fix: Use an event filter to avoid scrolling

[gselzer]

Following up on #432, @tlambert03 mentioned that what would be better than just ignoring scroll events would be to redirect them to the parent, since usually users want to scroll the table and not the contents. This PR uses an event filter to do just that.

Unfortunately, the sliders are still tricky, and I had to access the private _slider attribute of the SliderProxy to get it to work (as @tlambert03 foreshadowed in #432). This PR could be easily cleaned up and merged as is, but I'd prefer to spur discussion on how we make those pesky sliders behave.

Oh, and I need to fix the test I wrote for #432.

closes #372

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.55%. Comparing base (967fa6a) to head (4bfd3e8).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #433      +/-   ##
==========================================
+ Coverage   90.54%   90.55%   +0.01%     
==========================================
  Files          90       90              
  Lines        9853     9870      +17     
==========================================
+ Hits         8921     8938      +17     
  Misses        932      932              

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[tlambert03]

we also really need this on the device property table (perhaps even more than the groups/presets editor). that's what #372 was about. Can you see if you can get this to apply when running python examples/property_browser.py and scrolling on a slider

[tlambert03]

here's a self-contained QTableWidget that seems to do a good job preventing stuff bubbling up, without making assumptions about private stuff:

class NoWheelTableWidget(QTableWidget):
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)
        self.viewport().installEventFilter(self)

    def setCellWidget(self, row: int, column: int, widget: QWidget) -> None:
        for child in widget.findChildren(
            (QAbstractSpinBox, QAbstractSlider, QComboBox)
        ):
            child.installEventFilter(self)
        widget.installEventFilter(self)
        super().setCellWidget(row, column, widget)

    def eventFilter(self, obj: QObject, event: QEvent) -> bool:
        if isinstance(event, QWheelEvent):
            # Scroll the vertical scrollbar manually, to avoid recursion error.
            if sb := self.verticalScrollBar():
                delta = event.angleDelta().y()
                sb.setValue(sb.value() - delta)
            # Consume the event so child widgets don't process it
            return True
        return super().eventFilter(obj, event)

it can be used as the base class for, e.g. DevicePropertyTable and anything else that needs it. might need some more child checks too

[gselzer]

here's a self-contained QTableWidget that seems to do a good job preventing stuff bubbling up, without making assumptions about private stuff:

Thanks for the starter code @tlambert03! Threw it in _util.py, and extended it with both device properties and group presets. Added a test too!

[tlambert03]

perfect! This definitely closes #372

is this read to go? (and if so, in the future, can you please unmark your PRs as draft when you are happy to have them merged? I read "draft" as "please do not merge this, I am still working on it and it's not yet ready for final review)

[gselzer]

Oops, yes, ready to go!