29   view()->horizontalScrollBar()->setValue( 
view()->horizontalScrollBar()->value() - ( event->x() - mLastMousePos.x() ) );
 
   30   view()->verticalScrollBar()->setValue( 
view()->verticalScrollBar()->value() - ( event->y() - mLastMousePos.y() ) );
 
   31   mLastMousePos = 
event->pos();
 
   36   if ( event->button() == Qt::MiddleButton )
 
   38     view()->setTool( mPreviousViewTool );
 
   44   mLastMousePos = 
view()->mapFromGlobal( QCursor::pos() );
 
   45   mPreviousViewTool = 
view()->tool();
 
A QgsModelViewMouseEvent is the result of a user interaction with the mouse on a QgsModelGraphicsView...