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detect switch and perform switch in RLE path

This commit is contained in:
Youmu 2020-06-12 19:33:47 -04:00
parent 274542fa9f
commit c23b921fe9
1 changed files with 30 additions and 0 deletions
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30
Surface_mesh_topology/include/CGAL/Surface_mesh_topology/internal/Path_on_surface_with_rle.h
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@ -1214,6 +1214,15 @@ public:
return is_next_flat_can_be_extended_at_beginning(it, dh, dummy1, dummy2);
}
/// @return true iff the flat 'it' forms a switchable subpath (aka left-L-shape)
bool is_switchable(const List_iterator& it)
{
CGAL_assertion(is_valid_iterator(it));
if (it == m_path.begin() || std::next(it) == m_path.end()) { return false; }
std::size_t t=next_positive_turn(it);
return (t==1 && flat_length(it) >= 0);
}
/// Add the given dart 'dh' before the flat 'it'.
void add_dart_before(const List_iterator& it, Dart_const_handle dh,
Set_of_it& modified_flats)
@ -1452,6 +1461,27 @@ public:
it1=merge_modified_flats_when_possible(modified_flats);
}
/// Switch the left-L-shape of the subpath starting at 'it'
void switch_flat(List_iterator& it)
{
CGAL_assertion(is_switchable(it));
Set_of_it modified_flats;
/// Need to switch to t1-1 turn
List_iterator it_next = next_iterator(it);
Dart_const_handle d_new_first_dart = get_map().template beta<0, 2>(begin_of_flat(it));
Dart_const_handle d_new_flat_begin = get_map().template beta<2, 0>(d_new_first_dart);
Dart_const_handle d_new_flat_end = get_map().template beta<1, 2>(begin_of_flat(it_next));
add_dart_before(it, d_new_first_dart, modified_flats);
set_begin_of_flat(it, d_new_flat_begin, modified_flats);
set_end_of_flat(it, d_new_flat_end, modified_flats);
flat_modified(it, modified_flats);
reduce_flat_from_beginning(it_next, modified_flats);
flat_modified(it_next, modified_flats);
it=merge_modified_flats_when_possible(modified_flats);
}
/// Right push the path, if all all l-shape are pushed, otherwise only one.
/// @return true iff the path was pushed
bool right_push(bool all=true)