CenterHorizontally.cpp

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// -*- c-basic-offset: 4 -*-
#include "CenterHorizontally.h"

#include <vigra/copyimage.hxx>
#include <panodata/PanoramaData.h>
#include <nona/RemappedPanoImage.h>
#include <algorithms/basic/RotatePanorama.h>


namespace HuginBase {


void CenterHorizontally::centerHorizontically(PanoramaData& panorama)
{
    vigra::Size2D panoSize(360,180);
    
    // remap into minature pano.
    PanoramaOptions opts;
    opts.setHFOV(360);
    opts.setProjection(PanoramaOptions::EQUIRECTANGULAR);
    opts.setWidth(360);
    opts.setHeight(180);
    
    // remap image
    vigra::BImage panoAlpha(panoSize);
    Nona::RemappedPanoImage<vigra::BImage, vigra::BImage> remapped;
    
    // use selected images.
    const UIntSet allActiveImgs(panorama.getActiveImages());

    if (allActiveImgs.empty())
    {
        // do nothing if there are no images
        return;
    }
    
    //only check unlinked images
    UIntSet activeImgs;
    for (UIntSet::const_iterator it = allActiveImgs.begin(); it!= allActiveImgs.end(); ++it)
    {
        const SrcPanoImage & img=panorama.getImage(*it);
        bool consider=true;
        if(img.YawisLinked())
        {
            for(UIntSet::const_iterator it2=activeImgs.begin(); it2!=activeImgs.end(); ++it2)
            {
                if(img.YawisLinkedWith(panorama.getSrcImage(*it2)))
                {
                    consider=false;
                    break;
                };
            };
        };
        if(consider)
            activeImgs.insert(*it);
    };

    for (UIntSet::iterator it = activeImgs.begin(); it != activeImgs.end(); ++it)
    {
        remapped.setPanoImage(panorama.getSrcImage(*it), opts, vigra::Rect2D(0,0,360,180));
        // 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
    std::vector<int> borders;
    bool colOccupied = false;
    for (int h=0; h < 360; h++) {
        bool curColOccupied = false;
        for (int v=0; v< 180 && !curColOccupied; v++) {
            if (panoAlpha(h,v)) {
                // pixel is valid
                curColOccupied = true;
            }
        }
        if ((colOccupied && !curColOccupied) ||
            (!colOccupied && curColOccupied))
        {
            // change in position, save point.
            borders.push_back(h-180);
            colOccupied = curColOccupied;
        }
    }
    
    
    const int lastidx = borders.size() -1;
    if (lastidx == -1) {
        // empty pano
        return;
    }
    
    if (colOccupied) {
        // we have reached the right border, and the pano is still valid
        if (borders.size() == 1 && borders[0] == -180)
        {
            // pano covers full range, nothing to do
            return;
        };
        // shift right fragments by 360 deg
        // |11    2222|  -> |      222211     |
        std::vector<int> newBorders;
        newBorders.push_back(borders[lastidx]);
        for (int i = 0; i < lastidx; i++) {
            newBorders.push_back(borders[i]+360);
        }
        borders = newBorders;
    }
    
    const double dYaw=(borders[0] + borders[lastidx])/2;
    
    // apply yaw shift, takes also translation parameters into account
    RotatePanorama(panorama, -dYaw, 0, 0).run();
}

}