Show magnifier

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Tap and hold on a map to show a magnifier.

Image of show magnifier

Use case

Due to the limited screen size of some mobile devices, it may be difficult to identify individual features on a map where there is a high density of information, or the scale is very small. This can be the case when a mobile device is used for navigation, and the user wishes to magnify a particular area to better identify a road intersection.

How to use the sample

Tap and hold on the map to show a magnifier, then drag across the map to move the magnifier. You can also pan the map while holding the magnifier, by dragging the magnifier to the edge of the map.

How it works

Create a new ArcGISMapView with an ArcGISMapViewController, and assign an ArcGISMap to the ArcGISMapViewController.arcGISMap property.
Enable the magnifier by setting the ArcGISMapViewController.magnifiedEnabled property to true. This will set the magnifier to be shown on the ArcGISMap when the user performs a long press gesture. Note: The default value is false.
Optionally, set the ArcGISMapViewController.allowMagnifierToPanMap property to true to allow the map to be panned automatically when the magnifier gets near the edge of the ArcGISMap. Note: The default value is true.

Relevant API

ArcGISMap
ArcGISMapView
ArcGISMapViewController
ArcGISMapViewController.allowMagnifierToPanMap
ArcGISMapViewController.magnifiedEnabled

Sample Code

show_magnifier.dart
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//
// Copyright 2024 Esri
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

import 'package:arcgis_maps/arcgis_maps.dart';
import 'package:flutter/material.dart';

class ShowMagnifier extends StatelessWidget {
  const ShowMagnifier({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      // Add a map view to the widget tree and set a controller.
      body: ArcGISMapView(
        controllerProvider: () => ArcGISMapView.createController()
          // Set a map with an initial viewpoint.
          ..arcGISMap =
              ArcGISMap.withBasemapStyle(BasemapStyle.arcGISImageryStandard)
          ..arcGISMap!.initialViewpoint = Viewpoint.fromCenter(
            ArcGISPoint(
              x: -110.8258,
              y: 32.154089,
              spatialReference: SpatialReference.wgs84,
            ),
            scale: 2e4,
          )
          // Set the magnifier enabled property to true to show the magnifier on long press.
          ..magnifierEnabled = true,
      ),
    );
  }
}