graphics file

INTRODUCTION TO GRAPHICS

Computer graphics are graphics created using computers and, more generally,

the representation and manipulation of image data by a computer with help from

specialized software and hardware. The development of computer graphics has

made computers easier to interact with, and better for understanding and

interpreting many types of data. Developments in computer graphics have had a

profound impact on many types of media and have revolutionized

animation, movies and the video game industry.

The term computer graphics has been used in a broad sense to describe "almost

everything on computers that is not text or sound". Typically, the term computer

graphics refers to several different things:

the representation and manipulation of image data by a computer

the various technologies used to create and manipulate images

the images so produced, and

the sub-field of computer science which studies methods for digitally

synthesizing and manipulating visual content

Although computer graphics is a vast field that encompasses almost any graphical

aspect, we are mainly interested in the generation of images of 3-dimensional

scenes. Computer imagery has applications for film special effects, simulation and

training, games, medical imagery, flying logos, etc.

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http://en.wikipedia.org/wiki/Video_game

http://en.wikipedia.org/wiki/Movies

http://en.wikipedia.org/wiki/Animation

http://en.wikipedia.org/wiki/Graphics_hardware

http://en.wikipedia.org/wiki/Graphics_software

http://en.wikipedia.org/wiki/Computer

http://en.wikipedia.org/wiki/Data

http://en.wikipedia.org/wiki/Image

http://en.wikipedia.org/wiki/Manipulation

http://en.wikipedia.org/wiki/Representation

http://en.wikipedia.org/wiki/Computer

http://en.wikipedia.org/wiki/Graphics

Concepts and Principles

1. Image

In common usage, an image or picture is an artifact, usually two-dimensional, that has a similar appearance to some subject—usually a physical object or a person. Images may be two-dimensional, such as a photograph, screen display, and as well as a three-dimensional, such as a statue. They may be captured by optical devices—such as cameras, mirrors, lenses, telescopes, microscopes, etc. and natural objects and phenomena, such as the human eye or water surfaces.

2. Pixel

Each pixel is a sample of an original image, where more samples typically provide a more accurate representation of the original. The intensity of each pixel is variable; in color systems, each pixel has typically three or four components such as red, green, and blue, or cyan, magenta, yellow, and black.

3. Graphics

Graphics are visual presentations on some surface, such as a wall, canvas, computer screen, paper, or stone to brand, inform, illustrate, or entertain.

Examples are photographs , drawings, Line Art, graphs, diagrams, typography, numbers, symbols, geometric designs, maps, engineering drawings, or other images. Graphics often combine text, illustration, and color.

4. Rendering

Rendering is the process of generating an image from a model, by means of computer programs. The model is a description of three dimensional objects in a strictly defined language or data structure. It would contain geometry, viewpoint, texture, lighting, and shading information.

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APPLICATION OF GRAPHICS

Computers have become a powerful tool for the rapid and economical production of pictures. Advances in computer technology have made interactive computer graphics a practical tool. Today, computer graphics is used in the areas as science, engineering, medicine, business, industry, government, art, entertainment, advertising, education, and training.

Computer-aided design Computer simulation Digital art Education Graphic design Info graphics Information visualization Rational drug design Scientific visualization Video Games Virtual reality Web design

1. COMPUTER AIDED DESIGN

A major use of computer graphics is in design processes, particularly for

engineering and architectural systems. For some design applications; objects are

first displayed in a wireframe outline form that shows the overall sham and internal

features of objects. Software packages for CAD applications typically provide the

designer with a multi-window environment. Each window can show enlarged

sections or different views of objects. Standard shapes for electrical, electronic,

and logic circuits are often supplied by the design package. The connections

between the components have been mad automatically. Animations are often used

in CAD applications. When object designs are complete, realistic lighting models

and surface rendering are applied. Manufacturing process of object can also be

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controlled through CAD. Interactive graphics methods are used to layout the

buildings. Three-dimensional interior layouts and lighting also provided. With

virtual-reality systems, the designers can go for a simulated walk inside the

building.

