flutter_map_custom_marker

flutter_map_custom_marker.dart

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

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';

extension ToBitDescription on Widget {
  Future<BitmapDescriptor> toBitmapDescriptor({Size? logicalSize, Size? imageSize, Duration waitToRender = const Duration(milliseconds: 300), TextDirection textDirection = TextDirection.ltr}) async {
    final widget = RepaintBoundary(
      child: MediaQuery(data: const MediaQueryData(), child: Directionality(textDirection: TextDirection.ltr, child: this)),
    );
    final pngBytes = await createImageFromWidget(widget, waitToRender: waitToRender, logicalSize: logicalSize, imageSize: imageSize);
    return BitmapDescriptor.fromBytes(pngBytes);
  }
}

/// Creates an image from the given widget by first spinning up a element and render tree,
/// wait [waitToRender] to render the widget that take time like network and asset images

/// The final image will be of size [imageSize] and the the widget will be layout, ... with the given [logicalSize].
/// By default Value of  [imageSize] and [logicalSize] will be calculate from the app main window

Future<Uint8List> createImageFromWidget(Widget widget, {Size? logicalSize, required Duration waitToRender, Size? imageSize}) async {
  final RenderRepaintBoundary repaintBoundary = RenderRepaintBoundary();
  final view = ui.PlatformDispatcher.instance.views.first;
  logicalSize ??= view.physicalSize / view.devicePixelRatio;
  imageSize ??= view.physicalSize;

  // assert(logicalSize.aspectRatio == imageSize.aspectRatio);

  final RenderView renderView = RenderView(
    view: view,
    child: RenderPositionedBox(alignment: Alignment.center, child: repaintBoundary),
    configuration: ViewConfiguration(
      size: logicalSize,
      devicePixelRatio: 1.0,
    ),
  );

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

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

  final RenderObjectToWidgetElement<RenderBox> rootElement = RenderObjectToWidgetAdapter<RenderBox>(
    container: repaintBoundary,
    child: widget,
  ).attachToRenderTree(buildOwner);

  buildOwner.buildScope(rootElement);

  await Future.delayed(waitToRender);

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

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

  final ui.Image image = await repaintBoundary.toImage(pixelRatio: imageSize.width / logicalSize.width);
  final ByteData? byteData = await image.toByteData(format: ui.ImageByteFormat.png);

  return byteData!.buffer.asUint8List();
}


Future<BitmapDescriptor> getCustomIcon() async {
  return SizedBox(
    height: 200,
    width: 200,
    child: Image.asset("temp image"),
  ).toBitmapDescriptor();
}


 List<Marker> markerList = <Marker>[];

markerList.add(
          Marker(
            markerId: const MarkerId("MarkerId"),
            position: LatLng(21.000000, 72.000000),
            icon: await getCustomIcon(),
          ),
   )