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337 lines
11 KiB
337 lines
11 KiB
import collections
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import re
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from colorsys import hls_to_rgb
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from .parser import parse_one_component_value
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class RGBA(collections.namedtuple('RGBA', ['red', 'green', 'blue', 'alpha'])):
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"""An RGBA color.
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A tuple of four floats in the 0..1 range: ``(red, green, blue, alpha)``.
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.. attribute:: red
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Convenience access to the red channel. Same as ``rgba[0]``.
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.. attribute:: green
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Convenience access to the green channel. Same as ``rgba[1]``.
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.. attribute:: blue
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Convenience access to the blue channel. Same as ``rgba[2]``.
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.. attribute:: alpha
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Convenience access to the alpha channel. Same as ``rgba[3]``.
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"""
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def parse_color(input):
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"""Parse a color value as defined in `CSS Color Level 3
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<https://www.w3.org/TR/css-color-3/>`_.
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:type input: :obj:`str` or :term:`iterable`
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:param input: A string or an iterable of :term:`component values`.
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:returns:
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* :obj:`None` if the input is not a valid color value.
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(No exception is raised.)
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* The string ``'currentColor'`` for the ``currentColor`` keyword
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* Or a :class:`RGBA` object for every other values
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(including keywords, HSL and HSLA.)
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The alpha channel is clipped to [0, 1]
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but red, green, or blue can be out of range
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(eg. ``rgb(-10%, 120%, 0%)`` is represented as
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``(-0.1, 1.2, 0, 1)``.)
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"""
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if isinstance(input, str):
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token = parse_one_component_value(input, skip_comments=True)
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else:
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token = input
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if token.type == 'ident':
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return _COLOR_KEYWORDS.get(token.lower_value)
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elif token.type == 'hash':
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for multiplier, regexp in _HASH_REGEXPS:
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match = regexp(token.value)
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if match:
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channels = [
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int(group * multiplier, 16) / 255
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for group in match.groups()]
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if len(channels) == 3:
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channels.append(1.)
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return RGBA(*channels)
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elif token.type == 'function':
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args = _parse_comma_separated(token.arguments)
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if args:
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name = token.lower_name
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if name == 'rgb':
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return _parse_rgb(args, alpha=1.)
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elif name == 'rgba':
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alpha = _parse_alpha(args[3:])
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if alpha is not None:
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return _parse_rgb(args[:3], alpha)
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elif name == 'hsl':
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return _parse_hsl(args, alpha=1.)
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elif name == 'hsla':
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alpha = _parse_alpha(args[3:])
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if alpha is not None:
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return _parse_hsl(args[:3], alpha)
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def _parse_alpha(args):
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"""Parse a list of one alpha value.
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If args is a list of a single INTEGER or NUMBER token,
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return its value clipped to the 0..1 range. Otherwise, return None.
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"""
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if len(args) == 1 and args[0].type == 'number':
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return min(1, max(0, args[0].value))
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def _parse_rgb(args, alpha):
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"""Parse a list of RGB channels.
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If args is a list of 3 INTEGER tokens or 3 PERCENTAGE tokens, return RGB
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values as a tuple of 3 floats in 0..1. Otherwise, return None.
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"""
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types = [arg.type for arg in args]
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if (types == ['number', 'number', 'number'] and
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all(a.is_integer for a in args)):
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r, g, b = [arg.int_value / 255 for arg in args[:3]]
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return RGBA(r, g, b, alpha)
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elif types == ['percentage', 'percentage', 'percentage']:
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r, g, b = [arg.value / 100 for arg in args[:3]]
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return RGBA(r, g, b, alpha)
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def _parse_hsl(args, alpha):
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"""Parse a list of HSL channels.
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If args is a list of 1 INTEGER token and 2 PERCENTAGE tokens, return RGB
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values as a tuple of 3 floats in 0..1. Otherwise, return None.
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"""
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types = [arg.type for arg in args]
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if types == ['number', 'percentage', 'percentage'] and args[0].is_integer:
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r, g, b = hls_to_rgb(
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args[0].int_value / 360, args[2].value / 100, args[1].value / 100)
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return RGBA(r, g, b, alpha)
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def _parse_comma_separated(tokens):
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"""Parse a list of tokens (typically the content of a function token)
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as arguments made of a single token each, separated by mandatory commas,
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with optional white space around each argument.
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return the argument list without commas or white space;
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or None if the function token content do not match the description above.
