Short description

Using ErrorBarItem with PlotWidget causes small and gradual memleaks that become noticable when app is running a longer time.

Code to reproduce

This code is extracted from ErrorBarItem.drawPath() -> arrayToQPath(..., connect="pairs") which builds QPainterPath using QByteArray and numpy buffer interface.

Note that the same behaviour can be easily reproduced by calling ErrorBarItem.drawPath() repeatedly. Only the run is slower.

import numpy as np
from pyqtgraph.Qt import QtCore

if __name__ == '__main__':
    n = 1024

    for i in range(100000):
        if i % 1000 == 0:
            print('step', i)

        backstore = QtCore.QByteArray()
        backstore.resize(n * 8)
        np.frombuffer(backstore, dtype=[('x', '>f8')], count=n)

    input('done')

Tested environment(s)

• PyQtGraph version: 0.13.7
• Qt Python binding: PySide6 6.8.2 Qt 6.8.2
• Python version: 3.12.9
• NumPy version: 2.1.3
• Operating system: Linux HOST 5.4.191-el7.lime.2.x86_64 # 1 SMP Thu Jul 14 19:09:52 EDT 2022 x86_64 x86_64 x86_64 GNU/Linux
• Installation method: conda

Additional context

I'm not sure if this bug is part of Qt or numpy, but it triggers inside pyqtgraph. As a workaround it would help to clear QByteArray before end of arrayToQPath(). In which case the memory footprint of the leak is very small.