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[traverse] reverse meaning of isolation in difference
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@barendgehrels
barendgehrels committed Jul 8, 2021
1 parent 174c380 commit a7c26dc
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Showing 6 changed files with 113 additions and 62 deletions.
3 changes: 1 addition & 2 deletions include/boost/geometry/algorithms/detail/overlay/is_self_turn.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -26,8 +26,7 @@ struct is_self_turn_check
template <typename Turn>
static inline bool apply(Turn const& turn)
{
return turn.operations[0].seg_id.source_index
== turn.operations[1].seg_id.source_index;
return turn.is_self();
}
};

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98 changes: 55 additions & 43 deletions include/boost/geometry/algorithms/detail/overlay/traversal.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -621,31 +621,32 @@ public :
return m_turns[rp.turn_index].operations[rp.operation_index];
}

inline sort_by_side::rank_type select_rank(sbs_type const& sbs,
bool skip_isolated) const
inline sort_by_side::rank_type select_rank(sbs_type const& sbs) const
{
static bool const is_intersection
= target_operation == operation_intersection;

// Take the first outgoing rank corresponding to incoming region,
// or take another region if it is not isolated
turn_operation_type const& incoming_op
= operation_from_rank(sbs.m_ranked_points.front());
auto const& in_op = operation_from_rank(sbs.m_ranked_points.front());

for (std::size_t i = 0; i < sbs.m_ranked_points.size(); i++)
{
typename sbs_type::rp const& rp = sbs.m_ranked_points[i];
auto const& rp = sbs.m_ranked_points[i];
if (rp.rank == 0 || rp.direction == sort_by_side::dir_from)
{
continue;
}
turn_operation_type const& op = operation_from_rank(rp);
auto const& out_op = operation_from_rank(rp);

if (op.operation != target_operation
&& op.operation != operation_continue)
if (out_op.operation != target_operation
&& out_op.operation != operation_continue)
{
continue;
}

if (op.enriched.region_id == incoming_op.enriched.region_id
|| (skip_isolated && ! op.enriched.isolated))
if (in_op.enriched.region_id == out_op.enriched.region_id
|| (is_intersection && ! out_op.enriched.isolated))
{
// Region corresponds to incoming region, or (for intersection)
// there is a non-isolated other region which should be taken
Expand All @@ -660,7 +661,7 @@ public :
int& op_index, sbs_type const& sbs,
signed_size_type start_turn_index, int start_op_index) const
{
sort_by_side::rank_type const selected_rank = select_rank(sbs, false);
sort_by_side::rank_type const selected_rank = select_rank(sbs);

int current_priority = 0;
for (std::size_t i = 1; i < sbs.m_ranked_points.size(); i++)
Expand Down Expand Up @@ -688,49 +689,59 @@ public :
inline bool analyze_cluster_intersection(signed_size_type& turn_index,
int& op_index, sbs_type const& sbs) const
{
sort_by_side::rank_type const selected_rank = select_rank(sbs, true);
// Select the rank based on regions and isolation
sort_by_side::rank_type const selected_rank = select_rank(sbs);

if (selected_rank > 0)
if (selected_rank <= 0)
{
typename turn_operation_type::comparable_distance_type
min_remaining_distance = 0;
return false;
}

std::size_t selected_index = sbs.m_ranked_points.size();
for (std::size_t i = 0; i < sbs.m_ranked_points.size(); i++)
// From these ranks, select the index: the first, or the one with
// the smallest remaining distance
typename turn_operation_type::comparable_distance_type
min_remaining_distance = 0;

std::size_t selected_index = sbs.m_ranked_points.size();
for (std::size_t i = 0; i < sbs.m_ranked_points.size(); i++)
{
auto const& ranked_point = sbs.m_ranked_points[i];

if (ranked_point.rank > selected_rank)
{
break;
}
else if (ranked_point.rank == selected_rank)
{
typename sbs_type::rp const& ranked_point = sbs.m_ranked_points[i];
auto const& op = operation_from_rank(ranked_point);

if (ranked_point.rank == selected_rank)
if (op.visited.finalized())
{
turn_operation_type const& op = operation_from_rank(ranked_point);

if (op.visited.finalized())
{
// This direction is already traveled before, the same
// cannot be traveled again
continue;
}

