find collisions between rounded HUSL triads (for https://github.com/husl-colors/husl-site/pull/9)

find collisions between rounded HUSL triads.js

function intTo2DigitHex(integer) {
  if (integer < 16) {
    return '0' + integer.toString(16)
  } else {
    return integer.toString(16)
  }
}

function findCollisions(numDigitsRounding, quitAfterFindingOne) {
  var knownHusls = {};
  var numCollisionsFound = 0;

  for (var r = 0; r < 256; r++) {
    for (var g = 0; g < 256; g++) {
      for (var b = 0; b < 256; b++) {
        var thisHex = intTo2DigitHex(r) + intTo2DigitHex(g) + intTo2DigitHex(b);

        var husl = $.husl.fromHex(thisHex);
        roundedHuslString = husl.map(function(num){ return num.toFixed(numDigitsRounding) }).join(',');

        if (knownHusls[roundedHuslString]) {
          var oldHex = knownHusls[roundedHuslString];
          console.log("found collision", roundedHuslString, "for hexes", thisHex, "and", oldHex);
          numCollisionsFound++;
          if (quitAfterFindingOne) return;
        } else {
          knownHusls[roundedHuslString] = thisHex;
        }
      }
    }
    console.log("finished enumerating gs and bs for r =", r);
    console.log("collisions found so far:", numCollisionsFound);
  }
  
  console.log("collisions found:", numCollisionsFound);
}

findCollisions(2, false);