Point2D.Double copt = translatePoint(pt, tileCoordOffset(topleft));
int dx = (int)copt.x - r.width/2 - r.x;
int dy = (int)copt.y - r.height/2 - r.y;
Point2D.Double copt = translatePoint(pt, tileCoordOffset(topleft));
int dx = (int)copt.x - r.width/2 - r.x;
int dy = (int)copt.y - r.height/2 - r.y;