KU 5TH SEM ASSIGNMENT - BSIT (TA) - 51 (GRAPHICS & MULTIMEDIA)

Assignment: TA (Compulsory)

1.What is the meaning of interactive computer graphics? List the various applications of the computer graphics.
The term “interactive graphics” refers to devices and systems that facilitate the man-machine graphic communication, in a way, which is more convenient than the writing convention. For example, to draw a straight line between two points, one has to input the coordinates of the two end points. In interactive graphics with the help of graphical input technique by indicating two end points on the display screen draws the line.
Various applications of the computer graphics are listed below :-
i). Building Design and Construction
ii). Electronics Design
iii). Mechanical Design
iv). Entertainment and Animation
v). Aerospace Industry
vi). Medical Technology
vii). Cartography
viii). Art and Commerce.

2. Explain in detail the Hardware required for effective graphics on the computer system.
The hardware components required to generate interactive graphics are the input device, the outputdevice (usually display) and the computer system. The human operator is also an integral part of theinteractive system. The text and graphics displayed act as an input to the human vision system and, therefore, the reaction of the human being will depend on how quickly one can see and appreciate thegraphics present on the display.

3. Compare Raster scan system with random scan system.
In raster scan display, the electron beam is swept across the screen, one row at a time from top to bottom. The picture definition is stored in a memory area called refresh buffer or frame buffer. In random scan display unit, a CRT has the electron beam directed only to the parts of the screen where a picture is to be drawn. It draws a picture one line at a time and so it is referred to as vector displays.


Raster scan
The Most common type of graphics monitor employing a CRT is the raster-scan Display, based on television technology. In a raster- scan system; the electron beam is swept across the screen, one row at a time from top to bottom. The picture definition is stored in a memory area called the refresh buffer or frame buffer.  Each point on the screen is called pixel. On a black and system with one bit per pixel, the frame buffer is called bitmap. For systems with multiple bits per pixel, the frame buffer is referred to as a pix map. 

Refreshing on raster scan display is carried out at the rate of 60 to 80 frames per second. Some displays use interlaced refresh procedure. First, all points on the even numbered scan lines are displayed then all the points along odd numbered lines are displayed. This is an effective technique for avoiding flickering.


Random scan display
When operated as a random-scan display unit, a CRT has the electron beam directed only to the parts of the screen where a picture is to be drawn. Random scan monitors draw a picture one line at a time and for this reason they are also referred as vector displays (or stroke-writing or calligraphic displays). The component lines of a picture can be drawn and refreshed by a random-scan system in any specified order. A pen plotter operates in a similar way and is an example of a random-scan, hard-copy device.

Refresh rate on a random-scan system depends on the number of lines to be displayed. Picture definition is now stored as a set of line- drawing commands in an area of memory referred to as the refresh display file. Sometimes the refresh display file is called the display list, display program, or simply the refresh buffer.

4. How many colors are possible if
    a. 24 bits / pixel is used
    b. 8 bits / pixel is used  Justify your answer

   a). 24 bit color provides 16.7 million colors per pixels, That 24 bits are divided into 3 bytes; one each for the read, green, and blue components of a pixel.

   b). 256, 8 bits per pixel = 2^8 colours.

Widely accepted industry standard uses 3 bytes, or 24 bits, per pixel, with one byte for each primary color results in 256 different intensity levels for each primary color. Thus a pixel can take on a color from 256 X 256 X 256 or 16.7 million possible choices. In Bi-level image 
representation one bit per pixel is used to represent black-and white images. In gray level image 8 bits per pixel to allow a total of 256 intensity or gray levels. Image representation using lookup table can be viewed as a compromise between our desire to have a lower storage requirement and our need to support a reasonably sufficient number of simultaneous colors. 

5. List and explain different text mode built-in functions of C Programming language.
The different text mode built-in functions of C Programming language are listed below :-
i). 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 
ii). clrscr(); 
This function clears the entire screen and locates the cursor on the top left corner(1,1) Example clrscr(); // clears the screen 
iii). gotoxy(int x, int y); 
This function positions the cursor to the location specified by x and y. x represents the row number and y represents the column number. 
Example: gotoxy(10,20) // cursor is placed in 20th column of 10th row 
iv). textbackground (int color); 
This function changes the background color of the text mode. Valid colors for the CGA are from 0 to 6 namely BLACK, BLUE, GREEN, CYAN, RED, MAGENTA and BROWN. Example: textbackground(2); Or //changes background color to blue textbackground(BLUE); 
v). 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 
vi). 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 ( ); 
vii). insline() 
Inserts a blank line at the current cursor position Example: /* inserts line at the 3rd row */ gotoxy (3,5); insline ( ); 

6. 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);
bar(0,0,639,479);
setcolor(6);
rectangle(50,50,300,200);
setfillstyle(SOLID_FILL,6);
bar(50,50,300,100);
setfillstyle(SOLID_FILL,WHITE);
bar(50,100,300,150);
setfillstyle(SOLID_FILL,GREEN);
bar(50,150,300,200);
setcolor(BLUE);
rectangle(45,45,50,300);
setfillpattern(0x20,MAGENTA);
bar(45,45,50,400);
setcolor(BLUE);
circle(175,125,25);
line(175,125,200,125);
line(175,125,175,150);
line(175,125,150,125);
line(175,125,175,100);
line(175,125,159,107);
line(175,125,193,143);
line(175,125,159,143);
line(175,125,193,107);
setcolor(YELLOW);
rectangle(0,0,640,43);
setfillstyle(SOLID_FILL,YELLOW);
bar(0,0,640,43);
setcolor(BLACK);
settextstyle(1,HORIZ_DIR,5);
outtextxy(150,0,"INDIAN FLAG");
getch();
}

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