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"""
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tokens = [token for token in tokens
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if token.type not in ('whitespace', 'comment')]
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if not tokens:
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return []
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if len(tokens) % 2 == 1 and all(token == ',' for token in tokens[1::2]):
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return tokens[::2]
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_HASH_REGEXPS = (
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(2, re.compile('^{}$'.format(4 * '([\\da-f])'), re.I).match),
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(1, re.compile('^{}$'.format(4 * '([\\da-f]{2})'), re.I).match),
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(2, re.compile('^{}$'.format(3 * '([\\da-f])'), re.I).match),
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(1, re.compile('^{}$'.format(3 * '([\\da-f]{2})'), re.I).match),
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)
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# (r, g, b) in 0..255
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_BASIC_COLOR_KEYWORDS = [
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('black', (0, 0, 0)),
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('silver', (192, 192, 192)),
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('gray', (128, 128, 128)),
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('white', (255, 255, 255)),
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('maroon', (128, 0, 0)),
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('red', (255, 0, 0)),
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('purple', (128, 0, 128)),
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('fuchsia', (255, 0, 255)),
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('green', (0, 128, 0)),
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('lime', (0, 255, 0)),
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('olive', (128, 128, 0)),
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('yellow', (255, 255, 0)),
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('navy', (0, 0, 128)),
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('blue', (0, 0, 255)),
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('teal', (0, 128, 128)),
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('aqua', (0, 255, 255)),
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]
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# (r, g, b) in 0..255
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_EXTENDED_COLOR_KEYWORDS = [
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('aliceblue', (240, 248, 255)),
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('antiquewhite', (250, 235, 215)),
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('aqua', (0, 255, 255)),
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('aquamarine', (127, 255, 212)),
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('azure', (240, 255, 255)),
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('beige', (245, 245, 220)),
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('bisque', (255, 228, 196)),
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('black', (0, 0, 0)),
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('blanchedalmond', (255, 235, 205)),
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('blue', (0, 0, 255)),
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('blueviolet', (138, 43, 226)),
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('brown', (165, 42, 42)),
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('burlywood', (222, 184, 135)),
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('cadetblue', (95, 158, 160)),
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('chartreuse', (127, 255, 0)),
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('chocolate', (210, 105, 30)),
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('coral', (255, 127, 80)),
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('cornflowerblue', (100, 149, 237)),
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('cornsilk', (255, 248, 220)),
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('crimson', (220, 20, 60)),
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('cyan', (0, 255, 255)),
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('darkblue', (0, 0, 139)),
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('darkcyan', (0, 139, 139)),
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('darkgoldenrod', (184, 134, 11)),
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('darkgray', (169, 169, 169)),
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('darkgreen', (0, 100, 0)),
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('darkgrey', (169, 169, 169)),
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('darkkhaki', (189, 183, 107)),
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('darkmagenta', (139, 0, 139)),
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('darkolivegreen', (85, 107, 47)),
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('darkorange', (255, 140, 0)),
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('darkorchid', (153, 50, 204)),
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('darkred', (139, 0, 0)),
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('darksalmon', (233, 150, 122)),
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('darkseagreen', (143, 188, 143)),
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('darkslateblue', (72, 61, 139)),
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('darkslategray', (47, 79, 79)),
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('darkslategrey', (47, 79, 79)),
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('darkturquoise', (0, 206, 209)),
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('darkviolet', (148, 0, 211)),
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('deeppink', (255, 20, 147)),
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('deepskyblue', (0, 191, 255)),
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('dimgray', (105, 105, 105)),
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('dimgrey', (105, 105, 105)),
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('dodgerblue', (30, 144, 255)),
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('firebrick', (178, 34, 34)),
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('floralwhite', (255, 250, 240)),
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('forestgreen', (34, 139, 34)),
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('fuchsia', (255, 0, 255)),
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('gainsboro', (220, 220, 220)),
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('ghostwhite', (248, 248, 255)),
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('gold', (255, 215, 0)),
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('goldenrod', (218, 165, 32)),
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('gray', (128, 128, 128)),
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('green', (0, 128, 0)),
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('greenyellow', (173, 255, 47)),
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('grey', (128, 128, 128)),
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('honeydew', (240, 255, 240)),
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('hotpink', (255, 105, 180)),
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('indianred', (205, 92, 92)),
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('indigo', (75, 0, 130)),
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('ivory', (255, 255, 240)),
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('khaki', (240, 230, 140)),
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('lavender', (230, 230, 250)),
