Vega spec from Mon Jan 20 2025

spec.json

{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "background": "white",
  "padding": 5,
  "width": 200,
  "height": 200,
  "style": "cell",
  "data": [
    {
      "name": "brush_store",
      "transform": [{"type": "collect", "sort": {"field": "_vgsid_"}}]
    },
    {
      "name": "source_0",
      "url": "data/cars.json",
      "format": {"type": "json"},
      "transform": [
        {"type": "identifier", "as": "_vgsid_"},
        {
          "type": "filter",
          "expr": "isValid(datum[\"Horsepower\"]) && isFinite(+datum[\"Horsepower\"]) && isValid(datum[\"Miles_per_Gallon\"]) && isFinite(+datum[\"Miles_per_Gallon\"])"
        }
      ]
    }
  ],
  "signals": [
    {
      "name": "unit",
      "value": {},
      "on": [
        {"events": "mousemove", "update": "isTuple(group()) ? group() : unit"}
      ]
    },
    {
      "name": "brush",
      "update": "vlSelectionResolve(\"brush_store\", \"union\")"
    },
    {
      "name": "brush_tuple",
      "on": [
        {
          "events": [{"signal": "brush_screen_path"}],
          "update": "vlSelectionTuples(intersectLasso(\"marks\", brush_screen_path, unit), {unit: \"\"})"
        },
        {"events": [{"source": "view", "type": "dblclick"}], "update": "null"}
      ]
    },
    {
      "name": "brush_screen_path",
      "init": "[]",
      "on": [
        {
          "events": {"source": "scope", "type": "mousedown"},
          "update": "[[x(unit), y(unit)]]"
        },
        {
          "events": {
            "source": "window",
            "type": "mousemove",
            "consume": true,
            "between": [
              {"source": "scope", "type": "mousedown"},
              {"source": "window", "type": "mouseup"}
            ]
          },
          "update": "lassoAppend(brush_screen_path, clamp(x(unit), 0, width), clamp(y(unit), 0, height))"
        }
      ]
    },
    {
      "name": "brush_modify",
      "on": [
        {
          "events": {"signal": "brush_tuple"},
          "update": "modify(\"brush_store\", brush_tuple, true)"
        }
      ]
    }
  ],
  "marks": [
    {
      "name": "brush_brush",
      "type": "path",
      "encode": {
        "enter": {
          "fill": {"value": "#333"},
          "fillOpacity": {"value": 0.125},
          "stroke": {"value": "gray"},
          "strokeWidth": {"value": 2},
          "strokeDash": {"value": [8, 5]}
        },
        "update": {
          "path": [
            {
              "test": "data(\"brush_store\").length && data(\"brush_store\")[0].unit === \"\"",
              "signal": "lassoPath(brush_screen_path)"
            },
            {"value": "[]"}
          ]
        }
      }
    },
    {
      "name": "marks",
      "type": "symbol",
      "style": ["point"],
      "interactive": true,
      "from": {"data": "source_0"},
      "encode": {
        "update": {
          "opacity": {"value": 0.7},
          "fill": {"value": "transparent"},
          "stroke": [
            {
              "test": "!length(data(\"brush_store\")) || vlSelectionIdTest(\"brush_store\", datum)",
              "scale": "color",
              "field": "Cylinders"
            },
            {"value": "grey"}
          ],
          "ariaRoleDescription": {"value": "point"},
          "description": {
            "signal": "\"Horsepower: \" + (format(datum[\"Horsepower\"], \"\")) + \"; Miles_per_Gallon: \" + (format(datum[\"Miles_per_Gallon\"], \"\")) + \"; Cylinders: \" + (isValid(datum[\"Cylinders\"]) ? datum[\"Cylinders\"] : \"\"+datum[\"Cylinders\"])"
          },
          "x": {"scale": "x", "field": "Horsepower"},
          "y": {"scale": "y", "field": "Miles_per_Gallon"}
        }
      }
    }
  ],
  "scales": [
    {
      "name": "x",
      "type": "linear",
      "domain": {"data": "source_0", "field": "Horsepower"},
      "range": [0, {"signal": "width"}],
      "nice": true,
      "zero": true
    },
    {
      "name": "y",
      "type": "linear",
      "domain": {"data": "source_0", "field": "Miles_per_Gallon"},
      "range": [{"signal": "height"}, 0],
      "nice": true,
      "zero": true
    },
    {
      "name": "color",
      "type": "ordinal",
      "domain": {"data": "source_0", "field": "Cylinders", "sort": true},
      "range": "ordinal",
      "interpolate": "hcl"
    }
  ],
  "axes": [
    {
      "scale": "x",
      "orient": "bottom",
      "gridScale": "y",
      "grid": true,
      "tickCount": {"signal": "ceil(width/40)"},
      "domain": false,
      "labels": false,
      "aria": false,
      "maxExtent": 0,
      "minExtent": 0,
      "ticks": false,
      "zindex": 0
    },
    {
      "scale": "y",
      "orient": "left",
      "gridScale": "x",
      "grid": true,
      "tickCount": {"signal": "ceil(height/40)"},
      "domain": false,
      "labels": false,
      "aria": false,
      "maxExtent": 0,
      "minExtent": 0,
      "ticks": false,
      "zindex": 0
    },
    {
      "scale": "x",
      "orient": "bottom",
      "grid": false,
      "title": "Horsepower",
      "labelFlush": true,
      "labelOverlap": true,
      "tickCount": {"signal": "ceil(width/40)"},
      "zindex": 0
    },
    {
      "scale": "y",
      "orient": "left",
      "grid": false,
      "title": "Miles_per_Gallon",
      "labelOverlap": true,
      "tickCount": {"signal": "ceil(height/40)"},
      "zindex": 0
    }
  ],
  "legends": [
    {
      "stroke": "color",
      "symbolType": "circle",
      "title": "Cylinders",
      "encode": {
        "symbols": {
          "update": {
            "fill": {"value": "transparent"},
            "opacity": {"value": 0.7}
          }
        }
      }
    }
  ]
}