/**
* — HTML幻灯片外壳web component
*
* 提供功能：
* - 固定尺寸canvas（默认1920×1080）+ auto-scale + letterbox
* - 键盘导航（←/→/Space/Home/End/Esc）
* - 左右点击区域导航
* - slide counter (当前/总数)
* - localStorage持久化当前slide
* - Speaker notes postMessage (支持外层渲染)
* - Hash导航 (#slide-5 跳到第5张)
* - Print-to-PDF支持 (Cmd+P / Ctrl+P 一页一slide)
* - 自动给每个slide添加 data-screen-label
*
* 用法：
*
*
*
*
*
* 自定义尺寸：
* ...
*
* Speaker notes：在加
*
*/
(function() {
const STORAGE_KEY_PREFIX = 'deck-stage-slide-';
class DeckStage extends HTMLElement {
constructor() {
super();
this.attachShadow({ mode: 'open' });
this._currentSlide = 0;
this._slides = [];
this._storageKey = STORAGE_KEY_PREFIX + (location.pathname || 'default');
}
connectedCallback() {
this._width = parseInt(this.getAttribute('width')) || 1920;
this._height = parseInt(this.getAttribute('height')) || 1080;
// Shadow DOM 先渲染（独立于子节点，不受 parser 时机影响）
this._render();
// 防御：若 script 放在 里（而非 之后），
// parser 此刻可能还没处理完子 ，querySelectorAll 会返回空。
// 延迟到下一个事件循环，确保子节点都已 parse 完毕。
const init = () => {
this._collectSlides();
this._setupEventListeners();
this._restoreSlide();
this._updateDisplay();
this._setupPrintStyles();
};
if (this.ownerDocument.readyState === 'loading') {
// 文档还在 parse，等 DOMContentLoaded 一次搞定所有 section
this.ownerDocument.addEventListener('DOMContentLoaded', init, { once: true });
} else {
// 文档已 parse 完（script 在 body 底部或 defer），下一帧收集即可
requestAnimationFrame(init);
}
}
_render() {
this.shadowRoot.innerHTML = `
1 / 1
`;
}
_collectSlides() {
this._slides = Array.from(this.querySelectorAll(':scope > section'));
this._slides.forEach((slide, idx) => {
if (!slide.hasAttribute('data-screen-label')) {
const num = String(idx + 1).padStart(2, '0');
slide.setAttribute('data-screen-label', num);
}
if (!slide.hasAttribute('data-om-validate')) {
slide.setAttribute('data-om-validate', '');
}
});
}
_setupEventListeners() {
window.addEventListener('resize', () => this._updateScale());
document.addEventListener('keydown', (e) => {
if (e.target.matches('input, textarea, [contenteditable]')) return;
switch (e.key) {
case 'ArrowRight':
case ' ':
case 'PageDown':
e.preventDefault();
this.next();
break;
case 'ArrowLeft':
case 'PageUp':
e.preventDefault();
this.prev();
break;
case 'Home':
e.preventDefault();
this.goTo(0);
break;
case 'End':
e.preventDefault();
this.goTo(this._slides.length - 1);
break;
}
});
this.shadowRoot.getElementById('navLeft').addEventListener('click', () => this.prev());
this.shadowRoot.getElementById('navRight').addEventListener('click', () => this.next());
window.addEventListener('hashchange', () => this._handleHash());
if (location.hash) {
setTimeout(() => this._handleHash(), 0);
}
const observer = new MutationObserver(() => {
if (this.hasAttribute('noscale')) {
this._updateScale();
}
});
observer.observe(this, { attributes: true, attributeFilter: ['noscale'] });
}
_handleHash() {
const match = location.hash.match(/^#slide-(\d+)$/);
if (match) {
const idx = parseInt(match[1]) - 1;
if (idx >= 0 && idx < this._slides.length) {
this.goTo(idx);
}
}
}
_restoreSlide() {
try {
const stored = localStorage.getItem(this._storageKey);
if (stored !== null) {
const idx = parseInt(stored);
if (idx >= 0 && idx < this._slides.length) {
this._currentSlide = idx;
}
}
} catch (e) {}
}
_saveSlide() {
try {
localStorage.setItem(this._storageKey, String(this._currentSlide));
} catch (e) {}
}
_updateScale() {
if (this.hasAttribute('noscale')) {
const stage = this.shadowRoot.getElementById('stage');
stage.style.transform = 'none';
stage.style.top = '0';
stage.style.left = '0';
return;
}
const stage = this.shadowRoot.getElementById('stage');
if (!stage) return;
const viewportW = window.innerWidth;
const viewportH = window.innerHeight;
const scale = Math.min(viewportW / this._width, viewportH / this._height);
const scaledW = this._width * scale;
const scaledH = this._height * scale;
const offsetX = (viewportW - scaledW) / 2;
const offsetY = (viewportH - scaledH) / 2;
stage.style.transform = `translate(${offsetX}px, ${offsetY}px) scale(${scale})`;
stage.style.top = '0';
stage.style.left = '0';
}
_updateDisplay() {
this._slides.forEach((slide, idx) => {
slide.classList.toggle('active', idx === this._currentSlide);
});
const counter = this.shadowRoot.getElementById('counter');
if (counter) {
counter.textContent = `${this._currentSlide + 1} / ${this._slides.length}`;
}
this._updateScale();
try {
window.postMessage({
slideIndexChanged: this._currentSlide,
totalSlides: this._slides.length
}, '*');
} catch (e) {}
try {
if (window.parent && window.parent !== window) {
window.parent.postMessage({
slideIndexChanged: this._currentSlide,
totalSlides: this._slides.length
}, '*');
}
} catch (e) {}
}
_setupPrintStyles() {
const printStyle = document.createElement('style');
printStyle.textContent = `
@media print {
@page {
size: ${this._width}px ${this._height}px;
margin: 0;
}
body {
margin: 0;
padding: 0;
}
deck-stage {
position: static !important;
}
deck-stage > section {
display: block !important;
position: relative !important;
width: ${this._width}px !important;
height: ${this._height}px !important;
page-break-after: always;
overflow: hidden;
}
deck-stage > section:last-child {
page-break-after: auto;
}
}
`;
document.head.appendChild(printStyle);
}
next() {
if (this._currentSlide < this._slides.length - 1) {
this._currentSlide++;
this._saveSlide();
this._updateDisplay();
}
}
prev() {
if (this._currentSlide > 0) {
this._currentSlide--;
this._saveSlide();
this._updateDisplay();
}
}
goTo(idx) {
if (idx >= 0 && idx < this._slides.length) {
this._currentSlide = idx;
this._saveSlide();
this._updateDisplay();
}
}
get currentSlide() {
return this._currentSlide;
}
get totalSlides() {
return this._slides.length;
}
}
customElements.define('deck-stage', DeckStage);
window.DeckStage = DeckStage;
})();