selectandzoom.vl

{
    "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
    "data": {
        "sequence": {
            "as": "theta",
            "start": 0,
            "step": 0.1,
            "stop": 6.28
        }
    },
    "transform": [
        {
            "as": "y",
            "calculate": "cos(datum.theta)"
        }
    ],
    "vconcat": [
        {
            "encoding": {
                "x": {
                    "axis": null,
                    "field": "theta",
                    "type": "quantitative"
                },
                "y": {
                    "axis": null,
                    "field": "y",
                    "type": "quantitative"
                }
            },
            "mark": "line",
            "selection": {
                "brush": {
                    "encodings": [
                        "x",
                        "y"
                    ],
                    "init": {
                        "x": [
                            0.2,
                            6
                        ],
                        "y": [
                            -0.8,
                            0.8
                        ]
                    },
                    "type": "interval"
                }
            }
        },
        {
            "encoding": {
                "x": {
                    "field": "theta",
                    "scale": {
                        "domain": {
                            "field": "theta",
                            "selection": "brush"
                        }
                    },
                    "type": "quantitative"
                },
                "y": {
                    "field": "y",
                    "scale": {
                        "domain": {
                            "encoding": "y",
                            "selection": "brush"
                        }
                    },
                    "type": "quantitative"
                }
            },
            "mark": "circle"
        }
    ]
}