How to remove labels from a renderer

Web vtk.js
1

So, I have been generating multiple labels by using vtkLabelWidget in my vtk js project after a button is clicked. Now, I want to remove those labels from the view, so far I have tried creating the following events:

  • Cleaning the SVG Helpers after a button is clicked.
  • Removing the widgets from the widgetManager.
  • Setting the renderer from widget manager to null.

Any clue on how to implement this? Is there a general method I can use to delete all of the labels from my renderer?

2

Did you check the example ?

Note that for performance reasons, you might want to consider the PolyLineWidget without showing lines.

3

Didn’t check it before, seems to work at first, thank you so much.

Nevertheless, now I am getting a warning message and after two or three seconds an error triggers after calling the method multiple times (let’s say, removing labels in order to add new ones):

RenderWindow.js:231 WARNING: Too many active WebGL contexts. Oldest context will be lost.
TypeError: Cannot set properties of null (setting ‘width’).

Any idea of what this is or could be related to?

4

Seems to be related to be related to Chromium’s WebGL context limits, just tried setting –max-active-webgl-contexts= to a higher value and seems to crash no so early. But it looks like if I generate new labels, the contexts are accumulated somehow. Do labels count as WebGL context?

5

That error is related to creating lots of vtkRenderWindows. I’d suggest using techniques to reduce the number of active WebGL contexts in your app, e.g. ManyRenderWindows.

6

Not sure if it’s due to creating lots of renderWindows since I am using a single fullScreenRenderWindow, and the error only occurs after calling the method which deletes my vtkLabelWidget’s for a third time. Still have not found the issue…

          document.getElementById('btnDel').addEventListener('click', () => {
            widgetManager.addWidget(labelWidget).reset()
            widgetManager.removeWidget(handle);
            svgCleanupCallbacks.get(handle);
            svgCleanupCallbacks.delete(handle);
            handleTextProps.delete(handle);
            handle = null;
})

Am I properly deleting the labels from the renderer? Or could it be related to something else?