fix: canvas插入到Leaflet tilePane之后,确保在最上层渲染

Co-Authored-By: Claude <noreply@anthropic.com>

simple_analysis/templates/simple_analysis/simple_analysis.html

@@ -2753,20 +2753,34 @@ function trafficAnimate(timestamp) {
     _trafficAnimId = requestAnimationFrame(trafficAnimate);
 }
 
+let _trafficLeafletLayer = null;
+
 function _ensureTrafficCanvas() {
-    const container = document.getElementById('saMap');
-    if (!container) return null;
+    // Use Leaflet's internal renderer canvas for proper layering
+    if (!SA.map) return null;
+    // Access the internal canvas renderer
+    const pane = SA.map.getPane('overlayPane');
+    if (!pane) return null;
     let c = document.getElementById('saTrafficCanvas');
     if (!c) {
         c = document.createElement('canvas');
         c.id = 'saTrafficCanvas';
         c.style.cssText = 'position:absolute;top:0;left:0;pointer-events:none;z-index:99999;';
-        container.appendChild(c);
-    }
-    const rect = container.getBoundingClientRect();
-    if (c.width !== rect.width || c.height !== rect.height) {
-        c.width = rect.width; c.height = rect.height;
-        c.style.width = rect.width + 'px'; c.style.height = rect.height + 'px';
+        c.width = SA.map.getSize().x; c.height = SA.map.getSize().y;
+        c.style.width = c.width + 'px'; c.style.height = c.height + 'px';
+        // Insert AFTER the Leaflet canvas (tile pane)
+        const tilePane = SA.map.getPane('tilePane');
+        if (tilePane && tilePane.parentNode) {
+            tilePane.parentNode.appendChild(c);
+        } else {
+            pane.appendChild(c);
+        }
+        // Resize handler
+        SA.map.on('resize', () => {
+            const s = SA.map.getSize();
+            c.width = s.x; c.height = s.y;
+            c.style.width = s.x + 'px'; c.style.height = s.y + 'px';
+        });
     }
     return c;
 }