2. PRESENTATION GRAPHICS

It is used to produce illustrations for reports or to generate slide for with

projections. Examples of presentation graphics are bar charts, line graphs, surface

graphs, pie charts and displays showing relationships between parameters. 3-D

graphics can provide more attraction to the presentation.

3. COMPUTER ART

Computer graphics methods are widely used in both fine are and commercial art

applications. The artist uses a combination of 3D modeling packages, texture

mapping, drawing programs and CAD software. Pen plotter with specially

designed software can create “automatic art”. “Mathematical Art” can be produced

using mathematical functions, fractal procedures. These methods are also applied

in commercial art. Animations are also used frequently in advertising, and

television commercials are produced frame by frame. Film animations require 24

frames for each second in the animation sequence. A common graphics method

employed in many commercials is morphing, where one object is transformed into

another.

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4. ENTERTAINMENT

CG methods are now commonly used in making motion pictures, music videos and

television shows.Many TV series regularly employ computer graphics method.

Graphics objects can be combined with a live action.

5. EDUCATION AND TRAINING

Computer-generated models of physical, financial and economic systems are often

used as educational aids. For some training applications, special systems are

designed. Eg. Training of ship captains, aircraft pilots etc., Some simulators have

no video screens, but most simulators provide graphics screen for visual operation.

Some of them provide only the control panel.

6. VISUALIZATION

The numerical and scientific data are converted to a visual form for analysis and to

study the behavior called visualization. Producing graphical representation for

scientific data sets are calls scientific visualization. And business visualization is

used to represent the data sets related to commerce and industry. The visualization

can be either 2D or 3D.

7. IMAGE PROCESSING

Computer graphics is used to create a picture. Image processing applies techniques

to modify or interpret existing pictures. To apply image processing methods, the

image must be digitized first. Medical applications also make extensive use of

image processing techniques for picture enhancements, simulations of operations,

etc.

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8. GRAPHICAL USER INTERFACE

Nowadays software packages provide graphics user interface (GUI) for the user to

work easily. A major component in GUI is a window. Multiple windows can be

opened at a time. To activate any one of the window, the user needs just to check

on that window. Menus and icons are used for fast selection of processing

operations.

SOME INBUILT GRAPHICS FUNCTION

1. Initgraph( )

It is use to initialize the graph. Initgraph initializes the graphics system by loading a graphics driver from disk and putting the system into graphics mode.

To start the graphics system, first call the initgraph function. Initgraph loads the graphics driver and puts the system into graphics mode.

Syntax:-

#include <graphics.h>

void initgraph(int *graphdriver, int *graphmode, char *path driver);

2. Closegraph( )

It is used to close the graph . Closegraph deallocates all memory allocated by the graphics system, then restores the screen to the mode it was in before you called initgraph

Syntax:-

#include <graphics.h>

void closegraph(int wid=ALL_WINDOWS);

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3. Line( )

The line statement we use in C programming for graphics and it is a part of GRAPHICS.H header file

Syntax:-

line(x1, y1, x2, y2)

4. Arc( )

The arc statement we use in C programming for draw curve on The screen and it is a part of GRAPHICS.H

Syntax:-

arc (midx, midy, stangle, endangle, radius);

5. Circle( )

Circle function in computer graphics give value center of the circle and then its radius.

Syntax:-

circle(xcentre,ycentre,radius);

6. getmaxx( )

getmaxx() function is used to get the maximum x value of graphics screen, usually it is 639 for VGA driver and VGAHI graphics mode. getmaxy is used to get the maximum y value of graphics screen.

Syntax:-

rectangle(0,0,getmaxx(),getmaxy())

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7. Floodfill ( )

The floodfill is use to paint the screen or specific areawithin boundaries through a point , i.e.-e in Circle,Ellipse,Box, or any kind of shape which is fully locked area or two dimensional .

Syntax:-

floodfill (int x, int y, int border)

8. Setfillstyle ( )

It is used to choose the style and color .

