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CGAL 4.14 - 2D Envelopes
2D Envelopes Reference

Envelope_2.png
Ron Wein
This package consits of functions that computes the lower (or upper) envelope of a set of arbitrary curves in 2D. The output is represented as an envelope diagram, namely a subdivision of the \( x\)-axis into intervals, such that the identity of the curves that induce the envelope on each interval is unique.
Introduced in: CGAL 3.3
Depends on: 2D Arrangements
BibTeX: cgal:w-e2-19a
License: GPL

This package consists of functions that compute the lower (or upper) envelope of a set of arbitrary curves in 2D. The output is represented as an envelope diagram, namely a subdivision of the \( x\)-axis into intervals, such that the identity of the curves that induce the envelope over each interval is unique.

Classified Reference Pages

Functions

Concepts

Classes

Modules

 Concepts
 

Classes

class  CGAL::Envelope_diagram_1< Traits >
 This class is the default envelope-diagram class used by envelope functions to represent the minimization or the maximization diagram of a set of curves. More...
 

Functions

template<class InputIterator , class EnvelopeDiagram >
void CGAL::lower_envelope_2 (InputIterator begin, InputIterator end, EnvelopeDiagram &diag)
 Computes the lower envelope of a set of curves in \( \mathbb{R}^2\), as given by the range [begin, end). More...
 
template<class InputIterator , class EnvelopeDiagram >
void CGAL::lower_envelope_x_monotone_2 (InputIterator begin, InputIterator end, EnvelopeDiagram &diag)
 Computes the lower envelope of a set of \( x\)-monotone curves in \( \mathbb{R}^2\), as given by the range [begin, end). More...
 
template<class InputIterator , class EnvelopeDiagram >
void CGAL::upper_envelope_2 (InputIterator begin, InputIterator end, EnvelopeDiagram &diag)
 Computes the upper envelope of a set of curves in \( \mathbb{R}^2\), as given by the range [begin, end). More...
 
template<class InputIterator , class EnvelopeDiagram >
void CGAL::upper_envelope_x_monotone_2 (InputIterator begin, InputIterator end, EnvelopeDiagram &diag)
 Computes the upper envelope of a set of \( x\)-monotone curves in \( \mathbb{R}^2\), as given by the range [begin, end). More...
 

Function Documentation

◆ lower_envelope_2()

template<class InputIterator , class EnvelopeDiagram >
void CGAL::lower_envelope_2 ( InputIterator  begin,
InputIterator  end,
EnvelopeDiagram &  diag 
)

#include <CGAL/envelope_2.h>

Computes the lower envelope of a set of curves in \( \mathbb{R}^2\), as given by the range [begin, end).

The lower envelope is represented using the output minimization diagram diag.

Template Parameters
InputIteratormust be an input iterator with value type EnvelopeDiagram::Traits_2::Curve_2.
EnvelopeDiagrammust be a model of the concept EnvelopeDiagram_1.
Examples:
Envelope_2/envelope_circles.cpp.

◆ lower_envelope_x_monotone_2()

template<class InputIterator , class EnvelopeDiagram >
void CGAL::lower_envelope_x_monotone_2 ( InputIterator  begin,
InputIterator  end,
EnvelopeDiagram &  diag 
)

#include <CGAL/envelope_2.h>

Computes the lower envelope of a set of \( x\)-monotone curves in \( \mathbb{R}^2\), as given by the range [begin, end).

The lower envelope is represented using the output minimization diagram diag.

Template Parameters
InputIteratormust be an input iterator with value type EnvelopeDiagram::X_monotone_curve_2.
EnvelopeDiagrammust be a model of the concept EnvelopeDiagram_1.
Examples:
Envelope_2/convex_hull_2.cpp, and Envelope_2/envelope_segments.cpp.

◆ upper_envelope_2()

template<class InputIterator , class EnvelopeDiagram >
void CGAL::upper_envelope_2 ( InputIterator  begin,
InputIterator  end,
EnvelopeDiagram &  diag 
)

#include <CGAL/envelope_2.h>

Computes the upper envelope of a set of curves in \( \mathbb{R}^2\), as given by the range [begin, end).

The upper envelope is represented using the output maximization diagram diag.

Template Parameters
InputIteratormust be an input iterator with value type EnvelopeDiagram::Traits_2::Curve_2.
EnvelopeDiagrammust be a model of the concept EnvelopeDiagram_1.
Examples:
Envelope_2/envelope_circles.cpp.

◆ upper_envelope_x_monotone_2()

template<class InputIterator , class EnvelopeDiagram >
void CGAL::upper_envelope_x_monotone_2 ( InputIterator  begin,
InputIterator  end,
EnvelopeDiagram &  diag 
)

#include <CGAL/envelope_2.h>

Computes the upper envelope of a set of \( x\)-monotone curves in \( \mathbb{R}^2\), as given by the range [begin, end).

The upper envelope is represented using the output maximization diagram diag.

Template Parameters
InputIteratormust be an input iterator with value type EnvelopeDiagram::X_monotone_curve_2.
EnvelopeDiagrammust be a model of the concept EnvelopeDiagram_1.
Examples:
Envelope_2/convex_hull_2.cpp.