handl mous drag event param mous event process tigri gef base mode impl mous drag java awt event mous event mous drag mous event drag fig editor translat mous event point point point subtract offset click account user have initi click centr point translat deltax deltai path item placement strategi pip fig edg path item placement strategi drag fig pip set point point point pip point dx point drag base point dy point drag base point drag base point set locat point drag fig translat dx dy consum editor damag drag fig 