Improve PySide6 Support: swapBehavior for DoubleBuffer, BUTTONMAP as pyqt6, xfail test_context

[psobolewskiPhD]

Fixes #2407 by using SwapBehavior to set DoubleBuffer
PYSIDE6_API is included in the existing PYQT6_API logic:

vispy/vispy/app/backends/_qt.py

Lines 281 to 287 in 8bf4f9e

	if QT5_NEW_API or PYSIDE6_API:
	# Qt5 >= 5.4.0 - below options automatically enabled if nonzero.
	glformat.setSwapBehavior(glformat.DoubleBuffer if c['double_buffer']
	else glformat.SingleBuffer)
	elif PYQT6_API:
	glformat.setSwapBehavior(glformat.SwapBehavior.DoubleBuffer if c['double_buffer']
	else glformat.SwapBehavior.SingleBuffer)

This should work for PySide6 going back to at least 6.2 (LTS)
I found the Qt 6.2 (LTS) docs. The swap behavior was already present.
https://doc.qt.io/qt-6.2/qsurfaceformat.html#SwapBehavior-enum
https://doc.qt.io/qtforpython-6.2/PySide6/QtGui/QSurfaceFormat.html#PySide6.QtGui.PySide6.QtGui.QSurfaceFormat.SwapBehavior

Edit: Also uses the same BUTTONMAP as PyQT6
Plus, xfails the shared context tests: test_context.py
Fixes #2410

[djhoese]

So this drops support for older PySide versions (6.1 and 6.2 most likely), this is OK with me. With this single change to the if statement, do your tests from the related issue work now @psobolewskiPhD?

[psobolewskiPhD]

So this drops support for older PySide versions (6.1 and 6.2 most likely), this is OK with me. With this single change to the if statement, do your tests from the related issue work now @psobolewskiPhD?

pyside6 6.2 is still fine. the only question is 6.0 and 6.1. I can't install those or find any docs on them.
Alas, it turns out this solves the DoubleBuffer issue, but unmasks a new issue. When running turntable example and trying to interact with the object:

Traceback (most recent call last):
  File "/Users/piotrsobolewski/Dev/vispy/vispy/app/backends/_qt.py", line 515, in mouseReleaseEvent
    button=BUTTONMAP[ev.button()],
KeyError: <MouseButton.LeftButton: 1>
Traceback (most recent call last):
  File "/Users/piotrsobolewski/Dev/vispy/vispy/app/backends/_qt.py", line 515, in mouseReleaseEvent
    button=BUTTONMAP[ev.button()],
KeyError: <MouseButton.LeftButton: 1>

[djhoese]

That's probably an update needed here:

vispy/vispy/app/backends/_qt.py

Line 194 in 8bf4f9e

if PYQT6_API:

[psobolewskiPhD]

That's probably an update needed here:

vispy/vispy/app/backends/_qt.py

Line 194 in 8bf4f9e

if PYQT6_API:

Thanks for the tip!
Fixed.

I went through everywhere there is PYQT6_API and checked the PySide6 docs. I think everything should be correct now. And I get no errors.

I also added pyside6 to the xfails for shared context, so now the app tests can run without set fault on pyside6 (note that run individually, test_context.py does pass on pyside6 if se_shared_contexts() is set to TRUE, but run as all app tests still segfaults.
This adresses #2410

[djhoese]

Thanks @psobolewskiPhD!