7/27/2019 NIIT, 5th sem Common question answer on graphics and multimedia.pdf

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C .. Explain the principle of DVST system. Ans. TheDirect View Storage Tube (DVST) behaves like a CRT

with highly persistent phosphor. Pictures drawn on this

4 0screen will be seen for several minutes ( -5 0 minutes)

before fading. It i s similar to a CRT as far as the electronic

gun and phosphor-coated mechanisms are concerned.

However, instead of the electron beam directly writing the

pictures on the p hosphor coated CRT s creen, the writi ng is

done with the help of a fine-mesh wire grid. The grid made

of very thin, high quality wire is located with a dielectric

and is mounted just before the screen on the path of the

electron beam from the gun. A pattern of positive charges

is deposited on the grid and this pattern is transferred to the

phosphor coated CRT by a continuous flood of electrons.

This flood of electrons is mounted by a "flood gun", which

is separate from the electron gun that produces the main

electron beam. . C .Compare the merits and demerits ofraster and random scanning system. Ans. 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 6 0 8 0at the rate of to -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

3C . Develop a C program to draw a structure of a fishand give animation. Ans.

#include #include

#include #include #include

void main() {

int gdriver=DETECT,gmode; int i;

initgraph(&gdriver,&gmode,"e:\\tc\\bgi"); int

2 0max_y=getmaxy()/ ; i= ; setcolor(BLUE); while(!kbhit())

{

0 3 0 , 0l ine( +i,max_y+ +i,max_y-3 0 ); /*triangle*/

0 3 0 , 3 0 0l ine( +i,max_y+ +i,max_y) ; l ine( +i,max_y-

3 0 , 3 0 9 0 0 , 3 6 0 , 6 0 , 3 5+i,max_y); ellipse( +i,max_y, );

1 2 0c ircle( +i,max_y-5 , 5 3 6 3 5 0) ; i=i+ ; if (i>= ) i= ; de la y1 0 0( );

cleardevice();

} getch(); closegraph();

} Inform the students that the path e:\\tc\\bgi should be

changed according to the machine settings. The code given

3 . 0here has been tested on Turbo C .

4C . What is multimedia? Ans. Multimedia can be definedas 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.

3C List the different graphics functions along withexample. Ans. C supports various graphics functions, such

as: 1 1 2 2line(int x , int y , int x , int y ): This draws a line

1 1 2 2from position (x , y ) to (x , y ) Example:

1 0 , 5 0 , 1 0 , 1 0 0line( ); 1 1 2 2bar(int x , int y , int x , int y ): This

1 1draws a filled rectangle with diagonal from (x , y ) to

2 2 1 0 , 2 5 , 1 0 0 , 7 5(x ,y ) bar( ) circle(int x, int y, int r): This

draws a circle with center at (x, y) and radius of r.

5 0 , 5 0 , 1 0Example : c ir cle( ) a rc (int x, int y , int star t, int

end, int r): This draws an arc of circle with the center at

(x,y), radius r and start and end specified in degrees to

mention the portion of the circle that forms the arc.

1 0 0 , 1 0 0 , 0 , 9 0 , 2 0Example: arc( ) draws the first quarter of

1 0 0 , 1 0 0 2 0the c ir cle, a rc with cente r ( ) and rad ius .

C4 . Explain the meaning of the following terms:Morphing, Rendering, Wrapping. Ans. Morphing: Itis 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 Kaw asaki

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 part s of the image co uld 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.

C . Define pixel, resolution, and aspect ratio. Ans. Pixelcan 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 theimage is the ratio of the number of X pixels to the number

of Y pixels. The standard aspec 4 : 3t ratio for PCs is and

5 : 4some use .

C . Explain the working of Light pen along with a

diagram. Ans. Light pen has a very simple working. Every

pixel on the screen that is a part of the picture em its light.

All that the light pen does is to make use of this light signal

to indicate the position. A small aperture is held against the

portion of the pi cture to be modi fied and the li ght from the

pixels falls on a photocell, after passing through the

aperture. This photocell converts the light signal received

from the screen to an electrical pulse to be sent as a signal

sent to the computer. Since the electrical signal is rather

weak, an amplifier amplifies it before being sent to the

computer.

