Method parseCFA

src/librawspeed/decoders/DngDecoder.cpp:147–208

}

void DngDecoder::parseCFA(const TiffIFD* raw) {

  // Check if layout is OK, if present
  if (raw->hasEntry(CFALAYOUT) && raw->getEntry(CFALAYOUT)->getU16() != 1)
    ThrowRDE("Unsupported CFA Layout.");

  TiffEntry* cfadim = raw->getEntry(CFAREPEATPATTERNDIM);
  if (cfadim->count != 2)
    ThrowRDE("Couldn't read CFA pattern dimension");

  // Does NOT contain dimensions as some documents state
  TiffEntry* cPat = raw->getEntry(CFAPATTERN);

  iPoint2D cfaSize(cfadim->getU32(1), cfadim->getU32(0));
  if (cfaSize.area() != cPat->count) {
    ThrowRDE("CFA pattern dimension and pattern count does not "
             "match: %d.",
             cPat->count);
  }

  mRaw->cfa.setSize(cfaSize);

  static const map<uint32_t, CFAColor> int2enum = {
      {0, CFA_RED},     {1, CFA_GREEN},  {2, CFA_BLUE},  {3, CFA_CYAN},
      {4, CFA_MAGENTA}, {5, CFA_YELLOW}, {6, CFA_WHITE},
  };

  for (int y = 0; y < cfaSize.y; y++) {
    for (int x = 0; x < cfaSize.x; x++) {
      uint32_t c1 = cPat->getByte(x + y * cfaSize.x);
      CFAColor c2 = CFA_UNKNOWN;

      try {
        c2 = int2enum.at(c1);
      } catch (std::out_of_range&) {
        ThrowRDE("Unsupported CFA Color: %u", c1);
      }

      mRaw->cfa.setColorAt(iPoint2D(x, y), c2);
    }
  }

  // the cfa is specified relative to the ActiveArea. we want it relative (0,0)
  // Since in handleMetadata(), in subFrame() we unconditionally shift CFA by
  // activearea+DefaultCropOrigin; here we need to undo the 'ACTIVEAREA' part.
  if (!raw->hasEntry(ACTIVEAREA))
    return;

  TiffEntry* active_area = raw->getEntry(ACTIVEAREA);
  if (active_area->count != 4)
    ThrowRDE("active area has %d values instead of 4", active_area->count);

  const auto aa = active_area->getFloatArray(2);
  if (std::any_of(aa.cbegin(), aa.cend(), [](const auto v) {
        return v < std::numeric_limits<iPoint2D::value_type>::min() ||
               v > std::numeric_limits<iPoint2D::value_type>::max();
      }))
    ThrowRDE("Error decoding active area");