Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

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box_view

Makes a box behave like a ring or a range.

Description

Adapts a box to the Boost.Range concept, enabling the user to iterating box corners. The box_view is registered as a Ring Concept

Model of

Ring Concept

Synopsis

template<typename Box, bool Clockwise>
struct box_view
{
  // ...
};

Template parameter(s)

Parameter

Default

Description

typename Box

A type fulfilling the Box Concept

bool Clockwise

true

If true, walks in clockwise direction, otherwise it walks in counterclockwise direction

Constructor(s)

Function

Description

Parameters

box_view(Box const & box)

Constructor accepting the box to adapt.

Box const &: box:

Header

Either

#include <boost/geometry/geometry.hpp>

Or

#include <boost/geometry/views/box_view.hpp>

Complexity

Compile time

Example

Shows usage of the Boost.Range compatible view on a box

#include <iostream>

#include <boost/geometry.hpp>


int main()
{
    typedef boost::geometry::model::box
        <
            boost::geometry::model::point<double, 2, boost::geometry::cs::cartesian>
        > box_type;
        
    // Define the Boost.Range compatible type:
    typedef boost::geometry::box_view<box_type> box_view;        
        
    box_type box;
    boost::geometry::assign_values(box, 0, 0, 4, 4);
    
    box_view view(box);
    
    // Iterating in clockwise direction over the points of this box
    for (boost::range_iterator<box_view const>::type it = boost::begin(view);
        it != boost::end(view); ++it)
    {
        std::cout << " " << boost::geometry::dsv(*it);
    }
    std::cout << std::endl;
    
    // Note that a box_view is tagged as a ring, so supports area etc.
    std::cout << "Area: " << boost::geometry::area(view) << std::endl;
    
    return 0;
}

Output:

(0, 0) (0, 4) (4, 4) (4, 0) (0, 0)
Area: 16

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