A "tracking software" keeps track of the

position of the light pen alw ays. Through the us e of the

tracking software, a signal received by the light pen at any

point indicat es the portion of t he picture that needs to be

modified.

Note that, when the pen is being moved to itsposition, to the position w here the modificat ion is required,

it will encounter various other light sources on the way.

These light sources should not trigger the computer to

accept the signal. So the aperture of the light pen is

normally kept closed till the final position is reached, and

then it can be opened by a switch.

3C . Explain the use of getimage() and putimage() withexamples? Ans. The getimage() function captures the

image inside the rectangle whose diagonal is defined by

1 1 2 2 1 1 2 2(x , y ) , and (x ,y ) ,where x , y , x , and y a re the f ir st

four parameters of getimage(). The captured image isstored in an array, which is specified as the last parameter

of getimage().

For example, to capture a rectangle

1 0 5 0 5 0 1 2 5whose diagonal is defined by ( , ) and ( , ), you

can use the getimage() function as:

1 0 , 5 0 , 5 0 , 1 2 5int area = imagesize( );

unsigned char * buf = malloc(arear);

1 0 , 5 0 , 5 0 , 1 2 5getimage( , buf);

The putimage() function copies the image captured using

getimage(), starting at location (x, y), where x and y are

the first two parameters of this function. The image to be

captured is specified as the third parameter. The fourth

parameter of this funct ion specifies how the image has t o

be copied and takes any of the follow ing values:

0COPY_PUT or , which copies the image as it is

XOR_PUT o 1r , which performs an exclusive OR between

the background pixels and the image pi xels OR_PUT or2 , which performs an inclusive OR between the

background pixels and the image pi xels 3AND_PUT or ,

which performs an AND between the background pixels

and the image pixels 4NOT_PUT or , which invert s the

pixels of the i mage.

For e xample, animat e a rectangle

as it is you can use the COPY_PUT option in putimage:

1 0 , 5 0putimage( , buf, COPY _PUT);

4C . What is animation? Explain different types ofanimation 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 maintypes 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.

5C . What are editing Tools? Ans. Editing tools are usedto 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. 5C . What is FileFormat? 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 pageimages are standard formats that can be opened by any

program that support s it.

The various image fil e 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

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5C . Give the steps to use rubber stamp tool. Ans. To usethe rubber stamp tool (Clone tool), perform the following

steps: 1 )Open the image that you want to clone. 2 )Select

rubber stamp tool. 3 )Select an appropriate brush size and

style from the Brush drop down in the options bar at the

top. Also set values for other options such as blending

mode, opacity, and flow. Determine how you want to align

the sampled pixels. If you select Aligned, you can release

the mouse button without losing the current sampling point.

As a result, the sampled pixels are applied continuously, no

matter how many times you stop and resume painting. If

you deselect Aligned, the sampled pixels are applied from

the initial sampling point each time you stop and resume

painting. Selec t Use All L ayers to sample dat a from all

visible layers; deselect Use All Layers to sample only from

the active layer. 4 )Press Alt and click the image that you

want to clone, to select the source point for cloning. 5 )Usethe brush to clone the image by dragging the mouse on

another area. The image will be cloned in that area.

. What is sampling? Sampling is like breaking a sound

into tiny piece and storing each piece as a small, digital

sample of sound. The rate at which a sound is Sampled

can affect its quality. The higher the sampling rate (the

more pieces of sound that are stored) the better the quality

of sound. Higher quality of sound will occupy a lot of

space in hard disk because of more samples.

C Explain the working of Light pen along with a

diagram. Ans. Light pen has a very simple working. Every

pixel on the screen that is a part of the picture emi ts light.

All that the light pen does is to make use of this light signal

to indicate the position. A small aperture is held against the

portion of the picture to be mo dified and the l ight from the

pixels falls on a photocell, aft er passing through t he

aperture. This photocell converts the light signal received

from the screen to an electrical pulse to be sent as a signal

sent to the computer. Since the electrical signal is rather

weak, an amplifier amplifies it before being sent to the

computer.

A "tracking software" keeps track of the

position of th e light pen alw ays. Through the use of the

tracking software, a signal received by the light pen at any

point indicat es the portion of the picture that needs to be

modified.

