Dragging and dropping images can make the editor freeze about anki HOT 5 CLOSED

After some experimentation, I've found that the freeze can be eliminated by explicitly handling dragEnterEvent in EditorWebView, like this:

def dragEnterEvent(self, evt):
  evt.accept()

But this prevents the fields from receiving the dragover event, as a result, the onDragOver function in editor.ts is never called.
The issue does not seem to be caused by anything in editor.ts. merely handling dragEnterEvent fixes it, but introduces another problem.

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Thanks for digging into it, I'll have another play with it when I have a chance

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It seems that the dragover JavaScript event is triggered in the default dragEnterEvent handler of QWebEngineView.
The following causes the dragover event to be fired as usual but reintroduces the freeze:

def dragEnterEvent(self, evt):
    super().dragEnterEvent(evt)

Doing something similar in dropEvent eliminates the freeze:

def dropEvent(self, evt):
    super().dropEvent(evt)

But this brings with it the default handling of drop events in addtion to Anki's handling (e.g. dropped images will be opened and copied to fields). Also, calling evt.setDropAction(Qt.IgnoreAction) doesn't seem to help.

The whole thing can be reproduced outside Anki (as in this example).
I think this is ultimately a QT bug. I guess it would be more reasonable that JavaScript events fire regardless of custom QT event handlers.

from anki.

I've found a workaround:
abdnh@c46aaa0

Please let me know if it's any good.

from anki.

Thanks ANH - I didn't notice any problems, and it seems to work well here. I'm sure this will make a bunch of users happy!

Merged in #738

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