ImageData()
The ImageData()
constructor returns a newly instantiated ImageData
object built from the typed array given and having the specified width and height.
This constructor is the preferred way of creating such an object in a Worker
.
Syntax
new ImageData(width, height); new ImageData(width, height, settings); new ImageData(dataArray, width); new ImageData(dataArray, width, height); new ImageData(dataArray, width, height, settings);
Parameters
width
-
An unsigned long representing the width of the image.
height
-
An unsigned long representing the height of the image. This value is optional if an array is given: the height will be inferred from the array's size and the given width.
- settings Optional
-
An object with the following values:
colorSpace
-
One of
"srgb"
,"rec2020"
, or"display-p3"
. -
dataArray
Optional -
An array containing the underlying pixel representation of the image, one of
Uint8ClampedArray
,Uint16Array
, orFloat32Array
. If no such array is given, an image with a transparent black rectangle of the specifiedwidth
andheight
will be created.
Return value
A new ImageData
object.
Errors thrown
-
IndexSizeError
DOMException
-
Thrown if
array
is specified, but its length is not a multiple of(4 * width)
or(4 * width * height)
.
Examples
Creating a blank ImageData object
This example creates an ImageData
object that is 200 pixels wide and 100 pixels tall, containing a total of 20,000 pixels.
let imageData = new ImageData(200, 100); // ImageData { width: 200, height: 100, data: Uint8ClampedArray[80000] }
Initializing ImageData with an array
This example instantiates an ImageData
object with pixel colors defined by an array.
HTML
<canvas id="canvas"></canvas>
JavaScript
The array (arr
) has a length of 40000
: it consists of 10,000 pixels, each of which is defined by 4 values. The ImageData
constructor specifies a width
of 200
for the new object, so its height
defaults to 10,000 divided by 200, which is 50
.
const canvas = document.getElementById('canvas'); const ctx = canvas.getContext('2d'); const arr = new Uint8ClampedArray(40000); // Iterate through every pixel for (let i = 0; i < arr.length; i += 4) { arr[i + 0] = 0; // R value arr[i + 1] = 190; // G value arr[i + 2] = 0; // B value arr[i + 3] = 255; // A value } // Initialize a new ImageData object let imageData = new ImageData(arr, 200); // Draw image data to the canvas ctx.putImageData(imageData, 20, 20);
Result
Specifications
Specification |
---|
HTML Standard (HTML) # dom-imagedata-dev |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
ImageData |
42 |
14 |
29 |
No |
29 |
7 |
No |
42 |
29 |
? |
7 |
4.0 |
See also
-
CanvasRenderingContext2D.createImageData()
, the creator method that can be used outside workers.
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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/ImageData/ImageData