Class PuzzleRecognizer

utils/validate_single.js:49–197

const PUZZLE_PAD = 10;

class PuzzleRecognizer {
  constructor(bg, patch, y) {
    // console.log(bg);
    const imgBg = new PNGDecoder(Buffer.from(bg, 'base64'));
    const imgPatch = new PNGDecoder(Buffer.from(patch, 'base64'));

    // console.log(imgBg);

    this.bg = imgBg;
    this.patch = imgPatch;
    this.rawBg = bg;
    this.rawPatch = patch;
    this.y = y;
    this.w = imgBg.width;
    this.h = imgBg.height;
  }

  async run() {
    await this.bg.decodeToPixels();
    await this.patch.decodeToPixels();

    return this.recognize();
  }

  recognize() {
    const {ctx, w: width, bg} = this;
    const {width: patchWidth, height: patchHeight} = this.patch;
    const posY = this.y + PUZZLE_PAD + ((patchHeight - PUZZLE_PAD) / 2) - (PUZZLE_GAP / 2);
    // const cData = ctx.getImageData(0, a.y + 10 + 20 - 4, 360, 8).data;
    const cData = bg.getImageData(0, posY, width, PUZZLE_GAP).data;
    const lumas = [];

    for (let x = 0; x < width; x++) {
      var sum = 0;

      // y xais
      for (let y = 0; y < PUZZLE_GAP; y++) {
        var idx = x * 4 + y * (width * 4);
        var r = cData[idx];
        var g = cData[idx + 1];
        var b = cData[idx + 2];
        var luma = 0.2126 * r + 0.7152 * g + 0.0722 * b;

        sum += luma;
      }

      lumas.push(sum / PUZZLE_GAP);
    }

    const n = 2; // minium macroscopic image width (px)
    const margin = patchWidth - PUZZLE_PAD;
    const diff = 20; // macroscopic brightness difference
    const radius = PUZZLE_PAD;
    for (let i = 0, len = lumas.length - 2 * 4; i < len; i++) {
      const left = (lumas[i] + lumas[i + 1]) / n;
      const right = (lumas[i + 2] + lumas[i + 3]) / n;
      const mi = margin + i;
      const mLeft = (lumas[mi] + lumas[mi + 1]) / n;