toImage method

Future<Image> toImage({ double pixelRatio = 1.0, })

Method to convert the SfRadialGauge as an image.

Returns the dart:ui.image

As this method is in the widget’s state class, you have to use a global key to access the state to call this method.

final GlobalKey<SfRadialGaugeState> _radialGaugeKey = GlobalKey();
@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Column(
      children: [SfRadialGauge(key: _radialGaugeKey),
              RaisedButton(
               child: Text(
                  'To Image',
                ),
                onPressed: _renderImage,
                shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(20)),
              ),
      ],
    ),
  );
}
 Future<void> _renderImage() async {
  dart_ui.Image data = await
                    _radialGaugeKey.currentState.toImage(pixelRatio: 3.0);
  final bytes = await data.toByteData(format: dart_ui.ImageByteFormat.png);
  if (data != null) {
    await Navigator.of(context).push(
      MaterialPageRoute(
        builder: (BuildContext context) {
          return Scaffold(
            appBar: AppBar(),
            body: Center(
              child: Container(
                color: Colors.white,
                child: Image.memory(bytes.buffer.asUint8List()),
              ),
            ),
          );
        },
      ),
    );
  }
}

Implementation

///  Future<void> _renderImage() async {
///   dart_ui.Image data = await
///                     _radialGaugeKey.currentState.toImage(pixelRatio: 3.0);
///   final bytes = await data.toByteData(format: dart_ui.ImageByteFormat.png);
///   if (data != null) {
///     await Navigator.of(context).push(
///       MaterialPageRoute(
///         builder: (BuildContext context) {
///           return Scaffold(
///             appBar: AppBar(),
///             body: Center(
///               child: Container(
///                 color: Colors.white,
///                 child: Image.memory(bytes.buffer.asUint8List()),
///               ),
///             ),
///           );
///         },
///       ),
///     );
///   }
/// }
/// ```
Future<dart_ui.Image> toImage({double pixelRatio = 1.0}) async {
  final RenderRepaintBoundary? boundary =
      context.findRenderObject() as RenderRepaintBoundary?;
  final dart_ui.Image image = await boundary!.toImage(pixelRatio: pixelRatio);
  return image;
}