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('lavenderblush', (255, 240, 245)),
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('lawngreen', (124, 252, 0)),
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('lemonchiffon', (255, 250, 205)),
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('lightblue', (173, 216, 230)),
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('lightcoral', (240, 128, 128)),
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('lightcyan', (224, 255, 255)),
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('lightgoldenrodyellow', (250, 250, 210)),
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('lightgray', (211, 211, 211)),
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('lightgreen', (144, 238, 144)),
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('lightgrey', (211, 211, 211)),
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('lightpink', (255, 182, 193)),
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('lightsalmon', (255, 160, 122)),
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('lightseagreen', (32, 178, 170)),
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('lightskyblue', (135, 206, 250)),
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('lightslategray', (119, 136, 153)),
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('lightslategrey', (119, 136, 153)),
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('lightsteelblue', (176, 196, 222)),
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('lightyellow', (255, 255, 224)),
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('lime', (0, 255, 0)),
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('limegreen', (50, 205, 50)),
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('linen', (250, 240, 230)),
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('magenta', (255, 0, 255)),
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('maroon', (128, 0, 0)),
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('mediumaquamarine', (102, 205, 170)),
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('mediumblue', (0, 0, 205)),
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('mediumorchid', (186, 85, 211)),
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('mediumpurple', (147, 112, 219)),
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('mediumseagreen', (60, 179, 113)),
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('mediumslateblue', (123, 104, 238)),
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('mediumspringgreen', (0, 250, 154)),
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('mediumturquoise', (72, 209, 204)),
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('mediumvioletred', (199, 21, 133)),
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('midnightblue', (25, 25, 112)),
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('mintcream', (245, 255, 250)),
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('mistyrose', (255, 228, 225)),
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('moccasin', (255, 228, 181)),
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('navajowhite', (255, 222, 173)),
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('navy', (0, 0, 128)),
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('oldlace', (253, 245, 230)),
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('olive', (128, 128, 0)),
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('olivedrab', (107, 142, 35)),
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('orange', (255, 165, 0)),
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('orangered', (255, 69, 0)),
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('orchid', (218, 112, 214)),
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('palegoldenrod', (238, 232, 170)),
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('palegreen', (152, 251, 152)),
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('paleturquoise', (175, 238, 238)),
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('palevioletred', (219, 112, 147)),
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('papayawhip', (255, 239, 213)),
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('peachpuff', (255, 218, 185)),
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('peru', (205, 133, 63)),
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('pink', (255, 192, 203)),
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('plum', (221, 160, 221)),
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('powderblue', (176, 224, 230)),
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('purple', (128, 0, 128)),
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('red', (255, 0, 0)),
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('rosybrown', (188, 143, 143)),
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('royalblue', (65, 105, 225)),
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('saddlebrown', (139, 69, 19)),
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('salmon', (250, 128, 114)),
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('sandybrown', (244, 164, 96)),
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('seagreen', (46, 139, 87)),
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('seashell', (255, 245, 238)),
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('sienna', (160, 82, 45)),
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('silver', (192, 192, 192)),
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('skyblue', (135, 206, 235)),
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('slateblue', (106, 90, 205)),
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('slategray', (112, 128, 144)),
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('slategrey', (112, 128, 144)),
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('snow', (255, 250, 250)),
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('springgreen', (0, 255, 127)),
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('steelblue', (70, 130, 180)),
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('tan', (210, 180, 140)),
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('teal', (0, 128, 128)),
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('thistle', (216, 191, 216)),
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('tomato', (255, 99, 71)),
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('turquoise', (64, 224, 208)),
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('violet', (238, 130, 238)),
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('wheat', (245, 222, 179)),
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('white', (255, 255, 255)),
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('whitesmoke', (245, 245, 245)),
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('yellow', (255, 255, 0)),
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('yellowgreen', (154, 205, 50)),
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]
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# (r, g, b, a) in 0..1 or a string marker
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_SPECIAL_COLOR_KEYWORDS = {
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'currentcolor': 'currentColor',
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'transparent': RGBA(0., 0., 0., 0.),
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}
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# RGBA namedtuples of (r, g, b, a) in 0..1 or a string marker
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_COLOR_KEYWORDS = _SPECIAL_COLOR_KEYWORDS.copy()
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_COLOR_KEYWORDS.update(
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# 255 maps to 1, 0 to 0, the rest is linear.
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(keyword, RGBA(r / 255., g / 255., b / 255., 1.))
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for keyword, (r, g, b) in _BASIC_COLOR_KEYWORDS + _EXTENDED_COLOR_KEYWORDS)
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