Diverging stacked bar chart

[randyzwitch]

http://bl.ocks.org/wpoely86/e285b8e4c7b84710e463

[randyzwitch]

{
  "name": "Vega Visualization",
  "width": 450,
  "height": 450,
  "padding": "auto",
  "data": [
    {
      "name": "table_uquz4",
      "values": [
        {"x": 1,"group": 1,"y": 24},
        {"x": 1,"group": 2,"y": 294},
        {"x": 1,"group": 3,"y": 594},
        {"x": 1,"group": 4,"y": 1927},
        {"x": 1,"group": 5,"y": 376},
        {"x": 2,"group": 1,"y": 2},
        {"x": 2,"group": 2,"y": 2},
        {"x": 2,"group": 3,"y": 0},
        {"x": 2,"group": 4,"y": 7},
        {"x": 2,"group": 5,"y": 0},
        {"x": 3,"group": 1,"y": 2},
        {"x": 3,"group": 2,"y": 0},
        {"x": 3,"group": 3,"y": 2},
        {"x": 3,"group": 4,"y": 4},
        {"x": 3,"group": 5,"y": 2},
        {"x": 4,"group": 1,"y": 0},
        {"x": 4,"group": 2,"y": 2},
        {"x": 4,"group": 3,"y": 1},
        {"x": 4,"group": 4,"y": 7},
        {"x": 4,"group": 5,"y": 6},
        {"x": 5,"group": 1,"y": 0},
        {"x": 5,"group": 2,"y": 1},
        {"x": 5,"group": 3,"y": 3},
        {"x": 5,"group": 4,"y": 16},
        {"x": 5,"group": 5,"y": 4},
        {"x": 6,"group": 1,"y": 1},
        {"x": 6,"group": 2,"y": 1},
        {"x": 6,"group": 3,"y": 2},
        {"x": 6,"group": 4,"y": 9},
        {"x": 6,"group": 5,"y": 3},
        {"x": 7,"group": 1,"y": 0},
        {"x": 7,"group": 2,"y": 0},
        {"x": 7,"group": 3,"y": 1},
        {"x": 7,"group": 4,"y": 4},
        {"x": 7,"group": 5,"y": 0},
        {"x": 8,"group": 1,"y": 0},
        {"x": 8,"group": 2,"y": 0},
        {"x": 8,"group": 3,"y": 0},
        {"x": 8,"group": 4,"y": 0},
        {"x": 8,"group": 5,"y": 2}
      ]
    },
    {
      "name": "bars",
      "source": "table_uquz4",
      "transform": [
        {
          "sortby": ["group"],
          "offset": "normalize",
          "field": "y",
          "groupby": ["x"],
          "type": "stack"
        }
      ]
    },
    {
      "name": "bars_offset",
      "source": "bars",
      "transform": [{"type": "filter","test": "datum.group == 3"}]
    },
    {
      "name": "bars_adjusted",
      "source": "bars",
      "transform": [
        {
          "type": "lookup",
          "on": "bars_offset",
          "onKey": "x",
          "keys": ["x"],
          "as": ["obj"],
          "default": 0
        },
        {
          "type": "formula",
          "field": "bar_start",
          "expr": "datum.layout_start - datum.obj.layout_mid"
        },
        {
          "type": "formula",
          "field": "bar_end",
          "expr": "datum.layout_end - datum.obj.layout_mid"
        }
      ]
    }
  ],
  "scales": [
    {
      "name": "x",
      "range": "height",
      "domain": {"sort": true,"data": "table_uquz4","field": "x"},
      "type": "ordinal"
    },
    {
      "name": "y",
      "domain": {
        "data": "bars_adjusted",
        "field": ["bar_start","bar_end"]
      },
      "range": "width",
      "type": "linear",
      "nice": true
    },
    {
      "name": "group",
      "range": ["#c7001e","#f6a580","#cccccc","#92c6db","#086fad"],
      "domain": {"data": "table_uquz4","field": "group"},
      "type": "ordinal"
    }
  ],
  "axes": [
    {
      "layer": "front",
      "properties": {"title": {"fontSize": {"value": 14}}},
      "title": "y",
      "grid": false,
      "type": "x",
      "scale": "y"
    },
    {
      "layer": "front",
      "properties": {"title": {"fontSize": {"value": 14}}},
      "title": "x",
      "grid": false,
      "type": "y",
      "scale": "x"
    }
  ],
  "marks": [
    {
      "type": "rect",
      "from": {"data": "bars_adjusted"},
      "properties": {
        "enter": {
          "y": {"field": "x","scale": "x"},
          "height": {"offset": -1,"scale": "x","band": true},
          "x": {"field": "bar_start","scale": "y"},
          "x2": {"field": "bar_end","scale": "y"},
          "fill": {"field": "group","scale": "group"}
        }
      }
    },
    {
      "type": "rule",
      "properties": {
        "enter": {
          "x": {"scale": "y","value": 0},
          "y": {"value": 0},
          "y2": {"value": 450},
          "strokeWidth": {"value": 1},
          "stroke": {"value": "grey"},
          "strokeOpacity": {"value": 1}
        }
      }
    }
  ],
  "legends": [{"title": "Group","fill": "group"}]
}