/Splash

Hide and encode text into images

Primary LanguageJavaScript

Slash

What is it:

Started as a way to encode text into images using encoding algo outlined here: How-Encoding-works.

Now, it is mainly a library of wrapper classes around JIMP which lets you do some cool image manipulation.

Classes:

Image, EncodedImage, SquareImage, ImageFromFile

Inheritance tree:

graph LR
Image-->SquareImage
Image --> ImageFromFile
SquareImage-->EncodedImage
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Examples:

Generating an encoded Image:

const str = fs.readFileSync("./sample.txt", "utf-8");
let encodedImage = new EncodedImage(str, false);
   encodedImage.resize(1080);
   encodedImage.writeKey(0,0)

encodedImage.writeToFile("./exports/encodedImage.png");

Compositing two images on top of each other:

const str = fs.readFileSync("./sample.txt", "utf-8");

let encodedImage = new EncodedImage(str, false);
   encodedImage.resize(1080);

let pinkSquare = new SquareImage(1750, "#ff00bf");
let composite_positionX = 355;
let composite_positionY = 355;

pinkSquare.compositeUnder(encodedImage, composite_positionX, composite_positionY);

pinkSquare.writeToFile("./exports/compositeImage.png")

Replacing colors:

let patrick = new ImageFromFile("./assets/patrick.png");

// NOTE: Leave second parameter empty to remove color.
patrick.replaceColor("#ff9176", "#6495ED");

patrick.writeToFile("./exports/bluePatrick.png");
Before After

Using many classes and default JIMP features:

(See examples in App.js)

How encoding works:

Each triplet of characters is stored as an RGB value for a pixel. The alpha for that pixel is randomly chosen to better hide the string.

The key contains information about the starting and ending position of the encoded string, and can be set to any position on the EncodedImage using EncodedImage.setKey(positionX, positionY).

Dcoding:

Run Node Decode.js with an encoded image file.

Citations