window.ChartingAPI
The public ChartingAPI object provides methods to extend the canvas charting engine, register technical indicators, custom candles, drawing tools, horizontal options scales, and configure global watermark overlays.
Overview
The ChartingAPI is exposed globally on the window namespace. It serves as the bridge between native environments (iOS WKWebView / Android WebKit WebView) and the charting bundle scripts.
Candles & Rendering
registerCandleType(type, renderFn)
Method
Registers a new candle renderer function that draws custom style candles on the HTML5 canvas.
- type: string (e.g. 'heikin_ashi', 'hollow')
- renderFn: function(ctx, visibleBars, slot, bodyW, chartH, priceToY, themeColors, xOffset, chartInstance)
ChartingAPI.registerCandleType('my_candle', (ctx, bars, slot, bodyW, chartH, priceToY) => {
// custom rendering logic
});getCandleRenderer(type)
Method
Retrieves the registered candle renderer function by type name.
function | null
getAvailableCandleTypes()
Method
Returns a list of all registered candle renderer keys.
string[]
Custom Drawings
registerCustomDrawing(type, config)
Method
Registers a new vector drawing tool configuration.
- type: string
- config: object { clicks: number, render: function, renderPreview: function, hitTest: function }
getCustomDrawing(type)
Method
Retrieves a registered custom drawing config by name.
object | null
getAvailableCustomDrawings()
Method
Returns all custom drawing names.
saveDrawings(chart)
Method
Saves the vector drawings of the chart instance to browser LocalStorage.
loadDrawings(chart)
Method
Loads drawings from browser LocalStorage for the current chart symbol and renders them.
registerPriceScaleDrawingLabel(renderFn)
Method
Registers a renderer function for drawing label values on the vertical Y-axis price scale.
registerTimescaleDrawingLabel(renderFn)
Method
Registers a renderer function for drawing label values on the horizontal X-axis time scale.
Technical Indicators
registerIndicator(type, config)
Method
Registers a custom technical indicator (such as SMA, RSI, MACD, Bollinger Bands) to the charting engine registry.
- type: string
- config: object { name: string, type: 'pane' | 'overlay', params: object, calculate: function, render: function }
getIndicator(type)
Method
Retrieves the technical indicator configuration registered with the specified type.
getAvailableIndicators()
Method
Returns a list of all registered indicator types.
Horizontal Scales
registerHorizontalScale(type, scaleObj)
Method
Registers a new custom horizontal scale helper (e.g. yield-curve or option strikes scale mapping indices to x-axis positions).
- type: string
- scaleObj: object { barToX, xToBar, getVisibleRange, drawTimeScale, drawTimeBadge }
getHorizontalScale(type)
Method
Retrieves the registered horizontal scale helper object by its name.
getAvailableHorizontalScales()
Method
Returns keys of all registered horizontal scales.
Intervals & Loader
registerCustomInterval(resolution)
Method
Registers a new custom interval (resolution) to appear inside the timeframe selector dropdown toolbar.
getCustomIntervals()
Method
Returns all registered custom resolution intervals.
getSmartLoader()
Method
Retrieves the SmartLoader constructor class used to handle scrollback historical fetching.
Watermarks
setWatermark(settings)
Method
Sets global chart watermark overlay parameters dynamically and triggers a render sweep.
- show: boolean
- watermarkMode: 'always' | 'replay' | 'none'
- watermarkColor: string
- showWatermarkTicker: boolean
- showWatermarkDescription: boolean
- showWatermarkInterval: boolean
getWatermark()
Method
Returns the current watermark settings object.
getPendingWatermarkSettings()
Method
Returns pending watermark changes (used before chart init is finalized).