Refactor. Fires marker calibration

lib/zoomMapPlugin.dart

@@ -0,0 +1,58 @@
+import 'package:flutter/src/widgets/framework.dart';
+import 'package:flutter_map/plugin_api.dart';
+import 'package:flutter/material.dart';
+import 'package:comunes_flutter/comunes_flutter.dart';
+
+class ZoomMapPluginOptions extends LayerOptions {
+  final String text;
+
+  ZoomMapPluginOptions({this.text = ""});
+}
+
+// https://github.com/apptreesoftware/flutter_map/blob/master/flutter_map_example/lib/pages/plugin_api.dart
+class ZoomMapPlugin extends MapPlugin {
+  IconButton zoomButton(MapState mapState, IconData zoomIcon, int inc) {
+    return new IconButton(
+        icon: Icon(zoomIcon),
+        onPressed: () {
+          var currentZoom = mapState.zoom;
+          var currentCenter = mapState.center;
+          mapState.move(currentCenter, currentZoom + inc);
+        });
+  }
+
+  @override
+  Widget createLayer(LayerOptions options, MapState mapState) {
+    if (options is ZoomMapPluginOptions) {
+      /* print('point ${mapState
+        .getPixelBounds(mapState.zoom)
+        .bottomLeft}'); */
+      return LayoutBuilder(
+          builder: (context, constraints) =>
+              Stack(fit: StackFit.expand, children: <Widget>[
+                Positioned(
+                  top: constraints.maxHeight - 100,
+                  right: 10.0,
+                  // left: 10.0,
+                  child: new CenteredRow(
+                    children: <Widget>[
+                      new Column(
+                        children: <Widget>[
+                          zoomButton(mapState, Icons.zoom_in, 1),
+                          zoomButton(mapState, Icons.zoom_out, -1)
+                        ],
+                      )
+                    ],
+                  ),
+                )
+              ]));
+    }
+    throw ("Unknown options type for ZoomMapPlugin"
+        "plugin: $options");
+  }
+
+  @override
+  bool supportsLayer(LayerOptions options) {
+    return options is ZoomMapPluginOptions;
+  }
+}