FootprintFunctor.h

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/* 
 * 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/>.
 */
 
#if !defined(LSST_DETECTION_FOOTPRINT_FUNCTOR_H)
#define LSST_DETECTION_FOOTPRINT_FUNCTOR_H

#include "lsst/afw/detection/Footprint.h"
#include "lsst/afw/image/MaskedImage.h"

namespace lsst {
namespace afw { 
namespace detection {
/************************************************************************************************************/
template <typename ImageT>
class FootprintFunctor {
public:
    FootprintFunctor(ImageT const& image    
                    ) : _image(image) {}

    virtual ~FootprintFunctor() = 0;

    virtual void reset() {}
    virtual void reset(Footprint const&) {}

    void apply(Footprint const& foot,   
               int const margin=0       
              ) {
        reset();
        reset(foot);

        if (foot.getSpans().empty()) {
            return;
        }

        geom::Box2I const bbox = foot.getBBox();
        geom::Box2I region = foot.getRegion();
        if (!region.isEmpty() &&
            (!region.contains(bbox.getMin()) || !region.contains(bbox.getMax()))) {
            throw LSST_EXCEPT(
                lsst::pex::exceptions::LengthError,
                (boost::format("Footprint with BBox (%d,%d) -- (%dx%d)"
                               "doesn't fit in image with BBox (%d,%d) -- (%dx%d)"
                               ) % bbox.getMinX() % bbox.getMinY() 
                               % bbox.getMaxX() % bbox.getMaxY() 
                               % region.getMinX() % region.getMinY() 
                               % region.getMaxX() % region.getMaxY()
                ).str()
            );
        }

        // Current position of the locator (in the SpanList loop)
        int ox1 = 0, oy = 0;            
        
        int const x0 = _image.getX0();
        int const y0 = _image.getY0();

        typename ImageT::xy_locator loc = _image.xy_at(-x0, -y0); // Origin of the Image's pixels

        int const width = _image.getWidth();
        int const height = _image.getHeight();
        for (Footprint::SpanList::const_iterator siter = foot.getSpans().begin();
             siter != foot.getSpans().end(); siter++) {
            Span::Ptr const span = *siter;

            int const y = span->getY();
            if (y - y0 < margin || y - y0 >= height - margin) {
                continue;
            }
            int sx0 = span->getX0();
            int sx1 = span->getX1();
            if (sx0 - x0 < margin) {
                sx0 = margin + x0;
            }
            if (sx1 - x0 >= width - margin) {
                sx1 = width + x0 - margin - 1;
            }

            loc += lsst::afw::image::pair2I(sx0 - ox1, y - oy);

            for (int x = sx0; x <= sx1; ++x, ++loc.x()) {
                operator()(loc, x, y);
            }

            ox1 = sx1 + 1; oy = y;
        }
    }
    ImageT const& getImage() const { return _image; }    

    virtual void operator()(typename ImageT::xy_locator loc, int x, int y) = 0;
private:
    ImageT const _image;               // The image that the Footprints live in
};

template <typename ImageT>
FootprintFunctor<ImageT>::~FootprintFunctor() {}
            
}}}
#endif