Merge pull request #61 from SachinGanesh/invisible_image

example/lib/main.dart

@@ -14,6 +14,11 @@ class MyApp extends StatelessWidget {
     return MaterialApp(
       title: 'Flutter Demo',
       theme: ThemeData(
+        textTheme: TextTheme(
+            headline6: TextStyle(
+          color: Colors.yellow,
+          fontSize: 50,
+        )),
         // This is the theme of your application.
         //
         // Try running your application with "flutter run". You'll see the
@@ -98,15 +103,21 @@ class _MyHomePageState extends State<MyHomePage> {
                 'Capture An Invisible Widget',
               ),
               onPressed: () {
+                var container = Container(
+                    padding: const EdgeInsets.all(30.0),
+                    decoration: BoxDecoration(
+                      border: Border.all(color: Colors.blueAccent, width: 5.0),
+                      color: Colors.redAccent,
+                    ),
+                    child: Text(
+                      "This is an invisible widget",
+                      style: Theme.of(context).textTheme.headline6,
+                    ));
                 screenshotController
-                    .captureFromWidget(Container(
-                        padding: const EdgeInsets.all(30.0),
-                        decoration: BoxDecoration(
-                          border:
-                              Border.all(color: Colors.blueAccent, width: 5.0),
-                          color: Colors.redAccent,
-                        ),
-                        child: Text("This is an invisible widget")))
+                    .captureFromWidget(
+                        InheritedTheme.captureAll(
+                            context, Material(child: container)),
+                        delay: Duration(seconds: 1))
                     .then((capturedImage) {
                   ShowCapturedWidget(context, capturedImage);
                 });

example/pubspec.yaml

@@ -36,8 +36,8 @@ flutter:
   # the material Icons class.
   uses-material-design: true
   # To add assets to your application, add an assets section, like this:
-  # assets:
-  #  - images/a_dot_burr.jpeg
+  assets:
+   - assets/images/
   #  - images/a_dot_ham.jpeg
   # An image asset can refer to one or more resolution-specific "variants", see
   # https://flutter.io/assets-and-images/#resolution-aware.

lib/screenshot.dart

@@ -2,6 +2,7 @@ library screenshot;
 
 // import 'dart:io';
 import 'dart:async';
+import 'dart:developer';
 import 'dart:typed_data';
 import 'src/platform_specific/file_manager/file_manager.dart';
 import 'package:flutter/material.dart';
@@ -65,14 +66,13 @@ class ScreenshotController {
     //Delay is required. See Issue https://github.com/flutter/flutter/issues/22308
     return new Future.delayed(delay, () async {
       try {
-        var findRenderObject = this
-            ._containerKey
-            .currentContext
-            ?.findRenderObject();
-            if(findRenderObject==null){
-                return null;
-            }
-        RenderRepaintBoundary boundary = findRenderObject as RenderRepaintBoundary;
+        var findRenderObject =
+            this._containerKey.currentContext?.findRenderObject();
+        if (findRenderObject == null) {
+          return null;
+        }
+        RenderRepaintBoundary boundary =
+            findRenderObject as RenderRepaintBoundary;
         BuildContext? context = _containerKey.currentContext;
         if (pixelRatio == null) {
           if (context != null)
@@ -86,14 +86,45 @@ class ScreenshotController {
     });
   }
 
-  Future<Uint8List> captureFromWidget(Widget widget,
-      {Duration delay: const Duration(milliseconds: 20), double? pixelRatio,}) async {
+  ///
+  /// Value for [delay] should increase with widget tree size. Prefered value is 1 seconds
+  ///
+  ///[context] parameter is used to Inherit App Theme and MediaQuery data.
+  ///
+  ///
+  ///
+  Future<Uint8List> captureFromWidget(
+    Widget widget, {
+    Duration delay: const Duration(seconds: 1),
+    double? pixelRatio,
+    BuildContext? context,
+  }) async {
+    ///
+    ///Retry counter
+    ///
+    int retryCounter = 3;
+    bool isDirty = false;
+
+    Widget child = widget;
+
+    if (context != null) {
+      ///
+      ///Inherit Theme and MediaQuery of app
+      ///
+      ///
+      child = InheritedTheme.captureAll(
+        context,
+        MediaQuery(data: MediaQuery.of(context), child: child),
+      );
+    }
+
     final RenderRepaintBoundary repaintBoundary = RenderRepaintBoundary();
 
