{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "background": "white",
  "padding": 5,
  "style": "cell",
  "data": [
    {"name": "pts_store"},
    {
      "name": "source_0",
      "url": "data/cars.json",
      "format": {"type": "json"},
      "transform": [
        {"type": "identifier", "as": "_vgsid_"},
        {
          "type": "aggregate",
          "groupby": ["Cylinders", "Origin"],
          "ops": ["count"],
          "fields": [null],
          "as": ["__count"]
        },
        {"type": "identifier", "as": "_vgsid_"}
      ]
    }
  ],
  "signals": [
    {"name": "x_step", "value": 20},
    {"name": "width", "update": "bandspace(domain('x').length, 0, 0) * x_step"},
    {"name": "y_step", "value": 20},
    {
      "name": "height",
      "update": "bandspace(domain('y').length, 0, 0) * y_step"
    },
    {
      "name": "unit",
      "value": {},
      "on": [
        {"events": "mousemove", "update": "isTuple(group()) ? group() : unit"}
      ]
    },
    {
      "name": "pts",
      "update": "vlSelectionResolve(\"pts_store\", \"union\", true, true)"
    },
    {
      "name": "pts_tuple",
      "on": [
        {
          "events": [{"source": "scope", "type": "click"}],
          "update": "datum && item().mark.marktype !== 'group' ? {unit: \"\", fields: pts_tuple_fields, values: [(item().isVoronoi ? datum.datum : datum)[\"_vgsid_\"]]} : null",
          "force": true
        },
        {"events": [{"source": "view", "type": "dblclick"}], "update": "null"}
      ]
    },
    {"name": "pts_tuple_fields", "value": [{"type": "E", "field": "_vgsid_"}]},
    {
      "name": "pts_toggle",
      "value": false,
      "on": [
        {
          "events": [{"source": "scope", "type": "click"}],
          "update": "event.shiftKey"
        },
        {"events": [{"source": "view", "type": "dblclick"}], "update": "false"}
      ]
    },
    {
      "name": "pts_modify",
      "on": [
        {
          "events": {"signal": "pts_tuple"},
          "update": "modify(\"pts_store\", pts_toggle ? null : pts_tuple, pts_toggle ? null : true, pts_toggle ? pts_tuple : null)"
        }
      ]
    }
  ],
  "marks": [
    {
      "name": "marks",
      "type": "rect",
      "style": ["rect"],
      "interactive": true,
      "from": {"data": "source_0"},
      "encode": {
        "update": {
          "fill": [
            {
              "test": "!length(data(\"pts_store\")) || vlSelectionTest(\"pts_store\", datum)",
              "scale": "color",
              "field": "__count"
            },
            {"value": "grey"}
          ],
          "description": {
            "signal": "\"Cylinders: \" + (isValid(datum[\"Cylinders\"]) ? datum[\"Cylinders\"] : \"\"+datum[\"Cylinders\"]) + \"; Origin: \" + (isValid(datum[\"Origin\"]) ? datum[\"Origin\"] : \"\"+datum[\"Origin\"]) + \"; Count of Records: \" + (format(datum[\"__count\"], \"\"))"
          },
          "x": {"scale": "x", "field": "Cylinders"},
          "width": {"scale": "x", "band": 1},
          "y": {"scale": "y", "field": "Origin"},
          "height": {"scale": "y", "band": 1}
        }
      }
    }
  ],
  "scales": [
    {
      "name": "x",
      "type": "band",
      "domain": {"data": "source_0", "field": "Cylinders", "sort": true},
      "range": {"step": {"signal": "x_step"}},
      "paddingInner": 0,
      "paddingOuter": 0
    },
    {
      "name": "y",
      "type": "band",
      "domain": {"data": "source_0", "field": "Origin", "sort": true},
      "range": {"step": {"signal": "y_step"}},
      "paddingInner": 0,
      "paddingOuter": 0
    },
    {
      "name": "color",
      "type": "linear",
      "domain": {"data": "source_0", "field": "__count"},
      "range": "heatmap",
      "interpolate": "hcl",
      "zero": false
    }
  ],
  "axes": [
    {
      "scale": "x",
      "orient": "bottom",
      "grid": false,
      "title": "Cylinders",
      "labelAlign": "right",
      "labelAngle": 270,
      "labelBaseline": "middle",
      "zindex": 1
    },
    {
      "scale": "y",
      "orient": "left",
      "grid": false,
      "title": "Origin",
      "zindex": 1
    }
  ],
  "legends": [
    {
      "fill": "color",
      "gradientLength": {"signal": "clamp(height, 64, 200)"},
      "title": "Count of Records"
    }
  ]
}