AlgorithmicColorRamp

AMD: require(["esri/rest/support/AlgorithmicColorRamp"], (AlgorithmicColorRamp) => { /* code goes here */ });
ESM: import AlgorithmicColorRamp from "@arcgis/core/rest/support/AlgorithmicColorRamp";
Class: esri/rest/support/AlgorithmicColorRamp
Inheritance: AlgorithmicColorRamp ColorRamp Accessor
Since: ArcGIS API for JavaScript 4.20

Creates a color ramp for use in a raster renderer. The algorithmic color ramp is defined by specifying two colors and the algorithm used to traverse the intervening color spaces.

There are three algorithms that can be used to define the color values between the from and to colors: 'cie-lab', 'hsv', and 'lab-lch'. There is very little difference between these algorithms when the from and the to colors are of the same or very similar hues. However, when the hues for the from and to colors are different (Hue is different by 40 or more on a 0-360 scale), the algorithms produce different results. The 'hsv' algorithm traverses the hue difference in a purely linear fashion, resulting in a bright ramp where all intermediate colors are represented. For instance, a ramp from red to green would include orange, yellow, and yellow-green. The 'cie-lab' and 'lab-lch' produce a more blended result. Thus, a ramp from dark green to orange would not contain a bright yellow, but instead a more brown and green-gold or green-brown intermediate color. The advantage of the 'cie-lab' algorithm is that the colors of the ramp are visually equidistant, which can produce a better ramp.

Constructors

new AlgorithmicColorRamp(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.
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Name Type Summary Class
String

The algorithm used to generate the colors between the fromColor and toColor.

more details
AlgorithmicColorRamp
String

The name of the class.

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Accessor
Color

The first color in the color ramp.

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AlgorithmicColorRamp
Color

The last color in the color ramp.

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AlgorithmicColorRamp
String

A string value representing the color ramp type.

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AlgorithmicColorRamp

Property Details

algorithm String

The algorithm used to generate the colors between the fromColor and toColor. Each algorithm uses different methods for generating the intervening colors.

Possible Value Description
cie-lab Blends the from and to colors without traversing the intervening hue space.
lab-lch The hue, saturation, value (hsv) algorithm is a linear traverse of colors between pairs: Color 1 H to Color 2 H, Color 1 S to Color 2 S, and Color 1 V to Color 2 V.
hsv The lab-lch algorithm is very similar to the cie-lab but does not seek the shortest path between colors.

Possible Values:"cie-lab"|"lab-lch"|"hsv"

declaredClass Stringreadonly inherited

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

fromColor Color

The first color in the color ramp.

toColor Color

The last color in the color ramp.

type Stringreadonly

A string value representing the color ramp type.

For AlgorithmicColorRamp the type is always "algorithmic".

Default Value:algorithmic

Method Overview

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Name Return Type Summary Class

Adds one or more handles which are to be tied to the lifecycle of the object.

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Accessor
AlgorithmicColorRamp

Creates a deep clone of this object.

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AlgorithmicColorRamp
*

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

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ColorRamp
Boolean

Returns true if a named group of handles exist.

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Accessor

Removes a group of handles owned by the object.

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Accessor
Object

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

more details
ColorRamp

Method Details

addHandles(handleOrHandles, groupKey)inherited
Since: ArcGIS API for JavaScript 4.25

Adds one or more handles which are to be tied to the lifecycle of the object. The handles will be removed when the object is destroyed.

// Manually manage handles
const handle = reactiveUtils.when(
  () => !view.updating,
  () => {
    wkidSelect.disabled = false;
  },
  { once: true }
);

// Handle gets removed when the object is destroyed.
this.addHandles(handle);
Parameters
handleOrHandles WatchHandle|WatchHandle[]

Handles marked for removal once the object is destroyed.

groupKey *
optional

Key identifying the group to which the handles should be added. All the handles in the group can later be removed with Accessor.removeHandles(). If no key is provided the handles are added to a default group.

Creates a deep clone of this object.

Returns
Type Description
AlgorithmicColorRamp A deep clone of the AlgorithmicColorRamp instance that invoked this method.
fromJSON(json){*}static

Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product. 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
Type Description
* Returns a new instance of this class.
hasHandles(groupKey){Boolean}inherited
Since: ArcGIS API for JavaScript 4.25

Returns true if a named group of handles exist.

Parameter
groupKey *
optional

A group key.

Returns
Type Description
Boolean Returns true if a named group of handles exist.
Example
// Remove a named group of handles if they exist.
if (obj.hasHandles("watch-view-updates")) {
  obj.removeHandles("watch-view-updates");
}
removeHandles(groupKey)inherited
Since: ArcGIS API for JavaScript 4.25

Removes a group of handles owned by the object.

Parameter
groupKey *
optional

A group key or an array or collection of group keys to remove.

Example
obj.removeHandles(); // removes handles from default group

obj.removeHandles("handle-group");
obj.removeHandles("other-handle-group");
toJSON(){Object}inherited

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

Returns
Type Description
Object The ArcGIS portal JSON representation of an instance of this class.

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