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series-basics.md

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Series basics

Each series has a set of common properties and methods regardless of its type.

For example, to create any type of series you can pass the title parameter to set series title.

These "common" parameters and API are described here. If you want to see an API for a specific type of series - see relevant doc page.

Creating a series

To create any type of series you need to call the chart.add<type>Series method where <type> is a type of series you want to add to the chart.

For example:

  • to create line series:

    const lineSeries = chart.addLineSeries();

  • to create area series:

    const areaSeries = chart.addAreaSeries();

  • to create bar series:

    const barSeries = chart.addBarSeries();

Parameters

When you create the series you can specify parameters of series you want to change.

Here are common parameters for every series:

Name Type Default Description
priceScaleId string right if right scale is visible and left if not Target price scale to bind new series to
title string '' You can name series when adding it to a chart. This name will be displayed on the label next to the last value label
scaleMargins { top, bottom } undefined Margins of the price scale of series

Example:

const lineSeries = chart.addLineSeries({
    priceScaleId: 'left',
    title: 'Series title example',
    scaleMargins: {
        top: 0.1,
        bottom: 0.3,
    },
});

Binding to price scale

When adding any series to a chart, you can specify if you want target series to be attached to a certain price axis - left or right. By default, series are attached to the right price axis. This means one can scale the series with price axis. Note that price axis visible range depends on series values.

const lineSeries = chart.addLineSeries({
    priceScaleId: 'left',
});

In contrast, overlay series just draws itself on a chart independent from the visible price axis. To create overlay specify unique id as a priceScaleId or just keep is as empty string.

const lineSeries = chart.addLineSeries({
    priceScaleId: 'my-overlay-id',
});

At any moment you can get access to the price scale the series is bound to with priceScale method and change its options

const lineSeries = chart.addLineSeries({
    priceScaleId: 'my-overlay-id',
});
lineSeries.priceScale().applyOptions({
    scaleMargins: {
        top: 0.1,
        bottom: 0.3,
    },
});

Title

When adding any series to a chart, you can name it by adding a string to the title property. This name will be displayed on the label next to the last value label.

const lineSeries = chart.addLineSeries({
    title: 'Series title example',
});

Scale margins

Typically, we do not want series to be drawn too close to a chart border. It needs to have some margins on the top and bottom.

By default, the library keeps an empty space below the data (10%) and above the data (20%).

These values could be adjusted for visible axis using chart options. However, you can also define them for series.

The margins is an object with the following properties:

  • top
  • bottom

Each value of an object is a number between 0 (0%) and 1 (100%).

const lineSeries = chart.addLineSeries({
    priceScaleId: 'right,
    scaleMargins: {
        top: 0.6,
        bottom: 0.05,
    },
});

The code above places series at the bottom of a chart.

You can change margins using ChartApi.applyOptions for the certain axis:

chart.applyOptions({
    rightPriceScale: {
        scaleMargins: {
            top: 0.6,
            bottom: 0.05,
        },
    },
});

Overriding autoscale

By default, the chart scales data automatically based on visible data range. However, for some reasons one could need overriding this behavior. There is an option called autoscaleProvider that allows overriding visible price range for series

var firstSeries = chart.addLineSeries({
    autoscaleInfoProvider: () => {
        return {
            priceRange: {
                minValue: 0,
                maxValue: 100,
            },
        };
    },
});

So, you can just add a function that returns an object with priceRange field, if you want to override the original series' price range. For example, you can set the range from 0 to 100. These values are in prices.

You can also provide additional margins in pixels. Please be careful and never mix prices and pixels.

var firstSeries = chart.addLineSeries({
    autoscaleInfoProvider: () => {
        return {
            priceRange: {
                minValue: 0,
                maxValue: 100,
            },
            margins: {
                above: 10,
                below: 10,
            },
        };
    },
});

Actually, autoscaleInfoProvider function has an argument original which is the default implementation, so you can call it and adjust the result:

var firstSeries = chart.addLineSeries({
    autoscaleInfoProvider: (original) => {
        var res = original();
        if (res.priceRange !== null) {
            res.priceRange.minValue -= 10;
            res.priceRange.maxValue += 10;
        }
        return res;
    },
});

Note that both priceRange and margins could be null in the default result.

Removing series

Any series could be removed with

chart.removeSeries(series);

where series is an instance of any series type.

Data

Every series has its own data type. Please refer to series page to determine what type of data the series uses.

Methods

options

Returns the full set of currently applied options, including defaults.

applyOptions

This method is used to apply new options to series.

You can set options initially when you create series or use the applyOptions method of the series to change the existing options.

Note that you can only pass options you want to change.

Each series type has its own options. However, there are options that are common for all types of series.

Price line

The price line is a horizontal line drawn on the last price value level.

By default, its color is set by the last bar color (or by line color on Line and Area charts).

You can set the width, style and color of this line or disable it using the following options:

Name Type Default Description
priceLineVisible boolean true If true, a series' price line is displayed on a chart
priceLineSource PriceLineSource PriceLineSource.LastBar Source to be used for the horizontal price line
priceLineWidth number 1 Price line's width in pixels
priceLineColor string '' Price line's color
priceLineStyle LineStyle LineStyle.Dotted Price line's style

Example:

series.applyOptions({
    priceLineVisible: false,
    priceLineWidth: 2,
    priceLineColor: '#4682B4',
    priceLineStyle: 3,
});

Price labels

By default, the last visible data point price value is shown at relevant level of the price scale as a label. There is an option to hide it as well.

