true, each geometry instance will only be rendered in 3D to save GPU memory.
* @param {Boolean} [options.shouldAnimate=false] true if the clock should attempt to advance simulation time by default, false otherwise. This option takes precedence over setting {@link Viewer#clockViewModel}.
* @param {ClockViewModel} [options.clockViewModel=new ClockViewModel(options.clock)] The clock view model to use to control current time.
* @param {ProviderViewModel} [options.selectedImageryProviderViewModel] The view model for the current base imagery layer, if not supplied the first available base layer is used. This value is only valid if options.baseLayerPicker is set to true.
* @param {ProviderViewModel[]} [options.imageryProviderViewModels=createDefaultImageryProviderViewModels()] The array of ProviderViewModels to be selectable from the BaseLayerPicker. This value is only valid if options.baseLayerPicker is set to true.
* @param {ProviderViewModel} [options.selectedTerrainProviderViewModel] The view model for the current base terrain layer, if not supplied the first available base layer is used. This value is only valid if options.baseLayerPicker is set to true.
* @param {ProviderViewModel[]} [options.terrainProviderViewModels=createDefaultTerrainProviderViewModels()] The array of ProviderViewModels to be selectable from the BaseLayerPicker. This value is only valid if options.baseLayerPicker is set to true.
* @param {ImageryProvider} [options.imageryProvider=createWorldImagery()] The imagery provider to use. This value is only valid if options.baseLayerPicker is set to false.
* @param {TerrainProvider} [options.terrainProvider=new EllipsoidTerrainProvider()] The terrain provider to use
* @param {SkyBox} [options.skyBox] The skybox used to render the stars. When undefined, the default stars are used.
* @param {SkyAtmosphere} [options.skyAtmosphere] Blue sky, and the glow around the Earth's limb. Set to false to turn it off.
* @param {Element|String} [options.fullscreenElement=document.body] The element or id to be placed into fullscreen mode when the full screen button is pressed.
* @param {Boolean} [options.useDefaultRenderLoop=true] True if this widget should control the render loop, false otherwise.
* @param {Number} [options.targetFrameRate] The target frame rate when using the default render loop.
* @param {Boolean} [options.showRenderLoopErrors=true] If true, this widget will automatically display an HTML panel to the user containing the error, if a render loop error occurs.
* @param {Boolean} [options.useBrowserRecommendedResolution=false] If true, render at the browser's recommended resolution and ignore window.devicePixelRatio.
* @param {Boolean} [options.automaticallyTrackDataSourceClocks=true] If true, this widget will automatically track the clock settings of newly added DataSources, updating if the DataSource's clock changes. Set this to false if you want to configure the clock independently.
* @param {Object} [options.contextOptions] Context and WebGL creation properties corresponding to options passed to {@link Scene}.
* @param {SceneMode} [options.sceneMode=SceneMode.SCENE3D] The initial scene mode.
* @param {MapProjection} [options.mapProjection=new GeographicProjection()] The map projection to use in 2D and Columbus View modes.
* @param {Globe} [options.globe=new Globe(mapProjection.ellipsoid)] The globe to use in the scene. If set to false, no globe will be added.
* @param {Boolean} [options.orderIndependentTranslucency=true] If true and the configuration supports it, use order independent translucency.
* @param {Element|String} [options.creditContainer] The DOM element or ID that will contain the {@link CreditDisplay}. If not specified, the credits are added to the bottom of the widget itself.
* @param {Element|String} [options.creditViewport] The DOM element or ID that will contain the credit pop up created by the {@link CreditDisplay}. If not specified, it will appear over the widget itself.
* @param {DataSourceCollection} [options.dataSources=new DataSourceCollection()] The collection of data sources visualized by the widget. If this parameter is provided,
* the instance is assumed to be owned by the caller and will not be destroyed when the viewer is destroyed.
* @param {Number} [options.terrainExaggeration=1.0] A scalar used to exaggerate the terrain. Note that terrain exaggeration will not modify any other primitive as they are positioned relative to the ellipsoid.
* @param {Boolean} [options.shadows=false] Determines if shadows are cast by the sun.
* @param {ShadowMode} [options.terrainShadows=ShadowMode.RECEIVE_ONLY] Determines if the terrain casts or receives shadows from the sun.
* @param {MapMode2D} [options.mapMode2D=MapMode2D.INFINITE_SCROLL] Determines if the 2D map is rotatable or can be scrolled infinitely in the horizontal direction.
* @param {Boolean} [options.projectionPicker=false] If set to true, the ProjectionPicker widget will be created.
* @param {Boolean} [options.requestRenderMode=false] If true, rendering a frame will only occur when needed as determined by changes within the scene. Enabling reduces the CPU/GPU usage of your application and uses less battery on mobile, but requires using {@link Scene#requestRender} to render a new frame explicitly in this mode. This will be necessary in many cases after making changes to the scene in other parts of the API. See {@link https://cesium.com/blog/2018/01/24/cesium-scene-rendering-performance/|Improving Performance with Explicit Rendering}.
* @param {Number} [options.maximumRenderTimeChange=0.0] If requestRenderMode is true, this value defines the maximum change in simulation time allowed before a render is requested. See {@link https://cesium.com/blog/2018/01/24/cesium-scene-rendering-performance/|Improving Performance with Explicit Rendering}.
*
* @exception {DeveloperError} Element with id "container" does not exist in the document.
* @exception {DeveloperError} options.selectedImageryProviderViewModel is not available when not using the BaseLayerPicker widget, specify options.imageryProvider instead.
* @exception {DeveloperError} options.selectedTerrainProviderViewModel is not available when not using the BaseLayerPicker widget, specify options.terrainProvider instead.
*
* @see Animation
* @see BaseLayerPicker
* @see CesiumWidget
* @see FullscreenButton
* @see HomeButton
* @see SceneModePicker
* @see Timeline
* @see viewerDragDropMixin
*
* @demo {@link https://sandcastle.cesium.com/index.html?src=Hello%20World.html|Cesium Sandcastle Hello World Demo}
*
* @example
* //Initialize the viewer widget with several custom options and mixins.
