Question

Clip the line segment PQ having coordinates P(4,1) & Q(6,4) against the clip window having vertices A(3,2),B(7,2),C(7,6),D(3,6) using Cohen Sutherland line clipping algorithm and explain it in detail.

Answer 1

The Cohen-Sutherland line clipping algorithm is used to clip a line segment against a rectangular region called a clip window. This algorithm involves assigning codes to the endpoints of the line segment and the clip window vertices, and determining if the line is completely inside, completely outside, or partially inside the clip window. If the line is partially inside, intersection points are calculated to obtain the clipped line segment.

Step-by-step explanation:

The Cohen-Sutherland line clipping algorithm is used to clip a line segment against a rectangular region called a clip window. In this case, we need to clip the line segment PQ with endpoints P(4,1) and Q(6,4) against a clip window with vertices A(3,2), B(7,2), C(7,6), and D(3,6).

To perform the Cohen-Sutherland line clipping algorithm, we follow these steps:

1. Assign codes for the line endpoints and the clip window vertices using the Cohen-Sutherland coding scheme.
2. Determine if the line is completely inside the clip window based on the codes of its endpoints. If so, the clipped line segment is the same as the original line segment.
3. If the line is completely outside the clip window based on the codes of its endpoints, it is discarded.
4. If the line is neither completely inside nor outside the clip window, calculate the intersection point of the line segment with one of the clip window edges.
5. Repeat steps 2-4 for the remaining line segment and clip window edges, if necessary.

In this case, the line segment PQ is partially inside the clip window. We will need to calculate the intersection point of PQ with the clip window edges to obtain the clipped line segment.