ViewportModelImpl vm = (ViewportModelImpl)map.getViewportModel();
final ViewportPaneTiledSWT viewera = (ViewportPaneTiledSWT)viewer;
final ReferencedEnvelope bounds = vm.getBounds();
Coordinate currentc = vm.getCenter();
final Point newpnt = vm.worldToPixel(newLoc);
final Point oldpnt = vm.worldToPixel(currentc);
vm.setIsBoundsChanging(true);
int xoffset = oldpnt.x - newpnt.x;