Orientation

Orientation (from scenerystack/phet-core) is a two-valued EnumerationValue enumeration — Orientation.HORIZONTAL and Orientation.VERTICAL — used throughout layout-adjacent code (FlowBox, sliders, bamboo's GridLineSet/TickMarkSet/TickLabelSet and axis Nodes) so that logic can be written once and parameterized by orientation, instead of duplicated for the horizontal and vertical cases. Each value carries a bundle of orientation-specific string keys ('centerX' vs 'centerY', 'left'/'right' vs 'top'/'bottom', 'preferredWidth' vs 'preferredHeight', …) so you can index into a Node or Bounds2 generically: node[ orientation.centerCoordinate ] = value works for either orientation without an if.

import { Orientation } from 'scenerystack/phet-core';

A minimal example

function centerAlong( node: Node, orientation: Orientation, value: number ): void {
  // For HORIZONTAL this sets node.centerX; for VERTICAL it sets node.centerY.
  node[ orientation.centerCoordinate ] = value;
}

centerAlong( myNode, Orientation.HORIZONTAL, 100 );

// The opposite orientation, useful for "the other axis" logic.
Orientation.HORIZONTAL.opposite === Orientation.VERTICAL; // true

// Build a Vector-like value with the components in the right order for this orientation.
const size = Orientation.VERTICAL.toVector( 10, 20, Vector2 ); // Vector2( 20, 10 ) -- (secondary, primary) for VERTICAL

Values

Value	Meaning
Orientation.HORIZONTAL	The x-axis / left-right orientation
Orientation.VERTICAL	The y-axis / top-bottom orientation

Members

Every Orientation value carries these fields (all set in the constructor, readonly):

Member	HORIZONTAL value	VERTICAL value
coordinate	'x'	'y'
centerCoordinate	'centerX'	'centerY'
minCoordinate / maxCoordinate	'minX' / 'maxX'	'minY' / 'maxY'
minSide / maxSide	'left' / 'right'	'top' / 'bottom'
minSize / maxSize	'minWidth' / 'maxWidth'	'minHeight' / 'maxHeight'
rectCoordinate / rectSize	'rectX' / 'rectWidth'	'rectY' / 'rectHeight'
flowBoxOrientation / ariaOrientation	'horizontal'	'vertical'
size	'width'	'height'
line	'column'	'row'
preferredSize / localPreferredSize	'preferredWidth' / 'localPreferredWidth'	'preferredHeight' / 'localPreferredHeight'
sizable	'widthSizable'	'heightSizable'
opposite	Orientation.VERTICAL	Orientation.HORIZONTAL

And these methods:

Member	Description
modelToView( modelViewTransform, value ) / viewToModel( modelViewTransform, value )	Calls the transform's modelToViewX/Y (or viewToModelX/Y) method matching this orientation
toVector( primary, secondary, VectorType )	Builds a VectorType instance with components in the right slot for this orientation — (primary, secondary) for HORIZONTAL, (secondary, primary) for VERTICAL — zero-padded to support up to a 4-component vector type
Orientation.fromLayoutOrientation( 'horizontal' | 'vertical' )	Static helper converting a FlowBox-style string literal to the matching Orientation value

Prefer orientation.opposite over hardcoding a check

Because HORIZONTAL.opposite and VERTICAL.opposite are wired up as circular references right after both values are constructed, code that needs "the other axis" (e.g. bamboo's TickMarkSet, which positions a tick's tail using axisOrientation.opposite) can just read .opposite instead of writing orientation === Orientation.HORIZONTAL ? Orientation.VERTICAL : Orientation.HORIZONTAL. It also composes correctly if a third orientation value were ever added, which a hardcoded ternary would not.