Computer Graphics Short Complete

1 Defne computer graphics. Explain in brief where computer graphics methods are utitized.
Computer Graphics can be defined as, “Use of Computer to define,
store, manipulate, interrogate and present pictorial output of the data.”
Computer Graphics methods are utilized in Computer Aided Design (CAD) to produce the drawings
of certain parts of a machine from any viewing angle. Another area in the field of Computer Aided
Manufacturing (CAM) where by employing computer Graphics techniques, one may display the
manufacturing layout for a given part and trace the path taken by machine tools for a given manufacturing
process. Architects can use computer graphics to produce layouts of buildings and utilize them for ComputerAided-Design(CAD)

2. What are pointing devices? Give examples.
Ans.A pointing device is a hardware peripheral that allows user to point to objects on the screen and perform
operations on them, such as selecting, clicking, moving, and dragging. Mouse is an example of pointing
device.

3. What is the use of malloc() function in C.
Ans.The malloc() function allocates memory for an object. The number of bytes of memory to be allocated is
specified as its parameter.

4.What is multimedia?
Ans.Multimedia can be defined as presentation of information with integration of multiple media elements
that can be used on and manipulated by computer. This media includes graphic software, video, audio,
animation software, and computer hardware such as CD players, scanners and cameras.

5. What are the main components of Multimedia?
Ans.The components of Multimedia are as follows:
Text, Graphics ,Sound, Animation ,Video

7.What is the need for computer graphics?
Ans.Graphical communication is an old and more popular method of exchanging information than verbal
communication and is more convenient when computers are utilized for this purpose.
As the volume of information increases, problem of storage arises. Also, in the 21st century people do not have time
to read huge number of pages. This problem was solved by computer graphics. Two other prominent applications of
graphics are in the field of Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM). In CAD,
graphics techniques are used to produce the drawings of certain parts of a machine from any viewing angle. In CAM
computer graphics techniques, one may display the manufacturing layout for a given part and trace the path taken by
machine tools for a given manufacturing process.

8. list graphics input device and explain any one graphics input device.
9. With

illustration briefly narrate the origin and development of multimedia technology?

Ans.Multimedia is an effective medium to express information in a more attractive way. It makes use of text,
pictures, audio, animation, and video. It was started more then 25 years ago. However, it only became
popular with the advent of desktop computers.
Audio was the first multimedia data incorporated into desktop computing, with the introduction of soundboards built
around the tone-synthesis chips. In addition, video could also be captured, displayed and stored on a computer disk
with the help of digital overlay and capture boards installed on any ordinary computer.
However, the use of audio and video on desktop computers was limited due to their large size and high computing
power requirements. These limitations were overcome through the introduction of compression/decompression
engines for reducing the sizes of these files. As the demand increased for multi standard compression on the same
system, several manufacturers introduced a new generation of compression chips that supported software

programming. These chips contained hardware engines for operations requiring high computing power and also
integrated processors that can be programmed to control data flow within the chip. Such technologies made audio
and video boards capable of transferring data to computer systems efficiently, in some cases, in real time.
The latest breakthrough in the field of multimedia was the advent of the Internet and other high-speed
networking technologies. These have presented new opportunities such as video conferencing, medical
imaging, and scientific visualization

10 What are sound cards?
Ans.Sound card is the hardware for sound input and output. It is used with speakers, headphones, and
microphones to record and play sound. Some sound cards also include MIDI, .Wav, and MP3.

11. What is sampling?
Ans.The process of transfer of information from analog to digital is called sampling.

12. What is animation? Explain different types of animation techniques.
Ans.Animation is the process in which each frame of a film or movie is produced individually and viewed in
rapid succession to give an illusion of continuous movement. On PCs the two main types of animation
techniques are as follows:
Object animation: Is the moment of unchanged text and object around the screen
Cell animation/Frame animation: Is made of different frames on screen where they are
rapidly displayed to simulate motion.

13. Explain the meaning of the following terms: Morphing, Rendering, Wrapping.
Ans.
Morphing: It is the process of transformation of one image to another by the transformation
and distortion of corresponding points in both the images. The best example will be Kawasaki
advertisement where the motorbike changes into a cheetah.
Rendering: The process of converting your designed objects with texturing and animation
into an image or a series of images is called rendering.
Wrapping: It is the process where certain parts of the image could be marked for a change
and made to change to different one for example legs of cheetah to be morphed with the
wheels and head with head lights. Head can alone be marked and wrapped.

