feat: add dottedSpacingFactor to customize dotted polyline spacing

example/lib/pages/polyline.dart

@@ -111,6 +111,24 @@ class _PolylinePageState extends State<PolylinePage> {
         subtitle: 'Solid translucent color fill, with different color outline',
       ),
     ),
+    Polyline(
+      points: const [
+        LatLng(43.864797, 11.7112939),
+        LatLng(36.7948545, 10.2256785),
+        LatLng(35.566530, 5.584283),
+      ],
+      strokeWidth: 10,
+      color: Colors.blueAccent,
+      isDotted: true,
+      segmentSpacingFactor: 3,
+      borderStrokeWidth: 8,
+      borderColor: Colors.blue.withOpacity(0.5),
+      hitValue: (
+        title: 'Blue Dotted Line with Custom Spacing',
+        subtitle:
+            'Dotted line with segment spacing controlled by `segmentSpacingFactor`',
+      ),
+    ),
   ];
   late final _polylines =
       Map.fromEntries(_polylinesRaw.map((e) => MapEntry(e.hitValue, e)));

lib/src/layer/polyline_layer/painter.dart

@@ -200,7 +200,7 @@ class _PolylinePainter<R extends Object> extends CustomPainter {
       final borderRadius = (borderPaint?.strokeWidth ?? 0) / 2;
 
       if (isDotted) {
-        final spacing = strokeWidth * 1.5;
+        final spacing = strokeWidth * polyline.segmentSpacingFactor;
         if (borderPaint != null && filterPaint != null) {
           _paintDottedLine(borderPath, offsets, borderRadius, spacing);
           _paintDottedLine(filterPath, offsets, radius, spacing);

lib/src/layer/polyline_layer/polyline.dart

@@ -8,6 +8,15 @@ class Polyline<R extends Object> {
   /// The width of the stroke
   final double strokeWidth;
 
+  /// The multiplier used to calculate the spacing between segments in a dotted/
+  /// dashed polyline
+  ///
+  /// A value of 1.0 will result in spacing equal to the `strokeWidth`.
+  /// Increasing the value increases the spacing with respect to `strokeWidth`.
+  ///
+  /// Defaults to 1.5.
+  final double segmentSpacingFactor;
+
   /// The color of the line stroke.
   final Color color;
 
@@ -58,6 +67,7 @@ class Polyline<R extends Object> {
     this.strokeJoin = StrokeJoin.round,
     this.useStrokeWidthInMeter = false,
     this.hitValue,
+    this.segmentSpacingFactor = 1.5,
   });
 
   @override
@@ -69,6 +79,7 @@ class Polyline<R extends Object> {
           borderStrokeWidth == other.borderStrokeWidth &&
           borderColor == other.borderColor &&
           isDotted == other.isDotted &&
+          segmentSpacingFactor == other.segmentSpacingFactor &&
           strokeCap == other.strokeCap &&
           strokeJoin == other.strokeJoin &&
           useStrokeWidthInMeter == other.useStrokeWidthInMeter &&
@@ -90,6 +101,7 @@ class Polyline<R extends Object> {
         gradientColors,
         colorsStop,
         isDotted,
+        segmentSpacingFactor,
         strokeCap,
         strokeJoin,
         useStrokeWidthInMeter,