CGAL::Shape_regularization::Segments::Offset_regularization_2< GeomTraits, InputRange, SegmentMap > Class Template Reference

#include <CGAL/Shape_regularization/Segments/Offset_regularization_2.h>

Definition

template<typename GeomTraits, typename InputRange, typename SegmentMap = CGAL::Identity_property_map<typename GeomTraits::Segment_2>>
class CGAL::Shape_regularization::Segments::Offset_regularization_2< GeomTraits, InputRange, SegmentMap >

An offset-based regularization type for 2D segments that reinforces collinearity relationships.

The input groups of segments should each contain (near) parallel segments. In order to achieve that, one may use the class Segments::Angle_regularization_2 or the function Segments::parallel_groups(). Each group of parallel segments may be inserted using the method add_group().

Template Parameters

GeomTraits	a model of Kernel
InputRange	a model of Range whose iterator type is RandomAccessIterator
SegmentMap	a model of ReadWritePropertyMap whose key type is the value type of the InputRange and value type is GeomTraits::Segment_2. The default is CGAL::Identity_property_map<typename GeomTraits::Segment_2>.

Is model of

RegularizationType

Examples

Shape_regularization/regularize_100_segments_offsets.cpp, Shape_regularization/regularize_15_segments.cpp, and Shape_regularization/regularize_real_data_2.cpp.

Types
typedef GeomTraits::FT	FT
	Number type.

Initialization
template<typename NamedParameters = parameters::Default_named_parameters>
	Offset_regularization_2 (InputRange &input_range, const NamedParameters &np=parameters::default_values())
	initializes all internal data structures.
template<typename IndexRange >
void	add_group (const IndexRange &index_range)
	inserts a group of segments from input_range.

Access
FT	target (const std::size_t i, const std::size_t j) const
	calculates the target value between 2 parallel segments, which are direct neighbors to each other.
FT	bound (const std::size_t) const
	returns maximum_offset.
void	update (const std::vector< FT > &solution)
	applies new positions computed by the QuadraticProgramTraits to the initial segments.

Groups
template<typename OutIterator >
OutIterator	collinear_groups (OutIterator groups) const
	creates groups of indices, where each group represents collinear segments.

Miscellaneous
std::size_t	number_of_modified_segments () const
	returns the number of modified segments.
template<typename OutIterator >
OutIterator	unique_segments (OutIterator segments) const
	returns segments, which best-fit collinear groups.

Memory Management
void	clear ()
	clears all internal data structures.

Constructor & Destructor Documentation

Offset_regularization_2()

template<typename GeomTraits , typename InputRange , typename SegmentMap = CGAL::Identity_property_map<typename GeomTraits::Segment_2>>

template<typename NamedParameters = parameters::Default_named_parameters>

CGAL::Shape_regularization::Segments::Offset_regularization_2< GeomTraits, InputRange, SegmentMap >::Offset_regularization_2	(	InputRange &	input_range,
		const NamedParameters &	np = parameters::default_values()
	)

initializes all internal data structures.

Template Parameters

NamedParameters

a sequence of Named Parameters

Parameters

input_range	a range of 2D segments to be regularized
np	an optional sequence of Named Parameters among the ones listed below; this parameter can be omitted, the default values are then used

Optional Named Parameters

maximum_offset maximum allowed orthogonal distance between two parallel segments such that they are considered to be collinear Type: GeomTraits::FT Default: 0.5 unit length
segment_map an instance of SegmentMap that maps an item from input_range to GeomTraits::Segment_2 Default: SegmentMap()

Precondition

input_range.size() >= 2

maximum_offset >= 0

Member Function Documentation

add_group()

template<typename GeomTraits , typename InputRange , typename SegmentMap = CGAL::Identity_property_map<typename GeomTraits::Segment_2>>

template<typename IndexRange >

void CGAL::Shape_regularization::Segments::Offset_regularization_2< GeomTraits, InputRange, SegmentMap >::add_group

(

const IndexRange &

index_range

)

inserts a group of segments from input_range.

Each group of segments is provided as a collection of their indices and only segments within the group are being regularized that is no relationships between segments from different groups are taken into account.

The user must not use this method until he has meaningful groups of segments (see more in the user manual). By default, all segments are inserted as a group.

Template Parameters

IndexRange

a model of ConstRange whose value type is std::size_t

Parameters

index_range

a const range of segment indices

Precondition

index_range.size() >= 2

collinear_groups()

template<typename GeomTraits , typename InputRange , typename SegmentMap = CGAL::Identity_property_map<typename GeomTraits::Segment_2>>

template<typename OutIterator >

OutIterator CGAL::Shape_regularization::Segments::Offset_regularization_2< GeomTraits, InputRange, SegmentMap >::collinear_groups

(

OutIterator

groups

)

const

creates groups of indices, where each group represents collinear segments.

This method calls Segments::collinear_groups().

Template Parameters

OutIterator

a model of OutputIterator that accepts elements of type std::vector<std::size_t>

Parameters

groups

an output iterator with groups of segment indices

target()

template<typename GeomTraits , typename InputRange , typename SegmentMap = CGAL::Identity_property_map<typename GeomTraits::Segment_2>>

FT CGAL::Shape_regularization::Segments::Offset_regularization_2< GeomTraits, InputRange, SegmentMap >::target	(	const std::size_t	i,
		const std::size_t	j
	)		const

calculates the target value between 2 parallel segments, which are direct neighbors to each other.

The target value is the distance between two parallel segments i and j, where the distance is defined as the distance between the midpoint of the ith segment and the projection of this point onto the supporting line of the jth segment.

Parameters

i	index of the first segment
j	index of the second segment

Precondition

i >= 0 && i < input_range.size()

j >= 0 && j < input_range.size()

unique_segments()

template<typename GeomTraits , typename InputRange , typename SegmentMap = CGAL::Identity_property_map<typename GeomTraits::Segment_2>>

template<typename OutIterator >

OutIterator CGAL::Shape_regularization::Segments::Offset_regularization_2< GeomTraits, InputRange, SegmentMap >::unique_segments

(

OutIterator

segments

)

const

returns segments, which best-fit collinear groups.

This method first calls Segments::collinear_groups() and then substitutes each group of collinear segments by an average segment. The number of returned segments is the number of detected collinear groups.

Template Parameters

OutIterator

a model of OutputIterator that accepts segments of type GeomTraits::Segment_2

Parameters

segments

an output iterator with the simplified segments

update()

template<typename GeomTraits , typename InputRange , typename SegmentMap = CGAL::Identity_property_map<typename GeomTraits::Segment_2>>

void CGAL::Shape_regularization::Segments::Offset_regularization_2< GeomTraits, InputRange, SegmentMap >::update

(

const std::vector< FT > &

solution

)

applies new positions computed by the QuadraticProgramTraits to the initial segments.

Number of values in solution equals to the number n of segments being regularized + the number m of neighbor pairs between these segments. Each of n values is an offset that is added to the initial segment position.

Parameters

solution

a vector with offsets in unit lengths

Precondition

solution.size() >= 1