Qt Mobility Reference Documentation

thumbnailmodel.cpp Example File

mediabrowser/thumbnailmodel.cpp
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 #include "thumbnailmodel.h"

 #include <QtCore/qcryptographichash.h>
 #include <QtCore/qdir.h>
 #include <QtCore/qtconcurrentrun.h>
 #include <QtCore/qurl.h>
 #include <QtGui/qimagereader.h>

 #if defined(Q_WS_MAEMO_5)
 const QSize ThumbnailModel::thumbnailSize(124, 124);
 #else
 const QSize ThumbnailModel::thumbnailSize(128, 128);
 #endif

 ThumbnailModel::ThumbnailModel(QAbstractGallery *gallery, QObject *parent)
     : QGalleryQueryModel(gallery, parent)
 {
 }

 ThumbnailModel::~ThumbnailModel()
 {
 }

 #ifndef QT_NO_QFUTURE

 QVariant ThumbnailModel::data(const QModelIndex &index, int role) const
 {
     if (role == Qt::DecorationRole && index.isValid()) {
         QString id = itemId(index).toString();

         QFutureWatcher<QImage> *future = cache.object(id);

         if (!future) {
             future = new QFutureWatcher<QImage>;

             QString path = imagePath(index);

             if (!path.isEmpty()) {
                 future->setFuture(QtConcurrent::run(ThumbnailModel::load, path));

                 connect(future, SIGNAL(finished()), this, SLOT(thumbnailLoaded()));
             }

             cache.insert(id, future);
         }

         return !future->isCanceled()
                 ? future->result()
                 : QVariant();
     } else {
         return QGalleryQueryModel::data(index, role);
     }
 }

 QString ThumbnailModel::imagePath(const QModelIndex &index) const
 {
     QUrl url = itemUrl(index);

     return url.isValid() ? thumbnailPath(url) : QString();
 }

 QString ThumbnailModel::thumbnailPath(const QUrl &url) const
 {
 #if defined(Q_OS_UNIX) && !(defined(Q_OS_SYMBIAN) || defined(Q_OS_MAC))
 #if defined(Q_WS_MAEMO_5)
     QString thumbnailPath = QDir::homePath()
             + QLatin1String("/.thumbnails/cropped/")
             + QCryptographicHash::hash(url.toString().toUtf8(), QCryptographicHash::Md5).toHex()
             + QLatin1String(".jpeg");
 #else
     QString thumbnailPath = QDir::homePath()
             + QLatin1String("/.thumbnails/normal/")
             + QCryptographicHash::hash(url.toEncoded(), QCryptographicHash::Md5).toHex()
             + QLatin1String(".png");
 #endif
     if (QFile::exists(thumbnailPath))
         return thumbnailPath;
 #endif

     return url.path();
 }

 void ThumbnailModel::thumbnailLoaded()
 {
     emit dataChanged(index(0, 0), index(rowCount() - 1, columnCount() -1));
 }

 QImage ThumbnailModel::load(const QString &fileName)
 {
     QImageReader reader(fileName);
     reader.setQuality(25);

     if (reader.supportsOption(QImageIOHandler::Size)) {
         QSize size = reader.size();

         if (!reader.supportsOption(QImageIOHandler::ScaledSize)
                 && (size.width() > 1280 || size.height() > 1280)) {
             return QImage();
         }

         if (size.width() > thumbnailSize.width() || size.height() > thumbnailSize.height())
             size.scale(thumbnailSize, Qt::KeepAspectRatio);

         reader.setScaledSize(size);
     } else {
         reader.setScaledSize(thumbnailSize);
     }

     return reader.read();
 }

 #endif
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