1. A polygon can be clipped by using the Nicholl-Lee-Nicholl algorithm.
a) True
b) False
Explanation: The Nicholl–Lee–Nicholl algorithm is a fast line clipping algorithm that reduces the chances of clipping a single line segment multiple times.
2. The area around the clipping window is divided into a number of different ______________
a) pixels
b) squares
c) areas
d) lines
Explanation: The area around the clipping window is divided into a number of different areas, depending on the position of the initial point of the line to be clipped.
3. In how many areas the initial point should be present?
a) 3
b) 5
c) 2
d) 8
Explanation: The initial point should be in three predetermined areas; so that the line may have to be translated or rotated to bring it into the desired region.
4. These areas are given names depending on the location of ___________________
a) endpoints
b) initial points
c) intermediate points
d) intersection points
Explanation: These areas are then designated as L, LT, LB, or TR, depending on the location of the initial point.
5. What is the denotation of a ray if it intersects the top boundary?
a) L
b) T
c) P
d) B
Explanation: T – ray intersects top boundary; LT – ray intersects left and top boundary.
6. What is the denotation of a ray if it intersects the top and right boundary?
a) RT
b) TR
c) LR
d) LT
Explanation: R – ray intersects right boundary; TR – ray intersects top and right boundary.
7. The division of area is affected by the position of endpoints.
a) True
b) False
Explanation: The regions are determined by the property that, no matter where in the region the second point (endpoint) is, the segment will have to be intersected with the same boundaries of the window.
8. Sutherland-Hodgeman clipping is an example of_________________ algorithm.
a) line clipping
b) polygon clipping
c) text clipping
d) curve clipping
Explanation: The Sutherland–Hodgman algorithm is used for clipping polygons. Cohen- Sutherland is line clipping algorithm.
9. How many polygons are used in this method?
a) 4
b) 3
c) 2
d) 1
Explanation: Two polygons are used in this algorithm namely clip polygon and subject polygon.
10. Only vertices from the subject polygon that are on the _______________ are selected.
a) lower half
b) boundary
c) opaque side
d) visible side
Explanation: Only vertices from the subject polygon which are on the visible side are selected and rest of the vertices are clipped.