14. What is the meaning of file format?
Ans.The method by which software organizes the data in the saved file is called the file format. The file name
extension or suffixes indicate the format or usage of the file. Several different types of file formats are used by
various kinds of software. For example: the GIF file format used for Web page images is a standard format
that can be opened by any program that supports that standard format.

15. Why do we use a scanner? Name the different types of scanners?
Ans.Scanner is a peripheral device, which captures real object or image and saves it in a digital file as a
graphic. Different types of scanner are as follows:
Flatbed or Sheet-fed Scanner
Film Scanner
Handheld Scanner
3 D Scanner

16. What are the components of a multimedia system?
Ans.The components of a multimedia system are as follows:
Monitor ,CPU ,Mouse, Keyboard,Microphone, CD drive and discSpeaker ,Digital camera,Joystick Scanner ,Printer,
Web camera

17. Give the different applications of Computer Graphics.
Ans.Computer graphics is used in every field. Some of the major application areas are:
a.
b.
c.
d.
e.
f.
g.
h.

Building design and construction
Electronic Design
Mechanical Design
Entertainment and Animation
Aerospace industry
Medical Technology
Cartography
Art and Commerce.

18. Name the Computer languages that support Computer Graphics.
Ans.Some languages that support computer graphics are:
a.
b.
c.
d.

FORTRAN
BASIC
PASCAL
C

19. Why C language is popular for graphics programming?
Ans.C has become a choice for today's professionals, developers for graphics programming. C is a structured
language and is rich in expressive power and applicable to a wide variety of users. Because of the rich set of
graphical functions available, this language helps in designing for graphical applications. The C code is small, fast,
portable, and flexible.
20. How to make graphics processing faster?
Ans.Video/Graphic processing can be made faster in two ways: by using a graphic co-processor and a graphic
accelerator. The graphic co-processor boosts video performance by assuming tasks normally handled by the CPU.
An accelerator takes control of graphic task, which are otherwise performed by the CPU. However, an accelerator is
not programmable. It is a functioned processor, which caries out specific tasks hard-coded into the chip.
21. What is graphics processor? Why it is needed?
Ans.Graphics processor helps in managing the screen faster with an equivalent software algorithm executed on the
CPU. Through the use of these processors certain amount of parallelism can be achieved for executing graphic
commands. Several manufacturers of personal computers use a proprietary graphics processor.
22. Compare the merits and demerits of raster and random scanning system.
Ans.
1.

2.
3.

In raster scan display, the electron beam is swept across the screen, one row at a time
from top to bottom.
Random scan monitors draw a picture one line at a time and so they are also referred to as
vector displays.
Refreshing on raster scan display is carried out at the rate of 60 to 80- frames per second.
Refresh rate on a random scan system depends on the number of lines to be displayed.
The picture definition is stored in a memory area called refresh buffer or frame buffer in
case of a raster scan display. In case of random scan display, picture definition is stored
as a set of line-drawing commands in an area of memory referred to as the refresh display
file. Refresh display file is also called the display list, display program, or the refresh
buffer.

23. Define pixel, resolution, and aspect ratio.
Ans.Pixel can be defined as the smallest size object or color spot that can be displayed and addressed on a
monitor.
Image resolution refers to pixel spacing that is the distance from one pixel to the next pixel.
The aspect ratio of the image is the ratio of the number of X pixels to the number of Y pixels. The standard aspect
ratio for PC’s is 4:3 and some use 5:4.
24. What are the different graphical input interactive techniques?
Ans Following are the various graphical input interactive techniques:
a.
b.
c.
d.
e.
f.

Positioning
Constraints
Grids
Gravity Field
Rubber band methods
Dragging

7. Why refreshing is required in CRT?
Ans.When an electron beam strikes a dot of phosphor material, it glows for a fraction of a second and then fades. As
brightness of the dots begins to reduce, the screen image becomes unstable and gradually fades out. In order to
maintain a stable image, the electron beam must sweep the entire surface of the screen and return to redraw it
number of times per second. That is, the screen must be refreshed multiple times in a second.
25. Name the different positioning devices.
Ans.The various positioning devices are:







Mouse
Tablet
Joystick
Digitizer
Light pen
Track ball

26. What are pointing devices? Give examples.
Ans.A pointing device is a hardware peripheral that allows user to point to objects on the screen and perform
operations on them, such as selecting, clicking, moving, and dragging. Mouse is an example of pointing
device.
27. How many different choices are possible if we use 24 bits per pixel?
Ans. 16.7 million (224) colors.
28. If we use 3 bits for primary colors how many different colors are possible?
Ans.8 colors are possible.

