Calling update() on QtInteractor

[adam-grant-hendry]

When update() is called on QtInteractor, which method gets called? BasePlotter has an update() method, but if QVTKRenderWindowInteractor inherits from QWidget, it does too.

[larsoner]

Based on the standard MRO and subclass order I think it would go to the VTKRenderWindowInteractor.update()

pyvistaqt/pyvistaqt/plotting.py

Line 146 in 1e7f5af

class QtInteractor(QVTKRenderWindowInteractor, BasePlotter):

[adam-grant-hendry]

Hmmm...I wonder if that is problematic? We can always call self.parent().update() to reach the QWidget.update() method. Might we want to wrap update() so we can call BasePlotter.update()?

The two are doing two different things.

[larsoner]

It might actually be intended behavior here, but I'm not sure. QWidget.update schedules a repaint, which might eventually cause a rerender like what BasePlotter.update() does. I think the fact that it waits for the event loop to pick up the update/redraw request rather than being immediate is to be expected because that's how QWidget.update behaves, and this is all Qt-based. I think people expecting/requiring an immediate rerender (e.g., for drawing and capturing multiple frames for an animation or something) might expect they need to call render directly.

[adam-grant-hendry]

When upgrading our system to use mypy, I get the error:

Definition of "update" in base class "QWidget" is incompatible with definition in base class "BasePlotter"

which is where this all started. We can ignore/bypass the error in several ways. I just want to be sure of which update() we want to call.