ENH: Add pinch-to-zoom

[larsoner]

Closes #19

[akaszynski]

Looks good to me! Let me know when we need to push a release.

[akaszynski]

@larsoner, once you've been approved as a developer, you should be able to merge the PR. Let me know if you have any issues.

[larsoner]

@hoechenberger can you test and verify that it works for you ?

[hoechenberger]

@larsoner

@hoechenberger can you test and verify that it works for you ?

Will give it a shot in a couple hours and report back

[hoechenberger]

It's working 😍🥳🥂 Could be a little bit smoother (smaller steps, perhaps?) but otherwise works as expected!!

I suppose continuous update like shown below (with reduced quality until the action is finished) wouldn't be possible..?

[larsoner]

I think that's just as fast as the events get processed by qt. I experience the same thing with the scroll wheel

[banesullivan]

Smooth scrolling is possible while holding the control key (mac) plus click and drag. You may be able to use those same events to control the smoothness?

[hoechenberger]

Smooth scrolling is possible while holding the control key (mac) plus click and drag. You may be able to use those same events to control the smoothness?

Indeed this does work! I keep pressing Ctrl and then use pinch-to-zoom, and it's smooth. I think this behavior should be the default for pinch zooming :)

[banesullivan]

I'm not sure if we can (or should) change that default zoom style. There may be performance concerns. The change would likely be upstream in PyVista though

[hoechenberger]

I'm not sure if we can (or should) change that default zoom style. There may be performance concerns. The change would likely be upstream in PyVista though

I'm just talking about the new pinch zooming :) All other existing zoom functionality can remain the same.

[hoechenberger]

Smooth scrolling is possible while holding the control key (mac) plus click and drag.

I can also get this behavior by pressing right mouse button and then scrolling.

[banesullivan]

You may be able to trigger the control key events with what was implemented here to do it