interaction3.vl

{
    "mark": "point",
    "data": {
        "url": "https://vega.github.io/vega-lite/data/cars.json"
    },
    "$schema": "https://vega.github.io/schema/vega-lite/v3.json",
    "selection": {
        "myBrush": {
            "type": "interval"
        }
    },
    "encoding": {
        "color": {
            "value": "grey",
            "condition": {
                "field": "Cylinders",
                "selection": "myBrush",
                "type": "ordinal"
            }
        },
        "x": {
            "field": "Horsepower",
            "type": "quantitative"
        },
        "y": {
            "field": "Miles_per_Gallon",
            "type": "quantitative"
        }
    },
    "description": "Drag out a rectangular brush to highlight points"
}