Computer Graphics Interview Questions and Answers for freshers on “Window to Viewport Coordinate Transformation”.
1. The object space or the space in which the application model is defined is called ____________
a) World co-ordinate system
b) Screen co-ordinate system
c) World window
d) Interface window
Answer: a
Clarification: World Coordinate System also called as WCS is any coordinate systems that describe the physical coordinates associated with a data array. They also used for an astronomical image, or for determining the wavelength scale for a spectrum.
2. What is the name of the space in which the image is displayed?
a) World co-ordinate system
b) Screen co-ordinate system
c) World window
d) Interface window
Answer: b
Clarification: The coordinate system of the screen is a Cartesian coordinate system. The origin (0,0) is at the top left of the screen. Point is denoted by (x,y), where x is x co-ordinate and y is y co-ordinate.
3. What is the rectangle in the world defining the region that is to be displayed?
a) World co-ordinate system
b) Screen co-ordinate system
c) World window
d) Interface window
Answer: c
Clarification: The world window specifies which part of the window needs to be drawn. It also defines which part of the window should be drawn and which part outside the window should not be drawn and should be clipped away.
4. The window opened on the raster graphics screen in which the image will be displayed is called _____________
a) World co-ordinate system
b) Screen co-ordinate system
c) World window
d) Interface window
Answer: d
Clarification: In common words, it is termed as a Graphic user interface. It allows users to interact with electronic devices through graphical icons and visual indicators such as secondary notation.
5. The process of mapping a world window in World Coordinates to the Viewport is called Viewing transformation.
a) True
b) False
Answer: a
Clarification: The viewing transformation is the operation of computer graphics in which the maps are the perspective view of an object in world coordinates into a physical device’s display space.
6. The scale factor of viewport transformation for x co-ordinate is ________
a) Sx = (svmax – svmin)/ (swmax – swmin)
b) Sx = (svmax – svmin)/ (swmax + swmin)
c) Sx = (svmin – svmax)/ (swmax – swmin)
d) Sx = (svmax + svmin)/ (swmax – swmin)
Answer: a
Clarification: The mapping or transformation involves developing formulas that start with a point in the world window, say (xw, yw). The formula is used to produce a corresponding point in viewport coordinates, say (xv, yv). So after keeping it proportional in ‘x’ co-ordinate, we get, (svmax– svmin)/ (swmax – swmin).
7. The scale factor of viewport transformation for x co-ordinate is ________
a) Sy = (svmax + svmin)/ (swmax + swmin)
b) Sy = (svmax – svmin)/ (swmax + swmin)
c) Sy = (svmax – svmin)/ (swmax – swmin)
d) Sy = (svmax + svmin)/ (swmax – swmin)
Answer: c
Clarification: The mapping or transformation involves developing formulas that start with a point in the world window, say (xw, yw). The formula is used to produce a corresponding point in viewport coordinates, say (xv, yv). So after keeping it proportional in ‘y’ co-ordinate, we get, (svmax – svmin)/ (swmax – swmin).
8. Panning is a technique in which users can change the size of the area to be viewed in order to see more detail or less detail.
a) True
b) False
Answer: b
Clarification: The technique in which users can change the size of the area to be viewed in order to see more detail or less detail is called ‘Zooming’. Panning means sliding the camera.
9. Drawing of number of copies of the same image in rows and columns across the interface window so that they cover the entire window is called ____________
a) Roaming
b) Panning
c) Zooming
d) Tiling
Answer: d
Clarification: Drawing of number of copies of the same image in rows and columns across the interface window so that they cover the entire window is called ‘tilling’. To achieve tiling in computer graphics, the window remains static and the viewport is changed many times.
10. By changing the dimensions of the viewport, the _________ and ___________ of the objects being displayed can be manipulated.
a) Number of pixels and image quality
b) X co-ordinate and Y co-ordinate
c) Size and proportions
d) All of these
Answer: c
Clarification: By changing the dimensions of the viewport, the size and proportions of the objects being displayed can be manipulated, this leads to the zooming effect of the image by successively mapping different dimensioned clipping windows on a fixed sized viewport.