public void mousePressed(MouseEvent e) {
         // assigning correct mouse state.
        if (documentViewController != null){
            DocumentViewModel documentViewModel =
                    documentViewController.getDocumentViewModel();
            if (documentViewModel.isViewToolModeSelected(DocumentViewModel.DISPLAY_TOOL_ZOOM_IN)) {
                documentViewController.setViewCursor(DocumentViewController.CURSOR_ZOOM_IN);
            } else if (documentViewModel.isViewToolModeSelected(DocumentViewModel.DISPLAY_TOOL_ZOOM_OUT)) {
                documentViewController.setViewCursor(DocumentViewController.CURSOR_ZOOM_OUT);
            }
        }
    }