xfy
25eacc1c3c
纯现代化重构，行为不变（23 个回归测试全绿作证）：
- var → const/let（state、gotoIndex 的 newIndex 用 let，其余 const）
- 循环 for+var+IIFE包装 → for..of/forEach + const（天然捕获迭代变量，
消除旧 var 循环闭包必须立即执行函数固定变量的写法）
- 字符串拼接 → 模板字面量（counter 文本、transform、width/height）
- 事件处理 function() → 箭头函数（无 this 依赖场景）
- 拆掉外层 (function(){'use strict'; ... })()：ES module 作用域已封装，
IIFE 是历史遗留；辅助函数仍用 function 声明（openLightbox↔closeLightbox
互递归依赖提升）
几何纯函数（fitCentered/transformFor/originalUrl）已在 geometry.ts，
本文件只剩 DOM 胶水 + state 单例。
546 lines
18 KiB
TypeScript
546 lines
18 KiB
TypeScript
import { fitCentered, transformFor, originalUrl, type Rect } from "./geometry";
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import "./style.css";
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interface LightboxState {
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overlay: HTMLDivElement;
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img: HTMLImageElement;
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caption: HTMLElement;
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counter: HTMLDivElement;
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prevBtn: HTMLButtonElement | null;
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nextBtn: HTMLButtonElement | null;
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originNode: HTMLElement;
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gallery: HTMLElement[];
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index: number | null;
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isSingle: boolean;
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openScrollY: number;
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origSrc: string;
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altText: string;
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closing: boolean;
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reduced: boolean;
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scrollHandler: ((this: Window, ev: Event) => void) | null;
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keyHandler: ((this: Document, ev: KeyboardEvent) => void) | null;
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target?: Rect;
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baseW?: number;
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baseH?: number;
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}
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declare global {
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interface Window {
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__initLightbox: (selectors: string | string[]) => void;
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__lightboxSelectors?: string[];
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}
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}
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export {};
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// ============ 工具函数 ============
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function prefersReducedMotion(): boolean {
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return (
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!!window.matchMedia &&
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window.matchMedia("(prefers-reduced-motion: reduce)").matches
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);
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}
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// 读取元素当前在视口里的 rect（用于飞行起点/终点）。
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// 统一映射成 {x,y,w,h}：getBoundingClientRect 返回的 DOMRect 用
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// left/top/width/height，而 fitCentered/transformFor 用 x/y/w/h，
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// 这里转成一致格式，避免 .w 读到 undefined。
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function rectOf(el: Element): Rect {
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const r = el.getBoundingClientRect();
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return {
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x: r.left,
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y: r.top,
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w: r.width,
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h: r.height,
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};
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}
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// 注意：fitCentered / transformFor / originalUrl 已抽到 ./geometry.ts。
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// ============ 懒加载 ============
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// 为单个 .blur-img 容器初始化高清图懒加载。
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// IO 进入视口后把 data-src 写入 src，加载完成加 is-loaded 触发 CSS 淡入。
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function initLazyLoad(container: Element): void {
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const raw = container.querySelector(".blur-img-full");
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if (!(raw instanceof HTMLImageElement)) return;
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const fullImg: HTMLImageElement = raw;
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if (container.getAttribute("data-blur-init")) return;
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container.setAttribute("data-blur-init", "true");
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const fullSrc = fullImg.getAttribute("data-src");
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if (!fullSrc) return;
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const onFullLoaded = (): void => {
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// 给容器加 is-loaded，CSS 据此显式隐藏 placeholder。
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// 直接把 full 层 opacity 设为 1（清掉 transition），不依赖 CSS 的 opacity
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// 过渡：合成层重绘时机不稳定，可能导致 full 层卡在 opacity:0，直到一次
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// 强制重排才更新。
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container.classList.add("is-loaded");
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fullImg.style.transition = "none";
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fullImg.style.opacity = "1";
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};
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fullImg.addEventListener("load", onFullLoaded);
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// 缓存兜底：若设 src 时图片已在缓存（load 几乎立即触发，可能早于监听注册），
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// 用 complete 补一次。注意无 src 的 img complete 也为 true，故先判 src。
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if (fullImg.getAttribute("src") && fullImg.complete) {
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onFullLoaded();
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}
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if ("IntersectionObserver" in window) {
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const io = new IntersectionObserver(
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(entries: IntersectionObserverEntry[]): void => {