* var viewer = new Cesium.Viewer('cesiumContainer', {
* //Start in Columbus Viewer
* sceneMode : Cesium.SceneMode.COLUMBUS_VIEW,
* //Use Cesium World Terrain
* terrainProvider : Cesium.createWorldTerrain(),
* //Hide the base layer picker
* baseLayerPicker : false,
* //Use OpenStreetMaps
* imageryProvider : new Cesium.OpenStreetMapImageryProvider({
* url : 'https://a.tile.openstreetmap.org/'
* }),
* // Use high-res stars downloaded from https://github.com/AnalyticalGraphicsInc/cesium-assets
* skyBox : new Cesium.SkyBox({
* sources : {
* positiveX : 'stars/TychoSkymapII.t3_08192x04096_80_px.jpg',
* negativeX : 'stars/TychoSkymapII.t3_08192x04096_80_mx.jpg',
* positiveY : 'stars/TychoSkymapII.t3_08192x04096_80_py.jpg',
* negativeY : 'stars/TychoSkymapII.t3_08192x04096_80_my.jpg',
* positiveZ : 'stars/TychoSkymapII.t3_08192x04096_80_pz.jpg',
* negativeZ : 'stars/TychoSkymapII.t3_08192x04096_80_mz.jpg'
* }
* }),
* // Show Columbus View map with Web Mercator projection
* mapProjection : new Cesium.WebMercatorProjection()
* });
*
* //Add basic drag and drop functionality
* viewer.extend(Cesium.viewerDragDropMixin);
*
* //Show a pop-up alert if we encounter an error when processing a dropped file
* viewer.dropError.addEventListener(function(dropHandler, name, error) {
* console.log(error);
* window.alert(error);
* });
*/
function Viewer(container, options) {
//>>includeStart('debug', pragmas.debug);
if (!defined(container)) {
throw new DeveloperError('container is required.');
}
//>>includeEnd('debug');
container = getElement(container);
options = defaultValue(options, defaultValue.EMPTY_OBJECT);
var createBaseLayerPicker = (!defined(options.globe) || options.globe !== false) &&
(!defined(options.baseLayerPicker) || options.baseLayerPicker !== false);
//>>includeStart('debug', pragmas.debug);
// If not using BaseLayerPicker, selectedImageryProviderViewModel is an invalid option
if (!createBaseLayerPicker && defined(options.selectedImageryProviderViewModel)) {
throw new DeveloperError('options.selectedImageryProviderViewModel is not available when not using the BaseLayerPicker widget. \
Either specify options.imageryProvider instead or set options.baseLayerPicker to true.');
}
// If not using BaseLayerPicker, selectedTerrainProviderViewModel is an invalid option
if (!createBaseLayerPicker && defined(options.selectedTerrainProviderViewModel)) {
throw new DeveloperError('options.selectedTerrainProviderViewModel is not available when not using the BaseLayerPicker widget. \
Either specify options.terrainProvider instead or set options.baseLayerPicker to true.');
}
//>>includeEnd('debug')
var that = this;
var viewerContainer = document.createElement('div');
viewerContainer.className = 'cesium-viewer';
container.appendChild(viewerContainer);
// Cesium widget container
var cesiumWidgetContainer = document.createElement('div');
cesiumWidgetContainer.className = 'cesium-viewer-cesiumWidgetContainer';
viewerContainer.appendChild(cesiumWidgetContainer);
// Bottom container
var bottomContainer = document.createElement('div');
bottomContainer.className = 'cesium-viewer-bottom';
viewerContainer.appendChild(bottomContainer);
var scene3DOnly = defaultValue(options.scene3DOnly, false);
var clock;
var clockViewModel;
var destroyClockViewModel = false;
if (defined(options.clockViewModel)) {
clockViewModel = options.clockViewModel;
clock = clockViewModel.clock;
} else {
clock = new Clock();
clockViewModel = new ClockViewModel(clock);
destroyClockViewModel = true;
}
if (defined(options.shouldAnimate)) {
clock.shouldAnimate = options.shouldAnimate;
}
// Cesium widget
var cesiumWidget = new CesiumWidget(cesiumWidgetContainer, {
imageryProvider: createBaseLayerPicker || defined(options.imageryProvider) ? false : undefined,
clock : clock,
skyBox : options.skyBox,
skyAtmosphere : options.skyAtmosphere,
sceneMode : options.sceneMode,
mapProjection : options.mapProjection,
globe : options.globe,
orderIndependentTranslucency : options.orderIndependentTranslucency,
contextOptions : options.contextOptions,
useDefaultRenderLoop : options.useDefaultRenderLoop,
targetFrameRate : options.targetFrameRate,
showRenderLoopErrors : options.showRenderLoopErrors,
useBrowserRecommendedResolution : options.useBrowserRecommendedResolution,
creditContainer : defined(options.creditContainer) ? options.creditContainer : bottomContainer,
creditViewport : options.creditViewport,
scene3DOnly : scene3DOnly,
terrainExaggeration : options.terrainExaggeration,
shadows : options.shadows,
terrainShadows : options.terrainShadows,
mapMode2D : options.mapMode2D,
requestRenderMode : options.requestRenderMode,
maximumRenderTimeChange : options.maximumRenderTimeChange
});
var dataSourceCollection = options.dataSources;
var destroyDataSourceCollection = false;
if (!defined(dataSourceCollection)) {
dataSourceCollection = new DataSourceCollection();
destroyDataSourceCollection = true;
}
var scene = cesiumWidget.scene;
var dataSourceDisplay = new DataSourceDisplay({
scene : scene,
dataSourceCollection : dataSourceCollection
});
var eventHelper = new EventHelper();
eventHelper.add(clock.onTick, Viewer.prototype._onTick, this);
eventHelper.add(scene.morphStart, Viewer.prototype._clearTrackedObject, this);
// Selection Indicator
var selectionIndicator;
if (!defined(options.selectionIndicator) || options.selectionIndicator !== false) {
var selectionIndicatorContainer = document.createElement('div');
selectionIndicatorContainer.className = 'cesium-viewer-selectionIndicatorContainer';
viewerContainer.appendChild(selectionIndicatorContainer);
selectionIndicator = new SelectionIndicator(selectionIndicatorContainer, scene);
}
// Info Box
var infoBox;
if (!defined(options.infoBox) || options.infoBox !== false) {
var infoBoxContainer = document.createElement('div');
infoBoxContainer.className = 'cesium-viewer-infoBoxContainer';
viewerContainer.appendChild(infoBoxContainer);
infoBox = new InfoBox(infoBoxContainer);
var infoBoxViewModel = infoBox.viewModel;
eventHelper.add(infoBoxViewModel.cameraClicked, Viewer.prototype._onInfoBoxCameraClicked, this);
eventHelper.add(infoBoxViewModel.closeClicked, Viewer.prototype._onInfoBoxClockClicked, this);
}
// Main Toolbar
var toolbar = document.createElement('div');
toolbar.className = 'cesium-viewer-toolbar';
viewerContainer.appendChild(toolbar);
// Geocoder
var geocoder;
if (!defined(options.geocoder) || options.geocoder !== false) {
var geocoderContainer = document.createElement('div');
geocoderContainer.className = 'cesium-viewer-geocoderContainer';
toolbar.appendChild(geocoderContainer);
var geocoderService;
if (defined(options.geocoder) && typeof options.geocoder !== 'boolean') {
geocoderService = isArray(options.geocoder) ? options.geocoder : [options.geocoder];
}
geocoder = new Geocoder({
container : geocoderContainer,
geocoderServices : geocoderService,
scene : scene
});
// Subscribe to search so that we can clear the trackedEntity when it is clicked.
