diff options
Diffstat (limited to 'boost/geometry/algorithms/detail/overlay/assign_parents.hpp')
| -rw-r--r-- | boost/geometry/algorithms/detail/overlay/assign_parents.hpp | 45 |
1 files changed, 29 insertions, 16 deletions
diff --git a/boost/geometry/algorithms/detail/overlay/assign_parents.hpp b/boost/geometry/algorithms/detail/overlay/assign_parents.hpp index 78160f5204..c8ce651007 100644 --- a/boost/geometry/algorithms/detail/overlay/assign_parents.hpp +++ b/boost/geometry/algorithms/detail/overlay/assign_parents.hpp @@ -224,7 +224,8 @@ inline void assign_parents(Geometry1 const& geometry1, RingCollection const& collection, RingMap& ring_map, Strategy const& strategy, - bool check_for_orientation = false) + bool check_for_orientation = false, + bool discard_double_negative = false) { typedef typename geometry::tag<Geometry1>::type tag1; typedef typename geometry::tag<Geometry2>::type tag2; @@ -334,28 +335,38 @@ inline void assign_parents(Geometry1 const& geometry1, for (map_iterator_type it = boost::begin(ring_map); it != boost::end(ring_map); ++it) { - if (geometry::math::equals(it->second.get_area(), 0)) + ring_info_type& info = it->second; + if (geometry::math::equals(info.get_area(), 0)) { - it->second.discarded = true; + info.discarded = true; } - else if (it->second.parent.source_index >= 0 - && math::larger(it->second.get_area(), 0)) + else if (info.parent.source_index >= 0) { - const ring_info_type& parent = ring_map[it->second.parent]; + const ring_info_type& parent = ring_map[info.parent]; + bool const pos = math::larger(info.get_area(), 0); + bool const parent_pos = math::larger(parent.area, 0); - if (math::larger(parent.area, 0)) + bool const double_neg = discard_double_negative && ! pos && ! parent_pos; + + if ((pos && parent_pos) || double_neg) { // Discard positive inner ring with positive parent - it->second.discarded = true; + // Also, for some cases (dissolve), negative inner ring + // with negative parent shouild be discarded + info.discarded = true; + } + + if (pos || info.discarded) + { + // Remove parent ID from any positive or discarded inner rings + info.parent.source_index = -1; } - // Remove parent ID from any positive inner ring - it->second.parent.source_index = -1; } - else if (it->second.parent.source_index < 0 - && math::smaller(it->second.get_area(), 0)) + else if (info.parent.source_index < 0 + && math::smaller(info.get_area(), 0)) { // Reverse negative ring without parent - it->second.reversed = true; + info.reversed = true; } } } @@ -372,7 +383,7 @@ inline void assign_parents(Geometry1 const& geometry1, } -// Version for one geometry (called by buffer) +// Version for one geometry (called by buffer/dissolve) template < typename Geometry, @@ -384,13 +395,15 @@ inline void assign_parents(Geometry const& geometry, RingCollection const& collection, RingMap& ring_map, Strategy const& strategy, - bool check_for_orientation) + bool check_for_orientation, + bool discard_double_negative) { // Call it with an empty geometry as second geometry (source_id == 1) // (ring_map should be empty for source_id==1) Geometry empty; - assign_parents(geometry, empty, collection, ring_map, strategy, check_for_orientation); + assign_parents(geometry, empty, collection, ring_map, strategy, + check_for_orientation, discard_double_negative); } |