Creating centered label for polygons

lib/src/layer/label.dart

@@ -0,0 +1,45 @@
+import 'dart:math';
+
+import 'package:flutter/material.dart';
+
+class Label {
+  static void paintText(
+    Canvas canvas,
+    List<Offset> points,
+    String? labelText,
+    TextStyle? labelStyle,
+  ) {
+    var maxDx = 0.0;
+    var minDx = double.infinity;
+    var dx = points.map((e) => e.dx).toList().fold<double>(0.0,
+            (previousValue, element) {
+          maxDx = max(maxDx, element);
+          minDx = min(minDx, element);
+          return previousValue + element;
+        }) /
+        points.length;
+    var dy = points.map((e) => e.dy).toList().fold<double>(
+            0.0, (previousValue, element) => previousValue + element) /
+        points.length;
+
+    final textSpan = TextSpan(text: labelText, style: labelStyle);
+    final textPainter = TextPainter(
+      text: textSpan,
+      textAlign: TextAlign.center,
+      textDirection: TextDirection.ltr,
+      maxLines: 1,
+    );
+    if (dx > 0) {
+      textPainter.layout(minWidth: 0, maxWidth: double.infinity);
+      dx = dx - textPainter.width / 2;
+      dy = dy - textPainter.height / 2;
+
+      if (maxDx - minDx > textPainter.width) {
+        textPainter.paint(
+          canvas,
+          Offset(dx, dy),
+        );
+      }
+    }
+  }
+}

lib/src/layer/polygon_layer.dart

@@ -3,6 +3,7 @@ import 'dart:ui';
 
 import 'package:flutter/widgets.dart';
 import 'package:flutter_map/flutter_map.dart';
+import 'package:flutter_map/src/layer/label.dart';
 import 'package:flutter_map/src/map/map.dart';
 import 'package:latlong2/latlong.dart' hide Path; // conflict with Path from UI
 
@@ -37,6 +38,8 @@ class Polygon {
   final bool isDotted;
   final bool isFilled;
   late final LatLngBounds boundingBox;
+  final String? label;
+  final TextStyle labelStyle;
 
   Polygon({
     required this.points,
@@ -47,6 +50,8 @@ class Polygon {
     this.disableHolesBorder = false,
     this.isDotted = false,
     this.isFilled = false,
+    this.label,
+    this.labelStyle = const TextStyle(),
   }) : holeOffsetsList = null == holePointsList || holePointsList.isEmpty
             ? null
             : List.generate(holePointsList.length, (_) => []);
@@ -258,6 +263,15 @@ class PolygonPainter extends CustomPainter {
       canvas.drawPath(path, paint);
 
       _paintBorder(canvas);
+
+      if (polygonOpt.label != null) {
+        Label.paintText(
+          canvas,
+          polygonOpt.offsets,
+          polygonOpt.label,
+          polygonOpt.labelStyle,
+        );
+      }
     }
   }