pixel-getter
v2.0.1
Published
A powerful tool for retrieving image pixel information in Node.js. It supports various image formats and provides both Promise-based and callback-based APIs for flexibility.
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Pixel Getter
Pixel Getter is a powerful Node.js tool designed to extract pixel information from images. It offers support for various image formats and provides both Promise-based and callback-style APIs to cater to diverse programming preferences.
Important Notice: Breaking Changes
Version 2 introduces significant updates and breaking changes. If you're upgrading from v1, please carefully review the new usage instructions.
Installation
To incorporate Pixel Getter into your project, execute the following command:
$ npm install --save pixel-getter
Usage
Pixel Getter currently supports the following image formats: JPG
, PNG
, and GIF
.
Basic Usage
Begin by importing the Pixel Getter module:
const pixelGetter = require('pixel-getter');
You can retrieve pixel information by providing an image buffer, local filename, or remote URL.
Promise-based Approach
const result = await pixelGetter.get("example.jpg");
const result = await pixelGetter.get(Buffer.from(...));
const result = await pixelGetter.get("https://nodejs.org/images/logo-light.png");
Callback-based Approach
pixelGetter.get("example.jpg", (err, pixels) => {
if (err) {
console.error(err);
} else {
console.log(pixels);
}
});
pixelGetter.get(Buffer.from(...), (err, pixels) => {
if (err) {
console.error(err);
} else {
console.log(pixels);
}
});
pixelGetter.get("https://nodejs.org/images/logo-light.png", (err, pixels) => {
if (err) {
console.error(err);
} else {
console.log(pixels);
}
});
Options
Pixel Getter allows you to customize its behavior using an options
object. Here's the structure of the options object:
interface PixelGetterOptions<Type extends PixelType = PixelType.AUTO> {
pixelType?: Type;
frames?: number | [number, number];
timeout?: number;
}
pixelType
: Specifies the desired pixel type (RGB or RGBA) for the returned data.frames
: For GIF images, specifies which frame(s) to process. Can be a single number or an array of two numbers representing the start and end frames.timeout
: Sets a timeout (in milliseconds) for remote image retrieval.
You can pass the options object as the second argument in both Promise-based and callback-based approaches:
// Promise-based with options
const result = await pixelGetter.get('example.jpg', {
pixelType: pixelGetter.PixelType.RGB,
timeout: 5000,
});
// Callback-based with options
pixelGetter.get(
'animation.gif',
{
frames: [0, 5],
pixelType: pixelGetter.PixelType.RGBA,
},
(err, pixels) => {
if (err) {
console.error(err);
} else {
console.log(pixels);
}
}
);
Pixel Information Structure
The returned pixels
object contains the following information:
interface PixelInfo {
width: number;
height: number;
pixelsCount: number;
pixels: (RGB[] | RGBA[])[];
pixelType: PixelType.RGB | PixelType.RGBA;
}
pixels[0]
represents the pixel array of the first frame.JPG
andPNG
files always contain a single frame.
GIF Support
When working with GIF files, you can specify an optional frames
parameter in the options object. This can be either a single number or an array containing the start and end frame indices.
Promise-based GIF Processing
const result = await pixelGetter.get('animation.gif', { frames: 0 });
const result = await pixelGetter.get('animation.gif', { frames: [0, 1] });
Callback-based GIF Processing
pixelGetter.get('animation.gif', { frames: 0 }, (err, pixels) => {
if (err) {
console.error(err);
} else {
console.log(pixels);
}
});
pixelGetter.get('animation.gif', { frames: [0, 1] }, (err, pixels) => {
if (err) {
console.error(err);
} else {
console.log(pixels);
}
});
Timeout Configuration
For remote image retrieval, you can set a timeout duration using the timeout
option:
pixelGetter.get(
'http://example.com/image.jpg',
{ timeout: 10000 },
(err, pixels) => {
if (err) {
console.error(err);
} else {
console.log(pixels);
}
}
);
Pixel Type Specification
You can specify the desired pixel type (RGB or RGBA) for the returned data using the pixelType
option:
const result = await pixelGetter.get('example.jpg', {
pixelType: pixelGetter.PixelType.RGB,
});
Raw Pixel Data Retrieval
In addition to the get
function, Pixel Getter also provides a getRaw
function that returns raw pixel data as a Buffer. This can be useful for more advanced image processing tasks or when you need to work with the raw binary data directly.
Promise-based Raw Data Retrieval
const rawResult = await pixelGetter.getRaw("example.jpg");
const rawResult = await pixelGetter.getRaw(Buffer.from(...));
const rawResult = await pixelGetter.getRaw("https://nodejs.org/images/logo-light.png");
Callback-based Raw Data Retrieval
pixelGetter.getRaw('example.jpg', (err, rawPixels) => {
if (err) {
console.error(err);
} else {
console.log(rawPixels);
}
});
The getRaw
function accepts the same options as the get
function:
const rawResult = await pixelGetter.getRaw('example.jpg', {
pixelType: pixelGetter.PixelType.RGB,
timeout: 5000,
});
The returned rawPixels
object has the following structure:
interface RawPixelInfo {
width: number;
height: number;
pixelsCount: number;
pixels: Buffer[];
pixelType: PixelType.RGB | PixelType.RGBA;
}
Note that pixels
is an array of Buffers, where each Buffer represents the raw pixel data for a frame.
Contributing
We warmly welcome contributions to Pixel Getter! Feel free to fork the repository and submit pull requests to help improve this tool.