import marvin.utils.plot.colorbar as colorbar
linearlab, linearlab_r = colorbar.linearlab()

import matplotlib.pyplot as plt
fig, axes = plt.subplots(nrows=2, figsize=(6, 1))
fig.subplots_adjust(top=0.95, bottom=0.01, left=0.25, right=0.99)
gradient = np.array([np.linspace(0, 1, 256)])

for ax, cmap in zip(axes, (linearlab, linearlab_r)):
    ax.imshow(gradient, aspect='auto', cmap=cmap)
    pos = list(ax.get_position().bounds)
    y_text = pos[1] + pos[3] / 2.
    fig.text(0.02, y_text, cmap.name, va='center', ha='left', fontsize=16)
    ax.set_axis_off()