Baseline Widely available
Note: This feature is available in Web Workers.
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
.
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 properties:
colorSpace
: Specifies the color space of the image data. Can be set to "srgb"
for the sRGB color space or "display-p3"
for the display-p3 color space.pixelFormat
: Specifies the pixel format. Possible values:
"rgba-unorm8"
, for RGBA with 8 bit per component unsigned normalized format, using a Uint8ClampedArray
."rgba-float16"
, for RGBA with 16 bits per component, using a Float16Array
. Floating-point pixel values allow representing colors in arbitrarily wide gamuts and high dynamic range (HDR).dataArray
A Uint8ClampedArray
containing the underlying pixel representation of the image. If no such array is given, an image with a transparent black rectangle of the specified width
and height
will be created.
A new ImageData
object.
IndexSizeError
DOMException
Thrown if dataArray
is specified, but its length is not a multiple of (4 * width)
or (4 * width * height)
.
InvalidStateError
DOMException
Thrown if dataArray
is of type Uint8ClampedArray
and pixelFormat
is not set to "rgba-unorm8"
.
InvalidStateError
DOMException
Thrown if dataArray
is of type Float16Array
and pixelFormat
is not set to "rgba-float16"
.
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] }
ImageData using the display-p3 color space
This example creates an ImageData
object with the display-p3 color space.
let imageData = new ImageData(200, 100, { colorSpace: "display-p3" });
Floating-point pixel data for wide gamuts and high dynamic range (HDR)
Floating-point pixel values allow representing colors in arbitrarily wide gamuts and high dynamic range (HDR). You can set the pixelFormat
setting to "rgba-float16"
to use RGBA values with 16 bits per component. This requires the dataArray
to be a Float16Array
.
let floatArray = new Float16Array(4 * 200 * 200);
let imageData = new ImageData(floatArray, 200, 200, {
pixelFormat: "rgba-float16",
});
console.log(imageData.pixelFormat); // "rgba-float16"
Initializing ImageData with an array
This example instantiates an ImageData
object with pixel colors defined by an array.
<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(40_000);
// Fill the array with the same RGBA values
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 Browser compatibility See also
CanvasRenderingContext2D.createImageData()
, the creator method that can be used outside workers.RetroSearch is an open source project built by @garambo | Open a GitHub Issue
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