Every visible output is a plot: a series plus how to draw it. Lines, dashes, areas, histograms, step lines and indicator-side candles, all restylable at runtime.

Adding a plot

A plot is one output line on the chart. An indicator can own several: an SMA has one, MACD has three (line, signal, histogram), Bollinger Bands have three (upper, middle, lower). You build a Plot (namespace SabrTrader.Pipeline.Plots) over your output series and register it with the protected AddPlot helper. The Plot constructor is (string name, ISeries<double> values, PlotStyle style, ChartColor color, double lineWidthPx).

adding plotsprivate readonly ChunkedSeries<double> _macd   = new();
private readonly ChunkedSeries<double> _signal = new();
private readonly ChunkedSeries<double> _hist   = new();

public MyMacd(IIndicator? parent = null, ISeries<double>? input = null) : base(parent, input)
{
    // Order matters: earlier plots render BEHIND later ones.
    AddPlot(new Plot("Histogram", _hist,   PlotStyle.Histogram, new ChartColor(120, 120, 120), 1.0));
    AddPlot(new Plot("MACD",      _macd,   PlotStyle.Line,      new ChartColor(33, 150, 243), 1.5));
    AddPlot(new Plot("Signal",    _signal, PlotStyle.Line,      new ChartColor(244, 67, 54),  1.5));
}

Draw order follows registration order: add the histogram first so the lines sit on top of it. The Plot constructor and its setters validate their arguments: a blank name or a lineWidthPx <= 0 throws immediately. IndicatorBase.TryGetPlot(name, out plot) finds a registered plot by its exact name.

When to call AddPlot

Plot styles

PlotStyle selects the rendering primitive. NaN values are skipped: lines break, dots and bars are left out.

Runtime restyling

IPlot is mutable on purpose. The settings dialog recolours and restyles plots at runtime without reconstructing the indicator; the chart reads the properties again on the next render pass. A property change costs a repaint, not a recalculation.

mutating a plotIPlot signal = Plots[2];
signal.Color       = new ChartColor(255, 152, 0);
signal.Style       = PlotStyle.Dashed;
signal.LineWidthPx = 2.0;
signal.Visible     = false;     // hide without removing the plot

The settings dialog shows a style row per plot (colour, style, width, visibility) that writes these properties directly and persists them with the chart, so a plot's colour needs no separate parameter. Declare a ChartColor parameter for colours the indicator uses elsewhere, such as custom rendering or the per-bar colours below.

Price-axis markers

Each plot can paint a small filled label on the price axis at its most recent value via IPlot.ShowPriceMarker (default true). The indicator-level ShowPriceMarkers property (inherited from IndicatorBase) is a master gate: when false, no marker of this indicator paints, whatever the per-plot setting.

Per-bar colours and plot flags

To colour a line bar by bar (a slope-coloured moving average, for example), give the plot a ChunkedSeries<ChartColor> through PerBarColors and append one colour per bar in step with the values. Each segment takes the colour of the bar it ends on; a bar with no entry falls back to Color. It applies to Line, Dashed, Dotted and Dots. The series is output, not a setting: the workspace saves the plot's style but not this series, and a recalculation clears it together with the values.

per-bar coloursprivate readonly ChunkedSeries<double>     _ma     = new();
private readonly ChunkedSeries<ChartColor> _colors = new();

// constructor
AddPlot(new Plot("MA", _ma, PlotStyle.Line, new ChartColor(33, 150, 243), 2.0)
{
    PerBarColors = _colors,
});

// per bar, after appending to _ma
_colors.Append(_ma.Count > 1 && _ma[0] >= _ma[1] ? UpColor : DownColor);

Indicator-side candles

Some indicators are naturally per-bar OHLC rather than a single value. Cumulative Delta, for example, draws an open/high/low/close candle of the running delta. PlotStyle.Candle needs a plot that implements IOhlcPlot, which carries the four parallel series. OhlcPlot implements it and sets its style to Candle itself.

OHLC plot// OhlcPlot exposes OpenValues / HighValues / LowValues + Values (the close),
// all aligned by barsAgo, plus bull/bear colours and a body-fill ratio.
// bullishColor + bearishColor are required ctor arguments; wickWidthPx and
// bodyFillRatio are optional (default 1.0 and 0.7).
var ohlc = new OhlcPlot("CumDelta", _open, _high, _low, _close,
    bullishColor: new ChartColor(38, 166, 154),
    bearishColor: new ChartColor(239, 83, 80),
    bodyFillRatio: 0.7);
AddPlot(ohlc);

Plot semantics

PlotSemantics (namespace SabrTrader.Pipeline.Indicators) declares a plot's machine-readable meaning, so an automated consumer such as the AI assistant can interpret RSI = 71.6 without recognising the indicator by name. Set it on the Plot when you add it.

declaring semanticsAddPlot(new Plot("RSI", _rsi, PlotStyle.Line, new ChartColor(156, 39, 176), 1.5)
{
    Semantics = new PlotSemantics(
        Kind: PlotKind.Oscillator,
        RangeMin: 0, RangeMax: 100,
        Unit: PlotValueUnit.Percent,
        BullishDirection: PlotBullishDirection.Up,
        Reference: "30/70 oversold/overbought"),
});

Kind is one of Unspecified, Overlay, Oscillator, Histogram, Signal, Band. Unit is one of Unspecified, Price, Percent, Ratio, Ticks, Raw. BullishDirection is None, Up or Down. Leave RangeMin / RangeMax null for an unbounded value. A plot that declares nothing reports PlotSemantics.Default (semantics unknown).