LinearEquationPlot

LinearEquationPlot (from scenerystack/bamboo) renders the line described by a slope m and y-intercept b — y = mx + b — rather than a dataset of discrete points. Unlike LinePlot, which connects an array of (Vector2 | null) samples, LinearEquationPlot only needs the two numbers describing the equation: it extends scenerystack/scenery's Line and recomputes its endpoints to span the chart transform's full modelXRange (or modelYRange, for a vertical line) whenever m, b, or the transform changes. Passing m: Infinity or m: -Infinity draws a vertical line instead of throwing, which is the idiomatic way to represent an undefined slope.

import { ChartTransform, LinearEquationPlot } from 'scenerystack/bamboo';
import { Range } from 'scenerystack/dot';

A minimal example

const chartTransform = new ChartTransform( {
  viewWidth: 400,
  viewHeight: 200,
  modelXRange: new Range( -10, 10 ),
  modelYRange: new Range( -10, 10 )
} );

// y = 2x + 1, spanning the chart's full model x-range.
const linearEquationPlot = new LinearEquationPlot( chartTransform, 2, 1, {
  stroke: 'red',
  lineWidth: 2
} );

// A vertical line at x = 3.
const verticalLine = new LinearEquationPlot( chartTransform, Infinity, 3 );

Constructor

new LinearEquationPlot( chartTransform: ChartTransform, m: number, b: number, providedOptions?: LinearEquationPlotOptions )

m is the slope (Infinity/-Infinity for a vertical line), and b is the y-intercept. LinearEquationPlotOptions adds no options of its own beyond whatever it inherits from LineOptions (e.g. stroke, lineWidth); stroke defaults to 'black' and lineWidth defaults to 1.

Methods

Member	Description
m (getter/setter)	The slope. Setting it calls setSlope(), which recomputes the endpoints
setSlope( m )	Replaces the slope and redraws
b (getter/setter)	The y-intercept. Setting it calls setYIntercept(), which recomputes the endpoints
setYIntercept( b )	Replaces the y-intercept and redraws
solve( x )	Returns m * x + b — the y-value the equation predicts for a given x, without touching the rendered line
dispose()	Removes the chartTransform.changedEmitter listener before calling Line.dispose()

Use it for reference lines and fits, not for arbitrary curves

Because LinearEquationPlot always spans the transform's entire model range, it's a natural fit for things a dataset would be overkill for: a best-fit line overlaid on a ScatterPlot, a target/threshold line, or a y = x reference line. For anything that isn't representable as a single global slope and intercept — a curve, a piecewise function, or real sampled data — reach for LinePlot instead.