29. Compare the features of text and graphics mode?
Ans.The following table compares the text and graphics modes:
Text mode

Graphics mode

You can only handle text.

You can display, capture, and animate
figures.

You can display in 16 colors on a
color monitor.

You can display various colors.

Text mode display is in two forms,
25 rows of 40 columns or 25 rows of
80 columns.

The resolution of the graphics mode
depends on the adapter.

30. With the help of an illustration, explain how initgraph() function works.
Ans.The initgraph() function is used to initialize the graphics system to load appropriate graphics drive and
video mode used by the graphics functions. The syntax of this function is:
initgraph(int *driver, int *mode, char *path)
As its parameters, you must specify the graphics mode such as EGA, or VGA (depends on the
graphics adapter being used), the graphics driver (a program that interfaced between the
hardware and your C program), and path of the graphics driver.
For example, to initialize graphics mode in CGA high resolution mode:
int gdriver = 1, gmode=4;
initgraph(&gdriver, &gmode, "d:\\tc\\bgi");
For example, to select the best driver and mode possible on a computer:
int gdriver = DETECT, gmode;
initgraph(&gdriver, &gmode, "d:\\tc\\bgi");
31. With the help of an example explain text mode() C function.
In this mode it is possible to handle only text. Text mode display can be in two forms 25 rows of 40
columns or 25 rows of 80 columns. Text mode can have 2 colors in monochrome monitor and 16 colors in
color monitor. printf () function helps the text to be displayed on the monitor.
To display text in attractive manner many different functions can be used. To execute these functions
# include <conio.h> to be included in the program.
1. textmode( int mode);
This function sets the number of rows and columns of the screen, mode variable can take the values
0, 1, 1, or 3.
0: represents 40 column black and white
1: represents 40 column color
2: represents 80 column black and white
3: represents 80 column color
Example: textmode(2); // sets the screen to 80 column black and white
2. clrscr();
This function clears the entire screen and locates the cursor on the top left corner(1,1)
Example clrscr(); // clears the screen
7 With the help of example explain the following C function 1)textcolor() 2. Dellline()
5. textcolor (int color);
This function sets the subsequent text color numbered between 0 to 15 and 128 for blinking.
Example : textcolor(3); // set the next text color to Green

6. delline ();
It is possible to delete a line of text and after the deletion all the subsequent lines will be pushed up by
one line
Example : /* deletes the 5th line*/
gotoxy (5,4); delline();
32. what is meaning of gd=DETECT in c language?
Two important hardware settings must be properly selected to get the best results. One is the graphic
driver (gd) and the second one is the graphic mode(gm). During initialization one can incorporate necessary
instructions to select the best driver and mode, for example: gd=DETECT; // selects the best resolution
of the video unit
33. Use graphics function to draw concentric circles?
Ans.

#include<conio.h>
#include<graphics.h>
# include<stdio.h>
main() {
int gdriver = DETECT, gmode;
/* initialize graphics mode */
initgraph(&gdriver, &gmode, "d:\\tc\\bgi");
circle(100,100,90);
circle(100,100,50);
circle(100,100,30);
getch();
restorecrtmode();
}

34. How many colors are there in RGB Color mode?
Ans. RGB images use three colors, Red, Green, and Blue. These colors are known as primary colors.
35. What is gamut in Photoshop?
Ans. The series of colors that a color system can demonstrate or print is called gamut in Photoshop. A color
that can be displayed in RGB may be out of gamut, and therefore unprintable, for your CMYK setting.
36. Name the different selections tools.
Ans.The selection tools in Photoshop include the Lasso tool, Pen tools, Marquee Tool, and Path selection tool.
37 What are editing Tools? Why it is needed?
Ans. Editing tools are used to fine-tune or modify graphic elements. Photoshop delivers high-powered image
editing, photo retouching, and composition tools. It also supports features, such as Making Color
Adjustments, Auto Color Command, Adjustment Layers and Fill Layers, and Masking Layers to help you get
professional-quality results.

