeable difference`_ (JND). .. warning:: This implementation has yet to receive any significant testing (constructor methods for CIELab need to be added before this can be done). .. _Delta E: https://en.wikipedia.org/wiki/Color_difference .. _just-noticeable difference: https://en.wikipedia.org/wiki/Just-noticeable_difference .. _Euclidian distance: https://en.wikipedia.org/wiki/Euclidean_distance .. _CIE 1976: https://en.wikipedia.org/wiki/Color_difference#CIE76 .. _CIE 1994: https://en.wikipedia.org/wiki/Color_difference#CIE94 .. _CIEDE 2000: https://en.wikipedia.org/wiki/Color_difference#CIEDE2000 """ if isinstance(method, bytes): method = method.decode('ascii') if method == 'euclid': return sqrt(sum((Cs - Co) ** 2 for Cs, Co in zip(self, other))) elif method == 'cie1976': return self._cie1976(other) elif method.startswith('cie1994'): return self._cie1994(other, method) elif method == 'ciede2000': return self._ciede2000(other) else: raise ValueError('invalid method: %s' % method)
def _cie1976(self, other): return sqrt(sum((Cs - Co) ** 2 for Cs, Co in zip(self.cie_lab, other.cie_lab))) def _cie1994(self, other, method): L1, a1, b1 = self.cie_lab L2, a2, b2 = other.cie_lab dL = L1 - L2 C1 = sqrt(a1 ** 2 + b1 ** 2) C2 = sqrt(a2 ** 2 + b2 ** 2) dC = C1 - C2 # Don't bother with the sqrt here as due to limited float precision # we can wind up with a domain error (because the value is ever so # slightly negative - try it with black'n'white for an example) dH2 = (a1 - a2) ** 2 + (b1 - b2) ** 2 - dC ** 2 kL, K1, K2 = { 'cie1994g': (1, 0.045, 0.015), 'cie1994t': (2, 0.048, 0.014), }[method] SC = 1 + K1 * C1 SH = 1 + K2 * C1 return sqrt((dL ** 2 / kL) + (dC ** 2 / SC) + (dH2 / SH)) def _ciede2000(self, other): L1, a1, b1 = self.cie_lab L2, a2, b2 = other.cie_lab L_ = (L1 + L2) / 2 dL = L2 - L1 C1 = sqrt(a1 ** 2 + b1 ** 2) C2 = sqrt(a1 ** 2 + b1 ** 2) C_ = (C1 + C2) / 2 dC = C2 - C1 G = (1 - sqrt(C_ ** 7 / (C_ ** 7 + 25 ** 7))) / 2 a1 = (1 + G) * a1 a2 = (1 + G) * a2 h1 = 0.0 if b1 == a1 == 0 else degrees(atan2(b1, a1)) % 360 h2 = 0.0 if b2 == a2 == 0 else degrees(atan2(b2, a2)) % 360 if C1 * C2 == 0.0: dh = 0.0 h_ = h1 + h2 elif abs(h1 - h2) <= 180: dh = h2 - h1 h_ = (h1 + h2) / 2 else: if h2 <= h1: dh = h2 - h1 + 360 else: dh = h2 - h1 - 360 if h1 + h2 >= 360: h_ = (h1 + h2 + 360) / 2 else: h_ = (h1 + h2 - 360) / 2 dH = 2 * sqrt(C1 * C2) * sin(radians(dh / 2)) T = ( 1 - 0.17 * cos(radians(h_ - 30)) + 0.24 * cos(radians(2 * h_)) + 0.32 * cos(radians(3 * h_ + 6)) - 0.20 * cos(radians(4 * h_ - 63)) ) SL = 1 + (0.015 * (L_ - 50) ** 2) / sqrt(20 + (L_ - 50) ** 2) SC = 1 + 0.045 * C_ SH = 1 + 0.015 * C_ * T RT = -2 * sqrt(C_ ** 7 / (C_ ** 7 + 25 ** 7)) * sin(radians(60 * exp(-(((h_ - 275) / 25) ** 2)))) return sqrt((dL / SL) ** 2 + (dC / SC) ** 2 + (dH / SH) ** 2 + RT * (dC / SC) * (dH / SH))