import AlgorithmicColorRamp from "@arcgis/core/rest/support/AlgorithmicColorRamp.js";const AlgorithmicColorRamp = await $arcgis.import("@arcgis/core/rest/support/AlgorithmicColorRamp.js");- Since
- ArcGIS Maps SDK 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
Constructor
Parameters
| Parameter | Type | Description | Required |
|---|---|---|---|
| properties | | |
Properties
algorithm
- Type
- ColorRampAlgorithmType | null | undefined
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. |
Methods
| Method | Signature | Class |
|---|---|---|
| inherited static | fromJSON(json: any): any | |
| clone(): AlgorithmicColorRamp | | |
| inherited | toJSON(): any |
fromJSON
- Signature
-
fromJSON (json: any): any
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.
Parameters
| Parameter | Type | Description | Required |
|---|---|---|---|
| json | 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
- any
Returns a new instance of this class.
clone
- Signature
-
clone (): AlgorithmicColorRamp
Creates a deep clone of this object.
- Returns
- AlgorithmicColorRamp
A deep clone of the AlgorithmicColorRamp instance that invoked this method.
toJSON
- Signature
-
toJSON (): any
Converts an instance of this class to its ArcGIS portal JSON representation. See the Using fromJSON() guide topic for more information.
- Returns
- any
The ArcGIS portal JSON representation of an instance of this class.