@thi.ng/pixel-io-netpbm
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Multi-format NetPBM reader & writer support for @thi.ng/pixel
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# 
[](https://www.npmjs.com/package/@thi.ng/pixel-io-netpbm)
[](https://mastodon.thi.ng/@toxi)
> [!NOTE]
> This is one of 212 standalone projects, maintained as part
> of the [.ng/umbrella](https://github.com/thi-ng/umbrella/) monorepo
> and anti-framework.
>
> 🚀 Please help me to work full-time on these projects by [sponsoring me on
> GitHub](https://github.com/sponsors/postspectacular). Thank you! ❤️
- [About](#about)
- [Status](#status)
- [Installation](#installation)
- [Dependencies](#dependencies)
- [Usage examples](#usage-examples)
- [API](#api)
- [Authors](#authors)
- [License](#license)
## About
Multi-format NetPBM reader & writer support for [.ng/pixel](https://github.com/thi-ng/umbrella/tree/develop/packages/pixel).
This package can read & write binary
[NetPBM](https://en.wikipedia.org/wiki/Netpbm) image formats from byte
arrays/buffers to
[.ng/pixel](https://github.com/thi-ng/umbrella/tree/develop/packages/pixel)
pixel buffers (aka `PackedBuffer`).
| Source format | Destination format | Rec. file extension<sup>(1)</sup> |
|-------------------:|-----------------------|-----------------------------------|
| 1 bit | `GRAY8`<sup>(2)</sup> | `.pbm` |
| 2-8 bit grayscale | `GRAY8` | `.pgm` |
| 9-16 bit grayscale | `GRAY16` | `.pgm` |
| 24 bit RGB | `ARGB8888` | `.ppm` |
<sup>(1)</sup> no relevance to actual parse/export logic
<sup>(2)</sup> currently no support for actual 1-bit pixel buffers
Furthermore the `parseHeader()` function can be used to just extract image type,
size and other meta data (from comments), without parsing the full image.
## Status
**STABLE** - used in production
[Search or submit any issues for this package](https://github.com/thi-ng/umbrella/issues?q=%5Bpixel-io-netpbm%5D+in%3Atitle)
## Installation
```bash
yarn add .ng/pixel-io-netpbm
```
ESM import:
```ts
import * as pbm from "@thi.ng/pixel-io-netpbm";
```
Browser ESM import:
```html
<script type="module" src="https://esm.run/@thi.ng/pixel-io-netpbm"></script>
```
[JSDelivr documentation](https://www.jsdelivr.com/)
For Node.js REPL:
```js
const pbm = await import("@thi.ng/pixel-io-netpbm");
```
Package sizes (brotli'd, pre-treeshake): ESM: 1.24 KB
## Dependencies
- [.ng/api](https://github.com/thi-ng/umbrella/tree/develop/packages/api)
- [.ng/errors](https://github.com/thi-ng/umbrella/tree/develop/packages/errors)
- [.ng/pixel](https://github.com/thi-ng/umbrella/tree/develop/packages/pixel)
Note: .ng/api is in _most_ cases a type-only import (not used at runtime)
## Usage examples
One project in this repo's
[/examples](https://github.com/thi-ng/umbrella/tree/develop/examples)
directory is using this package:
| Screenshot | Description | Live demo | Source |
|:--------------------------------------------------------------------------------------------------------------------|:-------------------------------------------------------|:---------------------------------------------------|:--------------------------------------------------------------------------------|
| <img src="https://raw.githubusercontent.com/thi-ng/umbrella/develop/assets/examples/trace-bitmap.jpg" width="240"/> | Multi-layer vectorization & dithering of bitmap images | [Demo](https://demo.thi.ng/umbrella/trace-bitmap/) | [Source](https://github.com/thi-ng/umbrella/tree/develop/examples/trace-bitmap) |
## API
[Generated API docs](https://docs.thi.ng/umbrella/pixel-io-netpbm/)
```ts
import * as pbm from "@thi.ng/pixel-io-netpbm";
import * as fs "node:fs";
const src = fs.readFileSync("a.pbm");
// <Buffer 50 34 0a 23 20 67 65 6e 65 72 61 74 65 64 20 62 79...>
// parse image header data
// P4 type => 1bit bitmap
pbm.parseHeader(src)
// {
// type: 'P4',
// width: 12,
// height: 8,
// max: undefined,
// start: 47,
// comments: [ 'generated by @thi.ng/pixel-io-netpbm' ]
// }
const img = pbm.read(src);
// IntBuffer {
// width: 12,
// height: 8,
// format: [Object],
// data: Uint8Array(96) [
// 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
// 255, 255, 255, 0, 0, 255, 255, 255, 255, 255, 0, 255,
// 255, 255, 0, 0, 0, 0, 255, 255, 255, 0, 0, 255,
// 255, 0, 0, 255, 255, 0, 0, 255, 0, 0, 0, 255,
// 255, 0, 0, 0, 0, 0, 0, 255, 0, 0, 0, 255,
// 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255,
// 255, 0, 0, 255, 255, 0, 0, 255, 255, 255, 0, 255,
// 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255
// ]
// }
// convert to RGB image and export w/ additional meta data
// (will be stored in PBM header comments)
fs.writeFileSync(
"a-rgb.ppm",
pbm.asPPM(
img.as(RGB888),
[
"@prefix dc: http://purl.org/dc/terms/",
"dc:created 2021-02-08",
"dc:creator toxi"
]
)
);
```
## Authors
- [Karsten Schmidt](https://thi.ng)
If this project contributes to an academic publication, please cite it as:
```bibtex
{thing-pixel-io-netpbm,
title = "@thi.ng/pixel-io-netpbm",
author = "Karsten Schmidt",
note = "https://thi.ng/pixel-io-netpbm",
year = 2021
}
```
## License
© 2021 - 2025 Karsten Schmidt // Apache License 2.0