eventHelper.add(geocoder.viewModel.search.beforeExecute, Viewer.prototype._clearObjects, this);
}
// HomeButton
var homeButton;
if (!defined(options.homeButton) || options.homeButton !== false) {
homeButton = new HomeButton(toolbar, scene);
if (defined(geocoder)) {
eventHelper.add(homeButton.viewModel.command.afterExecute, function() {
var viewModel = geocoder.viewModel;
viewModel.searchText = '';
if (viewModel.isSearchInProgress) {
viewModel.search();
}
});
}
// Subscribe to the home button beforeExecute event so that we can clear the trackedEntity.
eventHelper.add(homeButton.viewModel.command.beforeExecute, Viewer.prototype._clearTrackedObject, this);
}
// SceneModePicker
// By default, we silently disable the scene mode picker if scene3DOnly is true,
// but if sceneModePicker is explicitly set to true, throw an error.
//>>includeStart('debug', pragmas.debug);
if ((options.sceneModePicker === true) && scene3DOnly) {
throw new DeveloperError('options.sceneModePicker is not available when options.scene3DOnly is set to true.');
}
//>>includeEnd('debug');
var sceneModePicker;
if (!scene3DOnly && (!defined(options.sceneModePicker) || options.sceneModePicker !== false)) {
sceneModePicker = new SceneModePicker(toolbar, scene);
}
var projectionPicker;
if (options.projectionPicker) {
projectionPicker = new ProjectionPicker(toolbar, scene);
}
// BaseLayerPicker
var baseLayerPicker;
var baseLayerPickerDropDown;
if (createBaseLayerPicker) {
var imageryProviderViewModels = defaultValue(options.imageryProviderViewModels, createDefaultImageryProviderViewModels());
var terrainProviderViewModels = defaultValue(options.terrainProviderViewModels, createDefaultTerrainProviderViewModels());
baseLayerPicker = new BaseLayerPicker(toolbar, {
globe : scene.globe,
imageryProviderViewModels : imageryProviderViewModels,
selectedImageryProviderViewModel : options.selectedImageryProviderViewModel,
terrainProviderViewModels : terrainProviderViewModels,
selectedTerrainProviderViewModel : options.selectedTerrainProviderViewModel
});
//Grab the dropdown for resize code.
var elements = toolbar.getElementsByClassName('cesium-baseLayerPicker-dropDown');
baseLayerPickerDropDown = elements[0];
}
// These need to be set after the BaseLayerPicker is created in order to take effect
if (defined(options.imageryProvider) && options.imageryProvider !== false) {
if (createBaseLayerPicker) {
baseLayerPicker.viewModel.selectedImagery = undefined;
}
scene.imageryLayers.removeAll();
scene.imageryLayers.addImageryProvider(options.imageryProvider);
}
if (defined(options.terrainProvider)) {
if (createBaseLayerPicker) {
baseLayerPicker.viewModel.selectedTerrain = undefined;
}
scene.terrainProvider = options.terrainProvider;
}
// Navigation Help Button
var navigationHelpButton;
if (!defined(options.navigationHelpButton) || options.navigationHelpButton !== false) {
var showNavHelp = true;
try {
//window.localStorage is null if disabled in Firefox or undefined in browsers with implementation
if (defined(window.localStorage)) {
var hasSeenNavHelp = window.localStorage.getItem('cesium-hasSeenNavHelp');
if (defined(hasSeenNavHelp) && Boolean(hasSeenNavHelp)) {
showNavHelp = false;
} else {
window.localStorage.setItem('cesium-hasSeenNavHelp', 'true');
}
}
} catch (e) {
//Accessing window.localStorage throws if disabled in Chrome
//window.localStorage.setItem throws if in Safari private browsing mode or in any browser if we are over quota.
}
navigationHelpButton = new NavigationHelpButton({
container : toolbar,
instructionsInitiallyVisible : defaultValue(options.navigationInstructionsInitiallyVisible, showNavHelp)
});
}
// Animation
var animation;
if (!defined(options.animation) || options.animation !== false) {
var animationContainer = document.createElement('div');
animationContainer.className = 'cesium-viewer-animationContainer';
viewerContainer.appendChild(animationContainer);
animation = new Animation(animationContainer, new AnimationViewModel(clockViewModel));
}
// Timeline
var timeline;
if (!defined(options.timeline) || options.timeline !== false) {
var timelineContainer = document.createElement('div');
timelineContainer.className = 'cesium-viewer-timelineContainer';
viewerContainer.appendChild(timelineContainer);
timeline = new Timeline(timelineContainer, clock);
timeline.addEventListener('settime', onTimelineScrubfunction, false);
timeline.zoomTo(clock.startTime, clock.stopTime);
}
// Fullscreen
var fullscreenButton;
var fullscreenSubscription;
var fullscreenContainer;
if (!defined(options.fullscreenButton) || options.fullscreenButton !== false) {
fullscreenContainer = document.createElement('div');
fullscreenContainer.className = 'cesium-viewer-fullscreenContainer';
viewerContainer.appendChild(fullscreenContainer);
fullscreenButton = new FullscreenButton(fullscreenContainer, options.fullscreenElement);
//Subscribe to fullscreenButton.viewModel.isFullscreenEnabled so
//that we can hide/show the button as well as size the timeline.
