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# coding: utf8 |
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# Copyright 2013-2015 Vincent Jacques <[email protected]> |
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""" |
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.. class:: Colorer |
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Objects passed as the ``colorer`` argument of :class:`.TurksHead` must implement this interface. |
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More precisely, they must implement **one** of the following methods: |
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.. py:method:: compute_color_hsv(knot, k, theta, altitude): |
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Return a tuple ``(h, s, v)`` of the color to be applied to the ``k``-th string of the ``knot``, |
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at angle ``theta``, at the given ``altitude``. |
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``h`` must be between 0 and 360 |
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``s`` and ``v`` must be between 0 and 1. |
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:param knot: the :class:`.TurksHead` instance. |
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:param k: the index of the current string. Between 0 and ``knot.d``. |
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:param theta: the angle on the current string. Between 0 and ``2 * knot.q_prime * math.pi``. |
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:param altitude: the altitude of the string at this point. Between -1 and 1. |
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.. py:method:: compute_color_rgb(knot, k, theta, altitude): |
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Return a tuple ``(r, g, b)`` of the color to be applied to the ``k``-th string of the ``knot``, |
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at angle ``theta``, at the given ``altitude``. |
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``r``, ``g`` and ``b`` must be between 0 and 1. |
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:param knot: the :class:`.TurksHead` instance. |
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:param k: the index of the current string. Between 0 and ``knot.d``. |
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:param theta: the angle on the current string. Between 0 and ``2 * knot.q_prime * math.pi``. |
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:param altitude: the altitude of the string at this point. Between -1 and 1. |
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""" |
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import collections |
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import math |
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import unittest |
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import cairo |
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from .color import hsv_to_rgb |
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from .knot import Knot |
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from .knot.knot import String, Segment, End, Bridge, Tunnel |
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from ._turkshead import Drawer |
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class DefaultColorer(object): |
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""" |
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The :class:`Colorer` used when you don't provide one explicitly to :class:`.TurksHead`. |
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It uses one color per string (spread on the spectrum) and makes it darker when the string goes down. |
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""" |
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def compute_color_hsv(self, knot, k, theta, altitude): |
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# @todo Could we (automatically) add this code to the generated doc? |
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h = k * 360. / knot.d |
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s = 0.5 |
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v = 0.5 + altitude / 2 |
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return h, s, v |
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class TurksHead(object): |
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""" |
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Turk's head knot objects. |
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:param bights: the number of times the string touches the outised of the knot. |
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:param leads: the number of times the string turns around the center. |
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:param inner: the radius of the empty area inside the knot. |
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:param outer: the radius of the knot. |
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:param line: the width of the string. |
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:param colorer: a :class:`.Colorer` instance. If ``None`` or not provided, a :class:`.DefaultColorer` will be used. |
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""" |
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def __init__(self, bights, leads, inner, outer, line, colorer=None): |
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knot = Knot(bights, leads) |
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self.__p = knot.p |
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self.__q = knot.q |
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self.__d = knot.d |
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self.__p_prime = knot.p_prime |
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self.__q_prime = knot.q_prime |
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self.__inner_radius = inner |
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self.__outer_radius = outer |
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self.__line_width = line |
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self.__drawer = Drawer( |
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knot=self, |
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colorer=colorer or DefaultColorer(), |
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strings=knot.strings, |
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) |
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@property |
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def p(self): |
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""" |
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The number of bights. |
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""" |
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return self.__p |
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@property |
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def q(self): |
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""" |
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The number of leads. |
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""" |
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return self.__q |
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@property |
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def d(self): |
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""" |
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The greatest common divisor of :attr:`~.TurksHead.p` and :attr:`~.TurksHead.q`. |
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""" |
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return self.__d |
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@property |
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def p_prime(self): |
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""" |
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:attr:`~.TurksHead.p` divided by :attr:`~.TurksHead.d`. |
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""" |
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return self.__p_prime |
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@property |
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def q_prime(self): |
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""" |
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:attr:`~.TurksHead.q` divided by :attr:`~.TurksHead.d`. |
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""" |
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return self.__q_prime |
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@property |
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def inner_radius(self): |
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""" |
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The radius of the empty area inside the knot. |
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""" |
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return self.__inner_radius |
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@property |
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def outer_radius(self): |
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""" |
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The radius of the knot. |
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""" |
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return self.__outer_radius |
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@property |
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def line_width(self): |
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""" |
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The width of the string. |
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""" |
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return self.__line_width |
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def draw(self, ctx): |
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""" |
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Draw the knot on a :class:`cairo.Context`. |
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See `documentation of PyCairo <http://www.cairographics.org/documentation/pycairo/2/reference/context.html>`__. |
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""" |
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self.__drawer.draw(ctx) |
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