HYTOS

        scenePos1 = self.imageViewer.mapToScene(pos.x() - 300, pos.y() - 300)

        scenePos2 = self.imageViewer.mapToScene(pos.x() + 300, pos.y() + 300)

        if isZoomIn:

            zoomArea = QRectF(QPointF(scenePos1.x(), scenePos1.y()), QPointF(scenePos2.x(), scenePos2.y()))

            viewBBox = self.imageViewer.zoomStack[-1] if len(self.imageViewer.zoomStack) else self.imageViewer.sceneRect()

            selectionBBox = zoomArea.intersected(viewBBox)

                self.imageViewer.zoomStack.append(selectionBBox)

                self.imageViewer.updateViewer()

        else:

            self.imageViewer.scene.setSelectionArea(QPainterPath())  # Clear current selection area.

            if len(self.imageViewer.zoomStack):

                self.imageViewer.zoomStack.pop()

                item = SymbolSvgItem.fromXml(symbol)

                if item is not None:

                    item.transfer.onRemoved.connect(self.itemRemoved)

                else:

                    pt = [float(x) for x in symbol.find('LOCATION').text.split(',')]

                    size = [float(x) for x in symbol.find('SIZE').text.split(',')]

            QApplication.processEvents()

            for item in symbols:

                self.itemTreeWidget.addTreeItem(self.itemTreeWidget.root, item)

            for line_no_node in root.find('LINENOS').iter('LINE_NO'):