SkyProjector型
リファレンスの説明と例は英語です。見出しと目次は日本語です。
How a page says where a star is: it gets the star's right ascension and declination in degrees and writes the spot on its screen into out. It answers false when the star is not in front of the camera (behind it, or beyond the horizon of the view).
インポート
import type { SkyProjector } from "@johnmorrisdotca/hoshi-stars/sky-labels";
定義
type SkyProjector = (rightAscension: number, declination: number, out: ScreenPoint) => boolean;
例
import type { SkyProjector } from "@johnmorrisdotca/hoshi-stars/sky-labels";
// a page that looks straight at the north celestial pole with the sky 200 pixels across a quarter turn
const project: SkyProjector = (ra, dec, out) => {
const r = ((90 - dec) / 90) * 200;
out.x = 300 + r * Math.cos((ra * Math.PI) / 180);
out.y = 300 - r * Math.sin((ra * Math.PI) / 180);
return dec > 0;
};
console.log(project(0, 90, { x: 0, y: 0 }));true出力(このページを作ったときに実行した結果)
この日本語は、まだ日本語を母語とする方の確認を受けていません。訂正を歓迎します。