jpg-url-to-minitel-rgb-mosaic.ts

import Jimp from "jimp";

const imageUrl = 'https://i.scdn.co/image/ab67616d00001e02e8b066f70c206551210d902b';
const outputImagePath = './output.jpg';

type RGB = [number, number, number];
type ColorMapping = { [color: string]: RGB };

// Colors mapping to their RGB values
const predefinedColors: ColorMapping = {
  BLACK:   [0,   0,   0],
  RED:     [255, 0,   0],
  GREEN:   [0,   255, 0],
  YELLOW:  [255, 255, 0],
  MAGENTA: [255, 0,   255],
  BLUE:    [0,   0,   255],
  CYAN:    [0,   255, 255],
  WHITE:   [255, 255, 255]
};

// Function to calculate Euclidean distance
function colorDistance(rgb1: RGB, rgb2: RGB): number {
  const [r1, g1, b1] = rgb1;
  const [r2, g2, b2] = rgb2;
  return Math.sqrt(Math.pow((r2 - r1), 2) + Math.pow((g2 - g1), 2) + Math.pow((b2 - b1), 2));
}

// Function to get closest color
function getClosestColor(inputColor: RGB): string {
  let minDistance = Infinity;
  let closestColor = "";

  for (const color in predefinedColors) {
    const distance = colorDistance(inputColor, predefinedColors[color]);
    if (distance < minDistance) {
      minDistance = distance;
      closestColor = color;
    }
  }

  return closestColor;
}

Jimp.read(imageUrl)
.then(image => {
  image.scan(0, 0, image.bitmap.width, image.bitmap.height, function (x, y, idx) {
    const red = this.bitmap.data[idx];
    const green = this.bitmap.data[idx + 1];
    const blue = this.bitmap.data[idx + 2];

    const closestColor = getClosestColor([red, green, blue]);

    this.bitmap.data[idx] = predefinedColors[closestColor][0];
    this.bitmap.data[idx + 1] = predefinedColors[closestColor][1];
    this.bitmap.data[idx + 2] = predefinedColors[closestColor][2];
  });

  return image
  .resize(40, Jimp.AUTO)
  .writeAsync(outputImagePath);
})
.catch(err => {
  console.error(err);
});