// Take turn with the smallest remaining distance
if (selected_index == sbs.m_ranked_points.size()
|| op.remaining_distance < min_remaining_distance)
{
selected_index = i;
min_remaining_distance = op.remaining_distance;
}
// This direction is already traveled,
// it cannot be traveled again
continue;
}
}

if (selected_index < sbs.m_ranked_points.size())
{
typename sbs_type::rp const& ranked_point = sbs.m_ranked_points[selected_index];
turn_index = ranked_point.turn_index;
op_index = ranked_point.operation_index;
return true;
if (selected_index == sbs.m_ranked_points.size()
|| op.remaining_distance < min_remaining_distance)
{
// It was unassigned or it is better
selected_index = i;
min_remaining_distance = op.remaining_distance;
}
}
}

return false;
if (selected_index == sbs.m_ranked_points.size())
{
// Should not happen, there must be points with the selected rank
return false;
}

auto const& ranked_point = sbs.m_ranked_points[selected_index];
turn_index = ranked_point.turn_index;
op_index = ranked_point.operation_index;
return true;
}

inline bool fill_sbs(sbs_type& sbs,
Expand Down Expand Up @@ -819,6 +830,7 @@ public :
return result;
}

// Analyzes a non-clustered "ii" intersection, as if it is clustered.
inline bool analyze_ii_intersection(signed_size_type& turn_index, int& op_index,
turn_type const& current_turn,
segment_identifier const& previous_seg_id)
Expand Down
49 changes: 39 additions & 10 deletions include/boost/geometry/algorithms/detail/overlay/traversal_switch_detector.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -89,7 +89,6 @@ struct traversal_switch_detector

enum isolation_type
{
isolation_unknown = -1,
isolation_no = 0,
isolation_yes = 1,
isolation_multiple = 2
Expand Down Expand Up @@ -121,7 +120,7 @@ struct traversal_switch_detector
struct region_properties
{
signed_size_type region_id = -1;
isolation_type isolated = isolation_unknown;
isolation_type isolated = isolation_no;
set_type unique_turn_ids;
connection_map connected_region_counts;
};
Expand Down Expand Up @@ -374,7 +373,7 @@ struct traversal_switch_detector
{
region_properties& properties = key_val.second;

if (properties.isolated == isolation_unknown
if (properties.isolated == isolation_no
&& has_only_isolated_children(properties))
{
properties.isolated = isolation_yes;
Expand All @@ -388,13 +387,36 @@ struct traversal_switch_detector
{
for (turn_type& turn : m_turns)
{
// For difference, for the input walked through in reverse,
// the meaning is reversed: what is isolated is actually not,
// and vice versa.
bool const reverseMeaningInTurn
= (Reverse1 || Reverse2)
&& ! turn.is_self()
&& ! turn.is_clustered()
&& uu_or_ii(turn)
&& turn.operations[0].enriched.region_id
!= turn.operations[1].enriched.region_id;

for (auto& op : turn.operations)
{
auto mit = m_connected_regions.find(op.enriched.region_id);
if (mit != m_connected_regions.end())
{
bool const reverseMeaningInOp
= reverseMeaningInTurn
&& ((op.seg_id.source_index == 0 && Reverse1)
|| (op.seg_id.source_index == 1 && Reverse2));

// It is assigned to isolated if it's property is "Yes",
// (one connected interior, or chained).
// "Multiple" doesn't count for isolation,
// neither for intersection, neither for difference.
region_properties const& prop = mit->second;
op.enriched.isolated = prop.isolated == isolation_yes;
op.enriched.isolated
= reverseMeaningInOp
? prop.isolated == isolation_no
: prop.isolated == isolation_yes;
}
}
}
Expand Down Expand Up @@ -478,8 +500,12 @@ struct traversal_switch_detector
// Discarded turns don't connect rings to the same region
// Also xx are not relevant
// (otherwise discarded colocated uu turn could make a connection)
return ! turn.discarded
&& ! turn.both(operation_blocked);
return ! turn.discarded && ! turn.both(operation_blocked);
}

inline bool uu_or_ii(turn_type const& turn) const
{
return turn.both(operation_union) || turn.both(operation_intersection);
}

