source: trunk/examples/webkit/imageanalyzer/imageanalyzer.cpp@ 933

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#include <QNetworkReply>
#include <QNetworkRequest>
#include <QNetworkAccessManager>
#include <QNetworkDiskCache>
#include "imageanalyzer.h"

/*!
 * This class operates as follows:
 * Parent calls the slot startAnalysis which shoves a list of QStrings into URLQueue and then calls fetchURLs.
 * FetchURLs sends out HTTP GETs for each image it can't get out of the cache.
 * As the responses come in, handleReply tries to create an image out of each and pushes those images into imageQueue.
 * On the last (detected by no outstandingFetches and URLQueue.isEmpty()) call to queueImage (from handleReply)
 * a thread is forked to process all the images. When it finishes, it emits a finished signal that is received
 * by our JavaScript code.
 */

//! [ ImageAnalyzer - Constructor ]
ImageAnalyzer::ImageAnalyzer(QNetworkDiskCache* netcache, QObject* parent)
    : QObject(parent), m_cache(netcache), m_outstandingFetches(0)
{
    /*  ImageAnalyzer only wants to receive http responses
        for requests that it makes, so that's why it has its own
        QNetworkAccessManager. */
    m_network = new QNetworkAccessManager(this);
    m_watcher = new QFutureWatcher<QRgb>(this);
    /*  We want to share a cache with the web browser,
        in case it has some images we want: */
    m_network->setCache(m_cache);

    QObject::connect(m_network, SIGNAL(finished(QNetworkReply*)),
                     this, SLOT(handleReply(QNetworkReply*)));
    QObject::connect(m_watcher, SIGNAL(finished()),
                     this, SLOT(doneProcessing()));
    QObject::connect(m_watcher, SIGNAL(progressValueChanged(int)),
                     this, SLOT(progressStatus(int)));
}
//! [ ImageAnalyzer - Constructor ]
ImageAnalyzer::~ImageAnalyzer()
{
    delete(m_watcher);
}


QRgb ImageAnalyzer::lastResults()
{
    int rTot = 0;
    int bTot = 0;
    int gTot = 0;
    int count = m_watcher->future().results().size();
    foreach(const QRgb & triplet, m_watcher->future().results())
    {
        rTot += qRed(triplet);
        bTot += qBlue(triplet);
        gTot += qGreen(triplet);
    }
    return qRgb(rTot/count, bTot/count, gTot/count);
}

float ImageAnalyzer::lastRed() { return qRed(lastResults())/2.55; }
float ImageAnalyzer::lastGreen() { return qGreen(lastResults())/2.55; }
float ImageAnalyzer::lastBlue() { return qBlue(lastResults())/2.55; }

void ImageAnalyzer::progressStatus(int newstat)
{
    emit updateProgress(newstat, m_watcher->progressMaximum());
}


bool ImageAnalyzer::isBusy()
{
    return m_watcher->isRunning();
}


//! [ ImageAnalyzer - startAnalysis ]
void ImageAnalyzer::startAnalysis(const QStringList & urls)
{
    m_URLQueue = urls;
    fetchURLs();
}
//! [ ImageAnalyzer - startAnalysis ]

/*!
 * Analyzes the entire queue - just starts all our http GETs.
 */
//! [ ImageAnalyzer - fetchURLs ]
void ImageAnalyzer::fetchURLs()
{
    while (!m_URLQueue.isEmpty())
    {
        QString url = m_URLQueue.takeFirst();
        QUrl URL = QUrl(url);
        QIODevice * pData = m_cache->data(URL);
        // Is image already loaded in cache?
        if (pData == 0) {
            // HTTP Get image over network.
            m_outstandingFetches++;
            QNetworkRequest request = QNetworkRequest(URL);
            request.setRawHeader("User-Agent", "Nokia - Custom QT app");
            m_network->get(request);
        } else {
            // Get image from cache
            QImage image;