Category: Computer Graphics Objective Questions

Computer Graphics multiple choice questions on Character Attributes.

1. Which of the following is the basic attribute of a character?
a) Font
b) Size and color
c) Orientation
d) All of the mentioned

Answer: d
Clarification: Font, size, color and orientation are the basic attribute of a character.

2. Attribute can be set for
a) Entire character strings
b) Individual characters defined as marker symbol
c) Neither a nor b
d) Both a and b

Answer: d
Clarification: Character attributes can be set to text as well as marker symbols defined as individual characters.

3. A particular font and associated styles can be set using the function
a) setTextfont (tf)
b) setfont (tf)
c) setFont (tf)
d) setTextFont()

Answer: a
Clarification: The function setTextfont (tf) can be used to set the font and its style. Where “tf” specifies the available fonts style.

4. When a character string is to be displayed, the which color is used to set the pixel value in frame buffer?
a) White color
b) Current color
c) Black color
d) Any color

Answer: b
Clarification: The current color is used to set the pixel value corresponding to the character shape and positions.

5. The Character size is specified by
a) Printers
b) Compositors
c) Frame buffer
d) Both a and b

Answer: d
Clarification: The Character size is specified by printers and compositors in points where 1 point is 0.013837 inch.

6. The distance between the bottom-line and the top-line of the character body is
a) Same for all character
b) Different for all character
c) Same for some character
d) Different for some character

Answer: a
Clarification: The distance between the bottom-line and the top-line of the character body is always same for all the characters.

7. The width of the text or character can be set using the function
a) setCharacterExpansionFactor (cw)
b) SetCharacterExpansionFactor (cw)
c) setCharacterFactor (cw)
d) setCharacterExpansionfactor (cw)

Answer: a
Clarification: In this function the parameter cw (character-width) sets the width of the character.

8.__________ is a single character that can be displayed in different colors and in different sizes.
a) String
b) Marker symbol
c) Only a
d) Symbols

Answer: b
Clarification: A marker symbols can be displayed in any colors and in any size.

9. A function that allows the user to select a particular character to be as marker symbol is
a) setmarkertype (mt)
b) setMarkersymbol(mt)
c) setMarkerType (mt)
d) SETMARKER()

Answer: c
Clarification: None.

10. The orientation for a displayed character string is set according to, which of the following function?
a) Setcharacterupvector()
b) setcharacterUpvector(upvect)
c) setCharacterUpVector(upvec)
d) only b

Answer: c
Clarification: According to the direction of the character up vector, the orientation for a displayed character string is set.

Computer Graphics test 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

Answer: a
Clarification: 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

Answer: b
Clarification: 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

Answer: d
Clarification: 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

Answer: a
Clarification: 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
d) hexadecimal search

Answer: b
Clarification: 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

Answer: b
Clarification: 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

Answer: d
Clarification: 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

Answer: a
Clarification: 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

Answer: c
Clarification: 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

Answer: b
Clarification: Fast clipping algorithm has similarities with Cohen–Sutherland. The start and end positions are classified by which portion of the 9-area grid they occupy, in both of the algorithms.

Computer Graphics Multiple Choice Questions & Answers (MCQs) on “Character Generation”.

1. Which of the following is a video editing tool that produces an animated text which can be inserted into video streams?
a) Character generator
b) Title generator
c) Video generator
d) Animation generator

Answer: a
Clarification: Character generator also called as CG in video editing is the software or hardware that produces animated text video streams.

2. Is it possible to have hardware as character generator?
a) True
b) False

Answer: a
Clarification: Character generators can be both hardware or software. Hardware character generators are used in television studios and video editing suites, whereas software CG(s) are used in animation.

3. Which type of character generators are used in television production studios?
a) Hardware character generators
b) Software character generators
c) Both Hardware and software character generators can be used
d) Title generators are used

Answer: a
Clarification: Generally, only Hardware character generators are used in television studios. They provide a key signal. While the compositing vision mixer can use an alpha channel to determine which areas of the CG video are translucent.