inline bool connects_same_region(turn_type const& turn) const
Expand All @@ -492,7 +518,7 @@ struct traversal_switch_detector
if (! turn.is_clustered())
{
// If it is a uu/ii-turn (non clustered), it is never same region
return ! (turn.both(operation_union) || turn.both(operation_intersection));
return ! uu_or_ii(turn);
}

if (BOOST_GEOMETRY_CONDITION(target_operation == operation_union))
Expand Down Expand Up @@ -568,7 +594,10 @@ struct traversal_switch_detector
void iterate()
{
#if defined(BOOST_GEOMETRY_DEBUG_TRAVERSAL_SWITCH_DETECTOR)
std::cout << "BEGIN SWITCH DETECTOR (region_ids and isolation)" << std::endl;
std::cout << "BEGIN SWITCH DETECTOR (region_ids and isolation)"
<< (Reverse1 ? " REVERSE_1" : "")
<< (Reverse2 ? " REVERSE_2" : "")
<< std::endl;
#endif

// Collect turns per ring
Expand Down Expand Up @@ -613,14 +642,14 @@ struct traversal_switch_detector
{
turn_type const& turn = m_turns[turn_index];

if ((turn.both(operation_union) || turn.both(operation_intersection))
&& ! turn.is_clustered())
if (uu_or_ii(turn) && ! turn.is_clustered())
{
std::cout << (turn.both(operation_union) ? "UU" : "II")
<< " " << turn_index
<< " (" << geometry::get<0>(turn.point)
<< ", " << geometry::get<1>(turn.point) << ")"
<< " -> " << std::boolalpha
<< " [" << turn.operations[0].seg_id.source_index << "/" << turn.operations[1].seg_id.source_index << "] "
<< "(" << turn.operations[0].enriched.region_id
<< " " << turn.operations[0].enriched.isolated
<< ") / (" << turn.operations[1].enriched.region_id
Expand Down
5 changes: 5 additions & 0 deletions include/boost/geometry/algorithms/detail/overlay/turn_info.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -138,6 +138,11 @@ struct turn_info
{
return cluster_id > 0;
}
inline bool is_self() const
{
return operations[0].seg_id.source_index
== operations[1].seg_id.source_index;
}

private :
inline bool has12(operation_type type1, operation_type type2) const
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7 changes: 3 additions & 4 deletions test/algorithms/set_operations/difference/difference_multi.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -209,10 +209,9 @@ void test_areal()
#endif
}

#if defined(BOOST_GEOMETRY_TEST_FAILURES)
// Generates a polygon with two interiors, i/o a multipoly with 3 rings
TEST_DIFFERENCE(issue_869_a, 3, 3600, 0, 0, 1);
#endif
// Requires reveral of isolation in ii turns. There should be 3 rings.
TEST_DIFFERENCE(issue_869_a, 3, 3600, 0, 0, 3);

// Areas and #clips correspond with POSTGIS (except sym case)
test_one<Polygon, MultiPolygon, MultiPolygon>("case_101_multi",
case_101_multi[0], case_101_multi[1],
Expand Down
13 changes: 10 additions & 3 deletions test/algorithms/set_operations/difference/test_difference.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -322,18 +322,25 @@ std::string test_one(std::string const& caseid,
bg::correct(g1);
bg::correct(g2);

std::string result = test_difference<OutputType>(caseid + "_a", g1, g2,
std::string result;

#if ! defined(BOOST_GEOMETRY_TEST_DIFFERENCE_ONLY_B)
result = test_difference<OutputType>(caseid + "_a", g1, g2,
expected_count1, expected_rings_count1, expected_point_count1,
expected_area1, false, settings);

#ifdef BOOST_GEOMETRY_DEBUG_ASSEMBLE
#endif
#if defined(BOOST_GEOMETRY_TEST_DIFFERENCE_ONLY_A)
return result;
#endif

test_difference<OutputType>(caseid + "_b", g2, g1,
expected_count2, expected_rings_count2, expected_point_count2,
expected_area2, false, settings);

#if defined(BOOST_GEOMETRY_TEST_DIFFERENCE_ONLY_B)
return result;
#endif

#if ! defined(BOOST_GEOMETRY_TEST_ALWAYS_CHECK_SYMDIFFERENCE)
if (settings.sym_difference)
#endif
Expand Down

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