getDataMaskBit static method

bool getDataMaskBit(int maskPattern, int x, int y)

Return the mask bit for "getMaskPattern" at "x" and "y". See 8.8 of JISX0510:2004 for mask pattern conditions.

Implementation

static bool getDataMaskBit(int maskPattern, int x, int y) {
  int intermediate;
  int temp;
  switch (maskPattern) {
    case 0:
      intermediate = (y + x) & 0x1;
      break;
    case 1:
      intermediate = y & 0x1;
      break;
    case 2:
      intermediate = x % 3;
      break;
    case 3:
      intermediate = (y + x) % 3;
      break;
    case 4:
      intermediate = ((y ~/ 2) + (x ~/ 3)) & 0x1;
      break;
    case 5:
      temp = y * x;
      intermediate = (temp & 0x1) + (temp % 3);
      break;
    case 6:
      temp = y * x;
      intermediate = ((temp & 0x1) + (temp % 3)) & 0x1;
      break;
    case 7:
      temp = y * x;
      intermediate = ((temp % 3) + ((y + x) & 0x1)) & 0x1;
      break;
    default:
      throw ArgumentError('Invalid mask pattern: $maskPattern');
  }
  return intermediate == 0;
}