uplot-vplugins/Source/Utils/@Ext/QuadTree.ts

Plugins for uPlot, by Venryx.

export function pointWithin(px, py, rlft, rtop, rrgt, rbtm) {
	return px >= rlft && px <= rrgt && py >= rtop && py <= rbtm;
}

const MAX_OBJECTS = 10;
const MAX_LEVELS = 4;

export class Quadtree {
	constructor(x: number, y: number, w: number, h: number, l?: number) {
		this.x = x;
		this.y = y;
		this.w = w;
		this.h = h;
		this.l = l || 0;
		this.o = [];
		this.q = null;
	}

	x: number;
	y: number;
	w: number;
	h: number;
	l: number;
	o: any[];
	q: any;

	split() {
		const t = this,
			x = t.x,
			y = t.y,
			w = t.w / 2,
			h = t.h / 2,
			l = t.l + 1;

		t.q = [
			// top right
			new Quadtree(x + w, y, w, h, l),
			// top left
			new Quadtree(x, y, w, h, l),
			// bottom left
			new Quadtree(x, y + h, w, h, l),
			// bottom right
			new Quadtree(x + w, y + h, w, h, l),
		];
	}
	// invokes callback with index of each overlapping quad
	quads(x, y, w, h, cb) {
		const t = this,
			q = t.q,
			hzMid = t.x + t.w / 2,
			vtMid = t.y + t.h / 2,
			startIsNorth = y < vtMid,
			startIsWest = x < hzMid,
			endIsEast = x + w > hzMid,
			endIsSouth = y + h > vtMid;

		// top-right quad
		startIsNorth && endIsEast && cb(q[0]);
		// top-left quad
		startIsWest && startIsNorth && cb(q[1]);
		// bottom-left quad
		startIsWest && endIsSouth && cb(q[2]);
		// bottom-right quad
		endIsEast && endIsSouth && cb(q[3]);
	}
	add(o) {
		const t = this;

		if (t.q != null) {
			t.quads(o.x, o.y, o.w, o.h, q=>{
				q.add(o);
			});
		} else {
			const os = t.o;

			os.push(o);

			if (os.length > MAX_OBJECTS && t.l < MAX_LEVELS) {
				t.split();

				for (let i = 0; i < os.length; i++) {
					const oi = os[i];

					t.quads(oi.x, oi.y, oi.w, oi.h, q=>{
						q.add(oi);
					});
				}

				t.o.length = 0;
			}
		}
	}
	get(x, y, w, h, cb) {
		const t = this;
		const os = t.o;

		for (let i = 0; i < os.length; i++) cb(os[i]);

		if (t.q != null) {
			t.quads(x, y, w, h, q=>{
				q.get(x, y, w, h, cb);
			});
		}
	}
	clear() {
		this.o.length = 0;
		this.q = null;
	}
}