fullscreenSubscription = subscribeAndEvaluate(fullscreenButton.viewModel, 'isFullscreenEnabled', function(isFullscreenEnabled) {
fullscreenContainer.style.display = isFullscreenEnabled ? 'block' : 'none';
if (defined(timeline)) {
timeline.container.style.right = fullscreenContainer.clientWidth + 'px';
timeline.resize();
}
});
}
// VR
var vrButton;
var vrSubscription;
var vrModeSubscription;
if (options.vrButton) {
var vrContainer = document.createElement('div');
vrContainer.className = 'cesium-viewer-vrContainer';
viewerContainer.appendChild(vrContainer);
vrButton = new VRButton(vrContainer, scene, options.fullScreenElement);
vrSubscription = subscribeAndEvaluate(vrButton.viewModel, 'isVREnabled', function(isVREnabled) {
vrContainer.style.display = isVREnabled ? 'block' : 'none';
if (defined(fullscreenButton)) {
vrContainer.style.right = fullscreenContainer.clientWidth + 'px';
}
if (defined(timeline)) {
timeline.container.style.right = vrContainer.clientWidth + 'px';
timeline.resize();
}
});
vrModeSubscription = subscribeAndEvaluate(vrButton.viewModel, 'isVRMode', function(isVRMode) {
enableVRUI(that, isVRMode);
});
}
//Assign all properties to this instance. No "this" assignments should
//take place above this line.
this._baseLayerPickerDropDown = baseLayerPickerDropDown;
this._fullscreenSubscription = fullscreenSubscription;
this._vrSubscription = vrSubscription;
this._vrModeSubscription = vrModeSubscription;
this._dataSourceChangedListeners = {};
this._automaticallyTrackDataSourceClocks = defaultValue(options.automaticallyTrackDataSourceClocks, true);
this._container = container;
this._bottomContainer = bottomContainer;
this._element = viewerContainer;
this._cesiumWidget = cesiumWidget;
this._selectionIndicator = selectionIndicator;
this._infoBox = infoBox;
this._dataSourceCollection = dataSourceCollection;
this._destroyDataSourceCollection = destroyDataSourceCollection;
this._dataSourceDisplay = dataSourceDisplay;
this._clockViewModel = clockViewModel;
this._destroyClockViewModel = destroyClockViewModel;
this._toolbar = toolbar;
this._homeButton = homeButton;
this._sceneModePicker = sceneModePicker;
this._projectionPicker = projectionPicker;
this._baseLayerPicker = baseLayerPicker;
this._navigationHelpButton = navigationHelpButton;
this._animation = animation;
this._timeline = timeline;
this._fullscreenButton = fullscreenButton;
this._vrButton = vrButton;
this._geocoder = geocoder;
this._eventHelper = eventHelper;
this._lastWidth = 0;
this._lastHeight = 0;
this._allowDataSourcesToSuspendAnimation = true;
this._entityView = undefined;
this._enableInfoOrSelection = defined(infoBox) || defined(selectionIndicator);
this._clockTrackedDataSource = undefined;
this._trackedEntity = undefined;
this._needTrackedEntityUpdate = false;
this._selectedEntity = undefined;
this._clockTrackedDataSource = undefined;
this._zoomIsFlight = false;
this._zoomTarget = undefined;
this._zoomPromise = undefined;
this._zoomOptions = undefined;
this._selectedEntityChanged = new Event();
this._trackedEntityChanged = new Event();
knockout.track(this, ['_trackedEntity', '_selectedEntity', '_clockTrackedDataSource']);
//Listen to data source events in order to track clock changes.
eventHelper.add(dataSourceCollection.dataSourceAdded, Viewer.prototype._onDataSourceAdded, this);
eventHelper.add(dataSourceCollection.dataSourceRemoved, Viewer.prototype._onDataSourceRemoved, this);
// Prior to each render, check if anything needs to be resized.
eventHelper.add(scene.postUpdate, Viewer.prototype.resize, this);
eventHelper.add(scene.postRender, Viewer.prototype._postRender, this);
// We need to subscribe to the data sources and collections so that we can clear the
// tracked object when it is removed from the scene.
// Subscribe to current data sources
var dataSourceLength = dataSourceCollection.length;
for (var i = 0; i < dataSourceLength; i++) {
this._dataSourceAdded(dataSourceCollection, dataSourceCollection.get(i));
}
this._dataSourceAdded(undefined, dataSourceDisplay.defaultDataSource);
// Hook up events so that we can subscribe to future sources.
eventHelper.add(dataSourceCollection.dataSourceAdded, Viewer.prototype._dataSourceAdded, this);
eventHelper.add(dataSourceCollection.dataSourceRemoved, Viewer.prototype._dataSourceRemoved, this);
// Subscribe to left clicks and zoom to the picked object.
function pickAndTrackObject(e) {
var entity = pickEntity(that, e);
if (defined(entity)) {
//Only track the entity if it has a valid position at the current time.
if (Property.getValueOrUndefined(entity.position, that.clock.currentTime)) {
that.trackedEntity = entity;
} else {
that.zoomTo(entity);
}
} else if (defined(that.trackedEntity)) {
that.trackedEntity = undefined;
}
}
function pickAndSelectObject(e) {
that.selectedEntity = pickEntity(that, e);
}
cesiumWidget.screenSpaceEventHandler.setInputAction(pickAndSelectObject, ScreenSpaceEventType.LEFT_CLICK);
cesiumWidget.screenSpaceEventHandler.setInputAction(pickAndTrackObject, ScreenSpaceEventType.LEFT_DOUBLE_CLICK);
}
defineProperties(Viewer.prototype, {
/**
* Gets the parent container.
* @memberof Viewer.prototype
* @type {Element}
* @readonly
*/
container : {
get : function() {
return this._container;
}
},
/**
* Gets the DOM element for the area at the bottom of the window containing the
* {@link CreditDisplay} and potentially other things.
* @memberof Viewer.prototype
* @type {Element}
* @readonly
*/
bottomContainer : {
get : function() {
return this._bottomContainer;
}
},
/**
* Gets the CesiumWidget.
* @memberof Viewer.prototype
* @type {CesiumWidget}
* @readonly
*/
cesiumWidget : {
get : function() {
return this._cesiumWidget;
}
},
/**
* Gets the selection indicator.
* @memberof Viewer.prototype
* @type {SelectionIndicator}
* @readonly
*/
selectionIndicator : {
get : function() {
return this._selectionIndicator;
}
},
/**
* Gets the info box.
* @memberof Viewer.prototype
* @type {InfoBox}
* @readonly
*/
infoBox : {
get : function() {
return this._infoBox;
}
},
/**
* Gets the Geocoder.
