img2teletext

This is a CLI application for converting images to teletext level 1 compatible data. Starting from the upper leftmost, the algorithm goes by 2x3 blocks of pixels, and translates them to teletext mosaic charachters. It can also be used as a Node.js library.

It handles images of any dimensions, they don't have to be within the constraints of a standard teletext page.

Requirements

• Node.js v14 or newer (recommended: v18 or newer)
• npm v6 or newer (comes with Node.js)

Installation

This module is distributed via npm.

$ npm install -g img2teletext

Command Line Usage

Basic Usage

$ img2teletext <image-file> [options]

Options

• -V, --version - Output the version number
• -b, --bin - Generate binary output (default)
• -e, --edittf - Generate edit.tf URL for online teletext editor
• -z, --zxnet - Generate ZXNet URL for online teletext editor
• --base64 - Generate base64 encoded output
• -j, --json - Generate JSON array output
• --hash - Generate teletext hash for edit.tf and zxnet compatibility
• -h, --help - Display help information

Examples

# Convert image to binary teletext data (default output)
$ img2teletext image.png

# Generate a JSON array of teletext character codes
$ img2teletext image.png --json

# Generate a shareable edit.tf URL
$ img2teletext image.png --edittf

# Generate a shareable ZXNet URL
$ img2teletext image.png --zxnet

# Generate base64 encoded data
$ img2teletext image.png --base64

# Generate teletext hash for compatibility
$ img2teletext image.png --hash

Supported Image Formats

• PNG (.png)
• JPEG (.jpg, .jpeg)

Using it as a Node.js library

JavaScript (ES5/CommonJS)

const img2teletext = require('img2teletext').default;
const { PNG } = require('pngjs');
const fs = require('fs');

const data = fs.readFileSync('./test/test.png');
const png = PNG.sync.read(data);
const teletextData = img2teletext(png.data, png.width);

console.log(teletextData);

TypeScript

import img2teletext from 'img2teletext';
import { PNG } from 'pngjs';
import fs from 'fs';

const data = fs.readFileSync('./test/test.png');
const png = PNG.sync.read(data);
const teletextData: Uint8Array = img2teletext(png.data, png.width);

console.log(teletextData);

Development

This project is written in TypeScript. To build the project:

npm install
npm run build

To run tests:

npm test

To watch for changes during development:

npm run dev

This code is released under the MIT license, feel free to do whatever you want with it.