function getMaskAt (maskPattern, i, j) {
  switch (maskPattern) {
    case exports.Patterns.PATTERN000: return (i + j) % 2 === 0
    case exports.Patterns.PATTERN001: return i % 2 === 0
    case exports.Patterns.PATTERN010: return j % 3 === 0
    case exports.Patterns.PATTERN011: return (i + j) % 3 === 0
    case exports.Patterns.PATTERN100: return (Math.floor(i / 2) + Math.floor(j / 3)) % 2 === 0
    case exports.Patterns.PATTERN101: return (i * j) % 2 + (i * j) % 3 === 0
    case exports.Patterns.PATTERN110: return ((i * j) % 2 + (i * j) % 3) % 2 === 0
    case exports.Patterns.PATTERN111: return ((i * j) % 3 + (i + j) % 2) % 2 === 0

    default: throw new Error('bad maskPattern:' + maskPattern)
  }
}
Return mask value at given position

@param  {Number} maskPattern Pattern reference value
@param  {Number} i           Row
@param  {Number} j           Column
@return {Boolean}            Mask value