"""

*****************

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')