4. Why aren’t camcorder CG used more frequently in the titler market?
a) They don’t record for longer time period
b) They use a background of video for title super imposition
c) They have low storage capacity
d) They are not economically feasible

Answer: c
Clarification: They have 2 drawbacks, first is that you have to give titles as you shoot and second, they have very low capacity in comparison to others.

5. How many Methods of character generations are there?
a) 2
b) 3
c) 4
d) 5

Answer: b
Clarification: There are three methods. Those 3 methods are Stroke method, Bitmap method and Starbust method. Each of them has different types of function.

6. Which method of character generation is also called Dot-matrix method?
a) Stroke method
b) Bitmap method
c) Starbust method
d) There isn’t that type of method

Answer: b
Clarification: Bitmap method is also called a dot-matrix method as it uses arrays of dots for character generation. These dots are the points for an array whose size is fixed.

7. In which method, graph is used in form of line to line?
a) Stroke method
b) Bitmap method
c) Starbust method
d) Dot-matrix method

Answer: a
Clarification: In Stroke method, graph is drawn in the form of line by line. Line drawing algorithm DDA follows this method for line drawing.

8. In which method, fixed pattern of a line is used to generate characters?
a) Stroke method
b) Bitmap method
c) Starbust method
d) Dot-matrix method

Answer: c
Clarification: In Starbust method, a combination of 24bit line segment is used. It is a method in which there is a particular pattern where only 24 strokes are defined for character generation.

9. Which method has the poorest character quality?
a) Stroke method
b) Bitmap method
c) Starbust method
d) Dot-matrix method

Answer: c
Clarification: Character quality is poor in Starbust method and is worse for curved characters. Whereas in Bitmap method and stroke method, it is very good as they use new technologies.

10. Character generators can produce _________________
a) Different type size but same fonts
b) Same type size but different fonts
c) Same type size and fonts
d) Different type size and fonts

Answer: d
Clarification: Character generators can produce different type sizes and fonts depending on the requirement. You can alter the type, size as well as colour of fonts too using character generators.

11. Font colours can be changed using character generators.
a) True
b) False

Answer: a
Clarification: Simple systems offer eight colours: black, white, yellow, red, magenta, blue, cyan and green. More sophisticated systems offer millions of colours.

Computer Graphics Questions and Answers for Entrance exams on “Sutherland-Hodgeman Polygon Clipping”.

1. Sutherland-Hodgeman clipping is an example of_________________ algorithm.
a) line clipping
b) polygon clipping
c) text clipping
d) curve clipping

Answer: b
Clarification: The Sutherland–Hodgman algorithm is used for clipping polygons. Cohen- Sutherland is line clipping algorithm.

2. How many polygons are used in this method?
a) 4
b) 3
c) 2
d) 1

Answer: c
Clarification: Two polygons are used in this algorithm namely clip polygon and subject polygon.

3. Only vertices from the subject polygon that are on the _______________ are selected.
a) lower half
b) boundary
c) opaque side
d) visible side

Answer: d
Clarification: Only vertices from the subject polygon which are on the visible side are selected and rest of the vertices are clipped.

4. The process is repeated iteratively for each clip polygon side, using the output list from one stage as the input list for the next.
a) True
b) False

Answer: a
Clarification: The process is repeated iteratively for each clip polygon side, using the output list from one stage as the input list for the next. When the process is completed, a new polygon is generated.

5. We can correctly clip a polygon by processing the polygon boundary as a whole against each ___________
a) side wall
b) top edge
c) window edge
d) bottom edge

Answer: c
Clarification: We can correctly clip a polygon by processing the polygon boundary as a whole against each window edge which can be accomplished by processing all polygon vertices against each rectangle.

6. How many edges of the clipping are/is present in 2D?
a) 1
b) 2
c) 3
d) 4

Answer: d
Clarification: If the algorithm is done in 2D, we have 4 edges of the clipping area. Left edge, right edge, top edge and bottom edge.

