How to dynamically adjust text label radius in a Vega-Lite pie chart when chart size changes?

[VikrantRamesh]

I am creating a pie chart in Vega-Lite and adding text labels on top of it. The chart’s size can vary dynamically (for example, when the window or container is resized), and I want the radius of the text labels to adjust automatically to match the chart’s new size.

What I tried: Right now, I can set a fixed radius value for the text marks, but that doesn’t scale correctly when the chart size changes.

I tried using radiusOffset for the text marks, hoping it would adjust relative to the pie radius, but it seems that radiusOffset only works when the radius channel is defined in the theta encoding. Unfortunately, setting radius in theta removes the dynamic resizing behavior of the pie chart, which I want to preserve.

Example (Vegalite Editor):

{
  "$schema": "https://vega.github.io/schema/vega-lite/v6.json",
  "description": "A simple radial chart with embedded data.",
  "data": {"values": [12, 23, 47, 6, 52, 19]},
  "encoding": {
    "theta": {"field": "data", "type": "quantitative", "stack": true},
    "color": {"field": "data", "type": "nominal", "legend": null}
  },
  "layer": [
    {"mark": {"type": "arc", "innerRadius": 20, "stroke": "#fff"}},
    {
      "mark": {"type": "text", "radiusOffset": 20},
      "encoding": {"text": {"field": "data", "type": "quantitative"}, "color": "black"}
      
    }
  ]
}

In this setup, the radiusOffset doesn’t take effect unless I explicitly define a radius encoding — but doing so fixes the pie radius, breaking the responsive scaling.

Question: Is there a way in Vega-Lite to make the text label radius (or offset) dynamic so it scales automatically with the chart size, without having to define a fixed radius in the theta encoding?