Set max extent

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Sample viewer app

Set a max extent on the map.

screenshot

Use case

Limit the view of a map to a particular area by setting a max extent to constrain the user's ability to pan or zoom away.

How to use the sample

The application loads with a map whose maximum extent has been set to the borders of Colorado. Note that you won't be able to pan far from the Colorado border or zoom out beyond the minimum scale set by the max extent. Use the toggle switch to disable the max extent to freely pan/zoom around the map.

How it works

  1. Create a Map object.
  2. Create an Envelope of the Colorado extent.
  3. Set the map to a MapView object.
  4. Set the maximum extent of the map to be the Colorado envelope with Map::setMaxExtent().
  5. Set MaxExtent to an empty envelope to disable the maximum extent of the map.

Relevant API

  • Envelope
  • Map

Tags

envelope, extent, limit panning, map, mapview, max extent, zoom

Sample Code

SetMaxExtent.cppSetMaxExtent.cppSetMaxExtent.hSetMaxExtent.qml
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// [WriteFile Name=SetMaxExtent, Category=Maps]
// [Legal]
// Copyright 2022 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
// http://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.
// [Legal]

#ifdef PCH_BUILD
#include "pch.hpp"
#endif // PCH_BUILD

#include "SetMaxExtent.h"

#include "Graphic.h"
#include "GraphicsOverlay.h"
#include "Map.h"
#include "MapQuickView.h"
#include "SimpleLineSymbol.h"

using namespace Esri::ArcGISRuntime;

SetMaxExtent::SetMaxExtent(QObject* parent /* = nullptr */):
  QObject(parent),
  m_map(new Map(BasemapStyle::ArcGISStreets, this))
{
}

SetMaxExtent::~SetMaxExtent() = default;

void SetMaxExtent::init()
{
  // Register the map view for QML
  qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView");
  qmlRegisterType<SetMaxExtent>("Esri.Samples", 1, 0, "SetMaxExtentSample");
}

MapQuickView* SetMaxExtent::mapView() const
{
  return m_mapView;
}

// Set the view (created in QML)
void SetMaxExtent::setMapView(MapQuickView* mapView)
{
  if (!mapView || mapView == m_mapView)
    return;

  m_coloradoOverlay = new GraphicsOverlay(this);
  // Create an envelope to be used as the Colorado geometry
  m_coloradoEnvelope = Envelope(-12138232, 4441198, -11362327, 5012861, SpatialReference(3857));

  m_mapView = mapView;
  m_mapView->setMap(m_map);
  m_mapView->graphicsOverlays()->append(m_coloradoOverlay);
  m_map->setMaxExtent(m_coloradoEnvelope);
  createExtentBorder();

  emit mapViewChanged();
}

void SetMaxExtent::createExtentBorder()
{
  m_coloradoOutline = new SimpleLineSymbol(SimpleLineSymbolStyle::Dash, QColor("red"), 3.0f, this);
  m_coloradoGraphic = new Graphic(m_coloradoEnvelope, m_coloradoOutline, this);
  m_coloradoOverlay->graphics()->append(m_coloradoGraphic);
}

void SetMaxExtent::toggleMaxExtent()
{
  m_maxExtentEnabled ? m_maxExtentEnabled = false : m_maxExtentEnabled = true;

  if (!m_maxExtentEnabled) {
    m_map->setMaxExtent(Envelope{});
  }
  else {
    m_map->setMaxExtent(m_coloradoEnvelope);
    m_mapView->setViewpointGeometry(m_coloradoEnvelope, 50);
  }
}

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