maplair/dist/esm/map/handler/ScrollWheelZoomHandler.js

JavaScript library for mobile-friendly interactive maps

import { getWheelDelta, off, on, stop } from "../../dom/DomEvent.js";
import { Handler } from "../../core/Handler.js";
//#region src/map/handler/ScrollWheelZoomHandler.js
var ScrollWheelZoomHandler = class ScrollWheelZoomHandler extends Handler {
	constructor(...args) {
		super(...args);
		this.callInitHooks(ScrollWheelZoomHandler);
	}
	addHooks() {
		on(this._map._container, "wheel", this._onWheelScroll, this);
		this._delta = 0;
	}
	removeHooks() {
		off(this._map._container, "wheel", this._onWheelScroll, this);
		clearTimeout(this._timer);
	}
	_onWheelScroll(e) {
		const delta = getWheelDelta(e);
		const debounce = this._map.options.wheelDebounceTime;
		this._delta += delta;
		this._lastMousePos = this._map.pointerEventToContainerPoint(e);
		if (!this._startTime) this._startTime = Date.now();
		const left = Math.max(debounce - (Date.now() - this._startTime), 0);
		clearTimeout(this._timer);
		this._timer = setTimeout(this._performZoom.bind(this), left);
		stop(e);
	}
	_performZoom() {
		const map = this._map, zoom = map.getZoom(), snap = this._map.options.zoomSnap ?? 0;
		map._stop();
		const d2 = this._delta / (this._map.options.wheelPxPerZoomLevel * 4), d3 = 4 * Math.log(2 / (1 + Math.exp(-Math.abs(d2)))) / Math.LN2, d4 = snap ? Math.ceil(d3 / snap) * snap : d3, delta = map._limitZoom(zoom + (this._delta > 0 ? d4 : -d4)) - zoom;
		this._delta = 0;
		this._startTime = null;
		if (!delta) return;
		if (map.options.scrollWheelZoom === "center") map.setZoom(zoom + delta);
		else map.setZoomAround(this._lastMousePos, zoom + delta);
	}
	static register(MaplairMap) {
		MaplairMap.mergeOptions({
			scrollWheelZoom: true,
			wheelDebounceTime: 40,
			wheelPxPerZoomLevel: 60
		});
		MaplairMap.addInitHook("addHandler", "scrollWheelZoom", ScrollWheelZoomHandler);
	}
};
//#endregion
export { ScrollWheelZoomHandler };

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