Point Clipping: Point clipping tells us whether the given point X,Y is within the given window or not; and decides whether we will use the minimum and maximum coordinates of the window. The X-coordinate of the given point is inside the window, if X lies in between Wx1 ≤ X ≤ Wx2.
Line clipping:  Line clipping is the process of removing (clipping) lines or portions of lines outside an area of interest (a viewport or view volume). Typically, any part of a line that is outside of the viewing area is removed.