CODEWITHSUNDEEP
pythonnumpymatplotlib
hdtx
hdtx

Reputation: 43

Can't save a figure of 920px width in matplotlib

I ran into a problem whilst trying to save a 920px width png from numpy data. One column is missing. It seems only this width causes the problem (I tried some others and the problem did not happen). MWE:

import matplotlib.pyplot as plt
import numpy as np
a1 = np.zeros((919, 100))
a2 = np.zeros((920, 100))
a3 = np.zeros((921, 100))
plt.imsave('test1.png', a1)
plt.imsave('test2.png', a2)
plt.imsave('test3.png', a3)

The resulting images all have a height of 100, but the widths are:

What is happening here?

Versions:

Upvotes: 4

Views: 75

Answers (1)

Warren Weckesser
Warren Weckesser

Reputation: 114946

It is a matplotlib bug: https://github.com/matplotlib/matplotlib/issues/4280. Apparently it was fixed in February 2016 (maybe in https://github.com/matplotlib/matplotlib/pull/5718), but I don't think there has been a release since the bug was fixed in the master branch.

A work-around is to use the argument dpi=1 in the imsave function, e.g.:

plt.imsave("foo.png", a, dpi=1)

but a DPI of 1 might confuse some software that reads the PNG file.

Upvotes: 2

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