* @memberof Viewer.prototype
* @type {Geocoder}
* @readonly
*/
geocoder : {
get : function() {
return this._geocoder;
}
},
/**
* Gets the HomeButton.
* @memberof Viewer.prototype
* @type {HomeButton}
* @readonly
*/
homeButton : {
get : function() {
return this._homeButton;
}
},
/**
* Gets the SceneModePicker.
* @memberof Viewer.prototype
* @type {SceneModePicker}
* @readonly
*/
sceneModePicker : {
get : function() {
return this._sceneModePicker;
}
},
/**
* Gets the ProjectionPicker.
* @memberof Viewer.prototype
* @type {ProjectionPicker}
* @readonly
*/
projectionPicker : {
get : function() {
return this._projectionPicker;
}
},
/**
* Gets the BaseLayerPicker.
* @memberof Viewer.prototype
* @type {BaseLayerPicker}
* @readonly
*/
baseLayerPicker : {
get : function() {
return this._baseLayerPicker;
}
},
/**
* Gets the NavigationHelpButton.
* @memberof Viewer.prototype
* @type {NavigationHelpButton}
* @readonly
*/
navigationHelpButton : {
get : function() {
return this._navigationHelpButton;
}
},
/**
* Gets the Animation widget.
* @memberof Viewer.prototype
* @type {Animation}
* @readonly
*/
animation : {
get : function() {
return this._animation;
}
},
/**
* Gets the Timeline widget.
* @memberof Viewer.prototype
* @type {Timeline}
* @readonly
*/
timeline : {
get : function() {
return this._timeline;
}
},
/**
* Gets the FullscreenButton.
* @memberof Viewer.prototype
* @type {FullscreenButton}
* @readonly
*/
fullscreenButton : {
get : function() {
return this._fullscreenButton;
}
},
/**
* Gets the VRButton.
* @memberof Viewer.prototype
* @type {VRButton}
* @readonly
*/
vrButton : {
get : function() {
return this._vrButton;
}
},
/**
* Gets the display used for {@link DataSource} visualization.
* @memberof Viewer.prototype
* @type {DataSourceDisplay}
* @readonly
*/
dataSourceDisplay : {
get : function() {
return this._dataSourceDisplay;
}
},
/**
* Gets the collection of entities not tied to a particular data source.
* This is a shortcut to [dataSourceDisplay.defaultDataSource.entities]{@link Viewer#dataSourceDisplay}.
* @memberof Viewer.prototype
* @type {EntityCollection}
* @readonly
*/
entities : {
get : function() {
return this._dataSourceDisplay.defaultDataSource.entities;
}
},
/**
* Gets the set of {@link DataSource} instances to be visualized.
* @memberof Viewer.prototype
* @type {DataSourceCollection}
* @readonly
*/
dataSources : {
get : function() {
return this._dataSourceCollection;
}
},
/**
* Gets the canvas.
* @memberof Viewer.prototype
* @type {Canvas}
* @readonly
*/
canvas : {
get : function() {
return this._cesiumWidget.canvas;
}
},
/**
* Gets the scene.
* @memberof Viewer.prototype
* @type {Scene}
* @readonly
*/
scene : {
get : function() {
return this._cesiumWidget.scene;
}
},
/**
* Determines if shadows are cast by the sun.
* @memberof Viewer.prototype
* @type {Boolean}
*/
shadows : {
get : function() {
return this.scene.shadowMap.enabled;
},
set : function(value) {
this.scene.shadowMap.enabled = value;
}
},
/**
* Determines if the terrain casts or shadows from the sun.
* @memberof Viewer.prototype
* @type {ShadowMode}
*/
terrainShadows : {
get : function() {
return this.scene.globe.shadows;
},
set : function(value) {
this.scene.globe.shadows = value;
}
},
/**
* Get the scene's shadow map
* @memberof Viewer.prototype
* @type {ShadowMap}
* @readonly
*/
shadowMap : {
get : function() {
return this.scene.shadowMap;
}
},
/**
* Gets the collection of image layers that will be rendered on the globe.
* @memberof Viewer.prototype
*
* @type {ImageryLayerCollection}
* @readonly
*/
imageryLayers : {
get : function() {
return this.scene.imageryLayers;
}
},
/**
* The terrain provider providing surface geometry for the globe.
* @memberof Viewer.prototype
*
* @type {TerrainProvider}
*/
terrainProvider : {
get : function() {
return this.scene.terrainProvider;
},
set : function(terrainProvider) {
this.scene.terrainProvider = terrainProvider;
}
},
/**
* Gets the camera.
* @memberof Viewer.prototype
*
* @type {Camera}
* @readonly
*/
camera : {
get : function() {
return this.scene.camera;
}
},
/**
* Gets the post-process stages.
* @memberof Viewer.prototype
*
* @type {PostProcessStageCollection}
* @readonly
*/
postProcessStages : {
get : function() {
return this.scene.postProcessStages;
}
},
/**
* Gets the clock.
* @memberof Viewer.prototype
* @type {Clock}
* @readonly
*/
clock : {
get : function() {
return this._clockViewModel.clock;
}
},
/**
* Gets the clock view model.
* @memberof Viewer.prototype
* @type {ClockViewModel}
* @readonly
*/
clockViewModel : {
get : function() {
return this._clockViewModel;
}
},
/**
* Gets the screen space event handler.
* @memberof Viewer.prototype
* @type {ScreenSpaceEventHandler}
* @readonly
*/
screenSpaceEventHandler : {
get : function() {
return this._cesiumWidget.screenSpaceEventHandler;
}
},
/**
* Gets or sets the target frame rate of the widget when useDefaultRenderLoop
* is true. If undefined, the browser's {@link requestAnimationFrame} implementation
* determines the frame rate. If defined, this value must be greater than 0. A value higher
* than the underlying requestAnimationFrame implementation will have no effect.
* @memberof Viewer.prototype
*
* @type {Number}
*/
targetFrameRate : {
get : function() {
return this._cesiumWidget.targetFrameRate;
},
set : function(value) {
this._cesiumWidget.targetFrameRate = value;
}
},
/**
* Gets or sets whether or not this widget should control the render loop.
* If set to true the widget will use {@link requestAnimationFrame} to
* perform rendering and resizing of the widget, as well as drive the
* simulation clock. If set to false, you must manually call the
* resize, render methods
* as part of a custom render loop. If an error occurs during rendering, {@link Scene}'s
* renderError event will be raised and this property
* will be set to false. It must be set back to true to continue rendering
* after the error.
