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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

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<title>Specifying Colors — Matplotlib 3.0.2 documentation</title>

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<div id="unreleased-message"> You are reading an old version of the documentation (v3.0.2). For the latest version see <a href="https://matplotlib.org/stable/tutorials/colors/colors.html">https://matplotlib.org/stable/tutorials/colors/colors.html</a></div>

<div style="float: left; position: absolute; width: 496px; bottom: 0; padding-bottom: 24px">Version 3.0.2</div>

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<h3><a href="../../contents.html">Table of Contents</a></h3>

<ul>

<li><a class="reference internal" href="#">Specifying Colors</a><ul>

<li><a class="reference internal" href="#cn-color-selection">"CN" color selection</a></li>

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<h1>Specifying Colors<a class="headerlink" href="#specifying-colors" title="Permalink to this headline">¶</a></h1>

Matplotlib recognizes the following formats to specify a color:

<li>an RGB or RGBA tuple of float values in <code class="docutils literal notranslate">[0, 1]</code> (e.g., <code class="docutils literal notranslate">(0.1, 0.2, 0.5)</code>

or <code class="docutils literal notranslate">(0.1, 0.2, 0.5, 0.3)</code>). RGBA is short for Red, Green, Blue, Alpha;</li>

<li>a hex RGB or RGBA string (e.g., <code class="docutils literal notranslate">'#0F0F0F'</code> or <code class="docutils literal notranslate">'#0F0F0F0F'</code>);</li>

<li>a string representation of a float value in <code class="docutils literal notranslate">[0, 1]</code> inclusive for gray

level (e.g., <code class="docutils literal notranslate">'0.5'</code>);</li>

<li>a X11/CSS4 color name;</li>

<li>a name from the <a class="reference external" href="https://xkcd.com/color/rgb/">xkcd color survey</a>;

prefixed with <code class="docutils literal notranslate">'xkcd:'</code> (e.g., <code class="docutils literal notranslate">'xkcd:sky blue'</code>);</li>

<li>one of <code class="docutils literal notranslate">{'tab:blue', 'tab:orange', 'tab:green',

'tab:red', 'tab:purple', 'tab:brown', 'tab:pink',

'tab:gray', 'tab:olive', 'tab:cyan'}</code> which are the Tableau Colors from the

'T10' categorical palette (which is the default color cycle);</li>

<li>a "CN" color spec, i.e. <code class="xref py py-obj docutils literal notranslate">'C'</code> followed by a single digit, which is an index

into the default property cycle (<code class="docutils literal notranslate">matplotlib.rcParams['axes.prop_cycle']</code>);

the indexing occurs at artist creation time and defaults to black if the

cycle does not include color.</li>

</ul>

"Red", "Green" and "Blue", are the intensities of those colors, the combination

of which span the colorspace.

How "Alpha" behaves depends on the <code class="docutils literal notranslate">zorder</code> of the Artist. Higher

<code class="docutils literal notranslate">zorder</code> 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 <code class="docutils literal notranslate">RGBold</code> and the RGB of the

pixel of the Artist being added is <code class="docutils literal notranslate">RGBnew</code> with Alpha <code class="docutils literal notranslate">alpha</code>,

then the RGB of the pixel is updated to:

<code class="docutils literal notranslate">RGB = RGBOld * (1 - Alpha) + RGBnew * Alpha</code>. 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.

All string specifications of color, other than "CN", are case-insensitive.

For more information on colors in matplotlib see

<li>the <a class="reference internal" href="../../gallery/color/color_demo.html">Color Demo</a> example;</li>

<li>the <a class="reference internal" href="../../api/colors_api.html#module-matplotlib.colors" title="matplotlib.colors"><code class="xref py py-obj docutils literal notranslate">matplotlib.colors</code></a> API;</li>

<li>the <a class="reference internal" href="../../gallery/color/named_colors.html">Visualizing named colors</a> example.</li>

</ul>

<h2>"CN" color selection<a class="headerlink" href="#cn-color-selection" title="Permalink to this headline">¶</a></h2>

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

example,

<div class="highlight-python notranslate"><div class="highlight"><pre>import numpy as np

import matplotlib.pyplot as plt

import matplotlib as mpl

th = <a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.linspace.html#numpy.linspace" title="View documentation for numpy.linspace">np.linspace</a>(0, 2*<a href="https://docs.scipy.org/doc/numpy/reference/constants.html#numpy.pi" title="View documentation for numpy.pi">np.pi</a>, 128)

def demo(sty):

<a href="../../api/style_api.html#matplotlib.style.use" title="View documentation for matplotlib.style.use">mpl.style.use</a>(sty)

fig, ax = <a href="../../api/_as_gen/matplotlib.pyplot.subplots.html#matplotlib.pyplot.subplots" title="View documentation for matplotlib.pyplot.subplots">plt.subplots</a>(figsize=(3, 3))

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

ax.plot(th, <a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.cos.html#numpy.cos" title="View documentation for numpy.cos">np.cos</a>(th), 'C1', label='C1')

ax.plot(th, <a href="https://docs.scipy.org/doc/numpy/reference/generated/numpy.sin.html#numpy.sin" title="View documentation for numpy.sin">np.sin</a>(th), 'C2', label='C2')

ax.legend()

demo('default')

demo('seaborn')

</pre></div>

</div>

</li>

</li>

</ul>

will use the first color for the title and then plot using the second

and third colors of each style's <code class="docutils literal notranslate">mpl.rcParams['axes.prop_cycle']</code>.

</div>

The xkcd colors are derived from a user survey conducted by the

webcomic xkcd. <a class="reference external" href="https://blog.xkcd.com/2010/05/03/color-survey-results/">Details of the survey are available on the xkcd blog</a>.

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 <code class="docutils literal notranslate">'blue'</code> maps to <code class="docutils literal notranslate">'#0000FF'</code>

where as <code class="docutils literal notranslate">'xkcd:blue'</code> maps to <code class="docutils literal notranslate">'#0343DF'</code>. Due to these name

collisions all of the xkcd colors have <code class="docutils literal notranslate">'xkcd:'</code> 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.

<div class="highlight-python notranslate"><div class="highlight"><pre>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 = <a href="../../api/_as_gen/matplotlib.pyplot.figure.html#matplotlib.pyplot.figure" title="View documentation for matplotlib.pyplot.figure">plt.figure</a>(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 = <a href="../../api/_as_gen/matplotlib.patches.Rectangle.html#matplotlib.patches.Rectangle" title="View documentation for matplotlib.patches.Rectangle">mpatch.Rectangle</a>((0, j), 1, 1, color=cn)

r2 = <a href="../../api/_as_gen/matplotlib.patches.Rectangle.html#matplotlib.patches.Rectangle" title="View documentation for matplotlib.patches.Rectangle">mpatch.Rectangle</a>((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')

</pre></div>

</div>

<a class="reference download internal" download="" href="../../_downloads/b29151564d938fd1823472497a612dc0/colors.py"><code class="xref download docutils literal notranslate">Download Python source code: colors.py</code></a></div>

<a class="reference download internal" download="" href="../../_downloads/9b44cc11428cb643b26d3f4deb4d31bb/colors.ipynb"><code class="xref download docutils literal notranslate">Download Jupyter notebook: colors.ipynb</code></a></div>

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Keywords: matplotlib code example, codex, python plot, pyplot

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Last updated on Nov 11, 2018.

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