view layer/ImageRegionFinder.cpp @ 590:241929c5d57c sonification

Check the scale width in the View (which has access to it); ask the layer to do something when the user clicks in the scale regardless of the edit mode, and continue with normal processing if the layer has nothing interesting to do

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2007 QMUL.
    
    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 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#include "ImageRegionFinder.h"

#include <QImage>
#include <cmath>
#include <stack>
#include <iostream>

ImageRegionFinder::ImageRegionFinder()
{
}

ImageRegionFinder::~ImageRegionFinder()
{
}

QRect
ImageRegionFinder::findRegionExtents(QImage *image, QPoint origin) const
{
    int w = image->width(), h = image->height();

    QImage visited(w, h, QImage::Format_Mono);
    visited.fill(0);

    std::stack<QPoint> s;
    s.push(origin);

    int xmin = origin.x();
    int xmax = xmin;
    int ymin = origin.y();
    int ymax = ymin;

    QRgb opix = image->pixel(origin);

    while (!s.empty()) {

        QPoint p = s.top();
        s.pop();

        visited.setPixel(p, 1);

        int x = p.x(), y = p.y();

        if (x < xmin) xmin = x;
        if (x > xmax) xmax = x;

        if (y < ymin) ymin = y;
        if (y > ymax) ymax = y;

        std::stack<QPoint> neighbours;

        int similarNeighbourCount = 0;

        for (int dx = -1; dx <= 1; ++dx) {
            for (int dy = -1; dy <= 1; ++dy) {

                if ((dx != 0 && dy != 0) ||
                    (dx == 0 && dy == 0)) 
                    continue;

                if (x + dx < 0 || x + dx >= w ||
                    y + dy < 0 || y + dy >= h)
                    continue;

                if (visited.pixelIndex(x + dx, y + dy) != 0)
                    continue;

                if (!similar(opix, image->pixel(x + dx, y + dy))) 
                    continue;

                neighbours.push(QPoint(x + dx, y + dy));
                ++similarNeighbourCount;
            }
        }

        if (similarNeighbourCount >= 2) {
            while (!neighbours.empty()) {
                s.push(neighbours.top());
                neighbours.pop();
            }
        }
    }

    return QRect(xmin, ymin, xmax - xmin, ymax - ymin);
}

bool
ImageRegionFinder::similar(QRgb a, QRgb b) const
{
    if (b == qRgb(0, 0, 0) || b == qRgb(255, 255, 255)) {
        // black and white are boundary cases, don't compare similar
        // to anything -- not even themselves
        return false;
    }

    float ar = float(qRed(a) / 255.f);
    float ag = float(qGreen(a) / 255.f);
    float ab = float(qBlue(a) / 255.f);
    float amag = sqrtf(ar * ar + ag * ag + ab * ab);
    float thresh = amag / 2;

    float dr = float(qRed(a) - qRed(b)) / 255.f;
    float dg = float(qGreen(a) - qGreen(b)) / 255.f;
    float db = float(qBlue(a) - qBlue(b)) / 255.f;
    float dist = sqrtf(dr * dr + dg * dg + db * db);

//    std::cerr << "thresh=" << thresh << ", dist=" << dist << std::endl;

    return (dist < thresh);
}