import random

import numpy as np
import pyqtgraph as pg
from pyqtgraph.Qt import QtCore
from pyqtgraph.graphicsItems.NonUniformImage import NonUniformImage

pg.mkQApp()
glw = pg.GraphicsLayoutWidget()
glw.show()

rng = np.random.default_rng(12345)
Z = rng.standard_normal(size=(50, 30))
x = np.arange(Z.shape[0])
y = np.arange(Z.shape[1])

images = []
images.append(pg.ImageItem(Z))
images.append(NonUniformImage(x, y, Z))
images.append(pg.PColorMeshItem(Z))

titles = ['Image', 'NonUniform', 'PColorMesh']
views = []
for idx, title in enumerate(titles):
    view = glw.addPlot(idx, 0, 1, 1, title=title)
    view.addItem(images[idx])
    views.append(view)

cbar = pg.ColorBarItem(colorMap='cividis', interactive=False)
cbar.setImageItem(images)
glw.addItem(cbar, 0, 1, 3, 1)

colormaps = pg.colormap.listMaps()

def update():
    # setting colormap on ColorBarItem propagates to all images
    cmap = pg.colormap.get(random.choice(colormaps))
    cbar.setColorMap(cmap)

timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(250)

pg.exec()