Note that, when the pen is being moved to its

position, t o the position where the modific ation is required,it will encounter various other light sources on the way.

These light sources should not trigger the computer to

accept the signal. So the aperture of the light pen is

normally kept closed till the final position is reached, and

then it can be opened by a switch.

C . Explain briefly the working principle of Shadow

mask CRT. Ans. The Shadow Mask CRT is based on the

principle of combi ning the basic colors - red, green and

blue. The shadow mask CRT, inst ead of using one el ectron

gun, uses three different guns placed adjacent to each other

to form a triangle or a "Delta". Each pixel point on the

screen is made up of three types of phosphors to produce

red, blue, and green colors. Just in front of the phosphor

screen, is a metal screen, called a "shadow mask". This

plate has holes pl aced strategically, so that the beam s from

the three electron guns are focused on particular color-

producing pixel onl y.

Now, unlike the beam

penetration CRTs, the acceleration of the electron beam

was being monitored, one can manipulate the intensity of

the three beams simultaneously. If the red beam is made

more intense, we get more of red color in the final

combination etc. Since fine-tuning of the beam intensitiesis comparatively simple, we can get much more

combination of colors than the beam penetration case.

6 . What are the different gra phical input interactivetechniques? Ans. Following are the various graphical input

interactive techniques: 1 )Positioning 2 )Constraints 3 )Grids

4 )Gravity Field 5 )Rubber band methods 6 )Dragging

3C . Write a C program to create Indian national flag.#include"graphics.h"

#include"conio.h"

void main(){int

gd=DETECT,gm,x,y;initgraph(&gd,&gm,"c:\\tc\\bgi");x=getmaxx();y=getmaxy();clearviewport();

setfillstyle(LINE_FILL,BLUE); 0 , 0 , 6 3 9 , 4 7 9bar( );

6setcolor( ); 5 0 , 5 0 , 3 0 0 , 2 0 0rectangle( );

6setfillstyle(SOLID_FILL, );

5 0 , 5 0 , 3 0 0 , 1 0 0bar( );setfillstyle(SO LID_FILL,WHITE);

5 0 , 1 0 0 , 3 0 0 , 1 5 0bar( );setfillstyle(SO LID_FILL,GREEN );

5 0 , 1 5 0 , 3 0 0 , 2 0 0bar( ); setcolor(BLUE);

4 5 , 4 5 , 5 0 , 3 0 0rectangle( ); 0 2 0setfillpattern( x ,MAGENTA);

4 5 , 4 5 , 5 0 , 4 0 0bar( ); setcolor(BLUE);

1 7 5 ,1 2 5 , 2 5 1 7 5 , 1 2 5 , 2 0 0 , 1 2 5circle( );line( );

1 7 5 , 1 2 5 , 1 7 5 , 1 5 0line( );

1 7 5 , 1 2 5 , 1 5 0 , 1 2 5line( );

1 7 5 , 1 2 5 , 1 7 5 , 1 0 0line( );

1 7 5 , 1 2 5 , 1 5 9 , 1 0 7line( );

1 7 5 , 1 2 5 , 1 9 3 , 1 4 3line( );

1 7 5 , 1 2 5 , 1 5 9 , 1 4 3line( );

1 7 5 , 1 2 5 , 1 9 3 , 1 0 7line( );

setcolor(YELLOW);

0 , 0 ,6 4 0 , 4 3rectangle( );

setfillstyle(SOLID_FILL,YELLOW);0 , 0 ,6 4 0 , 4 3bar( );

setcolor(BLACK);

settext 1 5style( ,HORIZ_DIR, );

1 5 0 , 0outtextxy( ,"INDIAN FLAG") ;

getch();

}

. What is the need for computer graphics?Computers

have become a powerful tool for the rapid and economical

production of pictu res. Computer Grap hics remains one of

the most exciting and rapidly growing fields. Old Chinese

saying One picture is worth of thousand words can bemodified in this computer era into One picture is worth of

many kilobytes of data. It is natural to expect that

graphical communication, which is an older and more

popular method of exchanging informati on than verbal

communication, will often be more convenient when

computers are utilized for this purpose. This is true because

one must represent objects in two-dimensional and three-

dimensional spaces. Computer Graphics has revolutionized

almost every computer-based application in science and

technology.

