subsurface/core/imagedownloader.h
Berthold Stoeger d33e3b22fc Dive pictures: refactor image downloader
Instead of generating one ImageDownloader object per image to be
downloaded and running every image download in a separate worker
thread, use one global ImageDownloader object owned by the UI thread.

The images are downloaded using event based IO (as probably was the
intention of the QNetworkManager class).

User-visible change: after download from the internet, the thumbnail
is shown without having to change dives.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2018-05-13 13:52:35 -07:00

59 lines
1.5 KiB
C++

// SPDX-License-Identifier: GPL-2.0
#ifndef IMAGEDOWNLOADER_H
#define IMAGEDOWNLOADER_H
#include <QImage>
#include <QFuture>
#include <QNetworkReply>
#include <QThreadPool>
class ImageDownloader : public QObject {
Q_OBJECT
public:
static ImageDownloader *instance();
ImageDownloader();
public slots:
void load(QString filename, bool fromHash);
signals:
void loaded(QString filename);
void failed(QString filename);
private:
QNetworkAccessManager manager;
void loadFromUrl(const QString &filename, const QUrl &);
void saveImage(QNetworkReply *reply);
};
class PictureEntry;
class Thumbnailer : public QObject {
Q_OBJECT
public:
static Thumbnailer *instance();
// Schedule a thumbnail for fetching or calculation.
// Returns a placehlder thumbnail. The actual thumbnail will be sent
// via a signal later.
QImage fetchThumbnail(PictureEntry &entry);
// If we change dive, clear all unfinished thumbnail creations
void clearWorkQueue();
static int maxThumbnailSize();
static int defaultThumbnailSize();
static int thumbnailSize(double zoomLevel);
public slots:
void imageDownloaded(QString filename);
void imageDownloadFailed(QString filename);
signals:
void thumbnailChanged(QString filename, QImage thumbnail);
private:
Thumbnailer();
void processItem(QString filename);
mutable QMutex lock;
QThreadPool pool;
QImage failImage; // Shown when image-fetching fails
QImage dummyImage; // Shown before thumbnail is fetched
QMap<QString,QFuture<void>> workingOn;
};
#endif // IMAGEDOWNLOADER_H