renderFlutterWidget static method

Future renderFlutterWidget(Widget widget, { required String key, Size logicalSize = const Size(200, 200), double pixelRatio = 1, })

Generate a screenshot based on a given widget. This method renders the widget to an image (png) file with the provided filename. The png file is saved to the App Group container and the full path is returned as a string. The filename is saved to UserDefaults using the provided key.

Implementation

static Future renderFlutterWidget(
  Widget widget, {
  required String key,
  Size logicalSize = const Size(200, 200),
  double pixelRatio = 1,
}) async {
  /// finding the widget in the current context by the key.
  final RenderRepaintBoundary repaintBoundary = RenderRepaintBoundary();

  /// create a new pipeline owner
  final PipelineOwner pipelineOwner = PipelineOwner();

  /// create a new build owner
  final BuildOwner buildOwner = BuildOwner(focusManager: FocusManager());

  try {
    final RenderView renderView = RenderView(
      view: ui.PlatformDispatcher.instance.implicitView!,
      child: RenderPositionedBox(
        alignment: Alignment.center,
        child: repaintBoundary,
      ),
      configuration: ViewConfiguration(
        size: logicalSize,
        devicePixelRatio: 1.0,
      ),
    );

    /// setting the rootNode to the renderview of the widget
    pipelineOwner.rootNode = renderView;

    /// setting the renderView to prepareInitialFrame
    renderView.prepareInitialFrame();

    /// setting the rootElement with the widget that has to be captured
    final RenderObjectToWidgetElement<RenderBox> rootElement =
        RenderObjectToWidgetAdapter<RenderBox>(
      container: repaintBoundary,
      child: Directionality(
        textDirection: TextDirection.ltr,
        child: Column(
          // image is center aligned
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            widget,
          ],
        ),
      ),
    ).attachToRenderTree(buildOwner);

    ///adding the rootElement to the buildScope
    buildOwner.buildScope(rootElement);

    ///adding the rootElement to the buildScope
    buildOwner.buildScope(rootElement);

    /// finalize the buildOwner
    buildOwner.finalizeTree();

    ///Flush Layout
    pipelineOwner.flushLayout();

    /// Flush Compositing Bits
    pipelineOwner.flushCompositingBits();

    /// Flush paint
    pipelineOwner.flushPaint();

    final ui.Image image =
        await repaintBoundary.toImage(pixelRatio: pixelRatio);

    /// The raw image is converted to byte data.
    final ByteData? byteData =
        await image.toByteData(format: ui.ImageByteFormat.png);

    try {
      late final String? directory;

      // coverage:ignore-start
      if (Platform.isIOS) {
        final PathProviderFoundation provider = PathProviderFoundation();
        assert(
          HomeWidget.groupId != null,
          'No groupId defined. Did you forget to call `HomeWidget.setAppGroupId`',
        );
        directory = await provider.getContainerPath(
          appGroupIdentifier: HomeWidget.groupId!,
        );
      } else {
        // coverage:ignore-end
        directory = (await getApplicationSupportDirectory()).path;
      }

      final String path = '$directory/home_widget/$key.png';
      final File file = File(path);
      if (!await file.exists()) {
        await file.create(recursive: true);
      }
      await file.writeAsBytes(byteData!.buffer.asUint8List());

      // Save the filename to UserDefaults if a key was provided
      _channel.invokeMethod<bool>('saveWidgetData', {
        'id': key,
        'data': path,
      });

      return path;
    } catch (e) {
      throw Exception('Failed to save screenshot to app group container: $e');
    }
  } catch (e) {
    throw Exception('Failed to render the widget: $e');
  }
}