OpacityVariable

require(["esri/renderers/visualVariables/OpacityVariable"], function(OpacityVariable) { /* code goes here */ });
Class: esri/renderers/visualVariables/OpacityVariable
Inheritance: OpacityVariable VisualVariable Accessor
Since: ArcGIS API for JavaScript 4.10

The opacity visual variable defines the opacity of each feature's symbol based on a numeric field value or number returned from an expression. You must specify stops to construct the opacity ramp.

renderer-vv-opacity

See also:
Examples:
const opacityVisualVariable = {
  type: "opacity",
  field: "PERCENTAGE",
  // maps data values to opacity values
  stops: [
    { value: 0, opacity: 0.1 },
    { value: 100, opacity: 1 }
  ]
};
renderer.visualVariables = [ opacVisVar ];
// opacity visual variable with arcade
const opacityVisualVariable = {
  type: "opacity",
  // calculate a value to visualize with opacity
  valueExpression: "( $feature.TOT_VOTES / $feature.REG_VOTERS ) * 100",
  stops: [
    { value: 30, opacity: 0.15 },
    { value: 70, opacity: 0.15 }
  ]
};
renderer.visualVariables = [ opacityVisVar ];

Constructors

new OpacityVariable(properties)
Parameter:
properties Object
optional

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

Property Overview

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

The name of the class.

more details
more detailsAccessor
String

The name of the numeric attribute field that contains the data values used to determine the color/opacity/size/rotation of each feature.

more details
more detailsVisualVariable
String|Number

The index of the visual variable in relation to its position in the visualVariables property of the renderer.

more details
more detailsVisualVariable
Object

An object providing options for displaying the visual variable in the Legend.

more details
more detailsVisualVariable
String

Name of the numeric attribute field by which to normalize the data.

more details
more detailsOpacityVariable
OpacityStop[]

An array of objects that defines the opacity to apply to features in a layer in a sequence of stops.

more details
more detailsOpacityVariable
String

The visual variable type.

more details
more detailsOpacityVariable
String

An Arcade expression evaluating to a number.

more details
more detailsVisualVariable
String

The title identifying and describing the associated Arcade expression as defined in the valueExpression property.

more details
more detailsVisualVariable

Property Details

declaredClass Stringreadonly inherited

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

The name of the numeric attribute field that contains the data values used to determine the color/opacity/size/rotation of each feature.

The index of the visual variable in relation to its position in the visualVariables property of the renderer.

legendOptions Object inherited

An object providing options for displaying the visual variable in the Legend.

Properties:
showLegend Boolean
optional

Indicates whether to show the visual variable in the legend.

title String
optional

The title describing the visualization of the visual variable in the Legend. This takes precedence over a field alias or valueExpressionTitle.

normalizationField String

Name of the numeric attribute field by which to normalize the data. If this field is used, then the values in stops should be normalized as percentages or ratios.

Autocasts from Object[]

An array of objects that defines the opacity to apply to features in a layer in a sequence of stops. You must specify 2 - 8 stops. In most cases, no more than five are needed. Features with data values that fall between the given stops will be assigned opacity values linearly interpolated along the ramp in relation to the stop values. The stops must be listed in ascending order based on the value of the value property in each stop.

type Stringreadonly

The visual variable type. For OpacityVariable, this value is always opacity.

valueExpression String inherited

An Arcade expression evaluating to a number. This expression can reference field values using the $feature global variable and perform mathematical calculations and logical evaluations at runtime. The values returned from this expression are the data used to drive the visualization. This takes precedence over field. Therefore, this property is typically used as an alternative to field in visual variables.

See also:
valueExpressionTitle String inherited

The title identifying and describing the associated Arcade expression as defined in the valueExpression property. This is displayed as the title of the corresponding visual variable in the Legend in the absence of a provided title in the legendOptions property.

Method Overview

NameReturn TypeSummaryClass
OpacityVariable

Creates a deep clone of the OpacityVariable.

more details
more detailsOpacityVariable
*

Creates a new instance of this class and initializes it with values from a JSON object generated from a product in the ArcGIS platform.

more details
more detailsOpacityVariable
Object

Converts an instance of this class to its ArcGIS portal JSON representation.

more details
more detailsOpacityVariable

Method Details

Creates a deep clone of the OpacityVariable.

Returns:
TypeDescription
OpacityVariableA deep clone of the opacity visual variable that invoked this method.
Example:
// Creates a deep clone of the visual variable
var renderer = renderer.visualVariables[0].clone();
fromJSON(json){*}static

Creates a new instance of this class and initializes it with values from a JSON object generated from a product in the ArcGIS platform. The object passed into the input json parameter often comes from a response to a query operation in the REST API or a toJSON() method from another ArcGIS product. See the Using fromJSON() topic in the Guide for details and examples of when and how to use this function.

Parameter:
json Object

A JSON representation of the instance in the ArcGIS format. See the ArcGIS REST API documentation for examples of the structure of various input JSON objects.

Returns:
TypeDescription
*Returns a new instance of this class.
toJSON(){Object}

Converts an instance of this class to its ArcGIS portal JSON representation. See the Using fromJSON() topic in the Guide for more information.

Returns:
TypeDescription
ObjectThe ArcGIS portal JSON representation of an instance of this class.

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