Syntax:

setsfillstyle( int pattern, int color)

9. Setcolor ( )

It can be sets the current drawing color.

Syntax:-

Setcolor(int color);

10. cleardevice ( )

Cleardevice erases (that is, fills with the current background color) the entire graphics screen and moves the CP (current position) to home (0,0).

Syntax

void cleardevice(void);

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11. delay ( )

Delay function is used to suspend execution of a program for a particular time.

Syntax :- void delay(unsigned int);

12.Outtextxy ( )

outtextxy displays a text string in the viewport at the given position (x, y), using the current justification settings and the current font, direction, and size. To maintain code compatibility when using several fonts, use textwidth and textheight to determine the dimensions of the string. If a string is printed with the default font using outtext or outtextxy, any part of the string that extends outside the current viewport is truncated. outtextxy is for use in graphics mode; it will not work in text mode.

Syntax:-

void outtextxy(int x, int y, char *textstring);

13.Rectangle ( )

This sets up a new Rectangle object called recOne. In between the round brackets of Rectangle, we have two sets of numbers. The first set (150, 10) is how far to the left you want your rectangle, and how far down. The second set (50, 200) is the width of the rectangle, and then the height.

Syntax:-

Rectangle recOne = new Rectangle( 150, 10, 50, 200 );

14.Ellipse ( )

It is used to draw the ellipse.

Syntax :-

ellipse(xcentre, ycentre, StAngle, EndAngle, xRadius, Yradius);

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15.Setbkcolor ( )

setbkcolor function changes current background color e.g.setbkcolor(YELLLOW) changes the current background color to YELLOW.Remember that default drawing color is WHITE and background color is BLACK.

Syntax :-

void setbkcolor(int color);

16.Getmaxy ( )

getmaxy function returns the maximum Y coordinate for current graphics mode and driver.

Syntax :-

int getmaxy();

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1. Program to show the ‘DIRECT METHOD” for drawing a line.

#include<iostream.h>

#include<conio.h>

#include<graphics.h>

void main()

{

clrscr();

int gd=DETECT, gm;

int x1,y1,x2,y2,m=0,c=0;

initgraph(&gd,&gm,"");

cout<<"Enter the value of starting and ending points";

cin>>x1>>y1>>x2>>y2;

m= (y2-y1)/(x2-x1);

c=y1-(m*x1);

while(x1<=x2)

{

if(m<=1)

{

y1=(m*x1)+c;

x1++;

putpixel(x1,y1,RED);

}

else

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{

x1=(y1-c)/m;

y1++;


}

}

getch();

closegraph();

}

OUTPUT:

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2. Program to show “DIGITAL DIFFERENTIAL ANALYZER”Algorithm.


#include<conio.h>


void main()

{

clrscr();

int gd=DETECT, gm;

int x1,y1,x2,y2,m=0,c=0;


cout<<"Enter the value of x1,y1,x2,y2";

cin>>x1>>y1>>x2>>y2;

m=(y2-y1)/(x2-x1);

c=y1-(m*x1);

while(x1<=x2)

{

if(m<=1)

{

x1=x1+1;

y1=y1+m;


}

else

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{

y1=y1+1;

x1=x1+1/m;


}

}

getch();

closegraph();

}

OUTPUT:

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3. Program to show “BRESENHAM LINE” Algorithm.


#include<conio.h>


void main()

{

clrscr();

int gd=DETECT, gm;

int x1,y1,x2,y2,dy,dx,f,fe,fne;


cout<<"Enter the value of x1 and y1";

cin>>x1>>y1;

cout<<"Enter the value of x2 and y2";

cin>>x2>>y2;

dy=y2-y1;

dx=x2-x1;

f=2dy-dx;

fe=2dy;

fne=2dy-2dx;

while(x1<=x2)

{

if(f<=0)

{

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f=f+fe;

x1++;

putpixel(x1,y1,WHITE);

}

else

{

f=f+fne;

x1++;

y1++;

putpixel(x1,y1,WHITE);

}

}

getch();

closegraph();

}

OUTPUT:

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4. Program of “DIRECT METHOD” to draw a circle.


