Line Chart with Scroll and Zoom

Five and a half years of daily values. The scrollbar on top holds a small copy of the whole line, so you can see where you are while you zoom into a few weeks.

  • Try it:
  • Drag the scrollbar handles to zoom
  • Then drag the chart to pan
Get the code JavaScript JSON
About this chart

When a scrollbar preview helps

Zoom into years of daily data and the big picture is gone. A preview in the scrollbar keeps it on screen, with the zoomed part highlighted, and moving to another stretch takes one drag.

Good for

  • Long daily or hourly series: prices, traffic, sensors
  • Finding one event and zooming into it
  • Dashboards where people explore on their own

Think twice when

  • Short series that fit the width: skip the scrollbar
  • Small screens: the preview takes height from the chart
  • Printed charts, where nobody can drag
For developers

Get the code.

Built with amCharts 5, a JavaScript library. The JavaScript includes your theme and renderer (canvas or SVG); the JSON also follows the changes you make with the controls.

Docs:Scrollbar with chart previewLine seriesXY chart
// Create root element
// https://www.amcharts.com/docs/v5/getting-started/#Root_element
var root = am5.Root.new("chartdiv");

// Set themes
// https://www.amcharts.com/docs/v5/concepts/themes/
root.setThemes([
  am5themes_Animated.new(root),
  am5themes_Responsive.new(root)
]);

// Create chart
// https://www.amcharts.com/docs/v5/charts/xy-chart/
var chart = root.container.children.push(am5xy.XYChart.new(root, {
  panX: true,       // drag the plot to pan...
  panY: true,       // ...in any direction
  wheelX: "panX",   // a horizontal wheel or trackpad swipe pans...
  wheelY: "zoomX",  // ...and the vertical wheel zooms in on the dates
  pinchZoomX: true, // pinch with two fingers to zoom on touch screens
  paddingLeft: 0    // the value labels sit at the chart's left edge
}));

// Add cursor
// https://www.amcharts.com/docs/v5/charts/xy-chart/cursor/
var cursor = chart.set("cursor", am5xy.XYCursor.new(root, {
  behavior: "none" // a drag over the plot pans the chart instead of zooming
}));
cursor.lineY.set("visible", false); // no horizontal cursor line

// Generate random data
var date = new Date();
date.setHours(0, 0, 0, 0);
var value = 100;

// the next day's data point, a few points up or down from the last
function generateData() {
  value = Math.round(Math.random() * 10 - 5 + value);

  am5.time.add(date, "day", 1);
  return { date: date.getTime(), value: value };
}

// count days of data in a row
function generateDatas(count) {
  var data = [];
  for (var i = 0; i < count; ++i) {
    data.push(generateData());
  }
  return data;
}

// Create axes
// https://www.amcharts.com/docs/v5/charts/xy-chart/axes/
var xAxis = chart.xAxes.push(am5xy.DateAxis.new(root, {
  baseInterval: { timeUnit: "day", count: 1 }, // one data point per day
  renderer: am5xy.AxisRendererX.new(root, {
    minorGridEnabled: true // faint grid lines between the main ones
  }),
  tooltip: am5.Tooltip.new(root, {}) // shows the hovered date on the axis
}));

var yAxis = chart.yAxes.push(am5xy.ValueAxis.new(root, {
  renderer: am5xy.AxisRendererY.new(root, {})
}));

// Add series
// https://www.amcharts.com/docs/v5/charts/xy-chart/series/
var series = chart.series.push(am5xy.LineSeries.new(root, {
  name: "Series",
  xAxis: xAxis,
  yAxis: yAxis,
  valueYField: "value",
  valueXField: "date",
  tooltip: am5.Tooltip.new(root, {
    labelText: "{valueY}" // the hovered value
  })
}));

// Add scrollbar
// https://www.amcharts.com/docs/v5/charts/xy-chart/scrollbars/
var scrollbar = chart.set("scrollbarX", am5xy.XYChartScrollbar.new(root, {
  orientation: "horizontal", // a scrollbar above the plot, with a preview of the data...
  height: 60                 // ...60px tall
}));

// the scrollbar holds a small chart of its own: these axes and series draw its preview of the data
var sbDateAxis = scrollbar.chart.xAxes.push(am5xy.DateAxis.new(root, {
  baseInterval: { // one point per day
    timeUnit: "day",
    count: 1
  },
  renderer: am5xy.AxisRendererX.new(root, {
    minorGridEnabled: true, // faint grid lines between the main ones
    minGridDistance: 70     // at least 70px between date labels
  })
}));

var sbValueAxis = scrollbar.chart.yAxes.push(
  am5xy.ValueAxis.new(root, {
    renderer: am5xy.AxisRendererY.new(root, {})
  })
);

var sbSeries = scrollbar.chart.series.push(am5xy.LineSeries.new(root, {
  valueYField: "value",
  valueXField: "date",
  xAxis: sbDateAxis,
  yAxis: sbValueAxis
}));

var data = generateDatas(2000);
series.data.setAll(data);
sbSeries.data.setAll(data); // the preview gets the same data

// Make stuff animate on load
// https://www.amcharts.com/docs/v5/concepts/animations/
series.appear(1000);
chart.appear(1000, 100);

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