PixelBlock | API Reference | ArcGIS Maps SDK for JavaScript 4.30

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

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Type	Summary	Class
String	The name of the class.	Accessor
Number	The height (or number of rows) of the PixelBlock in pixels.	PixelBlock
Uint8Array	An array of nodata mask.	PixelBlock
Boolean	Indicates whether mask should be used as alpha values.	PixelBlock
Array<(Array<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.	PixelBlock
String	The pixel type.	PixelBlock
Object []	An array of objects containing numeric statistical properties.	PixelBlock
Number	Number of valid pixels	PixelBlock
Number	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

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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
Uint8ClampedArray	Returns pixels and masks using a single array in bip format (e.g.	PixelBlock
Float32Array	Similar to getAsRGBA, but returns floating point data.	PixelBlock
Number	Returns the plane band count of the PixelBlock.	PixelBlock
Boolean	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");