"""
*****************
Specifying Colors
*****************

Matplotlib recognizes the following formats to specify a color:

* an RGB or RGBA (red, green, blue, alpha) tuple of float values in closed
  interval ``[0, 1]`` (e.g., ``(0.1, 0.2, 0.5)`` or ``(0.1, 0.2, 0.5, 0.3)``);
* a hex RGB or RGBA string (e.g., ``'#0f0f0f'`` or ``'#0f0f0f80'``;
  case-insensitive);
* a shorthand hex RGB or RGBA string, equivalent to the hex RGB or RGBA
  string obtained by duplicating each character, (e.g., ``'#abc'``, equivalent
  to ``'#aabbcc'``, or ``'#abcd'``, equivalent to ``'#aabbccdd'``;
  case-insensitive);
* a string representation of a float value in ``[0, 1]`` inclusive for gray
  level (e.g., ``'0.5'``);
* one of ``{'b', 'g', 'r', 'c', 'm', 'y', 'k', 'w'}``, they are the single
  character short-hand notations for blue, green, red, cyan, magenta, yellow,
  black, and white.
* a X11/CSS4 color name (case-insensitive);
* a name from the `xkcd color survey`_, prefixed with ``'xkcd:'`` (e.g.,
  ``'xkcd:sky blue'``; case insensitive);
* one of the Tableau Colors from the 'T10' categorical palette (the default
  color cycle): ``{'tab:blue', 'tab:orange', 'tab:green', 'tab:red',
  'tab:purple', 'tab:brown', 'tab:pink', 'tab:gray', 'tab:olive', 'tab:cyan'}``
  (case-insensitive);
* a "CN" color spec, i.e. ``'C'`` followed by a number, which is an index into
  the default property cycle (``matplotlib.rcParams['axes.prop_cycle']``); the
  indexing is intended to occur at rendering time, and defaults to black if the
  cycle does not include color.

.. _xkcd color survey: https://xkcd.com/color/rgb/

"Red", "Green", and "Blue" are the intensities of those colors, the combination
of which span the colorspace.

How "Alpha" behaves depends on the ``zorder`` of the Artist.  Higher
``zorder`` Artists are drawn on top of lower Artists, and "Alpha" determines
whether the lower artist is covered by the higher.
If the old RGB of a pixel is ``RGBold`` and the RGB of the
pixel of the Artist being added is ``RGBnew`` with Alpha ``alpha``,
then the RGB of the pixel is updated to:
``RGB = RGBOld * (1 - Alpha) + RGBnew * Alpha``.  Alpha
of 1 means the old color is completely covered by the new Artist, Alpha of 0
means that pixel of the Artist is transparent.

For more information on colors in matplotlib see

* the :doc:`/gallery/color/color_demo` example;
* the `matplotlib.colors` API;
* the :doc:`/gallery/color/named_colors` example.

"CN" color selection
--------------------

"CN" colors are converted to RGBA as soon as the artist is created.  For
example,
"""


import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl

th = np.linspace(0, 2*np.pi, 128)


def demo(sty):
    mpl.style.use(sty)
    fig, ax = plt.subplots(figsize=(3, 3))

    ax.set_title('style: {!r}'.format(sty), color='C0')

    ax.plot(th, np.cos(th), 'C1', label='C1')
    ax.plot(th, np.sin(th), 'C2', label='C2')
    ax.legend()

demo('default')
demo('seaborn')

###############################################################################
# will use the first color for the title and then plot using the second
# and third colors of each style's ``mpl.rcParams['axes.prop_cycle']``.
#
#
# .. _xkcd-colors:
#
# xkcd v X11/CSS4
# ---------------
#
# The xkcd colors are derived from a user survey conducted by the
# webcomic xkcd.  `Details of the survey are available on the xkcd blog
# <https://blog.xkcd.com/2010/05/03/color-survey-results/>`__.
#
# Out of 148 colors in the CSS color list, there are 95 name collisions
# between the X11/CSS4 names and the xkcd names, all but 3 of which have
# different hex values.  For example ``'blue'`` maps to ``'#0000FF'``
# where as ``'xkcd:blue'`` maps to ``'#0343DF'``.  Due to these name
# collisions all of the xkcd colors have ``'xkcd:'`` prefixed.  As noted in
# the blog post, while it might be interesting to re-define the X11/CSS4 names
# based on such a survey, we do not do so unilaterally.
#
# The name collisions are shown in the table below; the color names
# where the hex values agree are shown in bold.

import matplotlib._color_data as mcd
import matplotlib.patches as mpatch

overlap = {name for name in mcd.CSS4_COLORS
           if "xkcd:" + name in mcd.XKCD_COLORS}

fig = plt.figure(figsize=[4.8, 16])
ax = fig.add_axes([0, 0, 1, 1])

for j, n in enumerate(sorted(overlap, reverse=True)):
    weight = None
    cn = mcd.CSS4_COLORS[n]
    xkcd = mcd.XKCD_COLORS["xkcd:" + n].upper()
    if cn == xkcd:
        weight = 'bold'

    r1 = mpatch.Rectangle((0, j), 1, 1, color=cn)
    r2 = mpatch.Rectangle((1, j), 1, 1, color=xkcd)
    txt = ax.text(2, j+.5, '  ' + n, va='center', fontsize=10,
                  weight=weight)
    ax.add_patch(r1)
    ax.add_patch(r2)
    ax.axhline(j, color='k')

ax.text(.5, j + 1.5, 'X11', ha='center', va='center')
ax.text(1.5, j + 1.5, 'xkcd', ha='center', va='center')
ax.set_xlim(0, 3)
ax.set_ylim(0, j + 2)
ax.axis('off')