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for (const entry of entries) {
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if (entry.isIntersecting) {
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fullImg.src = fullSrc;
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io.unobserve(container);
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}
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}
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},
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{ rootMargin: "200px" }
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);
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io.observe(container);
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} else {
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fullImg.src = fullSrc;
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}
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}
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// ============ 图像收集 ============
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// 收集所有 selectors命中的 .blur-img 节点。
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// gallery: 正文图（组成图集）；singles: 带 lightbox-single class 的单张图（如封面）。
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function collectImages(roots: Element[]): { gallery: HTMLElement[]; singles: HTMLElement[] } {
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const gallery: HTMLElement[] = [];
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const singles: HTMLElement[] = [];
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for (const root of roots) {
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const nodes = root.querySelectorAll(".blur-img");
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for (const n of nodes) {
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if (!(n instanceof HTMLElement)) continue;
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if (n.classList.contains("lightbox-single")) {
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singles.push(n);
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} else {
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gallery.push(n);
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}
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}
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}
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return { gallery, singles };
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}
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// ============ 灯箱状态与开/关 ============
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// 当前灯箱状态（同时只允许一个灯箱）。
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let state: LightboxState | null = null;
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function openLightbox(originNode: HTMLElement, gallery: HTMLElement[], index: number | null): void {
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if (state) closeLightbox(true);
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const fullImgEl = originNode.querySelector(".blur-img-full");
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if (!(fullImgEl instanceof HTMLImageElement)) return;
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const dataSrc = fullImgEl.getAttribute("data-src") || "";
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const origSrc = originalUrl(dataSrc);
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const altText = fullImgEl.getAttribute("alt") || "";
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const isSingle =
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originNode.classList.contains("lightbox-single") ||
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gallery.length === 0;
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const vw = window.innerWidth;
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const vh = window.innerHeight;
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// 建 DOM
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const overlay = document.createElement("div");
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overlay.className = "lightbox-overlay";
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overlay.setAttribute("role", "dialog");
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overlay.setAttribute("aria-modal", "true");
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overlay.setAttribute("aria-label", "图片预览");
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overlay.setAttribute("tabindex", "-1");
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// 创建后立即设 opacity 0：append 到 DOM 时是透明的，避免在图片加载期间
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// （start() 执行前）显示全黑背景造成闪烁。start() 的渐变会把 opacity 升到 1。
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overlay.style.opacity = "0";
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const img = document.createElement("img");
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img.className = "lightbox-img";
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img.setAttribute("alt", altText);
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// 加载前先占 0 尺寸，避免原图（可能数千 px）在加载期间撑大文档
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// 可滚动区、触发非预期的 scroll 事件。start() 拿到 natural 尺寸后再设真实值。
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img.style.width = "0px";
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img.style.height = "0px";
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const caption = document.createElement("figcaption");
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caption.className = "lightbox-caption";
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caption.textContent = altText;
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if (!altText) caption.style.display = "none";
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const counter = document.createElement("div");
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counter.className = "lightbox-counter";
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if (isSingle || gallery.length === 0) {
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counter.style.display = "none";
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} else {
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counter.textContent = `${(index ?? 0) + 1} / ${gallery.length}`;
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}
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// 图集模式（>1 张）才加左右导航箭头；单张不显示。
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let prevBtn: HTMLButtonElement | null = null;
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let nextBtn: HTMLButtonElement | null = null;
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if (!isSingle && gallery.length > 1) {
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prevBtn = document.createElement("button");
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prevBtn.className = "lightbox-nav lightbox-prev";
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prevBtn.setAttribute("type", "button");
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prevBtn.setAttribute("aria-label", "上一张");
