arc_pie_normalize_tooltip.vg.json

{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "description": "Pie Chart with percentage_tooltip",
  "background": "white",
  "padding": 5,
  "width": 200,
  "height": 200,
  "data": [
    {
      "name": "source_0",
      "values": [
        {"category": 1, "value": 4},
        {"category": 2, "value": 6},
        {"category": 3, "value": 10},
        {"category": 4, "value": 3},
        {"category": 5, "value": 7},
        {"category": 6, "value": 8}
      ]
    },
    {
      "name": "data_0",
      "source": "source_0",
      "transform": [
        {
          "type": "stack",
          "groupby": [],
          "field": "value",
          "sort": {"field": ["category"], "order": ["ascending"]},
          "as": ["value_start", "value_end"],
          "offset": "normalize"
        },
        {
          "type": "filter",
          "expr": "isValid(datum[\"value\"]) && isFinite(+datum[\"value\"])"
        }
      ]
    }
  ],
  "marks": [
    {
      "name": "marks",
      "type": "arc",
      "style": ["arc"],
      "from": {"data": "data_0"},
      "encode": {
        "update": {
          "tooltip": {
            "signal": "{\"value\": format(datum[\"value_end\"]-datum[\"value_start\"], \".0%\"), \"category\": isValid(datum[\"category\"]) ? datum[\"category\"] : \"\"+datum[\"category\"]}"
          },
          "fill": {"scale": "color", "field": "category"},
          "description": {
            "signal": "\"value: \" + (format(datum[\"value_end\"]-datum[\"value_start\"], \".0%\")) + \"; category: \" + (isValid(datum[\"category\"]) ? datum[\"category\"] : \"\"+datum[\"category\"])"
          },
          "x": {"signal": "width", "mult": 0.5},
          "y": {"signal": "height", "mult": 0.5},
          "outerRadius": {"signal": "min(width,height)/2"},
          "innerRadius": {"value": 0},
          "startAngle": {"scale": "theta", "field": "value_end"},
          "endAngle": {"scale": "theta", "field": "value_start"}
        }
      }
    }
  ],
  "scales": [
    {
      "name": "theta",
      "type": "linear",
      "domain": [0, 1],
      "range": [0, 6.283185307179586],
      "zero": true
    },
    {
      "name": "color",
      "type": "ordinal",
      "domain": {"data": "data_0", "field": "category", "sort": true},
      "range": "category"
    }
  ],
  "legends": [{"fill": "color", "symbolType": "circle", "title": "category"}]
}