// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

#include "block.h"
#include "renderthread.h"

#include <QRandomGenerator>
#include <QRgb>

RenderThread::RenderThread(QObject *parent)
    : QThread(parent)
{
}

RenderThread::~RenderThread()
{
    wait();
}

//![processing the image (start)]
void RenderThread::processImage(const QImage &image)
{
    if (image.isNull())
        return;

    m_image = image;
    start();
}

void RenderThread::run()
{
    const int size = qMax(m_image.width()/20, m_image.height()/20);
    for (int s = size; s > 0; --s) {
        for (int c = 0; c < 400; ++c) {
//![processing the image (start)]
            const int x1 = qMax(0, QRandomGenerator::global()->bounded(m_image.width()) - s/2);
            const int x2 = qMin(x1 + s/2 + 1, m_image.width());
            const int y1 = qMax(0, QRandomGenerator::global()->bounded(m_image.height()) - s/2);
            const int y2 = qMin(y1 + s/2 + 1, m_image.height());
            int n = 0;
            int red = 0;
            int green = 0;
            int blue = 0;
            for (int i = y1; i < y2; ++i) {
                for (int j = x1; j < x2; ++j) {
                    const QRgb pixel = m_image.pixel(j, i);
                    red += qRed(pixel);
                    green += qGreen(pixel);
                    blue += qBlue(pixel);
                    n += 1;
                }
            }
//![processing the image (finish)]
            const Block block(QRect(x1, y1, x2 - x1 + 1, y2 - y1 + 1),
                        QColor(red/n, green/n, blue/n));
            emit sendBlock(block);
            if (isInterruptionRequested())
                return;
            msleep(10);
        }
    }
}
//![processing the image (finish)]