SpanPixelIterator.h

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// -*- lsst-c++ -*-

/* 
 * LSST Data Management System
 * Copyright 2008, 2009, 2010 LSST Corporation.
 * 
 * This product includes software developed by the
 * LSST Project (http://www.lsst.org/).
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the LSST License Statement and 
 * the GNU General Public License along with this program.  If not, 
 * see <http://www.lsstcorp.org/LegalNotices/>.
 */

#ifndef LSST_AFW_GEOM_SpanPixelIterator_h_INCLUDED
#define LSST_AFW_GEOM_SpanPixelIterator_h_INCLUDED

#include "boost/iterator/iterator_facade.hpp"

#include "lsst/afw/geom/Point.h"

namespace lsst { namespace afw { namespace geom {

class SpanPixelIterator :
        public boost::iterator_facade<SpanPixelIterator,Point2I const,boost::random_access_traversal_tag>
{
public:

    explicit SpanPixelIterator(Point2I const & p = Point2I()) : _p(p) {}

private:

    friend class boost::iterator_core_access;

    Point2I const & dereference() const { return _p; }

    void increment() { ++_p.getX(); }

    void decrement() { --_p.getX(); }

    void advance(int n) { _p.getX() += n; }

    bool equal(SpanPixelIterator const & other) const {
        return _p.getX() == other._p.getX() && _p.getY() == other._p.getY();
    }

    int distance_to(SpanPixelIterator const & other) const {
        assert(other._p.getY() == _p.getY());
        return other._p.getX() - _p.getX();
    }

    Point2I _p;
};

}}} // namespace lsst::afw::geom

#endif // !LSST_AFW_GEOM_SpanPixelIterator_h_INCLUDED