Scan-Feedback roter/grüner Rahmen + BarcodeDetector-Fallback + gestufte Kameraauflösung + HTTPS-Hinweis

app.js

@@ -8,6 +8,16 @@
 
   const $ = id => document.getElementById(id);
 
+  let barcodeDetector = null;
+  (async () => {
+    if ('BarcodeDetector' in window) {
+      try {
+        const f = await BarcodeDetector.getSupportedFormats();
+        if (f.includes('qr_code')) barcodeDetector = new BarcodeDetector({ formats: ['qr_code'] });
+      } catch (_) {}
+    }
+  })();
+
   if (location.search.includes('debug')) {
     document.body.classList.add('debug-mode');
   }
@@ -72,29 +82,41 @@
   /* ─── Camera ─── */
   let camStream = null;
   let camRaf = null;
+  let camVideoEl = null;
 
   async function camStart(videoId) {
     await camStop();
-    try {
-      camStream = await navigator.mediaDevices.getUserMedia({
-        video: { facingMode: { ideal: 'environment' }, width: { ideal: 1920 }, height: { ideal: 1080 } }
-      });
-    } catch (_) {
-      camStream = await navigator.mediaDevices.getUserMedia({ video: true });
+    let stream = null;
+    const resolutions = [
+      { facingMode: { ideal: 'environment' }, width: { ideal: 1920 }, height: { ideal: 1080 } },
+      { facingMode: { ideal: 'environment' }, width: { ideal: 1280 }, height: { ideal: 720 } },
+      { video: true }
+    ];
+    for (const vc of resolutions) {
+      try { stream = await navigator.mediaDevices.getUserMedia({ video: vc }); break; } catch (_) {}
     }
+    if (!stream) {
+      if (location.protocol !== 'https:' && location.hostname !== 'localhost' && location.hostname !== '127.0.0.1') {
+        throw new Error('Kamera benötigt HTTPS – verwende localhost oder lade ein Zertifikat');
+      }
+      throw new Error('Kamera nicht verfügbar oder verweigert');
+    }
+    camStream = stream;
     const v = $(videoId);
-    v.srcObject = camStream;
+    camVideoEl = v;
+    v.srcObject = stream;
     v.setAttribute('playsinline', '');
     v.classList.add('active');
     await v.play();
     try {
-      const track = camStream.getVideoTracks()[0];
+      const track = stream.getVideoTracks()[0];
       if (track) track.applyConstraints({ advanced: [{ focusMode: 'continuous' }] });
     } catch (_) {}
     return v;
   }
 
   function camStop() {
+    if (camVideoEl) { camVideoEl.classList.remove('scan-active', 'scan-done'); camVideoEl = null; }
     if (camRaf) { cancelAnimationFrame(camRaf); camRaf = null; }
     if (camStream) { camStream.getTracks().forEach(t => t.stop()); camStream = null; }
   }
@@ -104,21 +126,39 @@
     const c = $(canvasId);
     const ctx = c.getContext('2d', { willReadFrequently: true });
     let lastScan = 0;
+    v.classList.add('scan-active');
+
+    const detect = barcodeDetector
+      ? async () => {
+          const codes = await barcodeDetector.detect(v);
+          return codes.length ? codes[0].rawValue : null;
+        }
+      : async () => {
+          c.width = v.videoWidth; c.height = v.videoHeight;
+          ctx.drawImage(v, 0, 0);
+          const img = ctx.getImageData(0, 0, c.width, c.height);
+          const code = jsQR(img.data, img.width, img.height, { inversionAttempts: 'attemptBoth' });
+          return code ? code.data : null;
+        };
+
     camRaf = requestAnimationFrame(async function tick(now) {
       if (!v.videoWidth) { camRaf = requestAnimationFrame(tick); return; }
       if (now - lastScan < 100) { camRaf = requestAnimationFrame(tick); return; }
       lastScan = now;
-      c.width = v.videoWidth; c.height = v.videoHeight;
-      ctx.drawImage(v, 0, 0);
-      const img = ctx.getImageData(0, 0, c.width, c.height);
-      const code = jsQR(img.data, img.width, img.height, { inversionAttempts: 'dontInvert' });
-      if (code && code.data) {
-        try {
-          const bytes = decode45(code.data);
+      try {
+        const raw = await detect();
+        if (raw) {
+          const bytes = decode45(raw);
           const p = await unpack(bytes);
-          if (p.v === 1) { callback(p, code.data); return; }
-        } catch(e) {}
-      }
+          if (p.v === 1) {
+            v.classList.remove('scan-active');
+            v.classList.add('scan-done');
+            setTimeout(() => v.classList.remove('scan-done'), 600);
+            callback(p, raw);
+            return;
+          }
+        }
+      } catch (_) {}
       camRaf = requestAnimationFrame(tick);
     });
   }
@@ -291,7 +331,7 @@
       });
       $('btn-scan-answer').textContent = 'Scannen beenden';
     } catch (e) {
-      $('host-scan-status').textContent = 'Kamera-Fehler';
+      $('host-scan-status').textContent = e.message;
     }
   });
 
@@ -353,7 +393,7 @@
         await mesh.joinFromQR(raw);
       });
     } catch (e) {
-      $('join-scan-status').textContent = 'Kamera nicht verfügbar';
+      $('join-scan-status').textContent = e.message;
     }
   });
 

style.css

@@ -192,6 +192,15 @@ h3 {
   max-width: 320px;
   border-radius: var(--radius);
   border: 2px solid var(--border);
+  transition: border-color 0.15s, box-shadow 0.15s;
+}
+video.scan-active {
+  border-color: #ff4444 !important;
+  box-shadow: 0 0 12px rgba(255,68,68,0.4);
+}
+video.scan-done {
+  border-color: #44ff44 !important;
+  box-shadow: 0 0 12px rgba(68,255,68,0.4);
 }
 
 /* Protocol status */
@@ -341,6 +350,7 @@ h3 {
   border-radius: var(--radius);
   display: none;
   margin: 8px auto;
+  transition: border-color 0.15s, box-shadow 0.15s;
 }
 #host-camera.active {
   display: block;