Function EncodePointDelta

libs/coding/geometry_coding.hpp:36–42

// Writes the difference of two 2d vectors to sink.
template <typename Sink>
void EncodePointDelta(Sink & sink, m2::PointU const & curr, m2::PointU const & next)
{
  auto const dx = base::asserted_cast<int32_t>(next.x) - base::asserted_cast<int32_t>(curr.x);
  auto const dy = base::asserted_cast<int32_t>(next.y) - base::asserted_cast<int32_t>(curr.y);
  WriteVarInt(sink, dx);
  WriteVarInt(sink, dy);
}

// Reads the encoded difference from |source| and returns the
// point equal to |base| + difference.