Export actually exports: PDF by printing, PPTX as native objects

kits/slides/app/package.json

@@ -9,13 +9,14 @@
   "dependencies": {
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
-    "reifyui": "^0.4.1",
+    "reifyui": "^0.4.2",
     "echarts": "^5.5.1",
     "mermaid": "^11.4.1",
     "highlight.js": "^11.10.0",
     "lucide-react": "^0.469.0",
     "react-markdown": "^9.0.1",
-    "remark-gfm": "^4.0.0"
+    "remark-gfm": "^4.0.0",
+    "pptxgenjs": "^4.0.1"
   },
   "devDependencies": {
     "@vitejs/plugin-react": "^4.3.4",

kits/slides/app/src/App.jsx

@@ -15,7 +15,9 @@ function parseHash() {
   const raw = window.location.hash.replace(/^#\/?/, '');
   const [path, query = ''] = raw.split('?');
   const params = new URLSearchParams(query);
-  if (path === 'print') return { page: 'print' };
+  if (path === 'print') {
+    return { page: 'print', handoff: params.get('h') || '', id: params.get('deck') || '' };
+  }
   if (path.startsWith('d/')) {
     return { page: 'deck', id: decodeURIComponent(path.slice(2)),
              seed: params.get('seed') || '', template: params.get('tpl') || '' };
@@ -32,7 +34,7 @@ export default function App() {
     return () => window.removeEventListener('hashchange', onHash);
   }, []);
 
-  if (route.page === 'print') return <PrintPage />;
+  if (route.page === 'print') return <PrintPage handoff={route.handoff} id={route.id} />;
   if (route.page === 'deck') {
     return <DeckPage key={route.id} id={route.id} seed={route.seed} template={route.template} />;
   }

kits/slides/app/src/components/Dialog.jsx

@@ -59,3 +59,18 @@ export function NameDialog({ title, body, defaultValue = '', confirmLabel = 'Cre
     </Dialog>
   );
 }
+
+/** A message the person must acknowledge. In-app, never window.alert — a browser popup is the
+ *  clearest signal a product was not finished, and it cannot carry detail or styling. */
+export function AlertDialog({ title, body, detail, onClose }) {
+  return (
+    <Dialog onClose={onClose}>
+      <h3>{title}</h3>
+      <div className="body">
+        {Array.isArray(body) ? body.map((line, i) => <p key={i}>{line}</p>) : body}
+      </div>
+      {detail && <pre className="dlg-detail">{detail}</pre>}
+      <div className="foot"><button className="btn primary" onClick={onClose}>OK</button></div>
+    </Dialog>
+  );
+}

kits/slides/app/src/lib/exportPdf.js

@@ -0,0 +1,44 @@
+// PDF export: the browser's own print pipeline, pointed at a fixed print surface.
+//
+// There is no export service in this deployment, and this is not a compromise — printing #/print
+// renders the deck through the SAME components the canvas uses, so text stays selectable vector
+// and charts stay vector (the chart element already renders SVG). Any library that rasterises the
+// slide would be larger, slower and worse.
+//
+// The honest cost, stated in the UI rather than hidden: this opens the system print dialog. We
+// cannot name the file or choose the destination, so the menu says "Print to PDF…", not
+// "download".
+const KEY = 'slides.print.';
+const STALE_MS = 5 * 60 * 1000;
+
+/** Hand the LIVE deck to the print tab.
+ *
+ *  Deliberately not "let the print tab load it by id": autosave is debounced and is refused with
+ *  409 while a turn is running, so the file on disk is not always what the person is looking at.
+ *  Printing something other than what is on screen would be its own bug.
+ *
+ *  Must run inside the click. Opening the tab after an await loses user activation and the
+ *  browser blocks it as a popup.
+ */
+export function openPrintView(id, deck) {
+  for (const k of Object.keys(localStorage)) {
+    if (k.startsWith(KEY) && Date.now() - Number(k.slice(KEY.length)) > STALE_MS) {
+      localStorage.removeItem(k);   // a handoff nobody collected (tab closed, print cancelled)
+    }
+  }
+
+  const key = KEY + Date.now();
+  try {
+    localStorage.setItem(key, JSON.stringify({ id, deck }));
+  } catch {
+    throw new Error('This deck is too large to hand to the print view.');
+  }
+
+  const url = `${window.location.pathname}#/print?h=${encodeURIComponent(key)}`
+            + `&deck=${encodeURIComponent(id || '')}`;
+  const tab = window.open(url, '_blank');
+  if (!tab) {
+    localStorage.removeItem(key);
+    throw new Error('Your browser blocked the print tab. Allow pop-ups for this page, then try Export again.');
+  }
+}