Restore CSS/xkcd comparison plot.

Author: anntzer

doc/users/colors.rst

@@ -4,19 +4,57 @@
 Specifying Colors
 *****************
 
-In almost all places in matplotlib where a color can be specified by the user it can be provided as:
+In almost all places in matplotlib where a color can be specified by the user
+it can be provided as:
 
 * ``(r, g, b)`` tuples
 * ``(r, g, b, a)`` tuples
 * hex string, ex ``#OFOFOF``
 * float value between [0, 1] for gray level
 * One of ``{'b', 'g', 'r', 'c', 'm', 'y', 'k', 'w'}``
-* valid css4/X11 color names
-* valid name from the `XKCD color survey
+* valid CSS4/X11 color names
+* valid name from the `xkcd color survey
   <http://blog.xkcd.com/2010/05/03/color-survey-results/>`__ These
   names are prefixed with ``'xkcd:'`` (e.g., ``'xkcd:sky blue'``) to
   prevent name clashes with the CSS4/X11 names.
 
 All string specifications of color are case-insensitive.
 
 Internally, mpl is moving to storing all colors as RGBA float quadruples.
+
+There are 95 (out of 148 colors in the css color list) conflicts between the
+CSS4/X11 names and the xkcd names.  Given that the former are the standard
+color names of the web, matplotlib should follow them.  Thus, xkcd color names
+are prefixed with ``'xkcd:'``, for example ``'blue'`` maps to ``'#0000FF'``
+where as ``'xkcd:blue'`` maps to ``'#0343DF'``.
+
+.. plot::
+
+   import matplotlib.pyplot as plt
+   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)):
+       cn = mcd.CSS4_COLORS[n]
+       xkcd = mcd.XKCD_COLORS["xkcd:" + n].upper()
+       if cn != xkcd:
+           print(n, cn, xkcd)
+
+       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)
+       ax.add_patch(r1)
+       ax.add_patch(r2)
+       ax.axhline(j, color='k')
+
+   ax.text(.5, j + .1, 'X11', ha='center')
+   ax.text(1.5, j + .1, 'XKCD', ha='center')
+   ax.set_xlim(0, 3)
+   ax.set_ylim(0, j + 1)
+   ax.axis('off')