I am using Vega Lite in a Power BI custom visual called the Deneb Visual. I have created ovals in my visual. I can of course color these ovals with static HEX codes. But when I try to instead use a dynamic data label, no color appears (the oval is brown in the picture bc that is the background visual color). It should be green based on the data that I am passing in.

Here is my code for the mark:

"mark": {
              //at the rim area
              "type": "line",
              "opacity": 0.6,
              "point": false,
              "interpolate": "linear-closed",
              "stroke": null
            },
            "encoding": {
              "x": {
                "field": "x",
                "type": "quantitative",
                "scale": {"domain": [-250, 250]},
                "axis": null
              },
              "y": {
                "field": "y",
                "type": "quantitative",
                "scale": {"domain": [0, 470]},
                "axis": null
              },
              "fill": {
                "field": "At_the_rim_perc",
                "type": "quantitative",
                "scale": null
              },   
            "order": {"field": "path", "type": "ordinal"}
            },

At_the_rim_perc is a Power BI text measure that dynamically change. When I use the same measure to dynamically color the background in the Power BI report itself, it works fine. It just seems that the Vega Lite code/deneb custom visual aren’t interpretting it correctly. So it just shows no color.

Any thoughts?

enter image description here

I am simply looking for a way to dynamically change the colors of these ovals.