     Size logicalSize = ui.window.physicalSize / ui.window.devicePixelRatio;
     Size imageSize = ui.window.physicalSize;
 
-    assert(logicalSize.aspectRatio.toPrecision(5) == imageSize.aspectRatio.toPrecision(5));
+    assert(logicalSize.aspectRatio.toPrecision(5) ==
+        imageSize.aspectRatio.toPrecision(5));
 
     final RenderView renderView = RenderView(
       window: ui.window,
@@ -101,38 +132,87 @@ class ScreenshotController {
           alignment: Alignment.center, child: repaintBoundary),
       configuration: ViewConfiguration(
         size: logicalSize,
-        devicePixelRatio: 1.0,
+        devicePixelRatio: pixelRatio ?? 1.0,
       ),
     );
 
     final PipelineOwner pipelineOwner = PipelineOwner();
-    final BuildOwner buildOwner = BuildOwner(focusManager: FocusManager());
+    final BuildOwner buildOwner = BuildOwner(
+        focusManager: FocusManager(),
+        onBuildScheduled: () {
+          ///
+          ///current render is dirty, mark it.
+          ///
+          isDirty = true;
+        });
 
     pipelineOwner.rootNode = renderView;
     renderView.prepareInitialFrame();
 
     final RenderObjectToWidgetElement<RenderBox> rootElement =
         RenderObjectToWidgetAdapter<RenderBox>(
-      container: repaintBoundary,
-      child: Directionality(
-        textDirection: TextDirection.ltr,
-        child: widget,
-      ),
-    ).attachToRenderTree(buildOwner);
-
-    buildOwner.buildScope(rootElement);
-
-    await Future.delayed(delay);
+            container: repaintBoundary,
+            child: Directionality(
+              textDirection: TextDirection.ltr,
+              child: child,
+            )).attachToRenderTree(
+      buildOwner,
+    );
+    ////
+    ///Render Widget
+    ///
+    ///
 
-    buildOwner.buildScope(rootElement);
+    buildOwner.buildScope(rootElement,);
     buildOwner.finalizeTree();
 
     pipelineOwner.flushLayout();
     pipelineOwner.flushCompositingBits();
     pipelineOwner.flushPaint();
 
-    final ui.Image image = await repaintBoundary.toImage(
-        pixelRatio: pixelRatio ?? (imageSize.width / logicalSize.width));
+    ui.Image? image;
+
+    do {
+      ///
+      ///Reset the dirty flag
+      ///
+      ///
+      isDirty = false;
+
+      image = await repaintBoundary.toImage(
+          pixelRatio: pixelRatio ?? (imageSize.width / logicalSize.width));
+
+      ///
+      ///This delay shoud inceases with Widget tree Size
+      ///
+
+      await Future.delayed(delay);
+
+      ///
+      ///Check does this require rebuild
+      ///
+      ///
+      if (isDirty) {
+        ///
+        ///Previous capture has been updated, re-render again.
+        ///
+        ///
+        buildOwner.buildScope(
+          rootElement,
+        );
+        buildOwner.finalizeTree();
+        pipelineOwner.flushLayout();
+        pipelineOwner.flushCompositingBits();
+        pipelineOwner.flushPaint();
+      }
+      retryCounter--;
+
+      ///
+      ///retry untill capture is successfull
+      ///
+
+    } while (isDirty && retryCounter >= 0);
+
     final ByteData? byteData =
         await image.toByteData(format: ui.ImageByteFormat.png);
 
@@ -173,7 +253,6 @@ class ScreenshotState extends State<Screenshot> with TickerProviderStateMixin {
   }
 }
 
-
 extension Ex on double {
   double toPrecision(int n) => double.parse(toStringAsFixed(n));
-}
+}
\ No newline at end of file

pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.6.1"
+    version: "2.5.0"
   boolean_selector:
     dependency: transitive
     description:
@@ -92,7 +92,7 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.1"
+    version: "1.8.0"
   stack_trace:
     dependency: transitive
     description:
@@ -127,7 +127,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.0"
+    version: "0.2.19"
   typed_data:
     dependency: transitive
     description: