syncfusion_flutter_signaturepad 27.2.2

The Flutter Signature Pad widget allows you to capture smooth and more realistic signatures through drawn gestures and save it as an image.

example/lib/main.dart

import 'dart:ui' as ui;
import 'package:flutter/material.dart';
import 'package:syncfusion_flutter_signaturepad/signaturepad.dart';

void main() {
  return runApp(SignaturePadApp());
}

///Renders the SignaturePad widget.
class SignaturePadApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'SfSignaturePad Demo',
      home: _MyHomePage(),
    );
  }
}

class _MyHomePage extends StatefulWidget {
  _MyHomePage({Key? key}) : super(key: key);

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<_MyHomePage> {
  final GlobalKey<SfSignaturePadState> signatureGlobalKey = GlobalKey();

  @override
  void initState() {
    super.initState();
  }

  void _handleClearButtonPressed() {
    signatureGlobalKey.currentState!.clear();
  }

  void _handleSaveButtonPressed() async {
    final data =
        await signatureGlobalKey.currentState!.toImage(pixelRatio: 3.0);
    final bytes = await data.toByteData(format: ui.ImageByteFormat.png);
    await Navigator.of(context).push(
      MaterialPageRoute(
        builder: (BuildContext context) {
          return Scaffold(
            appBar: AppBar(),
            body: Center(
              child: Container(
                color: Colors.grey[300],
                child: Image.memory(bytes!.buffer.asUint8List()),
              ),
            ),
          );
        },
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: Column(
            children: [
          Padding(
              padding: EdgeInsets.all(10),
              child: Container(
                  child: SfSignaturePad(
                      key: signatureGlobalKey,
                      backgroundColor: Colors.white,
                      strokeColor: Colors.black,
                      minimumStrokeWidth: 1.0,
                      maximumStrokeWidth: 4.0),
                  decoration:
                      BoxDecoration(border: Border.all(color: Colors.grey)))),
          SizedBox(height: 10),
          Row(children: <Widget>[
            TextButton(
              child: Text('ToImage'),
              onPressed: _handleSaveButtonPressed,
            ),
            TextButton(
              child: Text('Clear'),
              onPressed: _handleClearButtonPressed,
            )
          ], mainAxisAlignment: MainAxisAlignment.spaceEvenly)
        ],
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.center));
  }
}