ImageUtils.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/>.
 */
 
/*
 * Image utility functions
 */
#ifndef LSST_AFW_IMAGE_IMAGEUTILS_H
#define LSST_AFW_IMAGE_IMAGEUTILS_H
 
#include <cmath>
 
namespace lsst {
namespace afw {
namespace image {
enum xOrY { X, Y };

const double PixelZeroPos = 0.0;

inline double indexToPosition(double ind  
) {
    return ind + PixelZeroPos;
}

inline int positionToIndex(double pos  
) {
    return static_cast<int>(std::floor(pos + 0.5 - PixelZeroPos));
}

inline int positionToIndex(double &residual,  
                           double pos         
) {
    double fullIndex = pos - PixelZeroPos;
    double roundedIndex = std::floor(fullIndex + 0.5);
    residual = fullIndex - roundedIndex;
    return static_cast<int>(roundedIndex);
}

inline std::pair<int, double> positionToIndex(double const pos,  
                                              bool               
) {
    double residual;                                 // fractional part of index
    int const ind = positionToIndex(residual, pos);  // integral part
 
    return std::pair<int, double>(ind, residual);
}
}  // namespace image
}  // namespace afw
}  // namespace lsst
 
#endif  // LSST_AFW_IMAGE_IMAGEUTILS_H