Fix: NOverlayImage.fromWidget cause Memory Leak by undisposed.

Author: note11g

example/integration_test/widget_to_image_test.dart

@@ -0,0 +1,102 @@
+import "package:flutter/material.dart";
+import "package:flutter_naver_map/flutter_naver_map.dart";
+import "package:flutter_naver_map/src/util/widget_to_image.dart";
+import "package:flutter_test/flutter_test.dart";
+
+void main() {
+  testWidgets("NOverlayImage.fromWidget MemoryLeak test", (tester) async {
+    const myAppPageKey = Key("MyApp");
+    const stfulWidgetKey = Key("stfulA");
+    await tester.pumpWidget(
+        const _MyApp(key: myAppPageKey, stfulWidgetKey: stfulWidgetKey));
+
+    await tester.pump();
+
+    final stfulWidgetFinder = find.byKey(stfulWidgetKey);
+    final _StFulTestWidgetState statefulWidgetState =
+        tester.state(stfulWidgetFinder);
+
+    expect(statefulWidgetState.count, 0);
+
+    // dispose test : case normal attach to widgetTree
+    final _MyAppState myAppState = tester.state(find.byKey(myAppPageKey));
+    myAppState.disposeStfulTestWidget();
+    await tester.pump();
+
+    print(statefulWidgetState.mounted);
+    expect(statefulWidgetState.mounted, false); // : isDisposed
+
+    // dispose test : case attach to NOverlayImage.fromWidget inner canvas (virtual canvas)
+    final buildContext = myAppState.context;
+    final widgetToImageBytes = await WidgetToImageUtil.widgetToImageByte(
+        const StFulTestWidget(),
+        size: const Size(40, 80),
+        context: buildContext);
+    print(widgetToImageBytes.length);
+    expect(widgetToImageBytes.length > 100, true); // successful created test
+
+    print("test end");
+  });
+}
+
+class _MyApp extends StatefulWidget {
+  final Key stfulWidgetKey;
+
+  const _MyApp({super.key, required this.stfulWidgetKey});
+
+  @override
+  State<_MyApp> createState() => _MyAppState();
+}
+
+class _MyAppState extends State<_MyApp> {
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+        home: Scaffold(
+      body: disposeSwitchFlag
+          ? const SizedBox()
+          : StFulTestWidget(key: widget.stfulWidgetKey),
+    ));
+  }
+
+  bool disposeSwitchFlag = false;
+
+  void disposeStfulTestWidget() {
+    disposeSwitchFlag = true;
+    setState(() {});
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    print("_MyApp dispose");
+  }
+}
+
+class StFulTestWidget extends StatefulWidget {
+  const StFulTestWidget({super.key});
+
+  @override
+  State<StFulTestWidget> createState() => _StFulTestWidgetState();
+}
+
+class _StFulTestWidgetState extends State<StFulTestWidget> {
+  final count = 0;
+
+  @override
+  Widget build(BuildContext context) {
+    return const Placeholder();
+  }
+
+  @override
+  void initState() {
+    print("initState: $this");
+    super.initState();
+  }
+
+  @override
+  void dispose() {
+    print("dispose: $this");
+    super.dispose();
+  }
+}

lib/src/util/widget_to_image.dart

@@ -1,24 +1,29 @@
 import "dart:typed_data" show Uint8List;
-import "dart:ui" show ImageByteFormat;
+import "dart:ui" show FlutterView, ImageByteFormat;
 
+import "package:flutter/material.dart";
 import "package:flutter/rendering.dart"
     show
         PipelineOwner,
         RenderPositionedBox,
         RenderRepaintBoundary,
         RenderView,
         ViewConfiguration;
-import "package:flutter/widgets.dart";
 
 class WidgetToImageUtil {
-  static Widget _setSizeAndTextDirection(Widget widget, Size size) {
+  static Widget _setSizeAndTextDirection(
+      Widget widget, Size size, BuildContext context, FlutterView view) {
     return SizedBox(
       width: size.width,
       height: size.height,
-      child: Directionality(
-        textDirection: TextDirection.ltr,
-        child: widget,
-      ),
+      child: MediaQuery(
+          data: MediaQueryData.fromView(view),
+          child: Theme(
+              data: Theme.of(context),
+              child: Directionality(
+                textDirection: TextDirection.ltr,
+                child: widget,
+              ))),
     );
   }
 
@@ -29,33 +34,52 @@ class WidgetToImageUtil {
   }) async {
     final renderBox = RenderRepaintBoundary();
     final view = View.of(context);
+
+    final renderPositionedBox =
+        RenderPositionedBox(alignment: Alignment.center, child: renderBox);
     final renderView = RenderView(
         view: view,
         configuration: ViewConfiguration(
             size: size, devicePixelRatio: view.devicePixelRatio),
-        child:
-            RenderPositionedBox(alignment: Alignment.center, child: renderBox));
+        child: renderPositionedBox);
 
     final pipelineOwner = PipelineOwner()..rootNode = renderView;
     renderView.prepareInitialFrame();
 
     final buildOwner = BuildOwner(focusManager: FocusManager());
-    final renderToWidget = RenderObjectToWidgetAdapter(
-            container: renderBox, child: _setSizeAndTextDirection(widget, size))
+    final rootElement = RenderObjectToWidgetAdapter(
+            container: renderBox,
+            child: _setSizeAndTextDirection(widget, size, context, view))
         .attachToRenderTree(buildOwner);
     buildOwner
-      ..buildScope(renderToWidget)
+      ..buildScope(rootElement)
       ..finalizeTree();
 
     pipelineOwner
       ..flushLayout()
       ..flushCompositingBits()
       ..flushPaint();
+    try {
+      final image = await renderBox.toImage(pixelRatio: view.devicePixelRatio);
+
+      final rawImage = await image
+          .toByteData(format: ImageByteFormat.png)
+          .then((b) => b!.buffer.asUint8List());
 
-    final image = await renderBox.toImage(pixelRatio: view.devicePixelRatio);
-    return image
-        .toByteData(format: ImageByteFormat.png)
-        .then((b) => b!.buffer.asUint8List());
+      return rawImage;
+    } finally {
+      final emptyRenderToWidgetAdapter =
+          RenderObjectToWidgetAdapter(container: renderBox);
+      rootElement.update(emptyRenderToWidgetAdapter); // renderbox child = null
+      buildOwner.finalizeTree();
+      renderView
+        ..detach()
+        ..dispose();
+      rootElement
+        ..detachRenderObject()
+        ..deactivate();
+      buildOwner.finalizeTree();
+    }
   }
 
   WidgetToImageUtil._();