Show labels on layers

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 // [WriteFile Name=ShowLabelsOnLayers, Category=DisplayInformation] // [Legal] // Copyright 2018 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  // sample headers #include "ShowLabelsOnLayers.h"  // ArcGIS Maps SDK headers #include "ArcadeLabelExpression.h" #include "Envelope.h" #include "Error.h" #include "FeatureLayer.h" #include "LabelDefinition.h" #include "LabelDefinitionListModel.h" #include "LayerListModel.h" #include "Map.h" #include "MapQuickView.h" #include "MapTypes.h" #include "Point.h" #include "ServiceFeatureTable.h" #include "SpatialReference.h" #include "SymbolTypes.h" #include "TextSymbol.h" #include "Viewpoint.h"  // Qt headers #include <QFuture>  using namespace Esri::ArcGISRuntime;  ShowLabelsOnLayers::ShowLabelsOnLayers(QQuickItem* parent /* = nullptr */):  QQuickItem(parent) { }  void ShowLabelsOnLayers::init() {  // Register the map view for QML  qmlRegisterType<MapQuickView>("Esri.Samples", 1, 0, "MapView");  qmlRegisterType<ShowLabelsOnLayers>("Esri.Samples", 1, 0, "ShowLabelsOnLayersSample"); }  void ShowLabelsOnLayers::componentComplete() {  QQuickItem::componentComplete();   // find QML MapView component  m_mapView = findChild<MapQuickView*>("mapView");   // Create a map using the light gray basemap  m_map = new Map(BasemapStyle::ArcGISLightGray, this);   // Create a feature layer  ServiceFeatureTable* featureTable = new ServiceFeatureTable(QUrl("https://services.arcgis.com/P3ePLMYs2RVChkJx/arcgis/rest/services/USA_116th_Congressional_Districts/FeatureServer/0"), this);  FeatureLayer* featureLayer = new FeatureLayer(featureTable, this);  connect(featureLayer, &FeatureLayer::doneLoading, this, [this, featureLayer](const Error& e)  {  if (!e.isEmpty())  return;   m_mapView->setViewpointAsync(Viewpoint(featureLayer->fullExtent().center(), 56759600));  });  m_map->operationalLayers()->append(featureLayer);   // Apply labels to the feature layer  LabelDefinition* republicanLabelDef = createRepublicanLabelDefinition();  LabelDefinition* democratLabelDef = createDemocratLabelDefinition();  featureLayer->labelDefinitions()->append(republicanLabelDef);  featureLayer->labelDefinitions()->append(democratLabelDef);  featureLayer->setLabelsEnabled(true);   // Set map to map view  m_mapView->setMap(m_map); }  LabelDefinition* ShowLabelsOnLayers::createRepublicanLabelDefinition() {  // This particular LabelDefinition will have the following characteristics:  // (1) The 'ArcadeLabelExpression' defines that the label text displayed comes from the fields 'NAME',  // the first letter of PARTY' (R or D), and 'CDFIPS' in the feature service in the format:  // Firstname Lastname (R)  // District #  // (2) The 'TextSymbol' for the labeled text will be red with a white halo centered in the target polygon.  // (3) The 'where' clause of the 'LabelDefinition' restricts the labels to data from Republican districts.   ArcadeLabelExpression* republicanArcadeLabelExpression = new ArcadeLabelExpression("$feature.NAME + ' (' + left($feature.PARTY,1) + ')\\nDistrict ' + $feature.CDFIPS", this);   TextSymbol* republicanTextSymbol = new TextSymbol(this);  republicanTextSymbol->setSize(11);  republicanTextSymbol->setColor(Qt::red);  republicanTextSymbol->setHaloColor(Qt::white);  republicanTextSymbol->setHaloWidth(2);  republicanTextSymbol->setHorizontalAlignment(HorizontalAlignment::Center);  republicanTextSymbol->setVerticalAlignment(VerticalAlignment::Middle);   LabelDefinition* republicanLabelDefinition = new LabelDefinition(republicanArcadeLabelExpression, republicanTextSymbol, this);  republicanLabelDefinition->setWhereClause("PARTY = 'Republican'");   return republicanLabelDefinition; }  LabelDefinition* ShowLabelsOnLayers::createDemocratLabelDefinition() {  // This particular LabelDefinition will have the following characteristics:  // (1) The 'ArcadeLabelExpression' defines that the label text displayed comes from the fields 'NAME',  // the first letter of PARTY' (R or D), and 'CDFIPS' in the feature service in the format:  // Firstname Lastname (D)  // District #  // (2) The 'TextSymbol' for the labeled text will be blue with a white halo centered in the target polygon.  // (3) The 'where' clause of the 'LabelDefinition' restricts the labels to data from Democrat districts.   ArcadeLabelExpression* democratArcadeLabelExpression = new ArcadeLabelExpression("$feature.NAME + ' (' + left($feature.PARTY,1) + ')\\nDistrict ' + $feature.CDFIPS", this);   TextSymbol* democratTextSymbol = new TextSymbol(this);  democratTextSymbol->setSize(11);  democratTextSymbol->setColor(Qt::blue);  democratTextSymbol->setHaloColor(Qt::white);  democratTextSymbol->setHaloWidth(2);  democratTextSymbol->setHorizontalAlignment(HorizontalAlignment::Center);  democratTextSymbol->setVerticalAlignment(VerticalAlignment::Middle);   LabelDefinition* democratLabelDefinition = new LabelDefinition(democratArcadeLabelExpression, democratTextSymbol, this);  democratLabelDefinition->setWhereClause("PARTY = 'Democrat'");   return democratLabelDefinition; }