7. If we used Left->Right->Up->Bottom, the final output will be the vertex list outputted by the ___________ edge.
a) left edge
b)right edge
c) top edge
d) bottom edge

Answer: d
Clarification: If we used Left->Right->Up->Bottom, the final output will be the vertex list outputted by the bottom edge. The final result is given by the last edge which is a bottom edge in this case.

8. If the subject polygon is concave at vertices outside the clipping polygon, the new polygon may have coincident edges.
a) True
b) False

Answer: a
Clarification: If the subject polygon was concave at vertices outside the clipping polygon, the new polygon may have coincident edges. The result will be the same in case of overlapping edges too.

9. In a convex polygon, each of the interior angles is less than ____degrees.
a) 90
b) 180
c) 360
d) 45

Answer: b
Clarification: A convex polygon is a simple polygon in which no line segment between two points on the boundary ever goes outside the polygon and interior angles are less than 180 degrees.

10. One of the drawbacks of Sutherland- Hodgeman algorithm is that it can’t produce ____________ areas.
a) connected
b) multiple
c) discrete
d) circular

Answer: a
Clarification: The Sutherland-Hodgeman algorithm is not able to produce connected areas. For connected areas, Weiler-Atherton Algorithm is used.

Computer Graphics Multiple Choice Questions & Answers (MCQs) on “Area Sampling”.

1. We can think a line as a _____________________ in the grid.
a) Parallelogram
b) Rectangle
c) Circle
d) Triangle

Answer: b
Clarification: A line can be viewed as a rectangle of defined thickness. It covers a desired area in the grid. Even the thinnest horizontal line has a thickness of one pixel.

2. Line should set an intensity of only a single pixel in a column to black.
a) True
b) False

Answer: b
Clarification: A line should not set an intensity of a single pixel in a column to black, but rather should contribute some amount of intensity to each pixel in the column, whose area it intersects.

3. A signal can also be represented as ____________________
a) Amplitude domain
b) Signal domain
c) Frequency domain
d) Phase domain

Answer: c
Clarification: The signal can also be represented as a frequency domain, that is why we may represent it as a sum of two different sine waves.

4. What is lower bound on the sampling rate known as?
a) Syquist rate
b) Nyquist rate
c) Hartley rate
d) Sampling rate

Answer: b
Clarification: Sampling theory tells us that a signal can be reconstructed by its samples. The original signal is sampled at a frequency larger than twice. This sampling rate is called Nyquist rate.

5. The equal area in area sampling contributes _______________
a) Equal intensity
b) Greater intensity
c) Lower intensity
d) Area is not dependent on the intensity

Answer: a
Clarification: The equal area contributes to equal intensity in area sampling. Only the total amount of overlapped area matters, regardless of the distance between the pixel’s centre.

6. Which of the following is NOT a type of area sampling?
a) Weighted area sampling
b) Unweighted area sampling
c) Anti-aliasing
d) Point sampling

Answer: d
Clarification: Weighted and unweighted area sampling are types of area sampling classified on the basis of proportionality of intensity. Anti-aliasing is another name of unweighted area sampling whereas, point sampling is not a type of area sampling.

7. The technique of setting the intensity proportional to the amount of area covered is used in weighted area sampling.
a) True
b) False

Answer: b
Clarification: The technique of setting the intensity proportional to the amount of area covered is used in unweighted area sampling. This technique produces noticeably better results than others.

8. What happens to intensity if an area of overlapping increases?
a) Intensity remains same
b) Intensity decreases
c) Intensity increases
d) Can’t say anything

Answer: c
Clarification: When the line covers pixel completely the intensity is a maximum while when the line doesn’t touch the pixel the intensity is zero. Hence we can say, the intensity is directly proportional to the overlapping area.

9. What is the effect of weighted area sampling on adjacent pixels?
a) Intensity is increased
b) Intensity is decreased
c) Contrast is increased
d) Contrast is decreased

Answer: d
Clarification: The net effect of weighted area sampling is to decrease the contrast of adjacent pixels. This gives a lot of help in order to provide smooth transactions.

