cmaps

Forked from hhuangwx cmaps repository

Make it easier to use user defined colormaps in matplotlib. Default colormaps are from NCL website.

Users can define a environmental variable CMAP_DIR pointing to the folder containing the self-defined rgb files.

Installation:

pip install git+https://github.com/amizyuk/cmaps

or:

git clone https://github.com/amizyuk/cmaps.git
pip install cmaps

In case you would like to improve the code:

...
pip install -e cmaps

Usage:

import matplotlib.pyplot as plt
import cmaps
import numpy as np

x = y = np.arange(-3.0, 3.01, 0.05)
X, Y = np.meshgrid(x, y)

sigmax = sigmay = 1.0
mux = muy = sigmaxy=0.0

Xmu = X-mux
Ymu = Y-muy

rho = sigmaxy/(sigmax*sigmay)
z = Xmu**2/sigmax**2 + Ymu**2/sigmay**2 - 2*rho*Xmu*Ymu/(sigmax*sigmay)
denom = 2*np.pi*sigmax*sigmay*np.sqrt(1-rho**2)
Z = np.exp(-z/(2*(1-rho**2))) / denom

plt.pcolormesh(X,Y,Z,cmap=cmaps.WhiteBlueGreenYellowRed)
plt.colorbar()

List the colormaps using the code in the examples:

import cmaps
import numpy as np
import inspect

import matplotlib.pyplot as plt
import matplotlib
from matplotlib import patheffects
matplotlib.rc('text', usetex=False)


def list_cmaps():
    attributes = inspect.getmembers(cmaps, lambda _: not (inspect.isroutine(_)))
    colors = [_[0] for _ in attributes if
              not (_[0].startswith('__') and _[0].endswith('__'))]
    return colors


if __name__ == '__main__':
    colormaps = list_cmaps()

    gradient = np.linspace(0, 1, 256)
    gradient = np.vstack((gradient, gradient))

    ncols = 8
    nrows = len(colormaps) // ncols + 1
    fig, axs = plt.subplots(figsize=(10, 8),nrows=nrows,ncols=ncols)
    fig.subplots_adjust(top=0.99, bottom=0.01, left=0.01, right=0.99,hspace=0.25,wspace=0.05)
    for (cmap,ax) in zip(colormaps,axs.flat):
        # ax.axis('off')
        ax.imshow(gradient, aspect='auto', cmap=getattr(cmaps, cmap), origin='lower')
        ax.text(.01, 0.5, cmap, va='center', ha='left', fontsize=7,
                transform=ax.transAxes,
                path_effects=[patheffects.withStroke(linewidth=1.1,
                                                        foreground="w")])
    for ax in axs.flat:
        ax.axis('off')
    fig.savefig('colormaps.png', dpi=300)

Note that "Slicing" function like list or numpy array is supported for cmaps:

cmaps.amwg256[20:-20:2]
cmaps.amwg256[-20:20:-2]