player/js/elements/svgElements/effects/SVGProLevelsFilter.js

function SVGProLevelsFilter(filter, filterManager) {
  this.filterManager = filterManager;
  var effectElements = this.filterManager.effectElements;
  var feComponentTransfer = createNS('feComponentTransfer');
  var feFuncR, feFuncG, feFuncB;

  if (effectElements[10].p.k || effectElements[10].p.v !== 0 || effectElements[11].p.k || effectElements[11].p.v !== 1 || effectElements[12].p.k || effectElements[12].p.v !== 1 || effectElements[13].p.k || effectElements[13].p.v !== 0 || effectElements[14].p.k || effectElements[14].p.v !== 1) {
    this.feFuncR = this.createFeFunc('feFuncR', feComponentTransfer);
  }
  if (effectElements[17].p.k || effectElements[17].p.v !== 0 || effectElements[18].p.k || effectElements[18].p.v !== 1 || effectElements[19].p.k || effectElements[19].p.v !== 1 || effectElements[20].p.k || effectElements[20].p.v !== 0 || effectElements[21].p.k || effectElements[21].p.v !== 1) {
    this.feFuncG = this.createFeFunc('feFuncG', feComponentTransfer);
  }
  if (effectElements[24].p.k || effectElements[24].p.v !== 0 || effectElements[25].p.k || effectElements[25].p.v !== 1 || effectElements[26].p.k || effectElements[26].p.v !== 1 || effectElements[27].p.k || effectElements[27].p.v !== 0 || effectElements[28].p.k || effectElements[28].p.v !== 1) {
    this.feFuncB = this.createFeFunc('feFuncB', feComponentTransfer);
  }
  if (effectElements[31].p.k || effectElements[31].p.v !== 0 || effectElements[32].p.k || effectElements[32].p.v !== 1 || effectElements[33].p.k || effectElements[33].p.v !== 1 || effectElements[34].p.k || effectElements[34].p.v !== 0 || effectElements[35].p.k || effectElements[35].p.v !== 1) {
    this.feFuncA = this.createFeFunc('feFuncA', feComponentTransfer);
  }

  if (this.feFuncR || this.feFuncG || this.feFuncB || this.feFuncA) {
    feComponentTransfer.setAttribute('color-interpolation-filters', 'sRGB');
    filter.appendChild(feComponentTransfer);
    feComponentTransfer = createNS('feComponentTransfer');
  }

  if (effectElements[3].p.k || effectElements[3].p.v !== 0 || effectElements[4].p.k || effectElements[4].p.v !== 1 || effectElements[5].p.k || effectElements[5].p.v !== 1 || effectElements[6].p.k || effectElements[6].p.v !== 0 || effectElements[7].p.k || effectElements[7].p.v !== 1) {

    feComponentTransfer.setAttribute('color-interpolation-filters', 'sRGB');
    filter.appendChild(feComponentTransfer);
    this.feFuncRComposed = this.createFeFunc('feFuncR', feComponentTransfer);
    this.feFuncGComposed = this.createFeFunc('feFuncG', feComponentTransfer);
    this.feFuncBComposed = this.createFeFunc('feFuncB', feComponentTransfer);
  }
}

SVGProLevelsFilter.prototype.createFeFunc = function (type, feComponentTransfer) {
  var feFunc = createNS(type);
  feFunc.setAttribute('type', 'table');
  feComponentTransfer.appendChild(feFunc);
  return feFunc;
};

SVGProLevelsFilter.prototype.getTableValue = function (inputBlack, inputWhite, gamma, outputBlack, outputWhite) {
  var cnt = 0;
  var segments = 256;
  var perc;
  var min = Math.min(inputBlack, inputWhite);
  var max = Math.max(inputBlack, inputWhite);
  var table = Array.call(null, { length: segments });
  var colorValue;
  var pos = 0;
  var outputDelta = outputWhite - outputBlack;
  var inputDelta = inputWhite - inputBlack;
  while (cnt <= 256) {
    perc = cnt / 256;
    if (perc <= min) {
      colorValue = inputDelta < 0 ? outputWhite : outputBlack;
    } else if (perc >= max) {
      colorValue = inputDelta < 0 ? outputBlack : outputWhite;
    } else {
      colorValue = (outputBlack + outputDelta * Math.pow((perc - inputBlack) / inputDelta, 1 / gamma));
    }
    table[pos++] = colorValue;
    cnt += 256 / (segments - 1);
  }
  return table.join(' ');
};

SVGProLevelsFilter.prototype.renderFrame = function (forceRender) {
  if (forceRender || this.filterManager._mdf) {
    var val, cnt, perc, bezier;
    var effectElements = this.filterManager.effectElements;
    if (this.feFuncRComposed && (forceRender || effectElements[3].p._mdf || effectElements[4].p._mdf || effectElements[5].p._mdf || effectElements[6].p._mdf || effectElements[7].p._mdf)) {
      val = this.getTableValue(effectElements[3].p.v, effectElements[4].p.v, effectElements[5].p.v, effectElements[6].p.v, effectElements[7].p.v);
      this.feFuncRComposed.setAttribute('tableValues', val);
      this.feFuncGComposed.setAttribute('tableValues', val);
      this.feFuncBComposed.setAttribute('tableValues', val);
    }


    if (this.feFuncR && (forceRender || effectElements[10].p._mdf || effectElements[11].p._mdf || effectElements[12].p._mdf || effectElements[13].p._mdf || effectElements[14].p._mdf)) {
      val = this.getTableValue(effectElements[10].p.v, effectElements[11].p.v, effectElements[12].p.v, effectElements[13].p.v, effectElements[14].p.v);
      this.feFuncR.setAttribute('tableValues', val);
    }

    if (this.feFuncG && (forceRender || effectElements[17].p._mdf || effectElements[18].p._mdf || effectElements[19].p._mdf || effectElements[20].p._mdf || effectElements[21].p._mdf)) {
      val = this.getTableValue(effectElements[17].p.v, effectElements[18].p.v, effectElements[19].p.v, effectElements[20].p.v, effectElements[21].p.v);
      this.feFuncG.setAttribute('tableValues', val);
    }

    if (this.feFuncB && (forceRender || effectElements[24].p._mdf || effectElements[25].p._mdf || effectElements[26].p._mdf || effectElements[27].p._mdf || effectElements[28].p._mdf)) {
      val = this.getTableValue(effectElements[24].p.v, effectElements[25].p.v, effectElements[26].p.v, effectElements[27].p.v, effectElements[28].p.v);
      this.feFuncB.setAttribute('tableValues', val);
    }

    if (this.feFuncA && (forceRender || effectElements[31].p._mdf || effectElements[32].p._mdf || effectElements[33].p._mdf || effectElements[34].p._mdf || effectElements[35].p._mdf)) {
      val = this.getTableValue(effectElements[31].p.v, effectElements[32].p.v, effectElements[33].p.v, effectElements[34].p.v, effectElements[35].p.v);
      this.feFuncA.setAttribute('tableValues', val);
    }

  }
};