38. What is File Format? Name the different image file formats?
Ans.The method by which the software organizes the data in the saved file is called the
file format. The file name extension or suffixes indicate the format or usage of a file and
a brief description of that format. Several different types of file format are used by
various kind of software to save files. For example, the GIF file format used for Web
page images are standard formats that can be opened by any program that supports it.
The various image file format are as follows:








Tagged-Image File Format (TIFF)
Graphics Interchange Format (GIF)
Joint Photographic Experts Group (JEPG)
Encapsulated PostScript (EPS)
Portable Document Format (PDF)
Portable Network Graphics (PNG)
TGA- Targa

39What is a layer?
Ans. Layers can be visualized as transparent sheets placed over one another in an image.
Creating a layered image refers to putting different objects on different levels in a
sequence. . You can create empty layers and add content to them, or you can create new
layers from existing content. When you create a new layer, it appears either above the
selected layer or within the selected layer set in the Layers palette.
40.What is photoshop?
Adobe Photoshop is said to be the world standard image editing solution to Multimedia Professionals.
It provides efficient, professional working environment that is the benchmark by which other
products are judged. It is having wide variety of toolsets for image editing. It provides integrated
tools for creating and outputting crisp, editable vector shapes and text.
41.different between bitmap images and vector graphics.?
Bitmap Images
Bitmap images, also called raster images, use a grid, or raster, of small squares known as pixels to
represent graphics. Each pixel in a bitmap images has a specific location and color value assigned to it.
For example, a 1-inch circle in the lower left corner of the page is made up of the collection of pixels in
that location, colored to give the appearance of circle. When working with bitmap images, you edit groups
of pixels rather than objects or shapes. Images created in Adobe Photoshop are bitmap images.
Because they can represent subtle gradations of shades and color, bitmap images are the most common
electronic medium for continuous-tone images, such as photographs or images created in painting programs.
Bitmap images are resolution-dependent and represent a fixed number of pixels.
Vector graphics
Vector graphics consist of line and curves defined by mathematical object called vectors describe
graphics according to their geometric characteristics. For example, when you draw a 1-inch circle in a
vector based program, the program creates the circle based on its shape and size. You can then move,
resize or change the color of the circle without losing the quality of the graphic. Graphics created in
Adobe Illustrator are vector graphics. Vector graphics are resolution-independent-that is, they are not
defined by a fixed number of pixels and so are automatically scaled to appear crisp and sharp on any
output device at any resolution. As a result, vector graphics are the best choice for type (especially small
type) and bold graphics, such as logos, which require crisp, clear lines that can be scaled to many sizes.
Note that computer displays are made up of a grid of pixels, both vector and pixel images are displayed as
pixels on-screen. Vector-based programs render their shapes into pixels for display.

42. Explain the following formats jpeg and pdf..
JPEG
The Joint Photographic Experts Group (JPEG) format is commonly used to display photographs and
other continuous-tone images in hypertext markup language (HTML) documents over the World Wide
Web and other online services. Unlike the GIF format, JPEG retains all the color information in an RGB
image. JPEG also uses a compression scheme that effectively reduces file size by identifying and discarding
extra data not essential to the display of the image. Opening a JPEG image automatically decompresses
PDF
Adobe Acrobat, Adobe’s electronic publishing software, uses the PDF format for Macintosh, Windows,
UN1X, and DOS. Based on the PostScript Level 2 language, PDF can represent both vector and bitmap
graphics. For the purpose of representing pages, PDF pages are identical to PostScript pages, but PDF
files can also contain electronic document search and navigation features.
PDF files, for example, can contain hypertext links and an electronic table of contents
43What is gamut in photoshop?
Ans. Gamut or color gamut is a certain complrte subset of color the most common uses refers to the subset of colors
which can be actually represented in a given circum stance .
44. What is openGL? What is the main feartures of openGL?
OpenGl is a software interface to graphics hardware.OpenGl consists about 150 distinct command.openGl itself isn’t
a programming language or a softwar library. It’s the specification of an application programming interface for
computer graphics programming .openGl was specially designed to be plateform independent. So it would work
across a whole range of computer hardware.
Features:A) It provides 3D geometric objects, such as lines , polygons , triangle meshes , spheres , cubes, quadric
surface, NURBS curves and surfaces;
B) It provides 3D modeling transformation , and viewing functions to create views of 3D scenes using the idea
of a virtual camera;
C) It supports high-quality rendering of scenes, including hidden surface removal, multiple light source,
material types, transparency, texture, blending, fog;
D) It provides display lists of creating graphics caches and hierarchical models. It also supports the interactive
“picking” of objects;
E) It supports the manipulation of images as pixels, enabling frame-buffer effects such as antialiasing, motion
blur, depth of field and soft shadows.