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prevBtn.textContent = "\u2039";
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nextBtn = document.createElement("button");
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nextBtn.className = "lightbox-nav lightbox-next";
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nextBtn.setAttribute("type", "button");
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nextBtn.setAttribute("aria-label", "下一张");
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nextBtn.textContent = "\u203a";
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}
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overlay.appendChild(img);
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overlay.appendChild(caption);
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overlay.appendChild(counter);
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if (prevBtn) overlay.appendChild(prevBtn);
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if (nextBtn) overlay.appendChild(nextBtn);
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document.body.appendChild(overlay);
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state = {
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overlay,
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img,
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caption,
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counter,
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prevBtn,
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nextBtn,
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originNode,
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gallery,
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index,
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isSingle,
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openScrollY: window.scrollY,
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origSrc,
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altText,
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closing: false,
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reduced: prefersReducedMotion(),
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scrollHandler: null,
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keyHandler: null,
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};
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// 焦点移入灯箱
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overlay.focus();
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// 立即绑定交互（不等图片加载）：加载期间 Esc/滚动/点背景也须可关闭。
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bindInteractions();
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// 图片加载后再做动画（naturalW/H 要等加载）
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const start = (): void => {
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if (!state) return; // 加载前可能已被关闭
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const naturalW = img.naturalWidth || img.clientWidth || 1;
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const naturalH = img.naturalHeight || img.clientHeight || 1;
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const originRect = rectOf(originNode);
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// 基准 = originRect（文章里图片的实际尺寸）。
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// img 的布局尺寸固定为 originRect，transform 的 scale 相对它缩放：
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// 首帧（文章位置）scale=1，居中态 scale=target.w/originRect.w。
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// 这样无论 target 比 originRect 大或小，动画都是「从文章图原样连续缩放」，
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// 视觉上是原地展开，不会像「从外面飞来」。灯箱图尺寸恒为视口最大（fitCentered）。
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const target = fitCentered(naturalW, naturalH, vw, vh);
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const baseW = originRect.w;
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const baseH = originRect.h;
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// 存基准与目标，供关闭/滚动关闭复用同一对（保证 scale 连续）。
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state.target = target;
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state.baseW = baseW;
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state.baseH = baseH;
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img.style.width = `${baseW}px`;
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img.style.height = `${baseH}px`;
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// reduced-motion：直接淡入居中
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if (state.reduced) {
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img.style.opacity = "0";
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img.style.transform = transformFor(target, baseW, baseH);
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img.style.left = "0";
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img.style.top = "0";
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overlay.style.opacity = "0";
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// 下一帧淡入
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requestAnimationFrame((): void => {
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if (!state) return;
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overlay.style.transition = "opacity 200ms ease-out";
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img.style.transition = "opacity 200ms ease-out";
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overlay.style.opacity = "1";
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img.style.opacity = "1";
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});
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return;
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}
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// 首帧：文章位置 + 原尺寸（scale=1），透明，且关闭 transition
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img.style.transition = "none";
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img.style.left = "0";
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img.style.top = "0";
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img.style.transform = transformFor(originRect, baseW, baseH);
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img.style.opacity = "0";
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overlay.style.opacity = "0";
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// 强制 reflow，确保首帧的 transform 已提交到渲染层。
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// 否则单层 rAF 里浏览器可能合并首帧与目标帧，动画从错误位置起跳。
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void img.offsetHeight;
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// double-rAF：第一帧绘制首帧（无动画），第二帧才启动 transition 到居中。
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requestAnimationFrame((): void => {
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if (!state) return;
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requestAnimationFrame((): void => {
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if (!state) return;
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img.style.transition =
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"transform 250ms ease-out, opacity 250ms ease-out";
