vtkimageSlice has a setOpacity value of 1

[ondaa]

Bug description

Hi, I'm using the 2D label map painting function.

I ran it by applying 1 to the setOpacity function of ImageSlice, and I tried to paint wideget, but I couldn't find any traces of painting. And when I applied 0.999 as the opacity value, I saw it.

Is this an issue? Example looked at the following.

https://kitware.github.io/vtk-js/examples/PaintWidget.html

Steps to reproduce

...
layerColorFun.addRGBPoint(1, 128 / 256, 174 / 256, 128 / 256);
layerPiecewiseFun.addPoint(0, 0);
layerPiecewiseFun.addPoint(1, 1.0);

layerActor.getProperty().setRGBTransferFunction(0, layerColorFun);  
layerActor.getProperty().setPiecewiseFunction(0, layerPiecewiseFun);
layerActor.getProperty().setOpacity(1); // <-- this setting

...

Detailed Behavior

No response

Expected Behavior

setOpacity(1.0) or setOpacity(1) show painting.

Environment

• vtk.js version: 32.7.0
• Browsers: Chrome
• OS: Windows

[finetjul]

I tried to modify the PaintWidget example from
labelMap.actor.getProperty().setOpacity(0.5);
to
labelMap.actor.getProperty().setOpacity(1);
and the labelmap still renders fine.

Can you please provide a non working example ?