DART

custom marker google maps flutter

Future<Uint8List> getBytesFromAsset(String path, int width) async {
    ByteData data = await rootBundle.load(path);
    ui.Codec codec = await ui.instantiateImageCodec(data.buffer.asUint8List(),
        targetWidth: width);
    ui.FrameInfo fi = await codec.getNextFrame();
    return (await fi.image.toByteData(format: ui.ImageByteFormat.png))!
        .buffer
        .asUint8List();
  }
 
 // init marker icon 
 
  final Uint8List markerIcon2 =
        await getBytesFromAsset('assets/images/m1.png', 99);
    final Uint8List markerIcon1 =
        await getBytesFromAsset('assets/images/camion.png', 139);
        
    teste1 = BitmapDescriptor.fromBytes(markerIcon2);
    teste2 = BitmapDescriptor.fromBytes(markerIcon1);
    
  // show marker 
    Marker(icon: teste1)
    Marker(icon: teste2)
     
            

flutter_map marker

 class _MapDataState extends State<MapData> {
      List<SitesList> sl = [];
      List<SnoTelSite> sts = [];
      var marker = <Marker>[];

      _MapDataState(){
        print("map data state");
        loadSites().then((sitesdata) {
          print('Loaded Sites Asset JSON');
          //clone sitesdata into sts array
          sts..addAll(sitesdata);
          sts.forEach((s) {
            marker.add(
              Marker(
                point: new LatLng(double.parse(s.lat),double.parse(s.lng)),
                builder: (ctx) => _MarkerPopUp(sitename: s.name, siteelevation: s.elevation, siteid: s.siteID,),
              ),
            );
          });
        });
      }

      // @override
      // initState() {
      //   print("INIT STATE");
      //   super.initState();
      // }

      //local load assets ... constants hold path snotelsitesjson
      Future<String> _loadSiteAssets() async {
        return await rootBundle.loadString(snotelsitesjson);
      }

      Future loadSites() async {
        String jsonString = await _loadSiteAssets();
        final jsonResponse = json.decode(jsonString);
        SitesList sitesList = new SitesList.fromJson(jsonResponse);
        return sitesList.sites;
      }

    //main build and screen layout
      @override
      Widget build(BuildContext context) {
        print("BUILD LAYOUT");
        return MaterialApp(
          theme: ThemeData(
            primarySwatch: Colors.cyan,
          ),
          home: Scaffold(
              appBar: AppBar(
                backgroundColor: Colors.white,
                leading: Icon(Icons.ac_unit),
                title: Text("SnoTel Map"),
                actions: <Widget>[
                  IconButton(
                    icon: Icon(Icons.favorite),
                    onPressed: () {
                      debugPrint("Favorites");
                    },
                  ),
                  IconButton(
                    icon: Icon(Icons.feedback),
                    onPressed: () {
                      debugPrint("Message sent");
                    },
                  ),
                ],
              ),
              body: _MapWidget()),
        );
      }
    }

flutter google maps custom marker

import 'dart:typed_data';
import 'dart:ui';

import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';

class MarkerInfo extends StatefulWidget {
  final Function getBitmapImage;
  final String text;
  MarkerInfo({Key key, this.getBitmapImage, this.text}) : super(key: key);

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

class _MarkerInfoState extends State<MarkerInfo> {
  final markerKey = GlobalKey();

  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) => getUint8List(markerKey)
        .then((markerBitmap) => widget.getBitmapImage(markerBitmap)));
  }

  Future<Uint8List> getUint8List(GlobalKey markerKey) async {
    RenderRepaintBoundary boundary =
        markerKey.currentContext.findRenderObject();
    var image = await boundary.toImage(pixelRatio: 2.0);
    ByteData byteData = await image.toByteData(format: ImageByteFormat.png);
    return byteData.buffer.asUint8List();
  }

  @override
  Widget build(BuildContext context) {
    return RepaintBoundary(
      key: markerKey,
      child: Container(
        padding: EdgeInsets.only(bottom: 29),
        child: Container(
          width: 100,
          height: 100,
          color: Color(0xFF000000),
          child: Text(
            widget.text,
            style: TextStyle(
              color: Color(0xFFFFFFFF),
            ),
          ),
        ),
      ),
    );
  }
}