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require(["esri/widgets/smartMapping/HeatmapSlider"], function(HeatmapSlider) { /* code goes here */ });
Class: esri/widgets/smartMapping/HeatmapSlider
Inheritance: HeatmapSlider Widget Accessor
Since: ArcGIS API for JavaScript 4.12

The HeatmapSlider widget is intended for authoring and exploring data-driven visualizations in any layer that can be rendered with a HeatmapRenderer. At a minimum you must set the stops property of the widget. The stops are used to render a color gradient on the track of the slider.

See the image below for a summary of the configurable options available on this slider.

HeatmapSlider with annotations

The fromRendererResult method can be used to conveniently create this slider from the result of the createRenderer method.

const params = {
  layer: layer,
  basemap: map.basemap,
  view: view
};

let rendererResult = null;

heatmapRendererCreator
  .createRenderer(params)
  .then(function(response) {
    rendererResult = response;
    layer.renderer = response.renderer;

    const slider = slider.fromRendererResult(rendererResult);
    colorSlider.container = "slider";
  })
   .catch(function(error) {
     console.log("there was an error: ", error);
   });

This slider should be used to update the colorStops in a HeatmapRenderer. It is the responsibility of the app developer to set up event listeners on this slider to update the renderer's color stops.

// when the user slides the handle(s), update the renderer
// with the updated color stops

slider.on(["thumb-change", "thumb-drag"], function() {
  const renderer = layer.renderer.clone();
  renderer.colorStops = slider.stops;
  layer.renderer = renderer;
});
For information about gaining full control of widget styles, see the Styling topic.
See also:

Constructors

new HeatmapSlider(properties)
Parameter:
properties Object
optional

See the properties for a list of all the properties that may be passed into the constructor.

Example:
const slider = new HeatmapSlider({
  stops: [
    { color: "rgba(63, 40, 102, 0)", ratio: 0 },
    { color: "#472b77", ratio: 0.083 },
    { color: "#4e2d87", ratio: 0.166 },
    { color: "#563098", ratio: 0.249 },
    { color: "#5d32a8", ratio: 0.332 },
    { color: "#6735be", ratio: 0.415 },
    { color: "#7139d4", ratio: 0.498 },
    { color: "#7b3ce9", ratio: 0.581 },
    { color: "#853fff", ratio: 0.664 },
    { color: "#a46fbf", ratio: 0.747 },
    { color: "#c29f80", ratio: 0.83 },
    { color: "#e0cf40", ratio: 0.913 },
    { color: "#ffff00", ratio: 1 }
  ]
});

Property Overview

Any properties can be set, retrieved or listened to. See the Working with Properties topic.
NameTypeSummaryClass
String|HTMLElement

The ID or node representing the DOM element containing the widget.

more details
more detailsWidget
String

The name of the class.

more details
more detailsAccessor
Boolean

When true, this property indicates whether the widget has been destroyed.

more details
more detailsWidget
String

The unique ID assigned to the widget when the widget is created.

more details
more detailsWidget
String

The HeatmapSlider widget's default label.

more details
more detailsHeatmapSlider
HeatmapColorStop[]

The colorStops of the HeatmapRenderer to associate with the slider.

more details
more detailsHeatmapSlider
HeatmapSliderViewModel

The view model for the Heatmap widget.

more details
more detailsHeatmapSlider

Property Details

The ID or node representing the DOM element containing the widget. This property can only be set once. The following examples are all valid use cases when working with widgets.

Examples:
// Create the HTML div element programmatically at runtime and set to the widget's container
const basemapGallery = new BasemapGallery({
  view: view,
  container: document.createElement("div")
});

// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
  position: "top-right"
});
// Specify an already-defined HTML div element in the widget's container

const basemapGallery = new BasemapGallery({
  view: view,
  container: basemapGalleryDiv
});

// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
  position: "top-right"
});

// HTML markup
<body>
  <div id="viewDiv"></div>
  <div id="basemapGalleryDiv"></div>
</body>
// Specify the widget while adding to the view's UI
const basemapGallery = new BasemapGallery({
  view: view
});

// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
  position: "top-right"
});
declaredClass Stringreadonly inherited

The name of the class. The declared class name is formatted as esri.folder.className.

destroyed Boolean inherited

When true, this property indicates whether the widget has been destroyed.

The unique ID assigned to the widget when the widget is created. If not set by the developer, it will default to the container ID, or if that is not present then it will be automatically generated.

label Stringreadonly

The HeatmapSlider widget's default label.

The colorStops of the HeatmapRenderer to associate with the slider.

Examples:
slider.stops = [
  { color: "rgba(63, 40, 102, 0)", ratio: 0 },
  { color: "#472b77", ratio: 0.083 },
  { color: "#4e2d87", ratio: 0.166 },
  { color: "#563098", ratio: 0.249 },
  { color: "#5d32a8", ratio: 0.332 },
  { color: "#6735be", ratio: 0.415 },
  { color: "#7139d4", ratio: 0.498 },
  { color: "#7b3ce9", ratio: 0.581 },
  { color: "#853fff", ratio: 0.664 },
  { color: "#a46fbf", ratio: 0.747 },
  { color: "#c29f80", ratio: 0.83 },
  { color: "#e0cf40", ratio: 0.913 },
  { color: "#ffff00", ratio: 1 }
];
slider.stops = layer.renderer.colorStops;

The view model for the Heatmap widget. This class contains all the logic (properties and methods) that controls this widget's behavior. See the esri/widgets/smartMapping/HeatmapSlider/HeatmapliderViewModel class to access all properties and methods on the HeatmapSlider widget.

