How to disable sigma mouse wheel events in v3?

[HectorHS]

I want to disable the mouse wheel zoom effect on sigma, and keep the default mouse wheel to scroll functionality. I used to be able to do something like mouseWheelEnabled: false on sigma's settings but I cannot see any similar setting on V3. I can set minCameraRatio: 1 & maxCameraRatio: 1 to effectively disable zoom but the default mouse wheel to scroll functionality is still prevented. I can do something like:

const renderer = new Sigma(graph, container, { allowInvalidContainer: true });

renderer.on("wheelStage", (event) => {
            event.event.sigmaDefaultPrevented = true;
});

which prevents sigma's zoom in functionality, but again scrolling is disabled.

Is there a simple way to prevent the zooming functionality and reinstate scrolling on wheelStage events?

[jacomyal]

Hi @HectorHS,

Good catch, it was not possible to handle this properly with sigma.
I just released sigma v3.0.0, with a fix for this. Basically, sigma stops preventing default mouse-wheel behavior in two different cases:

• the new enableCameraZooming setting is true (showcased here)
• the settings minCameraRatio or maxCameraRatio are set, and the user hits the zoom boundaries (I added those settings to the nodes pan story, so that it is testable somewhere)

[HectorHS]

Hi @jacomyal,

Amazing, thank you for this!

enableCameraZooming works great for my use case! I got it working as expected on my project but I couldn't see it working on the showcase you linked, maybe it's missing the latest version?

I was not very much concerned about the minCameraRatio & maxCameraRatio personally, so I might not be the best one to comment on that but it seems to me these settings will now result in a different behaviour for everyone who is using them which 1) doesn't feel better than before from a UX perspective (by scrolling up and down a page you accidentally zoom in and out of the graph that often just disappears), and 2) there doesn't seem to be a way to return to the previous behaviour.

I'd recommend to either a) keep preventing default mouse-wheel behaviour irrespective of zoom boundaries if minCameraRatio and maxCameraRatio are set, or b) allow the previous functionality when a combination of settings is set, eg

enableCameraZooming: true,
minCameraRatio: 1,
maxCameraRatio: 2 

by allowing zooming boundaries and preventing normal wheel events at all times withing the graph boundaries.

Just to be clear: just the implementation of enableCameraZooming works great for me, I am just worried of other people's implementations.

Many thanks for your work!

[jacomyal]

OK, I get your point. I agree that it's some kind of breaking change (though, it's between the beta and the v3 release, so I can live with that ^^), but I actually think it is better, UX-wise:

It means that, from now on, sigma only blocks the natural scroll flow of a webpage when it actually has something to do with the wheel event. It looks more like what happens when a user scrolls in a block that is itself in another scrollable block.

I hope to have a better separation between how sigma handles events flow, what the camera is allowed to do, and what users are allowed to do (in terms of interactions) once I tackle issue #1475.

[HectorHS]

Sounds good to me - I just didn't want to be the cause of breaking changes to minCameraRatio & maxCameraRatio, settings I am not even using myself. It sounds like this is moving towards where you want to go and I am more than happy to trust you with that!

Once again, thanks!