|
| 1 | +""" |
| 2 | +=========================================== |
| 3 | +Selecting individual colors from a colormap |
| 4 | +=========================================== |
| 5 | +
|
| 6 | +Sometimes we want to use more colors or a different set of colors than the default color |
| 7 | +cycle provides. Selecting individual colors from one of the provided colormaps can be a |
| 8 | +convenient way to do this. |
| 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. |
| 14 | +
|
| 15 | +For more details about manipulating colormaps, see :ref:`colormap-manipulation`. |
| 16 | +""" |
| 17 | + |
| 18 | +import matplotlib.pyplot as plt |
| 19 | + |
| 20 | +import matplotlib as mpl |
| 21 | + |
| 22 | +n_lines = 21 |
| 23 | + |
| 24 | +cmap = mpl.colormaps.get_cmap('plasma').resampled(n_lines) |
| 25 | + |
| 26 | +fig, ax = plt.subplots(layout='constrained') |
| 27 | + |
| 28 | +for i in range(n_lines): |
| 29 | + ax.plot([0, i], color=cmap(i)) |
| 30 | + |
| 31 | +plt.show() |
| 32 | + |
| 33 | +# %% |
| 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 |
| 43 | + |
| 44 | +with mpl.rc_context({'axes.prop_cycle': cycler(color=colors)}): |
| 45 | + |
| 46 | + fig, ax = plt.subplots(layout='constrained') |
| 47 | + |
| 48 | + for i in range(n_lines): |
| 49 | + ax.plot([0, i]) |
| 50 | + |
| 51 | +plt.show() |
| 52 | + |
| 53 | +# %% |
| 54 | +# |
| 55 | +# .. admonition:: References |
| 56 | +# |
| 57 | +# The use of the following functions, methods, classes and modules is shown |
| 58 | +# in this example: |
| 59 | +# |
| 60 | +# - `matplotlib.colors.Colormap` |
| 61 | +# - `matplotlib.colors.Colormap.resampled` |
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