@d3-maps/core / line

line

Table of contents

• Functions
  • createMidPoint()
  • getDefaultLine()
  • getLinePath()
  • getLineWithMidpoints()
• Interfaces
  • MapLineOptions
  • MapLineProps
• Type Aliases
  • MapLineCoordinates
  • MapLineCurve
  • MapLineMidpoint

Functions

createMidPoint()

function createMidPoint(pointsPair: [[number, number], [number, number]], midpoint?: MapLineMidpoint): [number, number];

Creates a generated midpoint for a segment and offsets it relative to the segment itself

midpoint values are percentages of the full segment length

Parameters

Parameter	Type
pointsPair	[[number, number], [number, number]]
midpoint	MapLineMidpoint

Returns

[number, number]

---

getDefaultLine()

function getDefaultLine(points: MapLineCoordinates, curve?: MapLineCurve): string | undefined;

Builds a line path directly from local points using the provided D3 curve

Parameters

Parameter	Type
points	MapLineCoordinates
curve?	MapLineCurve

Returns

string | undefined

---

getLinePath()

function getLinePath(context: MapContext | undefined, __namedParameters: MapLineOptions): string | undefined;

Returns an SVG path string for a line in one of three modes:

• geographic LineString rendering via context.path(...)
• projected custom rendering via d3.line()
• cartesian rendering for already-local coordinates

Parameters

Parameter	Type
context	MapContext
__namedParameters	MapLineOptions

Returns

string | undefined

---

getLineWithMidpoints()

function getLineWithMidpoints(
   points: MapLineCoordinates, 
   curve?: MapLineCurve, 
   midpoint?: MapLineMidpoint): string | undefined;

Inserts generated midpoints between consecutive points and renders the resulting path

Parameters

Parameter	Type
points	MapLineCoordinates
curve?	MapLineCurve
midpoint?	MapLineMidpoint

Returns

string | undefined

Interfaces

MapLineOptions

Core line rendering options shared by framework adapters

Extended by

• MapLineProps

Properties

Property	Type
cartesian?	boolean
coordinates	MapLineCoordinates
curve?	MapLineCurve
custom?	boolean
midpoint?	MapLineMidpoint

---

MapLineProps

Public map line props including map object styling and interaction support

Extends

• MapObjectProps<TStyle>.MapLineOptions

Type Parameters

Type Parameter	Default type
TStyle	unknown

Properties

Property	Type	Inherited from
cartesian?	boolean	MapLineOptions.cartesian
coordinates	MapLineCoordinates	MapLineOptions.coordinates
curve?	MapLineCurve	MapLineOptions.curve
custom?	boolean	MapLineOptions.custom
midpoint?	MapLineMidpoint	MapLineOptions.midpoint
styles?	Partial<Record<"default"	"hover"

Type Aliases

MapLineCoordinates

type MapLineCoordinates = [number, number][];

Geographic or cartesian line coordinates expressed as ordered [x, y] pairs

---

MapLineCurve

type MapLineCurve = CurveFactory | CurveFactoryLineOnly;

D3 curve factory used by custom and cartesian line rendering

---

MapLineMidpoint

type MapLineMidpoint = [number, number];

Midpoint adjustment expressed as percentages of the segment length

• first value: moves the generated midpoint along the segment direction
• second value: moves the generated midpoint perpendicular to the segment direction