I’m wondering if someone can guide to an idea, the algorithm, an example of how to create Power BI’s symmetry shading for scatter charts (https://learn.microsoft.com/en-us/power-bi/visuals/power-bi-visualization-scatter?tabs=powerbi-desktop#add-analytics-to-your-chart)

This

{
  "width": 600,
  "height": 600,
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "data": {
    "values": [
      {"ID": "I", "xVal": 3, "yVal": 2},
      {"ID": "I", "xVal": 4, "yVal": 6},
      {"ID": "II", "xVal": 3, "yVal": 3}
    ]
  },
  "mark": {
    "type": "circle"
  },
  "encoding": {
    "x": {
      "field": "xVal", "type":"quantitative",
      "scale": {"domain": [0, 7]}
    },
    "y": {
      "field": "yVal", "type":"quantitative",
      "scale": {"domain": [0, 7]}
    }
  }
}

can looks like this

in Power BI, with the feature symmetry shading enabled.

I’m interested in how to draw the “shapes”, being more precise, and getting/creating the coordinates of the shapes.

Any ideas?