added real portable mode

io/path.cpp

@@ -0,0 +1,16 @@
+#include "path.h"
+
+#include <QStandardPaths>
+#include <QFileInfo>
+#include <QCoreApplication>
+
+QString get_data_path() {
+    QString app_path = QCoreApplication::applicationFilePath();
+    QString app_dir = app_path.left(app_path.lastIndexOf('/'));
+
+    if (QFileInfo::exists(app_dir + "/portable")) {
+        return app_dir;
+    } else {
+        return QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
+    }
+}

io/path.h

@@ -0,0 +1,8 @@
+#ifndef PATH_H
+#define PATH_H
+
+#include <QString>
+
+QString get_data_path();
+
+#endif // PATH_H

io/previewgenerator.cpp

@@ -4,7 +4,7 @@
 #include "panels/viewer.h"
 #include "panels/project.h"
 #include "io/config.h"
-#include "io/crc32.h"
+#include "io/path.h"
 #include "debug.h"
 
 #include <QPainter>
@@ -14,8 +14,8 @@
 #include <QSemaphore>
 #include <QCryptographicHash>
 #include <QFile>
-#include <QStandardPaths>
 #include <QDir>
+#include <QDateTime>
 
 #define WAVEFORM_RESOLUTION 64
 
@@ -38,7 +38,7 @@ PreviewGenerator::PreviewGenerator(QTreeWidgetItem* i, Media* m, bool r) :
 	replace(r),
 	cancelled(false)
 {
-	data_path = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation) + "/previews";
+    data_path = get_data_path() + "/previews";
 	QDir data_dir(data_path);
 	if (!data_dir.exists()) {
 		data_dir.mkpath(".");