Dive pictures: give user option to recalculate thumbnails

Even though hashes of image contents are calculated, the hashes are
not compared to actual file contents in routine-operation. Therefore
give the user the option to recalculate thumbnails, should they have
edited the picture.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/imagedownloader.cpp

@@ -184,6 +184,23 @@ static void addThumbnailToCache(const QImage &thumbnail, const QString &picture_
 	file.commit();
 }
 
+void Thumbnailer::recalculate(QString filename)
+{
+	auto res = getHashedImage(filename, true);
+
+	// If we couldn't load the image from disk -> leave old thumbnail.
+	// The case "load from web" is a bit inconsistent: it will call into processItem() later
+	// and therefore a "broken" image symbol may be shown.
+	if (res.second || res.first.isNull())
+		return;
+	QImage thumbnail = res.first;
+	addThumbnailToCache(thumbnail, filename);
+
+	QMutexLocker l(&lock);
+	emit thumbnailChanged(filename, thumbnail);
+	workingOn.remove(filename);
+}
+
 void Thumbnailer::processItem(QString filename, bool tryDownload)
 {
 	QImage thumbnail = getThumbnailFromCache(filename);
@@ -236,6 +253,17 @@ QImage Thumbnailer::fetchThumbnail(PictureEntry &entry)
 	return dummyImage;
 }
 
+void Thumbnailer::calculateThumbnails(const QVector<QString> &filenames)
+{
+	QMutexLocker l(&lock);
+	for (const QString &filename: filenames) {
+		if (!workingOn.contains(filename)) {
+			workingOn.insert(filename,
+					 QtConcurrent::run(&pool, [this, filename]() { recalculate(filename); }));
+		}
+	}
+}
+
 void Thumbnailer::clearWorkQueue()
 {
 	QMutexLocker l(&lock);

core/imagedownloader.h

@@ -34,6 +34,9 @@ public:
 	// via a signal later.
 	QImage fetchThumbnail(PictureEntry &entry);
 
+	// Schedule multiple thumbnails for forced recalculation
+	void calculateThumbnails(const QVector<QString> &filenames);
+
 	// If we change dive, clear all unfinished thumbnail creations
 	void clearWorkQueue();
 	static int maxThumbnailSize();
@@ -46,6 +49,7 @@ signals:
 	void thumbnailChanged(QString filename, QImage thumbnail);
 private:
 	Thumbnailer();
+	void recalculate(QString filename);
 	void processItem(QString filename, bool tryDownload);
 
 	mutable QMutex lock;

desktop-widgets/tab-widgets/TabDivePhotos.cpp

@@ -54,27 +54,38 @@ void TabDivePhotos::contextMenuEvent(QContextMenuEvent *event)
 	popup.addSeparator();
 	popup.addAction(tr("Delete selected images"), this, SLOT(removeSelectedPhotos()));
 	popup.addAction(tr("Delete all images"), this, SLOT(removeAllPhotos()));
+	popup.addAction(tr("Recalculate selected thumbnails"), this, SLOT(recalculateSelectedThumbnails()));
 	popup.exec(event->globalPos());
 	event->accept();
 }
 
-void TabDivePhotos::removeSelectedPhotos()
+QVector<QString> TabDivePhotos::getSelectedFilenames() const
 {
+	QVector<QString> selectedPhotos;
 	if (!ui->photosView->selectionModel()->hasSelection())
-		return;
+		return selectedPhotos;
-	QModelIndexList indexes =  ui->photosView->selectionModel()->selectedRows();
+	QModelIndexList indexes = ui->photosView->selectionModel()->selectedRows();
 	if (indexes.count() == 0)
 		indexes = ui->photosView->selectionModel()->selectedIndexes();
-	QVector<QString> photosToDelete;
+	selectedPhotos.reserve(indexes.count());
-	photosToDelete.reserve(indexes.count());
 	for (const auto &photo: indexes) {
 		if (photo.isValid()) {
 			QString fileUrl = photo.data(Qt::DisplayPropertyRole).toString();
 			if (!fileUrl.isEmpty())
-				photosToDelete.push_back(fileUrl);
+				selectedPhotos.push_back(fileUrl);
 		}
 	}
-	DivePictureModel::instance()->removePictures(photosToDelete);
+	return selectedPhotos;
+}
+
+void TabDivePhotos::removeSelectedPhotos()
+{
+	DivePictureModel::instance()->removePictures(getSelectedFilenames());
+}
+
+void TabDivePhotos::recalculateSelectedThumbnails()
+{
+	Thumbnailer::instance()->calculateThumbnails(getSelectedFilenames());
 }
 
 //TODO: This looks overly wrong. We shouldn't call MainWindow to retrieve the DiveList to add Images.

desktop-widgets/tab-widgets/TabDivePhotos.h

@@ -26,11 +26,13 @@ private slots:
 	void addPhotosFromURL();
 	void removeAllPhotos();
 	void removeSelectedPhotos();
+	void recalculateSelectedThumbnails();
 	void changeZoomLevel(int delta);
 
 private:
 	Ui::TabDivePhotos *ui;
 	DivePictureModel *divePictureModel;
+	QVector<QString> getSelectedFilenames() const;
 };
 
 #endif