pixel-io-netpbm

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Discussion

Note

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• About
• Status
• Installation
• Dependencies
• Usage examples
• API
• Authors
• License

About

Multi-format NetPBM reader & writer support for @thi.ng/pixel.

This package can read & write binary NetPBM image formats from byte arrays/buffers to @thi.ng/pixel pixel buffers (aka PackedBuffer).

Source format	Destination format	Rec. file extension(1)
1 bit	GRAY8(2)	.pbm
2-8 bit grayscale	GRAY8	.pgm
9-16 bit grayscale	GRAY16	.pgm
24 bit RGB	ARGB8888	.ppm

⁽¹⁾ no relevance to actual parse/export logic ⁽²⁾ 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

Installation

yarn add @thi.ng/pixel-io-netpbm

ES module import:

<script type="module" src="https://cdn.skypack.dev/@thi.ng/pixel-io-netpbm"></script>

Skypack documentation

For Node.js REPL:

const pixelIoNetpbm = await import("@thi.ng/pixel-io-netpbm");

Package sizes (brotli'd, pre-treeshake): ESM: 1.24 KB

Dependencies

• @thi.ng/api
• @thi.ng/errors
• @thi.ng/pixel

Usage examples

One project in this repo's /examples directory is using this package:

Screenshot	Description	Live demo	Source
	Multi-layer vectorization & dithering of bitmap images	Demo	Source

API

Generated API docs

import * as pbm from "@thi.ng/pixel-io-netpbm";
import * as fs from "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

If this project contributes to an academic publication, please cite it as:

@misc{thing-pixel-io-netpbm,
  title = "@thi.ng/pixel-io-netpbm",
  author = "Karsten Schmidt",
  note = "https://thi.ng/pixel-io-netpbm",
  year = 2021
}

License

© 2021 - 2024 Karsten Schmidt // Apache License 2.0