Custom-Studies-OHLC-Plots.md

OHLC plots can be used to create custom OHLC study with candle or bars type.

Firstly, we should add new OHLC plot to the metainfo, using ohlcPlots field:

ohlcPlots: {
    plotcandle_0: {
        title: 'Plot candle title',
    },
},

ohlcPlots is an object, where keys are plot id and values are plots info. Plot info is an object with following fields:

* - Required

• title* - string, title of plot that will be used in settings dialog
• isHidden* - boolean
• drawBorder - boolean
• showLast - number

Now we need to declare default values for this plot (styles etc) in metainfo. Depending on the plot type you want to use there might be different schemas of the default object.

Example:

// ...
defaults: {
    ohlcPlots: {
        plotcandle_0: {
            plottype: 'ohlc_candles',
            borderColor: '#000000',
            color: '#2196F3',
            drawBorder: true,
            drawWick: true,
            visible: true,
            wickColor: '#737375',
        },
    },
},
// ...

OHLC plots are 'meta' plots, this means that under the hood there should be a set of simple plots in metainfo plots field.

Example:

plots: [
    {
        id: 'plot_0',
        type: 'ohlc_open',
        target: 'plotcandle_0',
    },
    {
        id: 'plot_1',
        type: 'ohlc_high',
        target: 'plotcandle_0',
    },
    {
        id: 'plot_2',
        type: 'ohlc_low',
        target: 'plotcandle_0',
    },
    {
        id: 'plot_3',
        type: 'ohlc_close',
        target: 'plotcandle_0',
    },
],

The main things here are type and target fields.

• type field must be one of the following: ohlc_open, ohlc_high, ohlc_low or ohlc_close, all four plots for every OHLC plot must be declared here.
• target - allows you to declare for which OHLC plot this 'simple' plot is. Here you should set an id of the OHLC plot (plotcandle_0).

Last but not least you have to return data for plots from your study's main function in constructor:

this.main = function(context, inputCallback) {
    this._context = context;
    this._input = inputCallback;

    var direction = Math.sign(Math.random() - 0.5);
    var value = Math.random() * 200;

    var open  = value + 8 * direction;
    var high = value + 15;
    var low = value - 15;
    var close = value - 8 * direction;

    return [open, high, low, close];
}

Full example:

{
    name: 'OHLC_sample',
    metainfo: {
        _metainfoVersion: 51,
        id: 'OHLC_sample@tv-basicstudies-1',
        scriptIdPart: '',
        description: 'OHLC_sample',
        shortDescription: 'OHLC_sample',
        is_hidden_study: false,
        is_price_study: false,
        isCustomIndicator: true,
        plots: [
            {
                id: 'plot_0',
                type: 'ohlc_open',
                target: 'plotcandle_0',
            },
            {
                id: 'plot_1',
                type: 'ohlc_high',
                target: 'plotcandle_0',
            },
            {
                id: 'plot_2',
                type: 'ohlc_low',
                target: 'plotcandle_0',
            },
            {
                id: 'plot_3',
                type: 'ohlc_close',
                target: 'plotcandle_0',
            },
        ],

        ohlcPlots: {
            plotcandle_0: {
                title: 'Plot candle title',
            },
        },

        defaults: {
            ohlcPlots: {
                plotcandle_0: {
                borderColor: '#000000',
                    color: '#2196F3',
                    drawBorder: true,
                    drawWick: true,
                    plottype: 'ohlc_candles', // might be 'ohlc_bars' for bars
                    visible: true,
                    wickColor: '#737375',
                },
            },
            precision: 4,
            inputs: {},
        },
        styles: {},
        inputs: [],
    },
    constructor: function() {
        this.main = function(context, inputCallback) {
            this._context = context;
            this._input = inputCallback;

            var direction = Math.sign(Math.random() - 0.5);
            var value = Math.random() * 200;

            var open  = value + 8 * direction;
            var high = value + 15;
            var low = value - 15;
            var close = value - 8 * direction;

            return [open, high, low, close];
        }
    }
}