#include<conio.h>


void main()

{

clrscr();

int gd=DETECT, gm;

int xc,yc,xend ,r;


cout<<”Enter x-centre, y-centre and radius”;

cin>>xc>>yc>>r;

int x=0;

xend=r/sqrt(2);

while(x<xend)

{

y=sqrt(r*r-x*x);

putpixel(x+xc, y+yc, WHITE);

putpixel(y+xc, x+yc, RED);

putpixel(y+xc, -x+yc, WHITE);

putpixel(-x+xc, y+yc, RED);

putpixel(-x+xc, -y+yc, WHITE);

putpixel(-y+xc, x+yc, RED);

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putpixel(x+xc,-y+yc,WHITE);

x++;

}

getch();

closegraph();

}

OUTPUT:

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5. Program of “POLAR COORDINATES METHOD” to draw a circle.


#include<conio.h>


void main()

{

clrscr();

int gd=DETECT,gm;

int xc,yc,x,y ,r,th;



cin>>xc>>yc>>r;

th=1/r;

x=0;

y=r;

while(x<y)

{







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float temp=y;

y=y*cos(th)+x*sin(th);

x=x*cos(th)-temp*sin(th);

}

getch();

}

OUTPUT:

6. Program of “MID-POINT METHOD” to draw a circle.

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#include<conio.h>


void main()

{

clrscr();

int gd=DETECT, gm;

int xc,yc,x,y,r,f;



cin>>xc>>yc>>r;

x=0;

y=r;

f=1-r;

while(x<=y)

{

if(f<0)

{

f=f+(3+2*x);

x++;

}

else {

f=f+(2*x-2*y+5)

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x++;

y--;

}








}

getch();

closegraph();

}

OUTPUT:

7. Program of “BRESENHAM’S ALGORITHM” to draw a circle.

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# include<iostream.h>

# include<conio.h>

# include<graphics.h>

void cpoint(int,int,int,int);

void main()

{

clrscr();

int xc,yc,r,f,fe,fse,x,y;

int gd=DETECT, gm;


cout<<"\nEnter x-center,y-center,radius : ";

cin>>xc>>yc>>r;

x=0;

y=r;

f=3-r;

while(x<=y)

{

if(f<0)

{

fe=4*x+6;

f=f+fe;

x++;

cpoint(x,y,xc,yc);

}

else if(f>0)

{fse=10+(4*x)-(4*y);

f=f+fse;

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x++;

y--;

cpoint(x,y,xc,yc);

}

}

getch();

}

void cpoint(int x,int y, int xc, int yc)

{

putpixel(x+xc,y+yc,1);

putpixel(y+xc,x+yc,1);

putpixel(-x+xc,y+yc,1);

putpixel(-y+xc,x+yc,1);

putpixel(-x+xc,-y+yc,1);

putpixel(-y+xc,-x+yc,1);

putpixel(x+xc,-y+yc,1);

putpixel(y+xc,-x+yc,1);

}

OUTPUT:-

8. Program to draw an Ellipse using Direct Method

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#include<conio.h>


#include<math.h>

void main()

{

int gd,gm;

float xc,yc,xr,yr;

gd=DETECT,gm;


cout<<"Enter xcentre ,ycentre, xradius,yradius";

cin>>xc>>yc>>xr>>yr;

float x=0;

float y=xr;

while(x<=y)

{

y=yr*sqrt(1-((x*x)/(xr*xr)));

putpixel(x+xc,y+yc,WHITE);

putpixel(-x+xc,y+yc,WHITE);

putpixel(-x+xc,-y+yc,WHITE);


x++;

}

getch();

}

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OUTPUT:

9.

