How to fill matplotlib bars with a gradient?

Just as depicted in Pyplot: vertical gradient fill under curve? one may use an image to create a gradient plot.

Since bars are rectangular the extent of the image can be directly set to the bar’s position and size. One can loop over all bars and create an image at the respective position. The result is a gradient bar plot.

import numpy as np
import matplotlib.pyplot as plt

fig, ax = plt.subplots()

bar =[1,2,3,4,5,6],[4,5,6,3,7,5])

def gradientbars(bars):
    grad = np.atleast_2d(np.linspace(0,1,256)).T
    ax = bars[0].axes
    lim = ax.get_xlim()+ax.get_ylim()
    for bar in bars:
        x,y = bar.get_xy()
        w, h = bar.get_width(), bar.get_height()
        ax.imshow(grad, extent=[x,x+w,y,y+h], aspect="auto", zorder=0)


enter image description here

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