live preview troubleshooting

templates/index_v2.html

@@ -1779,11 +1779,19 @@
 
         // Socket.IO connection
         function initializeSocket() {
-            socket = io({ transports: ['websocket', 'polling'] });
+            socket = io({
+                path: '/socket.io',
+                transports: ['websocket', 'polling'],
+                reconnection: true,
+                reconnectionAttempts: Infinity,
+                reconnectionDelay: 1000,
+                reconnectionDelayMax: 10000
+            });
             
             socket.on('connect', function() {
                 updateConnectionStatus(true);
                 showNotification('Connected to LED Matrix', 'success');
+                stopPreviewPolling();
             });
             
             socket.on('disconnect', function() {
@@ -1800,6 +1808,12 @@
                     }, delay);
                 };
                 retry();
+                startPreviewPolling();
+            });
+            
+            socket.on('connect_error', function(_err){
+                updateConnectionStatus(false);
+                startPreviewPolling();
             });
             
             socket.on('display_update', function(data) {
@@ -1807,6 +1821,24 @@
             });
         }
 
+        // Fallback polling when websocket is disconnected
+        let __previewPollTimer = null;
+        function startPreviewPolling(){
+            if (__previewPollTimer) return;
+            __previewPollTimer = setInterval(fetchCurrentDisplayOnce, 1000);
+        }
+        function stopPreviewPolling(){
+            if (__previewPollTimer) clearInterval(__previewPollTimer);
+            __previewPollTimer = null;
+        }
+        async function fetchCurrentDisplayOnce(){
+            try {
+                const res = await fetch('/api/display/current');
+                const data = await res.json();
+                if (data && data.image) updateDisplayPreview(data);
+            } catch (_) {}
+        }
+
         // Draw pixel grid lines on top of scaled image
         function drawGrid(canvas, logicalWidth, logicalHeight, scale) {
             const show = document.getElementById('toggleGrid')?.checked;

web_interface_v2.py

@@ -851,9 +851,23 @@ def get_current_display():
 def handle_connect():
     """Handle client connection."""
     emit('connected', {'status': 'Connected to LED Matrix Interface'})
-    # Send current display state
+    # Send current display state immediately after connect
-    if current_display_data:
+    try:
-        emit('display_update', current_display_data)
+        if display_manager and hasattr(display_manager, 'image'):
+            img_buffer = io.BytesIO()
+            display_manager.image.save(img_buffer, format='PNG')
+            img_str = base64.b64encode(img_buffer.getvalue()).decode()
+            payload = {
+                'image': img_str,
+                'width': display_manager.width,
+                'height': display_manager.height,
+                'timestamp': time.time()
+            }
+            emit('display_update', payload)
+        elif current_display_data:
+            emit('display_update', current_display_data)
+    except Exception as e:
+        logger.error(f"Error sending initial display_update on connect: {e}")
 
 @socketio.on('disconnect')
 def handle_disconnect():
@@ -872,7 +886,7 @@ if __name__ == '__main__':
     signal.signal(signal.SIGINT, signal_handler)
     signal.signal(signal.SIGTERM, signal_handler)
     
-    # Start the display monitor
+    # Start the display monitor (runs even if display is not started yet for web preview)
     display_monitor.start()
     
     # Run the app