PixelBlock

AMD: require(["esri/layers/support/PixelBlock"], (PixelBlock) => { /* code goes here */ });
ESM: import PixelBlock from "@arcgis/core/layers/support/PixelBlock.js";
Class: esri/layers/support/PixelBlock
Inheritance: PixelBlock Accessor
Since: ArcGIS Maps SDK for JavaScript 4.0

An object representing the pixel arrays in the view. It stores and decodes source data fetched from an image service associated with an ImageryLayer. This provides the user access to each pixel on the client via the pixels property. The PixelBlock object is designed to handle generic pixel arrays from any raster data source.

See also

Constructors

PixelBlock

Constructor
new PixelBlock(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.
Show inherited properties Hide inherited properties
Name Type Summary Class

The name of the class.

Accessor

The height (or number of rows) of the PixelBlock in pixels.

PixelBlock

An array of nodata mask.

PixelBlock

Indicates whether mask should be used as alpha values.

PixelBlock

A two dimensional array representing the pixels from the Image Service displayed on the client.

PixelBlock

The pixel type.

PixelBlock

An array of objects containing numeric statistical properties.

PixelBlock

Number of valid pixels

PixelBlock

The width (or number of columns) of the PixelBlock in pixels.

PixelBlock

Property Details

declaredClass

Inherited
Property
declaredClass Stringreadonly
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.7 Accessor since 4.0, declaredClass added at 4.7.

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

height

Property
height Number

The height (or number of rows) of the PixelBlock in pixels.

mask

Property
mask Uint8Array

An array of nodata mask. All pixels are valid when mask is null.

maskIsAlpha

Property
maskIsAlpha Boolean

Indicates whether mask should be used as alpha values. If no (default), a pixel is valid when corresponding mask value is truthy

A two dimensional array representing the pixels from the Image Service displayed on the client. The length of the first dimension is the same as the number of bands in the layer. The length of the second dimension is height * width. The length of each band is the same. The pixels in each band are arranged row by row in this format: [p_00, p_10, p_20, ... p_10, p_11, ...] where p_xy is the pixel value at the column x and row y.

Example
let pixels = imgLyr.pixelData.pixelBlock.pixels;
// Prints the number of bands in the layer
console.log(pixels.length);
// An array containing all the pixels in the first band
let band1 = pixels[0];

pixelType

Property
pixelType String

The pixel type.

Possible Values:"unknown" |"s8" |"s16" |"s32" |"u1" |"u2" |"u4" |"u8" |"u16" |"u32" |"f32" |"f64" |"c64" |"c128"

statistics

Property
statistics Object[]

An array of objects containing numeric statistical properties. Each object has the following specification if defined.

Properties
maxValue Number
optional

The maximum pixel value in the pixels array.

minValue Number
optional

The minimum pixel value in the pixels array.

noDataValue Number|null|undefined
optional

Value representing areas of no data.

validPixelCount

Property
validPixelCount Number

Number of valid pixels

width

Property
width Number

The width (or number of columns) of the PixelBlock in pixels.

Method Overview

Show inherited methods Hide inherited methods
Name Return Type Summary Class

Adds another plane to the PixelBlock.

PixelBlock

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

Accessor

Returns pixels and masks using a single array in bip format (e.g.

PixelBlock

Similar to getAsRGBA, but returns floating point data.

PixelBlock

Returns the plane band count of the PixelBlock.

PixelBlock

Returns true if a named group of handles exist.

Accessor

Removes a group of handles owned by the object.

Accessor

Method Details

addData

Method
addData(planeData)

Adds another plane to the PixelBlock.

Parameters
Specification
planeData Object

The data to add to the PixelBlock.

Specification
pixels Number[][]

A two dimensional array representing the pixels to add.

statistics Object[]

An array of objects containing numeric statistical properties. See statistics for details on the specifications of each object.

addHandles

Inherited
Method
addHandles(handleOrHandles, groupKey)
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, addHandles added at 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 }
);

this.addHandles(handle);

// Destroy the object
this.destroy();
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.

getAsRGBA

Method
getAsRGBA(){Uint8ClampedArray}

Returns pixels and masks using a single array in bip format (e.g. [p_00_r, p_00_g, p_00_b, p_00_a, p_10_r, p_10_g, p_10_b, p_10_a, .....]). Use this method to get an unsigned 8 bit pixel array. The result can be used to create a webgl texture.

Returns
Type Description
Uint8ClampedArray An unsigned 8-bit pixel array.

getAsRGBAFloat

Method
getAsRGBAFloat(){Float32Array}

Similar to getAsRGBA, but returns floating point data. The result can be used to create a webgl texture (OES_texture_float).

Returns
Type Description
Float32Array A floating point array.

getPlaneCount

Method
getPlaneCount(){Number}

Returns the plane band count of the PixelBlock.

Returns
Type Description
Number The plane band count.

hasHandles

Inherited
Method
hasHandles(groupKey){Boolean}
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, hasHandles added at 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

Inherited
Method
removeHandles(groupKey)
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, removeHandles added at 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");

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