PixelBlock

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

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.
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Name Type Summary Class
String

The name of the class.

more details
Accessor
Number

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

more details
PixelBlock
Number[]|Uint8Array

An array of nodata mask.

more details
PixelBlock
Boolean

Indicates whether mask should be used as alpha values.

more details
PixelBlock
Number[][]|Int8Array[]|Uint8Array[]|Uint8ClampedArray[]|Int16Array[]|Uint16Array[]|Int32Array[]|Uint32Array[]|Float32Array[]|Float64Array[]

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

more details
PixelBlock
String

The pixel type.

more details
PixelBlock
Object[]

An array of objects containing numeric statistical properties.

more details
PixelBlock
Number

Number of valid pixels

more details
PixelBlock
Number

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

more details
PixelBlock

Property Details

declaredClass Stringreadonly inherited
Since: ArcGIS API for JavaScript 4.7

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

height Number

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

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

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 String

The pixel type.

Possible Values:"unknown"|"s8"|"s16"|"s32"|"u8"|"u16"|"u32"|"f32"|"f64"

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
optional

Value representing areas of no data.

validPixelCount Number

Number of valid pixels

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.

more details
PixelBlock

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

more details
Accessor
Uint8ClampedArray

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

more details
PixelBlock
Float32Array

Similar to getAsRGBA, but returns floating point data.

more details
PixelBlock
Number

Returns the plane band count of the PixelBlock.

more details
PixelBlock
Boolean

Returns true if a named group of handles exist.

more details
Accessor

Removes a group of handles owned by the object.

more details
Accessor

Method Details

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(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.

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(){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(){Number}

Returns the plane band count of the PixelBlock.

Returns
Type Description
Number The plane band count.
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");

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