Fix image offset calculation

It seems this has never worked and nobody ever tested it. There was some
confusion with time zones since Qt takes by default local time when
converting from/to epoch while the exif library used UTC.

For my single test dive, this works now. But this needs more testing!!!

Signed-off-by: Robert C. Helling <helling@atdotde.de>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 7 insertions, 4 deletions

diff --git a/qt-ui/simplewidgets.cpp b/qt-ui/simplewidgets.cpp
index 7e8bc40e4..baae7cced 100644
--- a/qt-ui/simplewidgets.cpp
+++ b/qt-ui/simplewidgets.cpp
@@ -300,16 +300,18 @@ void ShiftImageTimesDialog::syncCameraClicked()
 	ui.DCImage->setScene(scene);
 
 	dcImageEpoch = picture_get_timestamp(fileNames.at(0).toUtf8().data());
-	dcDateTime.setTime_t(dcImageEpoch);
+	dcDateTime.setTime_t(dcImageEpoch - gettimezoneoffset(displayed_dive.when));
 	ui.dcTime->setDateTime(dcDateTime);
 	connect(ui.dcTime, SIGNAL(dateTimeChanged(const QDateTime &)), this, SLOT(dcDateTimeChanged(const QDateTime &)));
 }
 
 void ShiftImageTimesDialog::dcDateTimeChanged(const QDateTime &newDateTime)
 {
+	QDateTime newtime(newDateTime);
 	if (!dcImageEpoch)
 		return;
-	setOffset(newDateTime.toTime_t() - dcImageEpoch);
+	newtime.setTimeSpec(Qt::UTC);
+	setOffset(newtime.toTime_t() + gettimezoneoffset(displayed_dive.when) - dcImageEpoch);
 }
 
 void ShiftImageTimesDialog::matchAllImagesToggled(bool state)
@@ -355,7 +357,8 @@ void ShiftImageTimesDialog::updateInvalid()
 	bool allValid = true;
 	ui.warningLabel->hide();
 	ui.invalidLabel->hide();
-	ui.invalidLabel->clear();
+	time.setTime_t(displayed_dive.when - gettimezoneoffset(displayed_dive.when));
+	ui.invalidLabel->setText("Dive:" + time.toString() + "\n");
 
 	Q_FOREACH (const QString &fileName, fileNames) {
 		if (picture_check_valid(fileName.toUtf8().data(), m_amount))
@@ -364,7 +367,7 @@ void ShiftImageTimesDialog::updateInvalid()
 		// We've found invalid image
 		timestamp = picture_get_timestamp(fileName.toUtf8().data());
 		dcImageEpoch = timestamp;
-		time.setTime_t(timestamp + m_amount);
+		time.setTime_t(timestamp + m_amount - gettimezoneoffset(displayed_dive.when));
 		ui.invalidLabel->setText(ui.invalidLabel->text() + fileName + " " + time.toString() + "\n");
 		allValid = false;
 	}