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overlay.style.transition = "opacity 250ms ease-out";
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img.style.transform = transformFor(target, baseW, baseH);
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img.style.opacity = "1";
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overlay.style.opacity = "1";
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});
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});
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};
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if (img.complete && img.naturalWidth) {
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start();
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} else {
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img.addEventListener("load", start, { once: true });
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}
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img.src = origSrc;
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}
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function closeLightbox(immediate: boolean): void {
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if (!state || state.closing) return;
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state.closing = true;
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cleanupInteractions();
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const s = state;
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// 基准 = originRect 尺寸（与打开时一致），scale 相对它缩放。
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const baseW = s.baseW || (s.target ? s.target.w : 1);
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const baseH = s.baseH || (s.target ? s.target.h : 1);
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const originRect = rectOf(s.originNode); // 实时读，处理期间滚动过的情况
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if (s.reduced || immediate) {
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removeOverlay();
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return;
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}
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// 飞回 originRect：scale 从 1 缩到 originRect.w/baseW
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s.img.style.transition =
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"transform 250ms ease-out, opacity 250ms ease-out";
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s.overlay.style.transition = "opacity 250ms ease-out";
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s.img.style.transform = transformFor(originRect, baseW, baseH);
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s.img.style.opacity = "0";
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s.overlay.style.opacity = "0";
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const done = (): void => {
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removeOverlay();
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};
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// 250ms 兜底，避免 transitionend 不触发
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const timer = setTimeout(done, 280);
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s.img.addEventListener(
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"transitionend",
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(): void => {
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clearTimeout(timer);
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done();
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},
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{ once: true }
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);
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}
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function removeOverlay(): void {
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if (!state) return;
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const prev = state.originNode;
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if (state.overlay && state.overlay.parentNode) {
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state.overlay.parentNode.removeChild(state.overlay);
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}
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state = null;
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// 焦点归还：.blur-img 是 span 不可聚焦，让其内部 full img 获得焦点。
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// 用 preventScroll 抑制 focus() 默认的 scrollIntoView 行为——否则关闭灯箱后
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// 页面会自动滚动把原图完整纳入视口（用户只点了一半露出的图时尤其明显）。
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if (prev) {
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const f = prev.querySelector(".blur-img-full");
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if (f instanceof HTMLImageElement) {
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f.setAttribute("tabindex", "-1");
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f.focus({ preventScroll: true });
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}
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}
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}
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// ============ 图集切换 ============
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// 图集切换：淡入淡出，不飞行。newIndex 循环（首尾衔接）。
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function gotoIndex(rawIndex: number): void {
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if (!state || state.isSingle) return;
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const s = state;
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if (!s.gallery || s.gallery.length === 0) return;
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let newIndex = rawIndex;
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if (newIndex < 0) newIndex = s.gallery.length - 1;
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if (newIndex >= s.gallery.length) newIndex = 0;
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if (newIndex === s.index) return;
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const newNode = s.gallery[newIndex];
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const fullImgEl = newNode.querySelector(".blur-img-full");
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if (!(fullImgEl instanceof HTMLImageElement)) return;
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const origSrc = originalUrl(fullImgEl.getAttribute("data-src") || "");
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const altText = fullImgEl.getAttribute("alt") || "";
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// 淡出当前图
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s.img.style.transition = "opacity 150ms ease-out";
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s.img.style.opacity = "0";
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// 150ms 后换图淡入
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const swap = (): void => {
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if (!state) return; // 切换中可能已关闭
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const fade = (): void => {
