From 5255b301cb77e9db7003b0d313dd2709416cc42b Mon Sep 17 00:00:00 2001
From: lorenzo <lorenzo.pongetti@gmail.com>
Date: Fri, 7 Jun 2019 15:48:56 +0200
Subject: [PATCH] #230 fix When the point is out of bounds, marker widget
 disappears

---
 lib/src/core/bounds.dart        |  7 +++++++
 lib/src/layer/marker_layer.dart | 14 +++++++++++++-
 lib/src/map/map.dart            | 14 +++++++++++++-
 3 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/lib/src/core/bounds.dart b/lib/src/core/bounds.dart
index c19aa23d0..bcfc4015f 100644
--- a/lib/src/core/bounds.dart
+++ b/lib/src/core/bounds.dart
@@ -59,6 +59,13 @@ class Bounds<T extends num> {
         (b.max.y <= max.y);
   }
 
+  bool containsPartialBounds(Bounds<T> b) {
+    return (b.min.x <= max.x) &&
+        (b.max.x >= min.x) &&
+        (b.min.y <= max.y) &&
+        (b.max.y >= min.y);
+  }
+
   @override
   String toString() => 'Bounds($min, $max)';
 }
diff --git a/lib/src/layer/marker_layer.dart b/lib/src/layer/marker_layer.dart
index dec91a149..fa7a395b9 100644
--- a/lib/src/layer/marker_layer.dart
+++ b/lib/src/layer/marker_layer.dart
@@ -1,5 +1,6 @@
 import 'package:flutter/widgets.dart';
 import 'package:flutter_map/flutter_map.dart';
+import 'package:flutter_map/src/core/bounds.dart';
 import 'package:flutter_map/src/map/map.dart';
 import 'package:latlong/latlong.dart';
 
@@ -93,6 +94,17 @@ class MarkerLayer extends StatelessWidget {
 
   MarkerLayer(this.markerOpts, this.map, this.stream);
 
+  bool _boundsContainsMarker(Marker marker) {
+    var pixelPoint = map.project(marker.point);
+
+    final width = marker.width - marker.anchor.left;
+    final height = marker.height - marker.anchor.top;
+
+    var sw = CustomPoint(pixelPoint.x + width, pixelPoint.y - height);
+    var ne = CustomPoint(pixelPoint.x - width, pixelPoint.y + height);
+    return map.pixelBounds.containsPartialBounds(Bounds(sw, ne));
+  }
+
   @override
   Widget build(BuildContext context) {
     return StreamBuilder<int>(
@@ -109,7 +121,7 @@ class MarkerLayer extends StatelessWidget {
           var pixelPosY =
               (pos.y - (markerOpt.height - markerOpt.anchor.top)).toDouble();
 
-          if (!map.bounds.contains(markerOpt.point)) {
+          if (!_boundsContainsMarker(markerOpt)) {
             continue;
           }
 
diff --git a/lib/src/map/map.dart b/lib/src/map/map.dart
index c70312b09..53004701a 100644
--- a/lib/src/map/map.dart
+++ b/lib/src/map/map.dart
@@ -60,6 +60,7 @@ class MapState {
 
   LatLng _lastCenter;
   LatLngBounds _lastBounds;
+  Bounds _lastPixelBounds;
   CustomPoint _pixelOrigin;
   bool _initialized = false;
 
@@ -84,6 +85,8 @@ class MapState {
 
   LatLngBounds get bounds => getBounds();
 
+  Bounds get pixelBounds => getLastPixelBounds();
+
   void _init() {
     _zoom = options.zoom;
     move(options.center, zoom);
@@ -103,6 +106,7 @@ class MapState {
 
     _zoom = zoom;
     _lastCenter = center;
+    _lastPixelBounds = getPixelBounds(_zoom);
     _lastBounds = _calculateBounds();
     _pixelOrigin = getNewPixelOrigin(center);
     _onMoveSink.add(null);
@@ -153,8 +157,16 @@ class MapState {
     return _calculateBounds();
   }
 
+  Bounds getLastPixelBounds() {
+    if (_lastPixelBounds != null) {
+      return _lastPixelBounds;
+    }
+
+    return getPixelBounds(zoom);
+  }
+
   LatLngBounds _calculateBounds() {
-    var bounds = getPixelBounds(zoom);
+    var bounds = getLastPixelBounds();
     return LatLngBounds(
       unproject(bounds.bottomLeft),
       unproject(bounds.topRight),