Method Overview

NameReturn TypeSummaryClass
String

A utility method used for building the value for a widget's class property.

more details
more detailsWidget

Destroys the widget instance.

more details
more detailsWidget
Boolean

Emits an event on the instance.

more details
more detailsWidget
HeatmapSlider

A convenience function used to create a HeatmapSlider widget instance from the result of the heatmapRendererCreator.createRenderer() method.

more details
more detailsHeatmapSlider
Boolean

Indicates whether there is an event listener on the instance that matches the provided event name.

more details
more detailsWidget
Object

Registers an event handler on the instance.

more details
more detailsWidget

Widget teardown helper.

more details
more detailsWidget

This method is primarily used by developers when implementing custom widgets.

more details
more detailsWidget
Object

This method is primarily used by developers when implementing custom widgets.

more details
more detailsWidget

Renders widget to the DOM immediately.

more details
more detailsWidget

This method is primarily used by developers when implementing custom widgets.

more details
more detailsWidget

Method Details

classes(classNames){String}inherited

A utility method used for building the value for a widget's class property. This aids in simplifying CSS class setup.

Parameter:
classNames Array<(string|Array<string>|Object)>
repeatable

The class names.

Returns:
TypeDescription
StringThe computed class name.
See also:
Example:
// .tsx syntax showing how to set CSS classes while rendering the widget

render() {
  const dynamicIconClasses = {
    [CSS.myIcon]: this.showIcon,
    [CSS.greyIcon]: !this.showIcon
  };

  return (
    <div class={classes(CSS.root, CSS.mixin, dynamicIconClasses)} />
  );
}
destroy()inherited

Destroys the widget instance.

emit(type, event){Boolean}inherited

Emits an event on the instance. This method should only be used when creating subclasses of this class.

Parameters:
type String

The name of the event.

event Object
optional

The event payload.

Returns:
TypeDescription
Booleantrue if a listener was notified
fromHeatmapRendererResult(rendererResult){HeatmapSlider}static

A convenience function used to create a HeatmapSlider widget instance from the result of the heatmapRendererCreator.createRenderer() method.

Parameter:
rendererResult HeatmapRendererResult

The result object from the heatmapRendererCreator.createRenderer() method.

Returns:
TypeDescription
HeatmapSliderReturns a HeatmapSlider instance. This will not render until you assign it a valid container.
Example:
var params = {
  layer: layer,
  basemap: map.basemap,
  field: "POP",
  view: view
};
heatmapRendererCreator
  .createRenderer(params)
  .then(function(response) {
    // set generated renderer on the layer and add it to the map
    rendererResult = response;
    layer.renderer = response.renderer;

    var slider = HeatmapSlider.fromHeatmapRendererResult(response);
    slider.container = "slider";
  });
hasEventListener(type){Boolean}inherited

Indicates whether there is an event listener on the instance that matches the provided event name.

Parameter:
type String

The name of the event.

Returns:
TypeDescription
BooleanReturns true if the class supports the input event.
on(type, listener){Object}inherited

Registers an event handler on the instance. Call this method to hook an event with a listener.

Parameters:

A event type, or an array of event types, to listen for.

listener Function

The function to call when the event is fired.

Returns:
TypeDescription
ObjectReturns an event handler with a remove() method that can be called to stop listening for the event(s).
PropertyTypeDescription
removeFunctionWhen called, removes the listener from the event.
Example:
view.on("click", function(event){
  // event is the event handle returned after the event fires.
  console.log(event.mapPoint);
});
own(handles)inherited

Widget teardown helper. Any handles added to it will be automatically removed when the widget is destroyed.

Parameter:

Handles marked for removal once the widget is destroyed.

postInitialize()inherited

This method is primarily used by developers when implementing custom widgets. Executes after widget is ready for rendering.

render(){Object}inherited

This method is primarily used by developers when implementing custom widgets. It must be implemented by subclasses for rendering.

Returns:
TypeDescription
ObjectThe rendered virtual node.
renderNow()inherited

Renders widget to the DOM immediately.

scheduleRender()inherited

This method is primarily used by developers when implementing custom widgets. Schedules widget rendering. This method is useful for changes affecting the UI.

Event Overview

NameTypeSummaryClass
{index: Number,oldValue: Number,type: String,value: Number}

Fires when a user changes the value of a thumb via arrow keys and keyboard editing of the label on the widget.

more details
more detailsHeatmapSlider
{index: Number,state: String,type: String,value: Number}

Fires when a user drags a thumb on the widget.

more details
more detailsHeatmapSlider

Event Details

thumb-change

Fires when a user changes the value of a thumb via arrow keys and keyboard editing of the label on the widget.

Properties:
index Number

The 0-based index of the thumb emitting the event.

oldValue Number

The former value of the thumb before the change was made.

type String

The type of the event. For this event, the type is always thumb-change.

value Number

The value of the thumb when the event is emitted.

Example:
slider.on("thumb-change", function() {
  const renderer = layer.renderer.clone();
  renderer.colorStops = slider.stops;
  layer.renderer = renderer;
});
thumb-drag

Fires when a user drags a thumb on the widget.

Properties:
index Number

The 0-based index of the thumb emitting the event.

state String

The state of the drag.

Possible Values: start | drag

type String

The type of the event. For this event, the type is always thumb-drag.

value Number

The value of the thumb when the event is emitted.

Example:
slider.on("thumb-drag", function() {
  const renderer = layer.renderer.clone();
  renderer.colorStops = slider.stops;
  layer.renderer = renderer;
});

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