2 files changed, 57 insertions, 16 deletions

diff --git a/qt-models/divepicturemodel.cpp b/qt-models/divepicturemodel.cpp
index ff4e187ae..47e64492b 100644
--- a/qt-models/divepicturemodel.cpp
+++ b/qt-models/divepicturemodel.cpp
@@ -9,25 +9,28 @@
 
 extern QHash <QString, QImage> thumbnailCache;
 static QMutex thumbnailMutex;
+static const int maxZoom = 3;	// Maximum zoom: thrice of standard size
 
-static void scaleImages(PictureEntry &entry)
+static QImage getThumbnailFromCache(const PictureEntry &entry)
 {
 	QMutexLocker l(&thumbnailMutex);
-	if (thumbnailCache.contains(entry.filename) && !thumbnailCache.value(entry.filename).isNull()) {
-		entry.image = thumbnailCache.value(entry.filename);
-		return;
-	}
-	l.unlock();
+	return thumbnailCache.value(entry.filename);
+}
 
-	int dim = defaultIconMetrics().sz_pic;
-	QImage p = SHashedImage(entry.picture);
-	if(!p.isNull()) {
-		p = p.scaled(dim, dim, Qt::KeepAspectRatio);
+static void scaleImages(PictureEntry &entry, int size, int maxSize)
+{
+	QImage thumbnail = getThumbnailFromCache(entry);
+	// If thumbnails were written by an earlier version, they might be smaller than needed.
+	// Rescale in such a case to avoid resizing artifacts.
+	if (thumbnail.isNull() || (thumbnail.size().width() < maxSize && thumbnail.size().height() < maxSize)) {
+		thumbnail = SHashedImage(entry.picture).scaled(maxSize, maxSize, Qt::KeepAspectRatio);
 		QMutexLocker l(&thumbnailMutex);
-		if (!thumbnailCache.contains(entry.filename))
-			thumbnailCache.insert(entry.filename, p);
+		thumbnailCache.insert(entry.filename, thumbnail);
 	}
-	entry.image = p;
+
+	entry.imageProfile = thumbnail.scaled(maxSize / maxZoom, maxSize / maxZoom, Qt::KeepAspectRatio);
+	entry.image = size == maxSize ? thumbnail
+				      : thumbnail.scaled(size, size, Qt::KeepAspectRatio);
 }
 
 DivePictureModel *DivePictureModel::instance()
@@ -36,7 +39,9 @@ DivePictureModel *DivePictureModel::instance()
 	return self;
 }
 
-DivePictureModel::DivePictureModel() : rowDDStart(0), rowDDEnd(0)
+DivePictureModel::DivePictureModel() : rowDDStart(0),
+				       rowDDEnd(0),
+				       zoomLevel(0.0)
 {
 }
 
@@ -48,6 +53,33 @@ void DivePictureModel::updateDivePicturesWhenDone(QList<QFuture<void>> futures)
 	updateDivePictures();
 }
 
+void DivePictureModel::setZoomLevel(int level)
+{
+	zoomLevel = level / 10.0;
+	// zoomLevel is bound by [-1.0 1.0], see comment below.
+	if (zoomLevel < -1.0)
+		zoomLevel = -1.0;
+	if (zoomLevel > 1.0)
+		zoomLevel = 1.0;
+	updateThumbnails();
+	layoutChanged();
+}
+
+void DivePictureModel::updateThumbnails()
+{
+	// Calculate size of thumbnails. The standard size is defaultIconMetrics().sz_pic.
+	// We use exponential scaling so that the central point is the standard
+	// size and the minimum and maximum extreme points are a third respectively
+	// three times the standard size.
+	// Naturally, these three zoom levels are then represented by
+	// -1.0 (minimum), 0 (standard) and 1.0 (maximum). The actual size is
+	// calculated as standard_size*3.0^zoomLevel.
+	int defaultSize = defaultIconMetrics().sz_pic;
+	int maxSize = defaultSize * maxZoom;
+	int size = static_cast<int>(round(defaultSize * pow(maxZoom, zoomLevel)));
+	QtConcurrent::blockingMap(pictures, [size, maxSize](PictureEntry &entry){scaleImages(entry, size, maxSize);});
+}
+
 void DivePictureModel::updateDivePictures()
 {
 	if (!pictures.isEmpty()) {
@@ -68,12 +100,13 @@ void DivePictureModel::updateDivePictures()
 			if (dive->id == displayed_dive.id)
 				rowDDStart = pictures.count();
 			FOR_EACH_PICTURE(dive)
-				pictures.push_back({picture, picture->filename, QImage(), picture->offset.seconds});
+				pictures.push_back({picture, picture->filename, {}, {}, picture->offset.seconds});
 			if (dive->id == displayed_dive.id)
 				rowDDEnd = pictures.count();
 		}
 	}
-	QtConcurrent::blockingMap(pictures, scaleImages);
+
+	updateThumbnails();
 
 	beginInsertRows(QModelIndex(), 0, pictures.count() - 1);
 	endInsertRows();
@@ -100,6 +133,9 @@ QVariant DivePictureModel::data(const QModelIndex &index, int role) const
 		case Qt::DecorationRole:
 			ret = entry.image;
 			break;
+		case Qt::UserRole:	// Used by profile widget to access bigger thumbnails
+			ret = entry.imageProfile;
+			break;
 		case Qt::DisplayRole:
 			ret = QFileInfo(entry.filename).fileName();
 			break;
diff --git a/qt-models/divepicturemodel.h b/qt-models/divepicturemodel.h
index 53a72076a..74f92f449 100644
--- a/qt-models/divepicturemodel.h
+++ b/qt-models/divepicturemodel.h
@@ -10,6 +10,7 @@ struct PictureEntry {
 	struct picture *picture;
 	QString filename;
 	QImage image;
+	QImage imageProfile;	// For the profile widget keep a copy of a constant sized image
 	int offsetSeconds;
 };
 
@@ -24,9 +25,13 @@ public:
 	void updateDivePicturesWhenDone(QList<QFuture<void>>);
 	void removePicture(const QString& fileUrl, bool last);
 	int rowDDStart, rowDDEnd;
+public slots:
+	void setZoomLevel(int level);
 private:
 	DivePictureModel();
 	QList<PictureEntry> pictures;
+	double zoomLevel;	// -1.0: minimum, 0.0: standard, 1.0: maximum
+	void updateThumbnails();
 };
 
 #endif