Name Type Default Description
lastValueVisible boolean true If true, the label with the current price is displayed on the price scale

Example:

series.applyOptions({
    lastValueVisible: false,
});

Base line

The base line is a horizontal line drawn at the zero-level in percentage and indexedTo100 modes. You can set the width, style and color of this line or disable it using the following options:

Name Type Default Description
baseLineVisible boolean true If true, a series' base line is displayed on a chart
baseLineWidth number 1 Base line's width in pixels
baseLineColor string '#B2B5BE' Base line's color
baseLineStyle LineStyle LineStyle.Solid Base line's style

Example:

series.applyOptions({
    baseLineVisible: true,
    baseLineColor: '#ff0000',
    baseLineWidth: 3,
    baseLineStyle: 1,
});

Price format

Four price formats are provided for displaying on the price scale:

  • price format, which is set by default, displays absolute price value as it is
  • volume format reduces number of digits of values over 1000, replacing zeros by letters. For example, '1000' absolute price value is shown as '1K' in a volume format.
  • percent format replaces absolute values with their percentage change.
  • custom format uses a user-defined function for price formatting that could be used in some specific cases, that are not covered by standard formatters

The following options are available for setting the price format displayed by any type of series:

Name Type Default Description
type price | volume | percent | custom price Sets a type of price displayed by series
precision number 2 Specifies a number of decimal places used for price value display
minMove number 0.01 Sets the minimum possible step size for price value movement
formatter function | undefined undefined Sets a formatting function that is used when the type is custom

Examples:

series.applyOptions({
    priceFormat: {
        type: 'volume',
        precision: 3,
        minMove: 0.05,
    },
});
series.applyOptions({
    priceFormat: {
        type: 'custom',
        minMove: 0.02,
        formatter: function(price) {
            return '$' + price.toFixed(2);
        },
    }
});

setData

Allows to set/replace all existing data with new one.

An array of items is expected.

Examples:

lineSeries.setData([
    { time: '2018-12-12', value: 24.11 },
    { time: '2018-12-13', value: 31.74 },
]);
barSeries.setData([
    { time: '2018-12-19', open: 141.77, high: 170.39, low: 120.25, close: 145.72 },
    { time: '2018-12-20', open: 145.72, high: 147.99, low: 100.11, close: 108.19 },
]);

update

Adds new data item to the existing set (or updates the latest item if times of the passed/latest items are equal).

A single data item is expected.

Examples:

lineSeries.update({
    time: '2018-12-12',
    value: 24.11,
});
barSeries.update({
    time: '2018-12-19',
    open: 141.77,
    high: 170.39,
    low: 120.25,
    close: 145.72,
});

setMarkers

Allows to set/replace all existing series markers with new ones.

An array of items is expected. Each item should contain the following fields:

  • time (Time) - item time
  • position (aboveBar | belowBar | inBar) - item position
  • shape (circle | square | arrowUp | arrowDown) - item marker type
  • size (number | undefined) - size multiplier of the marker, the shape is hidden when set to 0, default value is 1
  • color (string) - item color
  • id (string | undefined) - item id, will be passed to click/crosshair move handlers
  • text (string | undefined) - item text to be shown

Example:

series.setMarkers([
    {
        time: '2019-04-09',
        position: 'aboveBar',
        color: 'black',
        shape: 'arrowDown',
    },
    {
        time: '2019-05-31',
        position: 'belowBar',
        color: 'red',
        shape: 'arrowUp',
        id: 'id3',
    },
    {
        time: '2019-05-31',
        position: 'belowBar',
        color: 'orange',
        shape: 'arrowUp',
        id: 'id4',
        text: 'example',
        size: 2,
    },
]);

chart.subscribeCrosshairMove(function(param) {
    console.log(param.hoveredMarkerId);
});

chart.subscribeClick(function(param) {
    console.log(param.hoveredMarkerId);
});

createPriceLine

Creates a horizontal price line at a certain price level. The method returns an object that has two methods:

  • options() - returns the price line options
  • applyOptions(options) - sets the price line options

You can set the price level, width, style and color of this line using the following options:

Name Type Default Description
price number 0 Price line's level
lineColor string '' Price line's color
lineWidth number 1 Price line's width in pixels
lineStyle LineStyle LineStyle.Solid Price line's style
axisLabelVisible boolean true If true, a label with the current price value is displayed on the price scale

Example:

const priceLine = series.createPriceLine({
    price: 80.0,
    color: 'green',
    lineWidth: 2,
    lineStyle: LightweightCharts.LineStyle.Dotted,
    axisLabelVisible: true,
});

priceLine.applyOptions({
    price: 90.0,
    color: 'red',
    lineWidth: 3,
    lineStyle: LightweightCharts.LineStyle.Dashed,
    axisLabelVisible: false,
});

removePriceLine

Removes the price line that was created before.

Example:

const priceLine = series.createPriceLine({ price: 80.0 });
series.removePriceLine(priceLine);

Taking screenshot

Takes the whole chart screenshot.

const screenshot = chart.takeScreenshot();

The function returns a canvas element with the chart drawn on it. Any Canvas methods like toDataURL() or toBlob() can be used to serialize the result.

Coordinates and prices converting

Each series has an associated price scale object. If the series has been created as an overlay, it has an invisible price scale to convert prices to coordinates and vice versa. There are two functions to access this price scale implicitly.

priceToCoordinate

This function accepts price value and returns corresponding coordinate or null.

const coordinate = series.priceToCoordinate(100.5);

coordinateToPrice

This function accepts coordinate and returns corresponding price value or null.

const price = series.coordinateToPrice(324);

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