Bug summary

The ScalarFormatter class takes an argument useOffset, either True, which will determine an automatic offset, False, which disables an offset or an numeric value, which is the used as an offset.
Since in python 1 == True --> True, trying to pass a numeric offset value of 1 just enables the automatic offset.

https://matplotlib.org/stable/api/ticker_api.html#matplotlib.ticker.ScalarFormatter

Code for reproduction

import matplotlib.pyplot as plt
import numpy as np
from matplotlib.ticker import ScalarFormatter

# Sample data
x = np.linspace(0, 10, 100)
y = np.linspace(0.999, 1.001, 100)

# Create the plot
fig, ax = plt.subplots()
ax.plot(x, y)

formatter = ScalarFormatter()
formatter.set_useOffset(1)
# identical to formatter = ScalarFormatter(useOffset=1)
ax.yaxis.set_major_formatter(formatter)

plt.show()

Actual outcome

Expected outcome

The y-Axis should be centered around zero, the expected offset of 1 is not used

Additional information

Happens only for useOffset = 1.
If the y values are changed (i.e. y = np.linspace(0.99999, 1.00001, 100)), the automatic offset actually uses an offset of 1, so the bug is not obvious then.

Operating system

Win 11

Matplotlib Version

3.7.2

Matplotlib Backend

module://matplotlib_inline.backend_inline

Python version

No response

Jupyter version

6.5.4

Installation

conda