Creates a BitmapDescriptor from an IconData object to be used for google_maps_flutter map markers. Read the Medium article here: https://medium.com/@JBXBergDev/how-to-use-googlemap-markers-with-flutter-material-icons-38c4c975e928

marker_icon_generator.dart

import 'dart:math';
import 'dart:ui';

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

class MarkerGenerator {
  final _markerSize;
  double _circleStrokeWidth;
  double _circleOffset;
  double _outlineCircleWidth;
  double _fillCircleWidth;
  double _iconSize;
  double _iconOffset;

  MarkerGenerator(this._markerSize) {
    // calculate marker dimensions
    _circleStrokeWidth = _markerSize / 10.0;
    _circleOffset = _markerSize / 2;
    _outlineCircleWidth = _circleOffset - (_circleStrokeWidth / 2);
    _fillCircleWidth = _markerSize / 2;
    final outlineCircleInnerWidth = _markerSize - (2 * _circleStrokeWidth);
    _iconSize = sqrt(pow(outlineCircleInnerWidth, 2) / 2);
    final rectDiagonal = sqrt(2 * pow(_markerSize, 2));
    final circleDistanceToCorners = (rectDiagonal - outlineCircleInnerWidth) / 2;
    _iconOffset = sqrt(pow(circleDistanceToCorners, 2) / 2);
  }

  /// Creates a BitmapDescriptor from an IconData
  Future<BitmapDescriptor> createBitmapDescriptorFromIconData(IconData iconData, Color iconColor, Color circleColor, Color backgroundColor) async {
    final pictureRecorder = PictureRecorder();
    final canvas = Canvas(pictureRecorder);

    _paintCircleFill(canvas, backgroundColor);
    _paintCircleStroke(canvas, circleColor);
    _paintIcon(canvas, iconColor, iconData);

    final picture = pictureRecorder.endRecording();
    final image = await picture.toImage(_markerSize.round(), _markerSize.round());
    final bytes = await image.toByteData(format: ImageByteFormat.png);

    return BitmapDescriptor.fromBytes(bytes.buffer.asUint8List());
  }

  /// Paints the icon background
  void _paintCircleFill(Canvas canvas, Color color) {
    final paint = Paint()
      ..style = PaintingStyle.fill
      ..color = color;
    canvas.drawCircle(Offset(_circleOffset, _circleOffset), _fillCircleWidth, paint);
  }

  /// Paints a circle around the icon
  void _paintCircleStroke(Canvas canvas, Color color) {
    final paint = Paint()
      ..style = PaintingStyle.stroke
      ..color = color
      ..strokeWidth = _circleStrokeWidth;
    canvas.drawCircle(Offset(_circleOffset, _circleOffset), _outlineCircleWidth, paint);
  }

  /// Paints the icon
  void _paintIcon(Canvas canvas, Color color, IconData iconData) {
    final textPainter = TextPainter(textDirection: TextDirection.ltr);
    textPainter.text = TextSpan(
        text: String.fromCharCode(iconData.codePoint),
        style: TextStyle(
          letterSpacing: 0.0,
          fontSize: _iconSize,
          fontFamily: iconData.fontFamily,
          color: color,
        )
    );
    textPainter.layout();
    textPainter.paint(canvas, Offset(_iconOffset, _iconOffset));
  }
}

You are the best! 😃

It's sad but we can't comment on specific gist lines...

You should also include the 'package' parameter to support other icon packages too - eg fontawesome icons.

So the _paintIcon method would look like this:

void _paintIcon(Canvas canvas, Color color, IconData iconData) {
    final textPainter = TextPainter(textDirection: TextDirection.ltr);
    textPainter.text = TextSpan(
        text: String.fromCharCode(iconData.codePoint),
        style: TextStyle(
          letterSpacing: 0.0,
          fontSize: _iconSize,
          fontFamily: iconData.fontFamily,
          package: iconData.fontPackage,
          color: color,
        ));
    textPainter.layout();
    textPainter.paint(canvas, Offset(_iconOffset, _iconOffset));
  }

Cool!
Is it possible to print into the Canvas not only an Icon or Text but any arbitrary Widget?

It's sad but we can't comment on specific gist lines...

You should also include the 'package' parameter to support other icon packages too - eg fontawesome icons.

So the _paintIcon method would look like this:

void _paintIcon(Canvas canvas, Color color, IconData iconData) {
    final textPainter = TextPainter(textDirection: TextDirection.ltr);
    textPainter.text = TextSpan(
        text: String.fromCharCode(iconData.codePoint),
        style: TextStyle(
          letterSpacing: 0.0,
          fontSize: _iconSize,
          fontFamily: iconData.fontFamily,
          package: iconData.fontPackage,
          color: color,
        ));
    textPainter.layout();
    textPainter.paint(canvas, Offset(_iconOffset, _iconOffset));
  }

You a hero 🙏🙏

Can we do a plugin for this?, most of us we have found usefull 🥇

thanks a lot bro !