Image disappears when using the mouse wheel before any other interaction

[amarandon]

Hello, we have a Trame app in which whenever we try to zoom on a visualization using the mouse wheel before doing anything else, the image completely disappears from the screen. However, if we change the orientation of the image by dragging it with the mouse, then we can zoom using the mouse wheel as much as we want and it works fine. This visualization is created with VtkLocalView.

In the Chrome debugger, I noticed this warning:

[[Violation] Added non-passive event listener to a scroll-blocking 'wheel' event.
Consider marking event handler as 'passive' to make the pag](trame-vtk.js:3518)

And also this error:

trame-vtk.js:1 
          Can not forward events without a current renderer on the interactor

However, I checked the source code of our application and we do seem to assign a renderer to the interactor:

        self.renderer = vtkRenderingCore.vtkRenderer()
        self.window = vtkRenderingCore.vtkRenderWindow()
        self.window.AddRenderer(self.renderer)
        self.interactor = vtkRenderingCore.vtkRenderWindowInteractor()
        self.interactor.SetRenderWindow(self.window)

I'm new to Trame and VTK but I'm familiar with Python and web development so I thought I might be able to debug this issue myself. I found a handler for the wheel event was added in vtk.js, but I don't know what would be the workflow to modify vtk.js and see the result of my modifications in our Trame app. I would need some guidance regarding the JavaScript build pipeline used by Trame. I tried editing the minified JS code inside the install directory of the trame-vtk Python package, but obviously that didn't take me very far.

[jourdain]

Indeed that is an issue with vtk.js and the wheel handling. I think that is because the wheel has no coordinates, and we can't poke the proper renderer (just a guess).

The best approach will be to reproduce and fix it in vtk.js.
Then, once that's done, we can update vue-vtk-js and trame-vtk to use the new version.

HTH

[marospekarik]

I am on vtk.js v30.5 and still experiencing this issue.

[jourdain]

Indeed until it is tracked/tackled on the vtk.js side, it won't happen. ;-)

[marospekarik]

Can you help with any possible workaround until the fix @jourdain?
Thanks

[jourdain]

It needs investigation and without dedicated support, we can not make it a priority.

[marospekarik]

I found a workaround - adding a dummy actor and removing it immediately. This happened only when I loaded the OBJ file with the OBJ Loader. @amarandon , maybe it can serve as a workaround for now.

[marospekarik]

Oh, none of this is necessary, make sure you reset the camera of the renderer!