dataFromWidget static method

Future<Uint8List?> dataFromWidget(Widget widget, { required BuildContext context, Alignment alignment = Alignment.center, Duration? wait, Size size = const Size(double.maxFinite, double.maxFinite), double devicePixelRatio = 1.0, double pixelRatio = 1.0, })

Convert the given widget to an image.

More info: https://github.com/flutter/flutter/issues/40064

Implementation

static Future<Uint8List?> dataFromWidget(
  Widget widget, {
  required BuildContext context,
  Alignment alignment = Alignment.center,
  Duration? wait,
  Size size = const Size(double.maxFinite, double.maxFinite),
  double devicePixelRatio = 1.0,
  double pixelRatio = 1.0,
}) async {
  final repaintBoundary = RenderRepaintBoundary();

  final renderView = RenderView(
    view: View.of(context),
    child: RenderPositionedBox(
        alignment: Alignment.center, child: repaintBoundary),
    configuration: ViewConfiguration(
      size: size,
      devicePixelRatio: devicePixelRatio,
    ),
  );

  final pipelineOwner = PipelineOwner();
  final buildOwner = BuildOwner(focusManager: FocusManager());

  pipelineOwner.rootNode = renderView;
  renderView.prepareInitialFrame();

  final rootElement = RenderObjectToWidgetAdapter<RenderBox>(
      container: repaintBoundary,
      child: MediaQuery(
        data: MediaQueryData(size: size),
        child: Directionality(
          textDirection: TextDirection.ltr,
          child: widget,
        ),
      )).attachToRenderTree(buildOwner);

  buildOwner.buildScope(rootElement);

  if (wait != null) {
    await Future.delayed(wait);
  }

  buildOwner
    ..buildScope(rootElement)
    ..finalizeTree();

  pipelineOwner
    ..flushLayout()
    ..flushCompositingBits()
    ..flushPaint();

  final image = await repaintBoundary.toImage(pixelRatio: pixelRatio);
  final byteData = await image.toByteData(format: ui.ImageByteFormat.png);

  return byteData?.buffer.asUint8List();
}