// -*- c-basic-offset: 4 -*-
/** @file CalculateFOV.cpp
 *
 *  @author Pablo d'Angelo <pablo.dangelo@web.de>
 *
 *  $Id: Panorama.h 1947 2007-04-15 20:46:00Z dangelo $
 *
 * !! from Panorama.h 1947 
 *
 *  This 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 2 of the License, or (at your option) any later version.
 *
 *  This software 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public
 *  License along with this software. If not, see
 *  <http://www.gnu.org/licenses/>.
 *
 */

#include "CalculateFOV.h"

#include <algorithm>
#include <vigra/copyimage.hxx>
#include <nona/RemappedPanoImage.h>

namespace HuginBase {

hugin_utils::FDiff2D CalculateFOV::calcFOV(const PanoramaData& panorama)
{
    if (panorama.getNrOfImages() == 0) {
        // no change
        return hugin_utils::FDiff2D(panorama.getOptions().getHFOV(), panorama.getOptions().getVFOV());
    }

    vigra::Size2D panoSize(360*2,180*2);

    // remap into minature pano.
    PanoramaOptions opts;
    opts.setHFOV(360);
    opts.setProjection(PanoramaOptions::EQUIRECTANGULAR);
    opts.setWidth(panoSize.x);
    opts.setHeight(panoSize.y);

    // remap image
    // DGSW - make sure the type is correct
    vigra::BImage panoAlpha(panoSize.x, panoSize.y,static_cast< unsigned char >(0));
    //    vigra::BImage panoAlpha(panoSize.x, panoSize.y,0);
    Nona::RemappedPanoImage<vigra::BImage, vigra::BImage> remapped;
    UIntSet activeImgs = panorama.getActiveImages();
    for (UIntSet::iterator it = activeImgs.begin(); it != activeImgs.end(); ++it) {
        //    for (unsigned int imgNr=0; imgNr < getNrOfImages(); imgNr++) {
        // DGSW FIXME - Unreferenced
        //	        const PanoImage & img = getImage(*it);
        remapped.setPanoImage(panorama.getSrcImage(*it), opts, vigra::Rect2D(0,0,panoSize.x,panoSize.y));
        //remapped.setPanoImage(*this, *it, vigra::Size2D(img.getWidth(), img.getHeight()), opts);
        // calculate alpha channel
        remapped.calcAlpha();
        // copy into global alpha channel.
        vigra::copyImageIf(vigra_ext::applyRect(remapped.boundingBox(),
                                                vigra_ext::srcMaskRange(remapped)),
                            vigra_ext::applyRect(remapped.boundingBox(),
                                                vigra_ext::srcMask(remapped)),
                            vigra_ext::applyRect(remapped.boundingBox(),
                                                destImage(panoAlpha)));
        }

    // get field of view
    hugin_utils::FDiff2D ul, lr;
    bool found = false;
    ul.x = DBL_MAX;
    ul.y = DBL_MAX;
    lr.x = -DBL_MAX;
    lr.y = -DBL_MAX;
    for (int v=0; v< panoSize.y; v++) {
        for (int h=0; h < panoSize.x; h++) {
            if (panoAlpha(h,v)) {
                // pixel is valid
                if ( ul.x > h ) {
                    found=true;
                    ul.x = h;
                }
                if ( ul.y > v ) {
                    found=true;
                    ul.y = v;
                }
                if ( lr.x < h) {
                    found=true;
                    lr.x = h;
                }
                if ( lr.y < v) {
                    found=true;
                    lr.y = v;
                }
            }
        }
    }
    if (!found) {
        // if nothing found, return current fov
        return hugin_utils::FDiff2D(panorama.getOptions().getHFOV(), panorama.getOptions().getVFOV());
    }
    ul = ul / 2.0 - hugin_utils::FDiff2D(0.5, 0.5) - hugin_utils::FDiff2D(180, 90);
    lr = lr / 2.0 + hugin_utils::FDiff2D(0.5, 0.5) - hugin_utils::FDiff2D(180, 90);
    hugin_utils::FDiff2D fov(2 * std::max(fabs(ul.x), fabs(lr.x)), 2 * std::max(fabs(ul.y), fabs(lr.y)));
    // the calculation above is done with a resolution of 1 deg
    // for small fov the calculated fov can be a little bit too small
    // so in this case add a small offset
    if(fov.x<40)
    {
        fov.x+=1;
    };
    if (fov.y < 40)
    {
        fov.y += 1;
    };
    return fov;
}

}