C .Define resolution.Ans:Image resolution refers as the

pixel spacing i .e. the distanc e from one pixel t o the next

pixel. A t ypical PC moni tor displays screen i mages with a

2 5 8 0resolution somewhere between pixels per inch and

pixels per inch. Pixel is the sm allest element of a displayed

image, and dots (red, green and blue) are the smallest

elements of a display surface (monitor screen). The dot

pitch is the m easure of screen resolutio n. The smaller t he

dot pitch, the higher the resolution, sharpness and detail ofthe image displayed.

4 . Why C language is popular for graphicsprogramming?

Turbo C++ is for C++ and C programmers. It is also

compatible with ANSI C standard and fully

supports Kernighan and Ritchie definitions. It includesC++ class libraries, mouse support, multiple overlapping

windows, Multi file editor, hypertext help, far objects and

error analysis. Turbo C++ comes with a complete set of

graphics functions to facilitate preparation of charts and

diagrams. It supports the same graphics adapters as turbo

7 0Pascal. The Graphics library consists of over graphics

functions ranging from high level support like facility to set

3view port, draw -D bar charts, draw polygons to

bitoriented functi ons like get i mage and put i mage. The

graphics library supports numerous objects, line styles and

provides several text fonts to enable o ne to justify and

orient text, horizontally and vertically. It may be noted that

graphics functions use far pointers and it is not supported in

the tiny memory model. 3C . How can you make an object

animate infinitely till you press the Enter key to exit?

Ans: You can make an object animate till you hit a key

using the kbhit() function. When this function is called it

returns true if an input character is available in the read

buffer for reading. If there i s nothing to be read, it returns

false. You can use this function as:

1int continue = ; while(continue) {

2 7if(kbhit()) { ch = getch(); if(ch == ) break;

} else { //animation code

}

}

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9 . Give the steps to use the image printing utility of Photoshop? Ans. In Photoshop,you can print a complete image, selected area of an image, or even one or more layers.

To print a complete image, select File --> Print from the main menu (or press Ctrl

+ P).

Ensure that the All radio button is selected. You can also set the print

resolution by selecting it from the Print Quality drop-down. After making the desired

print settings click OK to p rint.

To print a selected area, make a select ion in the

image using the Rectangular Marquee tool and select File >Print. Select the Selection

option button in the Print dialog box and click OK.

Note that by default, Photoshop

prints all visi ble layers and channel s. If you want t o print just cert ain layers or

channels, make them the only ones that are visible and then print.

You can also

choose to print the filename, along with crop marks, registration marks and a caption

6along with the image. To set such options, select File >Page Setup in Photoshop .

You can select the checkboxes if you want to include the corresponding options inthe printed image: Caption: Selecting this checkbox will print a caption with the

image. This caption can be set in the File Info dialog box. To open the File Info dialog

box select File > File Info, a nd choose Caption from the Section drop-down list. Type a

caption in the Caption text area and click OK . Calibration Bars: Select this

checkbox to print the calibration and color bars for your image. A calibration bar is a

1 1 1 1row of gray squares of different values. A color bar is a row of colors. These bars

can be helpful when trying to calibrate to a specific printer. This option is available

only for a PostScript printer. Registration Marks: Select this checkbox to print a

registration mark such as bull's eyes around the image. These marks can be helpful for

aligning color separations. Corner Crop Marks: Select this checkbox to view

horizontal and vertical lines around the corners of the image, defining where the image

should be trimmed. Center Crop Marks: Select this checkbox to view the exact

center of the image defined by two crossed lines. Labels: Select this checkbox to

print the file name next to t he image. Yo u can also print t he name of the ap propriate

color channel if you are using color separations. Negative: Select this checkbox to

print an image that appears like a negative of the original image . With this option

selected, the colors are reversed. Emulsion Down: Select this checkbox to print the

image as a horizontal mirror image of the original image. Interpolation:

Interpolation refers to a printer's ability to resample an image as they print it to improve

its resolution. This option is useful in case of low-resolution images.

The buttonson the left side also present some useful options such as printing a border around the

image and printing a background with the image.