.. note:: :class: sphx-glr-download-link-note Click :ref:`here ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_tutorials_colors_colors.py: ***************** Specifying Colors ***************** Matplotlib recognizes the following formats to specify a color: * an RGB or RGBA tuple of float values in ``[0, 1]`` (e.g., ``(0.1, 0.2, 0.5)`` or ``(0.1, 0.2, 0.5, 0.3)``). RGBA is short for Red, Green, Blue, Alpha; * a hex RGB or RGBA string (e.g., ``'#0F0F0F'`` or ``'#0F0F0F0F'``); * 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'}``; * a X11/CSS4 color name; * a name from the `xkcd color survey `__; prefixed with ``'xkcd:'`` (e.g., ``'xkcd:sky blue'``); * one of ``{'tab:blue', 'tab:orange', 'tab:green', 'tab:red', 'tab:purple', 'tab:brown', 'tab:pink', 'tab:gray', 'tab:olive', 'tab:cyan'}`` which are the Tableau Colors from the 'T10' categorical palette (which is the default color cycle); * a "CN" color spec, i.e. `'C'` followed by a single digit, which is an index into the default property cycle (``matplotlib.rcParams['axes.prop_cycle']``); the indexing occurs at artist creation time and defaults to black if the cycle does not include color. "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. All string specifications of color, other than "CN", are case-insensitive. "CN" color selection -------------------- "CN" colors are converted to RGBA as soon as the artist is created. For example, .. code-block:: python 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') .. rst-class:: sphx-glr-horizontal * .. image:: /tutorials/colors/images/sphx_glr_colors_001.png :class: sphx-glr-multi-img * .. image:: /tutorials/colors/images/sphx_glr_colors_002.png :class: sphx-glr-multi-img 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 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 `__. 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. .. code-block:: python 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') .. image:: /tutorials/colors/images/sphx_glr_colors_003.png :class: sphx-glr-single-img .. _sphx_glr_download_tutorials_colors_colors.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download :download:`Download Python source code: colors.py ` .. container:: sphx-glr-download :download:`Download Jupyter notebook: colors.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot `Gallery generated by Sphinx-Gallery `_