diff --git a/src/ui/cvimageviewer.cpp b/src/ui/cvimageviewer.cpp
index 937d3fa..1abbdc5 100644
--- a/src/ui/cvimageviewer.cpp
+++ b/src/ui/cvimageviewer.cpp
@@ -84,10 +84,7 @@ cv::Rect CvImageViewer::roiFromSelection()
 	transfromToSourceCoordinates(selectionRect_.x()+selectionRect_.width(), selectionRect_.y()+selectionRect_.height(), xB, yB);
 	selectionRect_ = QRect(0, 0, 0, 0);
 	cv::Rect roi;
-	if(xA > xB)
-		roi = cv::Rect(xB, yB, xA-xB, yA-yB);
-	else
-		roi = cv::Rect(xA, yA, xB-xA, yB-yA);
+	roi = cv::Rect(std::min(xA, xB), std::min(yA, yB), std::abs(xA-xB), std::abs(yA-yB));
 	return roi;
 }
 
@@ -261,7 +258,7 @@ void CvImageViewer::plotOnY()
 		QVector<double> keys;
 		QVector<double> values;
 		int x, y;
-		transfromToSourceCoordinates(xLine_.p1().x(), xLine_.p1().y(), x, y);
+		transfromToSourceCoordinates(yLine_.p1().x(), yLine_.p1().y(), x, y);
 		double max = 0;
 		for(int i = 0; i < origImage_.rows; ++i)
 		{