10. What is the name of the effect that causes different signals to become indistinguishable?
a) Aliasing
b) Anti-aliasing
c) Sampling
d) Staircase effect

Answer: a
Clarification: When the resolution is too low, visual stair-stepping of edges occurs in an image. That effect is called aliasing.

Computer Graphics multiple choice questions on Anti Aliasing.

1. The distortion of information due to low-frequency sampling is known as
a) Sampling
b) Aliasing
c) Inquiry function
d) Anti-aliasing

Answer: b
Clarification: The distortion of information is called aliasing.

2. To avoid losing information from periodic objects we need
a) Sampling frequency twice
b) Nyquist sampling frequency
c) Both a or b
d) Neither a nor b

Answer: c
Clarification: Because nyquist sampling frequency means sampling frequency twice.

3. Nyquist sampling frequency formula is
a) fs=2fmax
b) fs=2fmin
c) fs=fmax
d) fs=fmin

Answer: a
Clarification: None.

4. The sampling of object characteristic at a high resolution and displaying the result at a lower resolution is called?
a) Super-sampling
b) Post-filtering
c) Anti-aliasing
d) a or b

Answer: d
Clarification: Super-sampling is also called Post-filtering by computing intensities and combines results to obtain the pixel intensities.

5. Anti-aliasing by computing overlap areas is referred to as
a) Area-sampling
b) Super-sampling
c) Pixel phasing
d) Only b

Answer: a
Clarification: The intensity of pixel as a whole is determined without calculating sub-pixel intensity.

6. Area-sampling is also known as
a) Pre-filtering
b) Pixel phasing
c) Post-filtering
d) Anti-aliasing

Answer: a
Clarification: None.

7. Raster objects can also be anti-aliased by shifting the display location of pixel areas is known as
a) Super-sampling
b) Pixel shaping
c) Pixel phasing
d) Any of these

Answer: c
Clarification: This technique is applied by micro-positioning the electron beam in relation to object geometry.

8. If we want to use more intensity levels to anti-alias the line, then
a) We increase the number of sampling positions
b) We decrease the number of sampling positions
c) We increase the number of pixels
d) Only c

Answer: a
Clarification: We increase the number of sampling positions across each pixel to use more intensity levels.

9. The procedure that increases the number of intensity levels for each pixel to total number of sub-pixels is
a) Area-sampling
b) Anti-aliasing
c) Super-sampling procedure
d) Only c

Answer: d
Clarification: The super-sampling procedure increases the number of intensity levels for each pixel to total number of sub-pixels.

10. For a 45% line, the line path is________ on the polygon area.
a) Horizontal
b) Centered
c) Vertical
d) Any of these

Answer: b
Clarification: The line path is centered on the polygon area only if a line is 45%.

11. An array of values specifying the relative importance of sub-pixel is referred as________ of sub-pixel weights.
a) Sub-mask
b) Mask
c) Pixel phasing
d) Pixel weighting

Answer: c
Clarification: None.

12. The technique that is more accurate method for anti-aliasing lines is
a) Filtering
b) Area-sampling
c) Super-sampling
d) None

Answer: a
Clarification: In this technique we can imagine a continuous weighting surface covering the pixel.

13. Super-sampling methods can be applied by
a) Sub-dividing the total area
b) Determining the number of sub-pixels inside the area
c) Both a and b
d) Only b

Answer: c
Clarification: Super-sampling methods can be applied by sub-dividing the total area and determining the number of sub-pixels inside the area boundary.

14. Another method for determining the percentage of pixel area within a boundary is
a) Mid-print algorithm
b) Mid-point algorithm
c) Pixel intensity
d) By using inquiry functions

Answer: b
Clarification: This algorithm selects the next pixel along a line by determining which of 2 pixels is closer to the line between 2 pixels.

15. What is the use of Coherence techniques along and between scan lines?
a) To simplify the calculations
b) To determine the area edges
c) To find polygon region
d) To correct interior area

Answer: a
Clarification: Coherence techniques are used along and between scan lines to simplify the calculations.