code: function(p) {
  		var size = currentBB.topright.subtract(currentBB.bottomleft);
  		var sx = p.subtract(currentBB.bottomleft).divide(size.x).x * canvas.width;
  		var sy = p.subtract(currentBB.bottomleft).divide(size.y).y * canvas.height;
  		return new Springy.Vector(sx, sy);
  	}
docs: convert to/from screen coordinates