Override escape key behavior

[lee-deraud]

I have a visualization.gui-base app with a keystroke callback on the SceneWidget. The callback sees both the UP and DOWN events for the escape key, reports both as CONSUMED, yet the window still closes. I've also tried attaching a key event handler to the top-level window (Application.instance) with more or less the same result.

I would like to handle the escape key myself, (1) to use it as a 'reset' key for an operation, and (2) because it's just too easy to hit accidently and lose work. This is on WIndows 11, open3d 0.19.0, Python 3.12.X. Any suggestions?

[joseph-sch]

In my experience, it is impossible to catch the Escape keypress and prevent it from closing the window. I've run into the same problem as you for the same reasons.

FWIW, I've personally come to the conclusion that Open3D's GUI capabilities are too limited and too idiosyncratic, without upsides, for my use case. Within a day, I had Codex implement an export of my scene to a JSON format, and a Three.js-based web viewer with all the features I previously had in the Open3D GUI visualizer. Admittedly, I don't have at this stage callbacks - nor have I tested it yet on very large scenes, for which I will probably have to switch to binary serialization.

[lee-deraud]

Thanks. I was starting to lean toward "can't br done in open3d" as the answer, but clearly "end program" is not a normal behavior for the escape key on most Windows apps. Not sure about Mac/Linux, but I doubt it would be acceptable there either.
If nothing better comes up, I'll probably submit it as a bug/enhancement-request...vaguely surprised it wasn't on the to-be-fixed list years ago.