JavaScript ChartsSeries Markers

Version 14.2.0

Data points can be represented by markers in many series types, including line, area, scatter, and bubble.

Marker attributes such as shape, size, fill and stroke are configurable within each series.

These options are identical across series types, but differ in their location. Series without lines, such as scatter and bubble have these options on the series level, otherwise they are contained within the marker property.

{
    series: [
        {
            // ...
            marker: {
                shape: 'square', // defaults to 'circle'
                size: 20,
                fill: 'red',
                stroke: 'maroon',
            },
        },
    ],
}

Please see the API reference for the list of all available options.

Marker Shape, Size and Colour Copy Link

main.ts

import {
  AgChartOptions,
  AgCharts,
  CategoryAxisModule,
  LegendModule,
  LineSeriesModule,
  ModuleRegistry,
  NumberAxisModule,
} from "ag-charts-community";
import { getData } from "./data";

ModuleRegistry.registerModules([
  CategoryAxisModule,
  LegendModule,
  LineSeriesModule,
  NumberAxisModule,
]);

const options: AgChartOptions = {
  title: {
    text: "Fuel Spending (2019)",
  },
  data: getData(),
  series: [
    {
      type: "line",
      xKey: "quarter",
      yKey: "petrol",
      title: "Petrol",
      marker: {
        shape: "square",
        size: 10,
      },
    },
    {
      type: "line",
      xKey: "quarter",
      yKey: "diesel",
      title: "Diesel",
      stroke: "black",
      marker: {
        size: 15,
        fill: "gray",
        stroke: "black",
      },
    },
    {
      type: "line",
      xKey: "quarter",
      yKey: "electric",
      title: "Electric",
      stroke: "#8bc24a",
      marker: {
        shape: "cross",
        size: 20,
        fill: "#8bc24a",
        stroke: "#658d36",
      },
    },
  ],
};

options.container = document.getElementById("myChart");

const chart = AgCharts.create(options);

data.ts

export function getData(): any[] {
  return [
    {
      quarter: "Q1",
      petrol: 200,
      diesel: 100,
      electric: 50,
    },
    {
      quarter: "Q2",
      petrol: 300,
      diesel: 130,
      electric: 60,
    },
    {
      quarter: "Q3",
      petrol: 350,
      diesel: 160,
      electric: 70,
    },
    {
      quarter: "Q4",
      petrol: 400,
      diesel: 200,
      electric: 50,
    },
  ];
}

Notice how the shape and colour of the legend markers automatically match the shape and colour of the markers used by the series, but the size of the markers in the legend remains the same.

The legend item marker can be modified within the Legend Options.

Custom Marker Shapes Copy Link

You can easily define custom marker shapes by providing a callback function to create the desired shape. This function takes x and y parameters, representing the marker's position on the canvas, the size of the marker and the path instance. The path includes various drawing methods that allow you to apply specific drawing commands to construct the marker. If you are familiar with the standard Canvas API, you'll feel right at home here. The path API is very similar to that of CanvasRenderingContext2D.

For example, to draw a heart:

const rad = (degree) => {
    return (degree / 180) * Math.PI;
};

const heart = ({ x, y, path, size }) => {
    const r = size / 4;
    const yCoord = y + r / 2;

    path.clear();
    path.arc(x - r, yCoord - r, r, rad(130), rad(330));
    path.arc(x + r, yCoord - r, r, rad(220), rad(50));
    path.lineTo(x, yCoord + r);
    path.closePath();
};

All we do is render two partial circles with the cubicArc command and then two straight lines using the lineTo and closePath commands to get the shape of a heart.

Inside the marker config of a series we then use this callback function rather than using one of the predefined shape names:

{
    marker: {
        shape: heart,
        size: 16,
    },
}

The final result is shown in the example below.

main.ts

import {
  AgChartOptions,
  AgCharts,
  AgMarkerShapeFnParams,
  CategoryAxisModule,
  LegendModule,
  LineSeriesModule,
  ModuleRegistry,
  NumberAxisModule,
} from "ag-charts-community";
import { getData } from "./data";

const rad = (degree: number) => {
  return (degree / 180) * Math.PI;
};
const heart = ({ x, y, path, size }: AgMarkerShapeFnParams) => {
  const r = size / 4;
  const yCoord = y + r / 2;
  path.clear();
  path.arc(x - r, yCoord - r, r, rad(130), rad(330));
  path.arc(x + r, yCoord - r, r, rad(220), rad(50));
  path.lineTo(x, yCoord + r);
  path.closePath();
};
ModuleRegistry.registerModules([
  CategoryAxisModule,
  LegendModule,
  LineSeriesModule,
  NumberAxisModule,
]);

const options: AgChartOptions = {
  title: {
    text: "Fuel Spending (2019)",
  },
  data: getData(),
  series: [
    {
      type: "line",
      xKey: "quarter",
      yKey: "electric",
      title: "Electric",
      marker: {
        shape: heart,
        size: 16,
      },
    },
  ],
};

options.container = document.getElementById("myChart");

const chart = AgCharts.create(options);

data.ts

export function getData(): any[] {
  return [
    {
      quarter: "Q1",
      electric: 50,
    },
    {
      quarter: "Q2",
      electric: 70,
    },
    {
      quarter: "Q3",
      electric: 60,
    },
    {
      quarter: "Q4",
      electric: 40,
    },
  ];
}

API Reference Copy Link

Properties available on the AgSeriesMarkerOptions interface.

enabled boolean: Whether to show markers.
itemStyler Styler: Function used to return formatting for individual markers, based on the supplied information.
size PixelSize: The size in pixels of the markers.
shape AgMarkerShape: The shape to use for the markers. You can also supply a custom marker by providing a `AgMarkerShapeFn` function.
fill AgColorType: The colour for filling shapes. A colour string, or an object for a gradient, pattern, or image fill.
fillOpacity Opacity: The opacity of the fill colour.
stroke AgCssColorOrRef: The colour for the stroke.
strokeWidth PixelSize: The width of the stroke in pixels.
strokeOpacity Opacity: The opacity of the stroke colour.
lineDash PixelSize[]: An array specifying the length in pixels of alternating dashes and gaps.
lineDashOffset PixelSize: The initial offset of the dashed line in pixels.

Getting started

AI Features

Core features

Specialised Charts

Series

Gauges

JavaScript ChartsSeries Markers

Marker Shape, Size and Colour Copy Link

Custom Marker Shapes Copy Link

API Reference Copy Link