GridLineSet, TickMarkSet, and TickLabelSet

GridLineSet, TickMarkSet, and TickLabelSet (all from scenerystack/bamboo) are the three repeating-decoration primitives every bamboo chart uses alongside ChartTransform and the axis Nodes: they draw evenly-spaced lines, tick marks, and tick labels respectively, all driven by the same (chartTransform, axisOrientation, spacing) triple. Internally, each one calls chartTransform.forEachSpacing() to walk the model/view coordinate pairs at that spacing and clipping behavior, then builds its Shape (or, for TickLabelSet, its Text children) from those pairs. All three listen to changedEmitter and redraw automatically.

import { ChartTransform, GridLineSet, TickMarkSet, TickLabelSet } from 'scenerystack/bamboo';
import { Orientation } from 'scenerystack/phet-core';
import { Range } from 'scenerystack/dot';

A minimal example

const chartTransform = new ChartTransform( {
  viewWidth: 400,
  viewHeight: 200,
  modelXRange: new Range( 0, 10 ),
  modelYRange: new Range( -1, 1 )
} );

// Vertical lines every 1 model unit along x.
const verticalGridLines = new GridLineSet( chartTransform, Orientation.VERTICAL, 1, {
  stroke: 'lightGray'
} );

// Tick marks along the x axis (at model y = 0), every 1 unit.
const xTickMarks = new TickMarkSet( chartTransform, Orientation.HORIZONTAL, 1, {
  edge: 'min'
} );

// Numeric labels below the x tick marks.
const xTickLabels = new TickLabelSet( chartTransform, Orientation.HORIZONTAL, 1, {
  edge: 'min'
} );

All three constructors share the same shape:

new GridLineSet( chartTransform: ChartTransform, axisOrientation: Orientation, spacing: number, providedOptions?: GridLineSetOptions )
new TickMarkSet( chartTransform: ChartTransform, axisOrientation: Orientation, spacing: number, providedOptions?: TickMarkSetOptions )
new TickLabelSet( chartTransform: ChartTransform, axisOrientation: Orientation, spacing: number, providedOptions?: TickLabelSetOptions )

axisOrientation is the axis the ticks/gridlines progress along — a HORIZONTAL set has ticks marching along x (at x=0,1,2,…), producing vertical gridlines; a VERTICAL set marches along y and produces horizontal gridlines. spacing is in model coordinates.

Options

Option	Applies to	Default	Effect
value	all three	0	Model coordinate on the opposite axis where the ticks/gridlines are positioned (mutually exclusive with edge)
edge	all three	null	'min' or 'max' pins the ticks/gridlines to that edge of the chart instead of a value
origin	all three	0	Model-coordinate offset the spacing is measured from
skipCoordinates	TickMarkSet, TickLabelSet	[]	Model coordinates to skip — typically [0], to avoid drawing a redundant tick where the axes cross
extent	TickMarkSet, TickLabelSet	10 (TickMarkSet.DEFAULT_EXTENT)	Length of each tick mark in view coordinates (or, for TickLabelSet, the extent an implied tick would have, used only for label positioning)
clippingType	all three	'strict'	Rounding/clipping behavior for ChartTransform.forEachSpacing() — whether partially-out-of-range ticks are included
createLabel	TickLabelSet	value => new Text( toFixed( value, 1 ), { fontSize: 12 } )	Builds the label Node for a given model coordinate; returning null omits that label
positionLabel	TickLabelSet	positions below (HORIZONTAL) or to the left (VERTICAL) of the tick	Positions a created label relative to its tick's bounds

Methods

Member	Description
setSpacing( spacing ) / getSpacing()	Replaces the spacing (a no-op if unchanged) and recomputes; shared across all three
getSpacingBorders()	Returns the Range of model coordinates the current spacing/origin/clippingType actually produces ticks for; shared across all three
setCreateLabel( createLabel )	TickLabelSet only — swaps the label-creation function and calls invalidateTickLabelSet()
invalidateTickLabelSet()	TickLabelSet only — disposes every cached label and rebuilds, needed if createLabel's output for an already-seen value should change (e.g. switching from numeric to symbolic labels)
dispose()	Removes the chartTransform.changedEmitter listener before calling the superclass's dispose()

TickLabelSet caches label Nodes by model coordinate

TickLabelSet keeps a Map from model coordinate to the Node last built by createLabel, and reuses it across update() calls rather than reconstructing every label on every transform change — labels are only rebuilt when a coordinate scrolls out of range and a different one scrolls in. If createLabel's logic depends on external state (not just the coordinate value), call invalidateTickLabelSet() after that state changes, or stale labels will stick around.