|
7 | 7 | cycle provides. Selecting individual colors from one of the provided colormaps can be a |
8 | 8 | convenient way to do this. |
9 | 9 |
|
10 | | -Once we have hold of a `.Colormap` instance, the individual colors can be accessed |
11 | | -by passing it an index. If we want a specific number of colors taken at regular |
12 | | -intervals from a continuous colormap, we can create a new colormap using the |
13 | | -`~.Colormap.resampled` method. |
| 10 | +We can retrieve colors from any `.Colormap` by calling it with a float or a list of |
| 11 | +floats in the range [0, 1]; e.g. ``cmap(0.5)`` will give the middle color. See also |
| 12 | +`.Colormap.__call__`. |
14 | 13 |
|
15 | | -For more details about manipulating colormaps, see :ref:`colormap-manipulation`. |
| 14 | +Extracting colors from a continuous colormap |
| 15 | +-------------------------------------------- |
16 | 16 | """ |
17 | 17 |
|
18 | 18 | import matplotlib.pyplot as plt |
| 19 | +import numpy as np |
19 | 20 |
|
20 | 21 | import matplotlib as mpl |
21 | 22 |
|
22 | 23 | n_lines = 21 |
| 24 | +cmap = mpl.colormaps['plasma'] |
23 | 25 |
|
24 | | -cmap = mpl.colormaps.get_cmap('plasma').resampled(n_lines) |
| 26 | +# Take colors at regular intervals spanning the colormap. |
| 27 | +colors = cmap(np.linspace(0, 1, n_lines)) |
25 | 28 |
|
26 | 29 | fig, ax = plt.subplots(layout='constrained') |
27 | 30 |
|
28 | | -for i in range(n_lines): |
29 | | - ax.plot([0, i], color=cmap(i)) |
| 31 | +for i, color in enumerate(colors): |
| 32 | + ax.plot([0, i], color=color) |
30 | 33 |
|
31 | 34 | plt.show() |
32 | 35 |
|
33 | 36 | # %% |
34 | | -# Instead of passing colors one by one to `~.Axes.plot`, we can replace the default |
35 | | -# color cycle with a different set of colors. Specifying a `~cycler.cycler` instance |
36 | | -# within `.rcParams` achieves that. See :ref:`color_cycle` for details. |
37 | | - |
38 | | - |
39 | | -from cycler import cycler |
40 | | - |
41 | | -cmap = mpl.colormaps.get_cmap('Dark2') |
42 | | -colors = cmap(range(cmap.N)) # cmap.N is number of unique colors in the colormap |
| 37 | +# |
| 38 | +# Extracting colors from a discrete colormap |
| 39 | +# ------------------------------------------ |
| 40 | +# The list of all colors in a `.ListedColormap` is available as the ``colors`` |
| 41 | +# attribute. |
43 | 42 |
|
44 | | -with mpl.rc_context({'axes.prop_cycle': cycler(color=colors)}): |
| 43 | +colors = mpl.colormaps['Dark2'].colors |
45 | 44 |
|
46 | | - fig, ax = plt.subplots(layout='constrained') |
| 45 | +fig, ax = plt.subplots(layout='constrained') |
47 | 46 |
|
48 | | - for i in range(n_lines): |
49 | | - ax.plot([0, i]) |
| 47 | +for i, color in enumerate(colors): |
| 48 | + ax.plot([0, i], color=color) |
50 | 49 |
|
51 | 50 | plt.show() |
52 | 51 |
|
53 | 52 | # %% |
| 53 | +# See Also |
| 54 | +# -------- |
| 55 | +# |
| 56 | +# For more details about manipulating colormaps, see :ref:`colormap-manipulation`. To |
| 57 | +# change the default color cycle, see :ref:`color_cycle`. |
54 | 58 | # |
55 | 59 | # .. admonition:: References |
56 | 60 | # |
|
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