From f1d67cfbacd1e879725e5ebeb2774439246764a4 Mon Sep 17 00:00:00 2001
From: Tomaz Canabrava <tomaz.canabrava@intel.com>
Date: Sat, 31 May 2014 00:42:54 -0300
Subject: [PATCH] Add threaded processing of image pixmaps

This code adds threaded processing of a batch of images. It uses the
QtConcurrent implementations to call a function repeteadly using
MAX_THREADS (Qt gets that for us) and returns a list of it.

This call is blocking, so while the pixmaps are being scaled in threads,
it will wait for all scalling to be done.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
---
 qt-ui/divepicturewidget.cpp | 28 ++++++++++++++++++++++++++--
 qt-ui/divepicturewidget.h   |  4 ++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/qt-ui/divepicturewidget.cpp b/qt-ui/divepicturewidget.cpp
index 11849af5f..eda4ff68c 100644
--- a/qt-ui/divepicturewidget.cpp
+++ b/qt-ui/divepicturewidget.cpp
@@ -1,5 +1,6 @@
 #include "divepicturewidget.h"
 #include <dive.h>
+#include <qtconcurrentmap.h>
 
 void DivePictureDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
 {
@@ -11,29 +12,52 @@ DivePictureModel::DivePictureModel(QObject *parent): QAbstractTableModel(parent)
 
 }
 
+typedef QPair<QString, QPixmap> SPixmap;
+typedef QList<SPixmap> SPixmapList;
+
+SPixmap scaleImages(const QString& s){
+	QPixmap p = QPixmap(s).scaled(128,128, Qt::KeepAspectRatio);
+	SPixmap ret;
+	ret.first = s;
+	ret.second = p;
+	return ret;
+}
+
 void DivePictureModel::updateDivePictures(int divenr)
 {
+	qDebug() << "Updating dive pictures.";
 	beginRemoveRows(QModelIndex(), 0, numberOfPictures-1);
 	numberOfPictures = 0;
 	endRemoveRows();
 
+	QStringList pictures;
 	struct dive *d = get_dive(divenr);
-	if (!d)
+	if (!d){
+		qDebug() << "Got no dive, exiting.";
 		return;
+	}
 	// All pictures are set in *all* divecomputers. ( waste of memory if > 100 pictures? )
 	// so just get from the first one.
 	struct event *ev = d->dc.events;
 	while(ev){
 		if(ev->type == 123){ // 123 means PICTURE.
 			numberOfPictures++;
+			pictures.push_back(QString(ev->name));
 		}
 		ev = ev->next;
 	}
 
-	if (numberOfPictures == 0)
+	SPixmapList retList = QtConcurrent::blockingMapped<SPixmapList>( pictures, scaleImages);
+	Q_FOREACH(const SPixmap & pixmap, retList)
+		stringPixmapCache[pixmap.first] = pixmap.second;
+
+	if (numberOfPictures == 0){
+		qDebug() << "Got no pictures, exiting.";
 		return;
+	}
 	beginInsertRows(QModelIndex(), 0, numberOfPictures-1);
 	endInsertRows();
+	qDebug() << "Everything Ok.";
 }
 
 int DivePictureModel::columnCount(const QModelIndex &parent) const
diff --git a/qt-ui/divepicturewidget.h b/qt-ui/divepicturewidget.h
index 062e225d7..ff8d1aa8f 100644
--- a/qt-ui/divepicturewidget.h
+++ b/qt-ui/divepicturewidget.h
@@ -16,6 +16,10 @@ public:
 	void updateDivePictures(int divenr);
 private:
 	int numberOfPictures;
+	// Currently, load the images on the fly
+	// Later, use a thread to load the images
+	// Later, save the thumbnails so we don't need to reopen every time.
+	QHash<QString, QPixmap> stringPixmapCache;
 };
 
 class DivePictureDelegate : QStyledItemDelegate {