Reference · Names on the brightest stars and the constellation figures as faint lines, for a sky you draw yourself: a count or a magnitude, the figure under the pointer at full strength, a body that covers part of the sky, and a look set by settings alone

`createFigureLines`function

The constellation figures as lines for a sky of your own, faint, with the figure under the pointer at full strength and its name. strength 0 draws nothing. The figures are the package's own, from the positions of the stars: the 88 of the IAU, or with culture a sky culture's (the Japanese sky's 昴, the Chinese sky's mansions and asterisms).

After the first call nothing is allocated by update or point (a new culture in set makes its figures once).

Import it

import { createFigureLines } from "@johnmorrisdotca/hoshi-stars/sky-labels";

Definition

function createFigureLines(settings?: FigureLinesSettings): FigureLines

Parameters

Name	Type	Description
`settings` (optional)	`FigureLinesSettings`	The strength and what a pick needs.

Returns

FigureLines

The figures for this sky.

Examples

Example 1

import { createFigureLines } from "@johnmorrisdotca/hoshi-stars/sky-labels";

const lines = createFigureLines({ strength: 0.2 });
const project = (ra: number, dec: number, out: { x: number; y: number }): boolean => {
  out.x = 640 - (ra - 84) * 8;
  out.y = 360 - dec * 8;
  return Math.abs(ra - 84) < 60 && Math.abs(dec) < 40;
};
lines.update(project, { width: 1280, height: 720 });
lines.point(640, 360);
console.log(lines.count > 0, lines.picked?.abbreviation, lines.opacityOf(lines.picked!));

true Ori 1

What it prints (run when this page was built)

Example 2

import { createFigureLines } from "@johnmorrisdotca/hoshi-stars/sky-labels";
import { japanese } from "@johnmorrisdotca/hoshi-stars/cultures/japanese";

// the Japanese sky, its names in Japanese: the Pleiades are 昴, named by their reading
const lines = createFigureLines({ culture: japanese, lang: "ja" });
const project = (ra: number, dec: number, out: { x: number; y: number }): boolean => {
  out.x = 640 - (ra - 56.9) * 40;
  out.y = 360 - (dec - 24.1) * 40;
  return Math.abs(ra - 56.9) < 15 && Math.abs(dec - 24.1) < 9;
};
lines.update(project, { width: 1280, height: 720 });
const subaru = lines.figures.find((figure) => figure.abbreviation === "subaru")!;
lines.point(lines.segments[subaru.start * 4]!, lines.segments[subaru.start * 4 + 1]!);
console.log(lines.picked?.abbreviation, lines.name?.text);

subaru すばる