Point clipping determines whether the point lies inside the clipping window or not. Thus it determines whether point is visible or not.
Assuming that the clip window is a rectangular, we consider a point P(x, y). This point P will be considered inside the window if it satisfies the following two conditions:
WXmin ≤ x ≤ WXmax
WYmin ≤ y ≤ WYmax
where WXmin, WXmax, WYmin, WYmax, are the edges of rectangular window.
If any of these four conditions is not satisfied, the point lies outside the window and is not displayed. In practice, point_clipping is rarely used as most of the images are drawn using straight line segments or curves. However, this algorithm is used for background clipping, i.e. the background that is created by a dotted pattern.