MNT: Add support for QtPy

[GuillaumeFavelier]

This PR adds support for qtpy.

• QDesktopWidget and QApplication.desktop() are deprecated in Qt 5 and removed in Qt 6 so I migrated to QScreen: https://doc.qt.io/qt-6/widgets-changes-qt6.html#qdesktopwidget-and-qapplication-desktop
• Similarly to vtk, pyqtgraph checks Qt APIs by trying to import the package directly instead of looking for actual features : https://github.com/pyqtgraph/pyqtgraph/blob/master/pyqtgraph/Qt/__init__.py#L31-L51
  To fix this locally, I use the PYQTGRAPH_QT_LIB variable.

TODO:

• Make everything (important) work on all Qt platforms
• Merge MRG: Updates for qtpy in mne-qt-browser mne-python#10509

Then this PR is ready to go

[larsoner]

We should also port over the Qt job from MNE-Python https://github.com/mne-tools/mne-python/blob/main/azure-pipelines.yml#L147

[larsoner]

Looks like a good start so far!

[larsoner]

... actually all the CI jobs here are GH actions, so I would just add a new entry in qt_viz_tests.yml

[larsoner]

• Also keep in mind you'll want to rebase or merge with main because another PyQt5 import was added in the now merged https://github.com/mne-tools/mne-qt-browser/pull/85/files#diff-835cae3833968c10d566cdfb4f83de733e1a89736033836229493057266e1c2fR7

[larsoner]

I pushed a commit that at least made things work for me on PyQt5 again -- widget.screen() is only available on 5.14+.

On PySide6 I get this ugly error:

(qt6) $ mne browse_raw ~/mne_data/MNE-sample-data/MEG/sample/sample_audvis_raw.fif 
Traceback (most recent call last):
...
File "/Users/larsoner/python/mne-python/mne/viz/_figure.py", line 613, in _load_backend
    from mne_qt_browser import _pg_figure as backend
  File "/Users/larsoner/python/mne-qt-browser/mne_qt_browser/_pg_figure.py", line 2620, in <module>
    class MNEQtBrowser(BrowserBase, QMainWindow, metaclass=_PGMetaClass):
  File "/Users/larsoner/mambaforge/envs/qt6/lib/python3.9/abc.py", line 106, in __new__
    cls = super().__new__(mcls, name, bases, namespace, **kwargs)
TypeError: Shiboken.ObjectType.__new__(_PGMetaClass) is not safe, use type.__new__()

It has something to do with the _PGMetaClass stuff, not sure how to fix it :(

[larsoner]

Wow, green! Locally when trying any keyboard shortcut, though, I get things like:

Traceback (most recent call last):
  File "/Users/larsoner/python/mne-qt-browser/mne_qt_browser/_pg_figure.py", line 4331, in keyPressEvent
    'Ctrl': '4' in hex(int(event.modifiers())),
TypeError: int() argument must be a string, a bytes-like object or a number, not 'KeyboardModifier'
Traceback (most recent call last):
  File "/Users/larsoner/python/mne-qt-browser/mne_qt_browser/_pg_figure.py", line 4331, in keyPressEvent
    'Ctrl': '4' in hex(int(event.modifiers())),
TypeError: int() argument must be a string, a bytes-like object or a number, not 'KeyboardModifier'

@GuillaumeFavelier I'll stop here for now, feel free to continue when you want :)

[larsoner]

Modifier bugs were present in main actually, so I fixed them in #109

[larsoner]

Pushed another little commit to take care of the warnings due to using 'AnyStyle':

qt.qpa.fonts: Populating font family aliases took 198 ms. Replace uses of missing font family "AnyStyle" with one that exists to avoid this cost. 

[larsoner]

FYI I need mne-tools/mne-python#10508 for macOS + Python3.10. I'll see if I can replicate on CIs...

[larsoner]

Okay, PySide6, PyQt6, and PyQt5 all work on my macOS system!

[larsoner]

Setting back to WIP because, even though it's getting close, mne-tools/mne-python#10509 should go in first (which should also go in after mne-tools/mne-python#10500)

[larsoner]

This "caching" of the decimated times was causing problems with tests locally. Creating views (which slicing does) is a 100 ns-order operation:

In [1]: import numpy as np
In [2]: x = np.random.RandomState(0).randn(10000)
In [3]: %timeit x[100:1111]
136 ns ± 3.88 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)

So let's not bother, and instead just slice times at the same time / way as the data

[larsoner]

Okay @GuillaumeFavelier I think I'm actually done now :)

Feel free to review sometime next week and we can get this in once mne-tools/mne-python#10509 is merged

[larsoner]

@agramfort or @hoechenberger feel free to review and merge if it works for you on PyQt6 and/or PySide6

[agramfort]

thx @GuillaumeFavelier @larsoner it works like a charm !