Flutter Map Polygon Editor

A polygon and polyline editor for Flutter Map applications. This package provides interactive editing functionality that allows users to create, edit, and manipulate polygons and polylines directly on maps.

Demo

Polygon Editing

Polyline Editing

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  flutter_map_polygon_editor: ^1.0.0
  flutter_map: ^8.1.1
  latlong2: ^0.9.1

Then run:

flutter pub get

Quick Start

import 'package:flutter/material.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:flutter_map_polygon_editor/polygon_editor.dart';
import 'package:latlong2/latlong.dart';

class MapWithEditor extends StatefulWidget {
  @override
  _MapWithEditorState createState() => _MapWithEditorState();
}

class _MapWithEditorState extends State<MapWithEditor> {
  late final PolygonEditorController _controller;

  @override
  void initState() {
    super.initState();
    _controller = PolygonEditorController();
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: FlutterMap(
        options: MapOptions(
          initialCenter: const LatLng(51.5074, -0.1278),
          initialZoom: 10,
          onLongPress: (tapPosition, point) {
            _controller.addPoint(point);
          },
        ),
        children: [
          TileLayer(
            urlTemplate: 'https://tile.openstreetmap.org/{z}/{x}/{y}.png',
          ),
          PolygonEditor(
            controller: _controller,
            style: PolygonEditorStyle(
              borderColor: Colors.blue,
              fillColor: Colors.blue.withOpacity(0.3),
            ),
          ),
        ],
      ),
    );
  }
}

Usage

Basic Setup

1. Create a controller:

final controller = PolygonEditorController();

2. Add the editor to your map:

PolygonEditor(
  controller: controller,
)

3. Don't forget to dispose:

@override
void dispose() {
  controller.dispose();
  super.dispose();
}

Controller Operations

// Add points programmatically
controller.addPoint(LatLng(51.5074, -0.1278));

// Switch between modes
controller.setMode(PolygonEditorMode.line);
controller.setMode(PolygonEditorMode.polygon);

// Get current points
List<LatLng> points = controller.points;

// Clear all points
controller.clear();

// Listen to changes
controller.addListener(() {
  print('Points changed: ${controller.points.length}');
});

Customization

Custom Styling

PolygonEditor(
  controller: controller,
  style: PolygonEditorStyle(
    borderWidth: 3.0,
    borderColor: Colors.red,
    fillColor: Colors.red.withOpacity(0.2),
  ),
)

Custom Markers

PolygonEditor(
  controller: controller,
  pointBuilder: (context, position, isDragging) {
    return Container(
      width: 20,
      height: 20,
      decoration: BoxDecoration(
        color: isDragging ? Colors.red : Colors.blue,
        shape: BoxShape.circle,
        border: Border.all(color: Colors.white, width: 2),
      ),
    );
  },
  midpointBuilder: (context, position, isDragging) {
    return Container(
      width: 16,
      height: 16,
      decoration: BoxDecoration(
        color: Colors.green,
        shape: BoxShape.circle,
      ),
      child: Icon(Icons.add, size: 12, color: Colors.white),
    );
  },
)

Performance Tuning

PolygonEditor(
  controller: controller,
  throttleDuration: Duration(milliseconds: 16), // 60 FPS
  // Or disable throttling for maximum responsiveness
  throttleDuration: Duration.zero,
)

User Interactions

• Long press map: Add new point
• Drag point: Move existing point
• Long press point: Remove point
• Drag midpoint: Create new point at that position

API Reference

PolygonEditorController

Method	Description
addPoint(LatLng point)	Adds a point to the end of the list
insertPoint(int index, LatLng point)	Inserts a point at the specified index
updatePoint(int index, LatLng point)	Updates an existing point
removePoint(int index)	Removes a point by index
removeLast()	Removes and returns the last point
clear()	Removes all points
setPoints(List<LatLng> points)	Replaces all points
setMode(PolygonEditorMode mode)	Switches between polygon and line modes

PolygonEditorStyle

Property	Type	Default	Description
borderWidth	double	2.0	Width of the border stroke
borderColor	Color	Colors.red	Color of the border
fillColor	Color	Semi-transparent red	Fill color for polygons

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.