* @memberof Viewer.prototype
*
* @type {Boolean}
*/
useDefaultRenderLoop : {
get : function() {
return this._cesiumWidget.useDefaultRenderLoop;
},
set : function(value) {
this._cesiumWidget.useDefaultRenderLoop = value;
}
},
/**
* Gets or sets a scaling factor for rendering resolution. Values less than 1.0 can improve
* performance on less powerful devices while values greater than 1.0 will render at a higher
* resolution and then scale down, resulting in improved visual fidelity.
* For example, if the widget is laid out at a size of 640x480, setting this value to 0.5
* will cause the scene to be rendered at 320x240 and then scaled up while setting
* it to 2.0 will cause the scene to be rendered at 1280x960 and then scaled down.
* @memberof Viewer.prototype
*
* @type {Number}
* @default 1.0
*/
resolutionScale : {
get : function() {
return this._cesiumWidget.resolutionScale;
},
set : function(value) {
this._cesiumWidget.resolutionScale = value;
}
},
/**
* Boolean flag indicating if the browser's recommended resolution is used.
* If true, the browser's device pixel ratio is ignored and 1.0 is used instead,
* effectively rendering based on CSS pixels instead of device pixels. This can improve
* performance on less powerful devices that have high pixel density. When false, rendering
* will be in device pixels. {@link Viewer#resolutionScale} will still take effect whether
* this flag is true or false.
* @memberof Viewer.prototype
*
* @type {Boolean}
* @default false
*/
useBrowserRecommendedResolution : {
get : function() {
return this._cesiumWidget.useBrowserRecommendedResolution;
},
set : function(value) {
this._cesiumWidget.useBrowserRecommendedResolution = value;
}
},
/**
* Gets or sets whether or not data sources can temporarily pause
* animation in order to avoid showing an incomplete picture to the user.
* For example, if asynchronous primitives are being processed in the
* background, the clock will not advance until the geometry is ready.
*
* @memberof Viewer.prototype
*
* @type {Boolean}
*/
allowDataSourcesToSuspendAnimation : {
get : function() {
return this._allowDataSourcesToSuspendAnimation;
},
set : function(value) {
this._allowDataSourcesToSuspendAnimation = value;
}
},
/**
* Gets or sets the Entity instance currently being tracked by the camera.
* @memberof Viewer.prototype
* @type {Entity}
*/
trackedEntity : {
get : function() {
return this._trackedEntity;
},
set : function(value) {
if (this._trackedEntity !== value) {
this._trackedEntity = value;
//Cancel any pending zoom
cancelZoom(this);
var scene = this.scene;
var sceneMode = scene.mode;
//Stop tracking
if (!defined(value) || !defined(value.position)) {
this._needTrackedEntityUpdate = false;
if (sceneMode === SceneMode.COLUMBUS_VIEW || sceneMode === SceneMode.SCENE2D) {
scene.screenSpaceCameraController.enableTranslate = true;
}
if (sceneMode === SceneMode.COLUMBUS_VIEW || sceneMode === SceneMode.SCENE3D) {
scene.screenSpaceCameraController.enableTilt = true;
}
this._entityView = undefined;
this.camera.lookAtTransform(Matrix4.IDENTITY);
} else {
//We can't start tracking immediately, so we set a flag and start tracking
//when the bounding sphere is ready (most likely next frame).
this._needTrackedEntityUpdate = true;
}
this._trackedEntityChanged.raiseEvent(value);
this.scene.requestRender();
}
}
},
/**
* Gets or sets the object instance for which to display a selection indicator.
* @memberof Viewer.prototype
* @type {Entity}
*/
selectedEntity : {
get : function() {
return this._selectedEntity;
},
set : function(value) {
if (this._selectedEntity !== value) {
this._selectedEntity = value;
var selectionIndicatorViewModel = defined(this._selectionIndicator) ? this._selectionIndicator.viewModel : undefined;
if (defined(value)) {
if (defined(selectionIndicatorViewModel)) {
selectionIndicatorViewModel.animateAppear();
}
} else if (defined(selectionIndicatorViewModel)) {
// Leave the info text in place here, it is needed during the exit animation.
selectionIndicatorViewModel.animateDepart();
}
this._selectedEntityChanged.raiseEvent(value);
}
}
},
/**
* Gets the event that is raised when the selected entity changes.
* @memberof Viewer.prototype
* @type {Event}
* @readonly
*/
selectedEntityChanged : {
get : function() {
return this._selectedEntityChanged;
}
},
/**
* Gets the event that is raised when the tracked entity changes.
* @memberof Viewer.prototype
* @type {Event}
* @readonly
*/
trackedEntityChanged : {
get : function() {
return this._trackedEntityChanged;
}
},
/**
* Gets or sets the data source to track with the viewer's clock.
* @memberof Viewer.prototype
* @type {DataSource}
*/
clockTrackedDataSource : {
get : function() {
return this._clockTrackedDataSource;
},
set : function(value) {
if (this._clockTrackedDataSource !== value) {
this._clockTrackedDataSource = value;
trackDataSourceClock(this._timeline, this.clock, value);
}
}
}
});
/**
* Extends the base viewer functionality with the provided mixin.
* A mixin may add additional properties, functions, or other behavior
* to the provided viewer instance.
*
* @param {Viewer~ViewerMixin} mixin The Viewer mixin to add to this instance.
* @param {Object} [options] The options object to be passed to the mixin function.
*
* @see viewerDragDropMixin
*/
Viewer.prototype.extend = function(mixin, options) {
//>>includeStart('debug', pragmas.debug);
if (!defined(mixin)) {
throw new DeveloperError('mixin is required.');
}
//>>includeEnd('debug')
mixin(this, options);
};
/**
* Resizes the widget to match the container size.
* This function is called automatically as needed unless
* useDefaultRenderLoop is set to false.
