v_1.7

2026-09-13 20:23:05 +01:00
commit 34900bf069
45 changed files with 4879 additions and 0 deletions
@@ -0,0 +1,90 @@
+// Loads PDF.js (vendored first, CDN fallback) and renders one page at a time,
+// scaled to fit its container and sharp on high-DPI screens.
+
+let readyPromise = null;
+
+function loadScript(src) {
+  return new Promise((resolve, reject) => {
+    const s = document.createElement('script');
+    s.src = src;
+    s.onload = resolve;
+    s.onerror = () => reject(new Error('Failed to load ' + src));
+    document.head.appendChild(s);
+  });
+}
+
+export function ensurePdfjs() {
+  if (window.pdfjsLib) return Promise.resolve();
+  if (readyPromise) return readyPromise;
+
+  const CDN = 'https://cdnjs.cloudflare.com/ajax/libs/pdf.js/3.11.174';
+  readyPromise = loadScript('/vendor/pdfjs/pdf.min.js')
+    .then(() => {
+      if (!window.pdfjsLib) throw new Error('vendor missing');
+      window.__pdfWorker = '/vendor/pdfjs/pdf.worker.min.js';
+    })
+    .catch(() => loadScript(`${CDN}/pdf.min.js`).then(() => {
+      window.__pdfWorker = `${CDN}/pdf.worker.min.js`;
+    }))
+    .then(() => {
+      window.pdfjsLib.GlobalWorkerOptions.workerSrc = window.__pdfWorker;
+    });
+  return readyPromise;
+}
+
+export class PdfViewer {
+  constructor(container) {
+    this.container = container;
+    this.canvas = document.createElement('canvas');
+    this.canvas.className = 'pdf-canvas';
+    this.ctx = this.canvas.getContext('2d');
+    container.appendChild(this.canvas);
+    this.pdf = null;
+    this.numPages = 0;
+    this.page = 1;
+    this._busy = false;
+    this._queued = null;
+    this._onResize = () => this.refit();
+    window.addEventListener('resize', this._onResize);
+  }
+
+  async load(url) {
+    await ensurePdfjs();
+    this.pdf = await window.pdfjsLib.getDocument(url).promise;
+    this.numPages = this.pdf.numPages;
+    return this.numPages;
+  }
+
+  async render(n) {
+    if (!this.pdf) return;
+    n = Math.max(1, Math.min(this.numPages, Math.trunc(n) || 1));
+    this.page = n;
+    if (this._busy) { this._queued = n; return; }
+    this._busy = true;
+    try {
+      const page = await this.pdf.getPage(n);
+      const base = page.getViewport({ scale: 1 });
+      const cw = this.container.clientWidth || 800;
+      const ch = this.container.clientHeight || 600;
+      const dpr = Math.min(window.devicePixelRatio || 1, 2);
+      const fit = Math.min(cw / base.width, ch / base.height);
+      const vp = page.getViewport({ scale: fit * dpr });
+      this.canvas.width = Math.floor(vp.width);
+      this.canvas.height = Math.floor(vp.height);
+      this.canvas.style.width = Math.floor(vp.width / dpr) + 'px';
+      this.canvas.style.height = Math.floor(vp.height / dpr) + 'px';
+      await page.render({ canvasContext: this.ctx, viewport: vp }).promise;
+    } finally {
+      this._busy = false;
+      if (this._queued !== null) {
+        const q = this._queued;
+        this._queued = null;
+        if (q !== n) this.render(q);
+      }
+    }
+  }
+
+  refit() { if (this.pdf) this.render(this.page); }
+
+  destroy() { window.removeEventListener('resize', this._onResize); }
+}