docs: public Corners getImageCorners( int width , int height , Corners corners ) {
  
  		if( corners == null )
  			corners = new Corners();
  
  		int w = width;
  		int h = height;
  
  		tranCurrToWorld.compute(0,0,work); corners.p0.set(work.x, work.y);
  		tranCurrToWorld.compute(w,0,work);    corners.p1.set(work.x, work.y);
  		tranCurrToWorld.compute(w,h,work);       corners.p2.set(work.x, work.y);
  		tranCurrToWorld.compute(0,h,work);    corners.p3.set(work.x, work.y);
  
  		return corners;
  	}