ndarray-pixels

Convert ndarray ↔ image data, on Web and Node.js.
Designed to be used with other ndarray-based packages.
Supported Formats
Known Bugs
Quickstart
npm install --save ndarray-pixels
Web
import { getPixels, savePixels } from 'ndarray-pixels';
const bytesIn = await fetch('./input.png')
.then((res) => res.arrayBuffer())
.then((arrayBuffer) => new Uint8Array(arrayBuffer));
const pixels = await getPixels(bytesIn, 'image/png');
const [width, height] = pixels.shape;
for (let x = 0; x < width; ++x) {
for (let y = 0; y < height; ++y) {
pixels.set(x, y, 0, 255);
pixels.set(x, y, 1, 0.0);
pixels.set(x, y, 2, 0.0);
pixels.set(x, y, 3, 255);
}
}
const bytesOut = await savePixels(pixels, 'image/png');
Node.js
const fs = require('fs');
const { getPixels, savePixels } = require('ndarray-pixels');
const bufferIn = fs.readFileSync('./input.png');
const pixels = await getPixels(bufferIn, 'image/png');
const [width, height] = pixels.shape;
for (let x = 0; x < width; ++x) {
for (let y = 0; y < height; ++y) {
pixels.set(x, y, 0, 255);
pixels.set(x, y, 1, 0.0);
pixels.set(x, y, 2, 0.0);
pixels.set(x, y, 3, 255);
}
}
const bufferOut = await savePixels(pixels, 'image/png');
fs.writeFileSync('./output.png', bufferOut);
API
Function: getPixels()
getPixels(data
, mimeType
): Promise
<NdArray
<Uint8Array
<ArrayBufferLike
>>>
Defined in: index.ts:17
Decodes image data to an ndarray
.
MIME type is optional when given a path or URL, and required when given a Uint8Array.
Accepts image/png
or image/jpeg
in Node.js, and additional formats on browsers with
the necessary support in Canvas 2D.
Parameters
data
Uint8Array
mimeType
string
image/jpeg
, image/png
, etc.
Returns
Promise
<NdArray
<Uint8Array
<ArrayBufferLike
>>>
Function: savePixels()
savePixels(pixels
, typeOrOptions
): Promise
<Uint8Array
<ArrayBufferLike
>>
Defined in: index.ts:37
Encodes an ndarray
as image data in the given format.
If the source ndarray
was constructed manually with default stride, use
ndarray.transpose(1, 0)
to reshape it and ensure an identical result from getPixels(). For an
ndarray created by getPixels(), this isn't necessary.
Accepts image/png
or image/jpeg
in Node.js, and additional formats on browsers with
the necessary support in Canvas 2D.
Parameters
pixels
NdArray
<Uint8Array
<ArrayBufferLike
> | Uint8ClampedArray
<ArrayBufferLike
>>
ndarray of shape W x H x 4.
typeOrOptions
object with encoding options or just the type
string
|
{ quality?
: number
; type?
: string
; }
object with encoding options or just the type
quality?
number
quality as a number from 0 to 1, inclusive
type?
string
target format (image/jpeg
, image/png
, image/webp
, etc.)
Returns
Promise
<Uint8Array
<ArrayBufferLike
>>