Android onTouchEvent MotionEvent中的坐标是如何构建的？

I'm wondering what are the origin point, i.e. (0, 0), of the coordinates in a MotionEvent when you touch or move across the screen in Android? I know getRawX() and getRawY() get the overall screen coordinates. But I'd like to know the origin point for getX() and getY().I'm wondering what are the origin point, i.e. (