Simple Mosaic chart

[apb-reports]

Just wanted to share a simple masaic chart. Thought it might be interesting for someone out there.
Height of bars reflects total percentage.

{
  "$schema": "https://vega.github.io/schema/vega-lite/v6.json",
  "data": {"url": "data/barley.json"},
  "description": "Mosaic Chart of Barley Yields (Variety vs Site)",
  "width": 400,
  "height": 400,
  "transform": [
    {
      "aggregate": [{"op": "sum", "field": "yield", "as": "sum_yield"}],
      "groupby": ["variety", "site"]
    },
    {
      "joinaggregate": [{"op": "sum", "field": "sum_yield", "as": "GrandTotal"}]
    },
    {
      "joinaggregate": [
        {"op": "sum", "field": "sum_yield", "as": "TotalVarietyYield"}
      ],
      "groupby": ["variety"]
    },
    {"window": [{"op": "row_number", "as": "rank"}], "groupby": ["variety"]},
    {
      "calculate": "datum.rank == 1 ? max(datum.TotalVarietyYield, datum.GrandTotal * 0.01) : 0",
      "as": "HeightValues"
    },
    {
      "stack": "HeightValues",
      "as": ["y1_step", "y2_step"],
      "groupby": [],
      "sort": [{"field": "TotalVarietyYield", "order": "ascending"}]
    },
    {
      "joinaggregate": [
        {"op": "min", "field": "y1_step", "as": "y1"},
        {"op": "max", "field": "y2_step", "as": "y2"}
      ],
      "groupby": ["variety"]
    },
    {"calculate": "(datum.y1 + datum.y2) / 2", "as": "yc"},
    {
      "stack": "sum_yield",
      "as": ["x1", "x2"],
      "groupby": ["variety"],
      "offset": "normalize",
      "sort": [{"field": "site", "order": "ascending"}]
    }
  ],
  "layer": [
    {
      "mark": {"type": "rect", "stroke": "white", "strokeWidth": 0.5},
      "encoding": {
        "y": {
          "field": "y1",
          "type": "quantitative",
          "axis": null,
          "scale": {"nice": false}
        },
        "y2": {"field": "y2"},
        "x": {
          "field": "x1",
          "type": "quantitative",
          "axis": {"format": ".0%", "title": null, "orient": "top"},
          "scale": {"domain": [0, 1]}
        },
        "x2": {"field": "x2"},
        "color": {"field": "site", "type": "nominal", "legend": null},
        "tooltip": [
          {"field": "variety", "title": "Variety"},
          {"field": "site", "title": "Site"},
          {"field": "sum_yield", "title": "Yield", "format": ".1f"},
          {
            "field": "TotalVarietyYield",
            "title": "Total Variety Yield",
            "format": ".1f"
          }
        ]
      }
    },
    {
      "mark": {"type": "text", "align": "right", "dx": -10, "fontSize": 11},
      "encoding": {
        "y": {"field": "yc", "type": "quantitative", "aggregate": "max"},
        "x": {"value": 0},
        "text": {"field": "variety"},
        "color": {"value": "black"}
      }
    }
  ],
  "config": {"view": {"stroke": null}}
}