fix more than needed rebuilds on canvas children

this used a stupid builderFunc instead of a widget so flutter wasn't able to optimise those widget builds and it was simply a blanket rebuild. Added more examples as well
2025-07-26 17:47:42 +00:00
parent 96e55a7157
commit 7ad54a92cb
8 changed files with 427 additions and 12 deletions
@@ -0,0 +1,86 @@
+import 'package:flutter/material.dart';
+import 'package:infinite_lazy_grid/infinite_lazy_grid.dart';
+import 'widgets/build_counter_widget.dart';
+
+class CachingTestApp extends StatefulWidget {
+  const CachingTestApp({super.key});
+
+  @override
+  State<CachingTestApp> createState() => _CachingTestAppState();
+}
+
+class _CachingTestAppState extends State<CachingTestApp> {
+  final LazyCanvasController controller = LazyCanvasController(debug: false);
+
+  @override
+  void initState() {
+    super.initState();
+
+    // Add some test widgets
+    for (int i = 0; i < 20; i++) {
+      controller.addChild(
+        Offset((i % 5) * 120.0, (i ~/ 5) * 120.0),
+        BuildCounterWidget(color: Colors.primaries[i % Colors.primaries.length], label: 'Widget $i'),
+      );
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('Widget Caching Test'),
+        actions: [
+          IconButton(
+            onPressed: () {
+              // Force a rebuild by calling notifyListeners
+              // In this new approach, Flutter handles the caching
+              ScaffoldMessenger.of(context).showSnackBar(
+                const SnackBar(
+                  content: Text('Flutter automatically handles widget caching - no manual invalidation needed!'),
+                ),
+              );
+            },
+            icon: const Icon(Icons.refresh),
+            tooltip: 'Flutter Auto-Caching Info',
+          ),
+        ],
+      ),
+      body: Column(
+        children: [
+          Container(
+            padding: const EdgeInsets.all(16),
+            color: Colors.yellow[100],
+            child: const Text(
+              'Instructions:\n'
+              '• Pan around the canvas - widgets should only build once initially\n'
+              '• Watch the console for build messages\n'
+              '• Use the refresh button to force rebuilds\n'
+              '• Zoom in/out to see caching in action',
+              style: TextStyle(fontSize: 12),
+            ),
+          ),
+          Expanded(
+            child: LazyCanvas(controller: controller, canvasBackground: const DotGridBackround()),
+          ),
+        ],
+      ),
+      floatingActionButton: Column(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          FloatingActionButton(
+            heroTag: 'zoom_in',
+            onPressed: () => controller.updateScalebyDelta(0.1),
+            child: const Icon(Icons.zoom_in),
+          ),
+          const SizedBox(height: 8),
+          FloatingActionButton(
+            heroTag: 'zoom_out',
+            onPressed: () => controller.updateScalebyDelta(-0.1),
+            child: const Icon(Icons.zoom_out),
+          ),
+        ],
+      ),
+    );
+  }
+}