# Computer Graphics Questions & Answers – Line Clipping Using Non Rectangular Clip Windows

«
»

This set of Computer Graphics test focuses on “Line Clipping Using Non Rectangular Clip Windows”.

1. Which method of clipping is based on duality?
a) Skala
b) Sutherland clipping
c) Liam Barsky method
d) NLN clipping

Explanation: Skala is a method of clipping whose algorithm is based on homogeneous coordinates and duality.

2. Which method of clipping is used against convex polygon?
a) Lg N clipping algorithm
b) Skala
c) NLN clipping
d) Sutherland clipping

Explanation: Skala can be used for a line or line-segment clipping against a rectangular window, as well as against a convex polygon.

3. Which algorithm classifies vertices against the given line?
a) P algorithm
b) NLN clipping algorithm
c) Skala
d) O algorithm

Explanation: O algorithm classifies vertices against the given line in the implicit form p: ax + by + c = 0. Another name of O algorithm is Lg N algorithm.

4. O algorithm is also known as __________________
a) Lg N algorithm
b) Lg P algorithm
c) Lg M algorithm
d) Lg O algorithm

Explanation: Another name of O algorithm is Lg N algorithm. This algorithm classifies vertices against the given line in the implicit form p: ax + by + c = 0.

5. Which type of search can be applied to O algorithm?
a) interpolation search
b) binary search
c) simple search

Explanation: Binary search can be applied to O algorithm which leads to run-time complexity.

6. O algorithm is simple and easy to implement.
a) True
b) False

Explanation: Skala is simple and easy to implement whereas O algorithm shows run time complexity.

7. The polygon is assumed to be _____________ and vertices are ordered clockwise or anti-clockwise while applying line clipping algorithms.
a) cylindrical
b)concave
c) plane
d) convex

Explanation: The polygon is assumed to be convex and vertices are ordered clockwise or anti-clockwise while applying line clipping algorithms. Anti-convex polygons are not used.

8. A plane duality is a map from a ______________________ to its dual plane.
a) projective plane
b) incident plane
c) parallel plane
d) reference plane

Explanation: A plane duality is a map from a projective plane C = (P, L, I) to its dual plane C∗ = (L, P, I); which preserves incidence.

9. Fast clipping algorithm is an example of ____________ clipping algorithm.
a) text
b) polygon
c) line
d) curve

Explanation: Line clipping is the process of removing lines or portions of lines outside an area of interest and fast clipping algorithm is an example of line clipping algorithm.

10. Fast clipping algorithm has similarities with Liam Barsky algorithm.
a) True
b) False 