{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "description": "Stock prices of four large companies as a small multiples of area charts.",
  "background": "white",
  "padding": 5,
  "data": [
    {
      "name": "source_0",
      "url": "data/stocks.csv",
      "format": {"type": "csv", "parse": {"date": "date"}},
      "transform": [
        {"type": "filter", "expr": "datum.symbol !== 'GOOG'"},
        {
          "type": "formula",
          "expr": "datum[\"symbol\"]===\"MSFT\" ? 0 : datum[\"symbol\"]===\"AAPL\" ? 1 : datum[\"symbol\"]===\"IBM\" ? 2 : datum[\"symbol\"]===\"AMZN\" ? 3 : 4",
          "as": "row_symbol_sort_index"
        },
        {
          "type": "impute",
          "field": "price",
          "groupby": ["symbol", "symbol"],
          "key": "date",
          "method": "value",
          "value": 0
        },
        {
          "type": "stack",
          "groupby": ["date", "symbol"],
          "field": "price",
          "sort": {"field": ["symbol"], "order": ["descending"]},
          "as": ["price_start", "price_end"],
          "offset": "zero"
        }
      ]
    },
    {
      "name": "row_domain",
      "source": "source_0",
      "transform": [
        {
          "type": "aggregate",
          "groupby": ["symbol"],
          "fields": ["row_symbol_sort_index"],
          "ops": ["max"],
          "as": ["row_symbol_sort_index"]
        }
      ]
    }
  ],
  "signals": [
    {"name": "child_width", "value": 300},
    {"name": "child_height", "value": 40}
  ],
  "layout": {
    "padding": 20,
    "offset": {"rowTitle": 10},
    "columns": 1,
    "bounds": "full",
    "align": "all"
  },
  "marks": [
    {
      "name": "row-title",
      "type": "group",
      "role": "row-title",
      "title": {
        "text": "Symbol",
        "orient": "left",
        "style": "guide-title",
        "offset": 10
      }
    },
    {
      "name": "row_header",
      "type": "group",
      "role": "row-header",
      "from": {"data": "row_domain"},
      "sort": {
        "field": "datum[\"row_symbol_sort_index\"]",
        "order": "ascending"
      },
      "title": {
        "text": {
          "signal": "isValid(parent[\"symbol\"]) ? parent[\"symbol\"] : \"\"+parent[\"symbol\"]"
        },
        "orient": "left",
        "style": "guide-label",
        "frame": "group",
        "offset": 10
      },
      "encode": {"update": {"height": {"signal": "child_height"}}},
      "axes": [
        {
          "scale": "y",
          "orient": "left",
          "grid": false,
          "title": "Price",
          "labelOverlap": true,
          "tickCount": {"signal": "ceil(child_height/40)"},
          "zindex": 0
        }
      ]
    },
    {
      "name": "column_footer",
      "type": "group",
      "role": "column-footer",
      "encode": {"update": {"width": {"signal": "child_width"}}},
      "axes": [
        {
          "scale": "x",
          "orient": "bottom",
          "grid": false,
          "title": "Time",
          "format": "%Y",
          "labelFlush": true,
          "labelOverlap": true,
          "tickCount": {"signal": "ceil(child_width/40)"},
          "zindex": 0
        }
      ]
    },
    {
      "name": "cell",
      "type": "group",
      "style": "cell",
      "from": {
        "facet": {
          "name": "facet",
          "data": "source_0",
          "groupby": ["symbol"],
          "aggregate": {
            "fields": ["row_symbol_sort_index"],
            "ops": ["max"],
            "as": ["row_symbol_sort_index"]
          }
        }
      },
      "sort": {
        "field": ["datum[\"row_symbol_sort_index\"]"],
        "order": ["ascending"]
      },
      "encode": {
        "update": {
          "width": {"signal": "child_width"},
          "height": {"signal": "child_height"}
        }
      },
      "marks": [
        {
          "name": "child_pathgroup",
          "type": "group",
          "from": {
            "facet": {
              "name": "faceted_path_child_main",
              "data": "facet",
              "groupby": ["symbol"]
            }
          },
          "encode": {
            "update": {
              "width": {"field": {"group": "width"}},
              "height": {"field": {"group": "height"}}
            }
          },
          "marks": [
            {
              "name": "child_marks",
              "type": "area",
              "style": ["area"],
              "sort": {"field": "datum[\"date\"]"},
              "from": {"data": "faceted_path_child_main"},
              "encode": {
                "update": {
                  "orient": {"value": "vertical"},
                  "fill": {"scale": "color", "field": "symbol"},
                  "description": {
                    "signal": "\"Time: \" + (timeFormat(datum[\"date\"], '%Y')) + \"; Price: \" + (format(datum[\"price\"], \"\")) + \"; symbol: \" + (isValid(datum[\"symbol\"]) ? datum[\"symbol\"] : \"\"+datum[\"symbol\"])"
                  },
                  "x": {"scale": "x", "field": "date"},
                  "y": {"scale": "y", "field": "price_end"},
                  "y2": {"scale": "y", "field": "price_start"},
                  "defined": {
                    "signal": "isValid(datum[\"date\"]) && isFinite(+datum[\"date\"]) && isValid(datum[\"price\"]) && isFinite(+datum[\"price\"])"
                  }
                }
              }
            }
          ]
        }
      ]
    }
  ],
  "scales": [
    {
      "name": "x",
      "type": "time",
      "domain": {"data": "source_0", "field": "date"},
      "range": [0, {"signal": "child_width"}]
    },
    {
      "name": "y",
      "type": "linear",
      "domain": {"data": "source_0", "fields": ["price_start", "price_end"]},
      "range": [{"signal": "child_height"}, 0],
      "nice": true,
      "zero": true
    },
    {
      "name": "color",
      "type": "ordinal",
      "domain": {"data": "source_0", "field": "symbol", "sort": true},
      "range": "category"
    }
  ],
  "legends": [{"fill": "color", "symbolType": "circle", "title": "symbol"}]
}