Program to draw an Ellipse using Polar Co-ordinates Method


#include<conio.h>


#include<math.h>

void main()

{

int gd=DETECT, gm;

clrscr();

initgraph(&gd,&gm," ");

float xc,yc,xr,yr;

cout<<"Enter xc,yc,xr,yr";


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float theta1=0;

float theta2=90;

while(theta1<theta2)

{

float x=xr*cos(theta1);

float y=yr*sin(theta1);





theta1++;

}

getch();

}

OUTPUT:

10 .Program to draw an Ellipse using Mid Point method.

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#include<conio.h>


#include<math.h>

void main()

{

int gd=DETECT, gm;


float xc,yc,x,y,xr,yr,f;

cout<<"Enter xc,yc,xr ,yr";


x=0;

y=yr;

f=(yr*yr)+(xr*xr)/4-(xr*xr)*yr;

while(2*(yr*yr)*x<=2*(xr*xr)*y)

{

if(f<=0)

{

f=f+(3+(2*x))*(yr*yr);

x++;





}

else

{

f=f+3*(yr*yr)+2*x*(yr*yr)+2*(xr*xr)-2*y*(xr*xr);

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x++;

y--;





}

}

f=(yr*yr)/4-2*(xr*xr)*yr+(xr*xr);

while(y>=0)

{

if(f<=0)

{ f=f+(3-(2*y))*(xr*xr);

x++;

y--;





}

else

{ f=f+2*(yr*yr)+2*x*(yr*yr)+3*(xr*xr)-2*y*(xr*xr);

y--;





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}

}

getch();

closegraph();

}

OUTPUT:

STATIC APPLICATION

11. Program to make a flag.


#include<conio.h>


void main()

{

int gd = DETECT,gm;

clrscr();


setcolor(5);

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line(20,50,20,180);

line(20,50,100,50);

line(20,70,100,70);

line(20,90,100,90);

line(20,110,100,110);

line(100,50,100,110);

circle(60,80,10);

line(52,80,68,80);

line(60,72,60,88);

setfillstyle(SOLID_FILL,22);

floodfill(21,51,5);


floodfill(21,75,5);


floodfill(21,95,5);


floodfill(81,75,5);


floodfill(61,81,5);

getch();

closegraph();

}

Output:-

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DYNAMIC APPLICATIONS

12. Program to show stars and moon on the screen .


#include<stdlib.h>


#include<conio.h>

#include<dos.h>

void main()

{

int x,y,i;

int gd=DETECT,gm;


outtextxy(350,350,"GOOD NIGHT JI");

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circle(200,200,50);

setfillstyle(1,15);

floodfill(200,200,15);

setcolor(0);

setfillstyle(1,0);

circle(180,180,50);

floodfill(180,180,0);

for (i=0;i<1000;i++)

{

x = random(1500);

y = random(1500);

putpixel(x,y,15);

}

getch();

closegraph();

}

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Output:-

13. Program to implement an application of circle to show the different patterns and colors.


#include<stdlib.h>

#include<conio.h>


#include<dos.h>

#include<math.h>

void circlepoints(float,float,float,float);

void main()

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{

int gd=DETECT,gm;


float x,y,xc,yc,r,xend;

cout<<"enter xc,yc,radius";

cin>>xc>>yc>>r;

x=0;

xend=r/sqrt(2);

while(x<xend)

{

y=sqrt(r*r-x*x);

circlepoints(x,y,xc,yc);

delay(100);

x++;

}

while(!kbhit())

{

setfillstyle(random(10),random(7));

floodfill(xc,yc,7);

}

getch();

closegraph();

void circlepoints(float x,float y,float xc,float yc)

{

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putpixel(x+xc,y+yc,7);

putpixel(y+xc,x+yc,7);

putpixel(-y+xc,x+yc,7);

putpixel(-x+xc,y+yc,7);

putpixel(-x+xc,-y+yc,7);

putpixel(-y+xc,-x+yc,7);

putpixel(x+xc,-y+yc,7);

putpixel(y+xc,-x+yc,7);

}

Output

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graphics file

Technology

term computer graphics

computer imagery

computer screen

computer technology

graphicscomputer graphics

interactive graphics

subfield of computer

design applications