*/
Viewer.prototype.resize = function() {
var cesiumWidget = this._cesiumWidget;
var container = this._container;
var width = container.clientWidth;
var height = container.clientHeight;
var animationExists = defined(this._animation);
var timelineExists = defined(this._timeline);
cesiumWidget.resize();
if (width === this._lastWidth && height === this._lastHeight) {
return;
}
var panelMaxHeight = height - 125;
var baseLayerPickerDropDown = this._baseLayerPickerDropDown;
if (defined(baseLayerPickerDropDown)) {
baseLayerPickerDropDown.style.maxHeight = panelMaxHeight + 'px';
}
if (defined(this._geocoder)) {
var geocoderSuggestions = this._geocoder.searchSuggestionsContainer;
geocoderSuggestions.style.maxHeight = panelMaxHeight + 'px';
}
if (defined(this._infoBox)) {
this._infoBox.viewModel.maxHeight = panelMaxHeight;
}
var timeline = this._timeline;
var animationContainer;
var animationWidth = 0;
var creditLeft = 0;
var creditBottom = 0;
if (animationExists && window.getComputedStyle(this._animation.container).visibility !== 'hidden') {
var lastWidth = this._lastWidth;
animationContainer = this._animation.container;
if (width > 900) {
animationWidth = 169;
if (lastWidth <= 900) {
animationContainer.style.width = '169px';
animationContainer.style.height = '112px';
this._animation.resize();
}
} else if (width >= 600) {
animationWidth = 136;
if (lastWidth < 600 || lastWidth > 900) {
animationContainer.style.width = '136px';
animationContainer.style.height = '90px';
this._animation.resize();
}
} else {
animationWidth = 106;
if (lastWidth > 600 || lastWidth === 0) {
animationContainer.style.width = '106px';
animationContainer.style.height = '70px';
this._animation.resize();
}
}
creditLeft = animationWidth + 5;
}
if (timelineExists && window.getComputedStyle(this._timeline.container).visibility !== 'hidden') {
var fullscreenButton = this._fullscreenButton;
var vrButton = this._vrButton;
var timelineContainer = timeline.container;
var timelineStyle = timelineContainer.style;
creditBottom = timelineContainer.clientHeight + 3;
timelineStyle.left = animationWidth + 'px';
var pixels = 0;
if (defined(fullscreenButton)) {
pixels += fullscreenButton.container.clientWidth;
}
if (defined(vrButton)) {
pixels += vrButton.container.clientWidth;
}
timelineStyle.right = pixels + 'px';
timeline.resize();
}
this._bottomContainer.style.left = creditLeft + 'px';
this._bottomContainer.style.bottom = creditBottom + 'px';
this._lastWidth = width;
this._lastHeight = height;
};
/**
* This forces the widget to re-think its layout, including
* widget sizes and credit placement.
*/
Viewer.prototype.forceResize = function() {
this._lastWidth = 0;
this.resize();
};
/**
* Renders the scene. This function is called automatically
* unless useDefaultRenderLoop is set to false;
*/
Viewer.prototype.render = function() {
this._cesiumWidget.render();
};
/**
* @returns {Boolean} true if the object has been destroyed, false otherwise.
*/
Viewer.prototype.isDestroyed = function() {
return false;
};
/**
* Destroys the widget. Should be called if permanently
* removing the widget from layout.
*/
Viewer.prototype.destroy = function() {
var i;
this.screenSpaceEventHandler.removeInputAction(ScreenSpaceEventType.LEFT_CLICK);
this.screenSpaceEventHandler.removeInputAction(ScreenSpaceEventType.LEFT_DOUBLE_CLICK);
// Unsubscribe from data sources
var dataSources = this.dataSources;
var dataSourceLength = dataSources.length;
for (i = 0; i < dataSourceLength; i++) {
this._dataSourceRemoved(dataSources, dataSources.get(i));
}
this._dataSourceRemoved(undefined, this._dataSourceDisplay.defaultDataSource);
this._container.removeChild(this._element);
this._element.removeChild(this._toolbar);
this._eventHelper.removeAll();
if (defined(this._geocoder)) {
this._geocoder = this._geocoder.destroy();
}
if (defined(this._homeButton)) {
this._homeButton = this._homeButton.destroy();
}
if (defined(this._sceneModePicker)) {
this._sceneModePicker = this._sceneModePicker.destroy();
}
if (defined(this._projectionPicker)) {
this._projectionPicker = this._projectionPicker.destroy();
}
if (defined(this._baseLayerPicker)) {
this._baseLayerPicker = this._baseLayerPicker.destroy();
}
if (defined(this._animation)) {
this._element.removeChild(this._animation.container);
this._animation = this._animation.destroy();
}
if (defined(this._timeline)) {
this._timeline.removeEventListener('settime', onTimelineScrubfunction, false);
this._element.removeChild(this._timeline.container);
this._timeline = this._timeline.destroy();
}
if (defined(this._fullscreenButton)) {
this._fullscreenSubscription.dispose();
this._element.removeChild(this._fullscreenButton.container);
this._fullscreenButton = this._fullscreenButton.destroy();
}
if (defined(this._vrButton)) {
this._vrSubscription.dispose();
this._vrModeSubscription.dispose();
this._element.removeChild(this._vrButton.container);
this._vrButton = this._vrButton.destroy();
}
if (defined(this._infoBox)) {
this._element.removeChild(this._infoBox.container);
this._infoBox = this._infoBox.destroy();
}
if (defined(this._selectionIndicator)) {
this._element.removeChild(this._selectionIndicator.container);
this._selectionIndicator = this._selectionIndicator.destroy();
}
if (this._destroyClockViewModel) {
this._clockViewModel = this._clockViewModel.destroy();
}
this._dataSourceDisplay = this._dataSourceDisplay.destroy();
this._cesiumWidget = this._cesiumWidget.destroy();
if (this._destroyDataSourceCollection) {
this._dataSourceCollection = this._dataSourceCollection.destroy();
}
return destroyObject(this);
};
/**
* @private
*/
Viewer.prototype._dataSourceAdded = function(dataSourceCollection, dataSource) {
var entityCollection = dataSource.entities;
entityCollection.collectionChanged.addEventListener(Viewer.prototype._onEntityCollectionChanged, this);
};
/**
* @private
*/
Viewer.prototype._dataSourceRemoved = function(dataSourceCollection, dataSource) {
var entityCollection = dataSource.entities;
entityCollection.collectionChanged.removeEventListener(Viewer.prototype._onEntityCollectionChanged, this);
if (defined(this.trackedEntity)) {
if (entityCollection.getById(this.trackedEntity.id) === this.trackedEntity) {
this.trackedEntity = undefined;
}
}
if (defined(this.selectedEntity)) {
if (entityCollection.getById(this.selectedEntity.id) === this.selectedEntity) {
this.selectedEntity = undefined;
}
}
};
/**
* @private
*/
Viewer.prototype._onTick = function(clock) {
var time = clock.currentTime;
