matplotlib/examples/api/image_zcoord.py at master · Nodd/matplotlib · GitHub

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"""

==================================

Modifying the coordinate formatter

==================================

Modify the coordinate formatter to report the image "z"

value of the nearest pixel given x and y

"""

import numpy as np

import matplotlib.pyplot as plt

# Fixing random state for reproducibility

np.random.seed(19680801)

X = 10*np.random.rand(5, 3)

fig, ax = plt.subplots()

ax.imshow(X, interpolation='nearest')

numrows, numcols = X.shape

def format_coord(x, y):

col = int(x + 0.5)

row = int(y + 0.5)

if col >= 0 and col < numcols and row >= 0 and row < numrows:

z = X[row, col]

return 'x=%1.4f, y=%1.4f, z=%1.4f' % (x, y, z)

else:

return 'x=%1.4f, y=%1.4f' % (x, y)

ax.format_coord = format_coord

plt.show()