code: function rgbaToColorMatrix(red, green, blue) {
    var alpha = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : 0;
  
    var decToFloat = function decToFloat(value) {
      return Math.round(value / 255 * 10) / 10;
    };
    var redFloat = decToFloat(red);
    var greenFloat = decToFloat(green);
    var blueFloat = decToFloat(blue);
    var alphaFloat = decToFloat(alpha);
    return '0 0 0 0 ' + redFloat + ' 0 0 0 0 ' + greenFloat + ' 0 0 0 0 ' + blueFloat + ' 0 0 0 1 ' + alphaFloat;
  }
docs: SVG color matrix filter