var isUpdated = this._dataSourceDisplay.update(time);
if (this._allowDataSourcesToSuspendAnimation) {
this._clockViewModel.canAnimate = isUpdated;
}
var entityView = this._entityView;
if (defined(entityView)) {
var trackedEntity = this._trackedEntity;
var trackedState = this._dataSourceDisplay.getBoundingSphere(trackedEntity, false, boundingSphereScratch);
if (trackedState === BoundingSphereState.DONE) {
entityView.update(time, boundingSphereScratch);
}
}
var position;
var enableCamera = false;
var selectedEntity = this.selectedEntity;
var showSelection = defined(selectedEntity) && this._enableInfoOrSelection;
if (showSelection && selectedEntity.isShowing && selectedEntity.isAvailable(time)) {
var state = this._dataSourceDisplay.getBoundingSphere(selectedEntity, true, boundingSphereScratch);
if (state !== BoundingSphereState.FAILED) {
position = boundingSphereScratch.center;
} else if (defined(selectedEntity.position)) {
position = selectedEntity.position.getValue(time, position);
}
enableCamera = defined(position);
}
var selectionIndicatorViewModel = defined(this._selectionIndicator) ? this._selectionIndicator.viewModel : undefined;
if (defined(selectionIndicatorViewModel)) {
selectionIndicatorViewModel.position = Cartesian3.clone(position, selectionIndicatorViewModel.position);
selectionIndicatorViewModel.showSelection = showSelection && enableCamera;
selectionIndicatorViewModel.update();
}
var infoBoxViewModel = defined(this._infoBox) ? this._infoBox.viewModel : undefined;
if (defined(infoBoxViewModel)) {
infoBoxViewModel.showInfo = showSelection;
infoBoxViewModel.enableCamera = enableCamera;
infoBoxViewModel.isCameraTracking = (this.trackedEntity === this.selectedEntity);
if (showSelection) {
infoBoxViewModel.titleText = defaultValue(selectedEntity.name, selectedEntity.id);
infoBoxViewModel.description = Property.getValueOrDefault(selectedEntity.description, time, '');
} else {
infoBoxViewModel.titleText = '';
infoBoxViewModel.description = '';
}
}
};
/**
* @private
*/
Viewer.prototype._onEntityCollectionChanged = function(collection, added, removed) {
var length = removed.length;
for (var i = 0; i < length; i++) {
var removedObject = removed[i];
if (this.trackedEntity === removedObject) {
this.trackedEntity = undefined;
}
if (this.selectedEntity === removedObject) {
this.selectedEntity = undefined;
}
}
};
/**
* @private
*/
Viewer.prototype._onInfoBoxCameraClicked = function(infoBoxViewModel) {
if (infoBoxViewModel.isCameraTracking && (this.trackedEntity === this.selectedEntity)) {
this.trackedEntity = undefined;
} else {
var selectedEntity = this.selectedEntity;
var position = selectedEntity.position;
if (defined(position)) {
this.trackedEntity = this.selectedEntity;
} else {
this.zoomTo(this.selectedEntity);
}
}
};
/**
* @private
*/
Viewer.prototype._clearTrackedObject = function() {
this.trackedEntity = undefined;
};
/**
* @private
*/
Viewer.prototype._onInfoBoxClockClicked = function(infoBoxViewModel) {
this.selectedEntity = undefined;
};
/**
* @private
*/
Viewer.prototype._clearObjects = function() {
this.trackedEntity = undefined;
this.selectedEntity = undefined;
};
/**
* @private
*/
Viewer.prototype._onDataSourceChanged = function(dataSource) {
if (this.clockTrackedDataSource === dataSource) {
trackDataSourceClock(this.timeline, this.clock, dataSource);
}
};
/**
* @private
*/
Viewer.prototype._onDataSourceAdded = function(dataSourceCollection, dataSource) {
if (this._automaticallyTrackDataSourceClocks) {
this.clockTrackedDataSource = dataSource;
}
var id = dataSource.entities.id;
var removalFunc = this._eventHelper.add(dataSource.changedEvent, Viewer.prototype._onDataSourceChanged, this);
this._dataSourceChangedListeners[id] = removalFunc;
};
/**
* @private
*/
Viewer.prototype._onDataSourceRemoved = function(dataSourceCollection, dataSource) {
var resetClock = (this.clockTrackedDataSource === dataSource);
var id = dataSource.entities.id;
this._dataSourceChangedListeners[id]();
this._dataSourceChangedListeners[id] = undefined;
if (resetClock) {
var numDataSources = dataSourceCollection.length;
if (this._automaticallyTrackDataSourceClocks && numDataSources > 0) {
this.clockTrackedDataSource = dataSourceCollection.get(numDataSources - 1);
} else {
this.clockTrackedDataSource = undefined;
}
}
};
/**
* Asynchronously sets the camera to view the provided entity, entities, or data source.
* If the data source is still in the process of loading or the visualization is otherwise still loading,
* this method waits for the data to be ready before performing the zoom.
*
* The offset is heading/pitch/range in the local east-north-up reference frame centered at the center of the bounding sphere. * The heading and the pitch angles are defined in the local east-north-up reference frame. * The heading is the angle from y axis and increasing towards the x axis. Pitch is the rotation from the xy-plane. Positive pitch * angles are above the plane. Negative pitch angles are below the plane. The range is the distance from the center. If the range is * zero, a range will be computed such that the whole bounding sphere is visible.
* *In 2D, there must be a top down view. The camera will be placed above the target looking down. The height above the * target will be the range. The heading will be determined from the offset. If the heading cannot be * determined from the offset, the heading will be north.
* * @param {Entity|Entity[]|EntityCollection|DataSource|ImageryLayer|Cesium3DTileset|TimeDynamicPointCloud|Promise.The offset is heading/pitch/range in the local east-north-up reference frame centered at the center of the bounding sphere. * The heading and the pitch angles are defined in the local east-north-up reference frame. * The heading is the angle from y axis and increasing towards the x axis. Pitch is the rotation from the xy-plane. Positive pitch * angles are above the plane. Negative pitch angles are below the plane. The range is the distance from the center. If the range is * zero, a range will be computed such that the whole bounding sphere is visible.
* *In 2D, there must be a top down view. The camera will be placed above the target looking down. The height above the * target will be the range. The heading will be determined from the offset. If the heading cannot be * determined from the offset, the heading will be north.
* * @param {Entity|Entity[]|EntityCollection|DataSource|ImageryLayer|Cesium3DTileset|TimeDynamicPointCloud|Promise.