/// Initializes the region by the specified corners
///
/// @code
/// a0
/// +--------------+
/// | |
/// | |
/// | |
/// +--------------+ a1
/// @endcode
///
/// @note There is no sorting of coordinates, the positions a0/a1 must
/// already be top/left,bottom/right ordering. There is no automatic
/// way to sort them because of the international date line.
///
/// @param[in] a0 Position top/left
/// @param[in] a1 Position bottom/right
/// @exception std::invalid_argument Positions are not correct. The latitude
/// of the second point <tt>p1</tt> is northerly than <tt>p0</tt>. Or positions
/// are party or fully the same.
///
region::region(const position & a0, const position & a1)
: p0_(a0)
, p1_(a1)
{
if ((a0.lat() == a1.lat()) || (a0.lon() == a1.lon()))
throw std::invalid_argument{"specified region lacks a dimension"};
if (a0.lat() < a1.lat())
throw std::invalid_argument{"specified region is upside down"};
}
/// Returns true if the specified position is inside (inclusive)
/// the region.
///
/// @param[in] p Point to test.
/// @retval true Point is in the region or on regions boundary.
/// @retval false Point outside the region.
///
bool region::inside(const position & p) const
{
// testing latitude is easy, there is no date line, no wrap-arround
if (p.lat() > p0_.lat())
return false;
if (p.lat() < p1_.lat())
return false;
// testint longitude
// shifted longitudes, now between 0..360 (date line, eastwards)
const double plon_s = 180.0 + p.lon();
const double p0lon_s = 180.0 + p0_.lon();
const double p1lon_s = 180.0 + p1_.lon();
// p is west of p0, but not west enough to reach p1
if ((plon_s < p0lon_s) && (plon_s > p1lon_s))
return false;
return true;
}