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if (!state) return;
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s.img.style.transition = "opacity 150ms ease-out";
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s.img.style.opacity = "1";
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};
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if (s.img.complete && s.img.naturalWidth) {
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// 缓存命中，直接淡入
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s.img.src = origSrc;
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fade();
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} else {
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s.img.addEventListener("load", fade, { once: true });
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s.img.src = origSrc;
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}
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s.caption.textContent = altText;
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s.caption.style.display = altText ? "" : "none";
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s.counter.textContent = `${newIndex + 1} / ${s.gallery.length}`;
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// 更新 originNode 为新图，使后续关闭/滚动关闭飞回新图位置
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s.originNode = newNode;
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s.index = newIndex;
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s.openScrollY = window.scrollY; // 重置滚动关闭基线
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};
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setTimeout(swap, 150);
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}
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// ============ 交互绑定 ============
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function bindInteractions(): void {
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const s = state;
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if (!s) return;
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// 点背景关闭（点图片本身不关，因箭头在图上、避免误关）
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s.overlay.addEventListener("click", (ev: MouseEvent): void => {
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if (state && ev.target === state.overlay) closeLightbox(false);
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});
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// 滚动驱动关闭：任何 scroll 都触发，用 scrollY 偏移算进度。
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// 关键：逐帧读 originNode 实时 rect，文章滚多少图就回多少。
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s.scrollHandler = (): void => {
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if (!state) return;
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const st = state;
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if (st.closing) return;
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const dy = Math.abs(window.scrollY - st.openScrollY);
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if (st.reduced) {
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// reduced-motion：立即关
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closeLightbox(true);
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return;
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}
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const target = st.target;
|
||
const baseW = st.baseW || (target ? target.w : 1);
|
||
const baseH = st.baseH || (target ? target.h : 1);
|
||
const originRect = rectOf(st.originNode);
|
||
if (!target) return; // 无 target 时不插值（忠实原 JS 的兜底语义）
|
||
// 在 originRect 与居中 target 之间按 progress 线性插值
|
||
const progress = Math.min(dy / 120, 1);
|
||
const cur: Rect = {
|
||
x: target.x + (originRect.x - target.x) * progress,
|
||
y: target.y + (originRect.y - target.y) * progress,
|
||
w: target.w + (originRect.w - target.w) * progress,
|
||
h: target.h + (originRect.h - target.h) * progress,
|
||
};
|
||
st.img.style.transition = "none";
|
||
st.img.style.transform = transformFor(cur, baseW, baseH);
|
||
st.img.style.opacity = String(1 - progress);
|
||
st.overlay.style.opacity = String(1 - progress);
|
||
if (progress >= 1) {
|
||
// 已飞回原位：文章停在当前滚动位置，移除灯箱
|
||
st.closing = true;
|
||
cleanupInteractions();
|
||
removeOverlay();
|
||
}
|
||
};
|
||
window.addEventListener("scroll", s.scrollHandler, { passive: true });
|
||
|
||
// 键盘：Esc 关；图集模式 ←→ 切换
|
||
s.keyHandler = (ev: KeyboardEvent): void => {
|
||
if (!state) return;
|
||
if (ev.key === "Escape") {
|
||
closeLightbox(false);
|
||
} else if (!state.isSingle && state.gallery.length > 1) {
|
||
if (ev.key === "ArrowLeft") {
|
||
ev.preventDefault();
|
||
gotoIndex((state.index ?? 0) - 1);
|
||
} else if (ev.key === "ArrowRight") {
|
||
ev.preventDefault();
|
||
gotoIndex((state.index ?? 0) + 1);
|
||
}
|
||
}
|
||
};
|
||
document.addEventListener("keydown", s.keyHandler);
|
||
|
||
// 图集导航箭头点击（stopPropagation 防止冒泡到 overlay 触发关闭）
|
||
s.prevBtn?.addEventListener("click", (ev: MouseEvent): void => {
|
||
ev.stopPropagation();
|
||
if (state) gotoIndex((state.index ?? 0) - 1);
|
||
});
|
||
s.nextBtn?.addEventListener("click", (ev: MouseEvent): void => {
|
||
ev.stopPropagation();
|
||
if (state) gotoIndex((state.index ?? 0) + 1);
|
||
});
|
||
}
|
||
|
||
function cleanupInteractions(): void {
|
||
if (!state) return;
|
||
if (state.scrollHandler) {
|
||
window.removeEventListener("scroll", state.scrollHandler);
|
||
state.scrollHandler = null;
|
||
}
|
||
if (state.keyHandler) {
|
||
document.removeEventListener("keydown", state.keyHandler);
|
||
state.keyHandler = null;
|
||
}
|
||
}
|
||
|
||
// ============ 初始化入口 ============
|
||
|
||
window.__initLightbox = (selectors: string | string[]): void => {
|
||
// selectors 可以是字符串、字符串数组
|
||
const sels = Array.isArray(selectors) ? selectors : [selectors];
|
||
const roots: Element[] = [];
|
||
for (const sel of sels) {
|
||
const found = document.querySelectorAll(sel);
|
||
for (const el of found) roots.push(el);
|
||
}
|
||
|
||
// 先对所有图片做懒加载（图集与单张都做）
|
||
const collected = collectImages(roots);
|
||
for (const node of collected.gallery.concat(collected.singles)) {
|
||
initLazyLoad(node);
|
||
}
|
||
|
||
// 正文图：带 index。for..of + const 天然捕获每次迭代的 idx，
|
||
// 无需旧 IIFE 包装（旧 var 循环闭包必须立即执行函数固定变量）。
|
||
const gallery = collected.gallery;
|
||
gallery.forEach((node, idx) => {
|
||
node.addEventListener("click", (e: MouseEvent) => {
|
||
e.preventDefault();
|
||
openLightbox(node, gallery, idx);
|
||
});
|
||
});
|
||
// 单张图（封面）：index = null，gallery 传空数组表示单张
|
||
for (const node of collected.singles) {
|
||
node.addEventListener("click", (e: MouseEvent) => {
|
||
e.preventDefault();
|
||
openLightbox(node, [], null);
|
||
});
|
||
}
|
||
};
|
||
|
||
// ============ 自启动 ============
|
||
// 方案 iii：双保险契约，无需轮询。
|
||
// 1) Rust 内联 eval 先跑（常态）：设 __lightboxSelectors，此时 __initLightbox 可能未定义 → 只设配置；
|
||
// lightbox.js 后加载完 → 读到配置 → 这里自启动。
|
||
// 2) lightbox.js 先加载完：__initLightbox 就绪但无配置 → 不自启动；
|
||
// Rust eval 后跑 → 设配置 + 兜底 if(__initLightbox) 显式调用 → 初始化。
|
||
if (Array.isArray(window.__lightboxSelectors)) {
|
||
window.__initLightbox(window.__lightboxSelectors);
|
||
}
|