computer graphics lab file

1. GOVT. ENGINEERING COLLEGE, BILASPUR
Computer Graphics labs File
Name : AalhaRam
Branch: Comuter science &engg.(6th
sem)
Roll No. : 3072214301

2. List of Experiments:
1. Write a programto draw the line using DDA algorithm.
2. Write a programto draw the line using Bresenham’s algorithm.
3. Write a programto draw circle using Bresenham’s algorithm.
4. Write a programto draw circle using mid-point algorithm.
5. Write a programto demonstratedraw ellipse using midpoint algorithm.
6. Write a programRotation of Triangle.
7. Write a programTranslation of Line.
8. Write a programto performscaling of line.
9. Write a programshearing of Rectangle.
10. Write a programto implement boundary –fill algorithm.
11. Write a programto implement flood –fill algorithm.
12. Write a programto implement Bezier curve using four control points.
13. Write a programto implement CohenSutherland line clipping algorithm.
14. Write a programto implement Liang Barsky line clipping algorithm.
15. Write a programto implement face of a cartoon.

3. EXPERIMENT-1
1. Write aprogram to draw the line using DDA algorithm.
CODING:
#include <graphics.h>/*include the necessary header files*/
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
void draw(intxa,intya,intxb,intyb);
void main()
{
intxa,ya,xb,yb;
clrscr();
printf("LineDDA algorithm");
printf("n Enter the value of xa, ya:");
scanf("%d%d",&xa,&ya);
printf("n Enter the value of xb, yb:");
scanf("%d%d",&xb,&yb);
draw(xa,ya,xb,yb);
}
void draw(intxa,intya,intxb,intyb)
{
intxin,yin,x,y,dx,dy,steps,k; /*request autodetection*/
intgdriver=DETECT,gmode,errorcode; /*initialize graphics andlocal
variables */
initgraph(&gdriver,&gmode, "c:tcbgi") /* readresult of initialization*/
errorcode=graphresult(); /*an error occurred*/
if (errorcode!=grOk)
{
printf("Graphics error: %sn", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1);
}
dx=xb-xa;
dy=yb-ya;
if(abs(dx)>abs(dy)) /*if the conditionis satisfied*/
{ /* calculate the value of the conditionvariable*/
steps=abs(dx);

4. }
else
{
steps=abs(dy);
}
xin=dx/steps;
yin=dy/steps;
x=xa;
y=ya;
putpixel(x,y,1); /* draw the first pixel for the line*/
for(k=1;k<=steps;k++) /*for each value of the conditionvariable, */
{
x=x+xin; /* calculate the values of (x,y) and draw the pixel*/
y=y+yin;
putpixel(x,y,1);
} /* cleanup */
getch();
closegraph();
}
Output:

5. EXPERIMENT-2
2. Write aprogram to draw the line using Bresenham’s algorithm.
CODING:
#include <graphics.h>/*include the necessary header files*/
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
void draw(intxa, intya, intxb, intyb);
void main()
{
intxa, ya, xb, yb;
clrscr();
printf("Bresenhnams algorithm"); /*get the coordinates of the line*/
printf("n Enter the value of xa, ya:");
scanf("%d%d",&xa,&ya);
printf("n Enter the value of xb, yb:");
scanf("%d%d",&xb,&yb);
draw(xa,ya,xb,yb);
}
void draw(intxa, intya, intxb, intyb)
{
intx,y,dx,dy,xend,p; /*request autodetection*/
intgdriver=DETECT,gmode,errorcode; /*initialize graphics andlocal
variables */
initgraph(&gdriver,&gmode,"c:tcbgi"); /*readresult of initialization*/
errorcode=graphresult(); /*an error occurred*/
if(errorcode!=grOk)
{
printf("Graphics error: %sn", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1);
}
dx=xb-xa;
dy=yb-ya;

6. p=2*dy-dx; /* calculate the value of the conditionvariable*/
if(xa>xb) /* depending on the positionof the coordinates*/
{
x=xb; /* assignthe values for (x,y)*/
y=yb;
xend=xa;
}
else if(xb>xa)
{
x=xa;
y=ya;
xend=xb;
}
putpixel(x,y,1); /* draw the pixel on the screen*/
while(x<xend) /* depending onthe control conditiondraw the pixels*/
{
x=x+1;
if(p<0)
{
p=p+2*dy;
}
else
{
y=y+1;
p=p+2*dy;
}
putpixel(x,y,1);
} /* cleanup */
getch();
closegraph();
}

7. OUTPUT:

8. EXPERIMENT NO. 03
3 :Write aprogram to implement Bresenham’s Circlealgorithm.
PROGRAM
# include <stdio.h>
# include <conio.h>
# include <graphics.h>
void circle ( int , int ) ;
void main ( )
{
intx , y , p , r , i ;
intgd=DETECT , gm ;
initgraph( &gd , &gm , “tcbgi”) ;
setbkcolor (WHITE) ;
printf( “Enter the radius = “) ;
scanf ( “%d” , &r) ;
x = 0 ; y = r ;

9. p = 3 – 2 * r ;
putpixel( x , y , RED) ;
while ( x< = y )
{
if (p < 0)
p + = 4 * x + 6;
else
{
p + = 4 * ( x - y) + 10 ;
y - - ;
}
x ++ ;

10. circle p ( x , y) ;
}
getch( ) ;
closegraph( ) ;
}
void circle p ( int a , int b)
{
intx , y ;
x = a ; y = b ;
putpixel ( 300+x , 300 + y , 1 ) ;
putpixel( 300 + y , 300 + x , 1 ) ;
putpixel( 300 - x , 300 + y , 1 ) ;
putpixel( 300 + x , 300 - y , 1 ) ;
putpixel( 300 - x , 300 - y , 1 ) ;
putpixel( 300 - y , 300 - x , 1 ) ;

11. putpixel( 300 + y , 300 - x , 1 ) ;
putpixel( 300 - y , 300 + x , 1 ) ;
}
getch( ) ;
}
OUTPUT:

12. EXPERIMENT-4
4. Write aprogram to draw circle using mid-point algorithm.
CODING:
#include<stdio.h>/* include the necessary header files*/
#include<conio.h>
#include<math.h>
#include<graphics.h>
main()
{
intgd=DETECT,gin;
intxcenter,ycenter,radius;
intp,x,y,twox,twoy; /*request autodetect*/
initgraph(&gd,&gin,"C:tcbgi");
x=0;
printf("nEnter the radius value:"); /* get the value of the radius and
center values*/
scanf("%d",&radius);
printf("Enter the center values:");
scanf("%d %d",&xcenter,&ycenter);
plotpoints(xcenter,ycenter,x,y); /*call the plotpoints function*/
y=radius;
p=1-radius;
twox=2*x;
twoy=2*y;
printf("nptxtyt2xt2yn");
printf("n%dt%dt%dt%dt%dn",p,x,y,twox,twoy);
while(x<y) /* in the conditional loopcompute the value of the x and y
values*/
{
if(p<0)
x=x+1;
else
{
x=x+1;
y=y-1;
}

13. if(p<0)
p=p+2*x+1;
else
p=p+2*(x-y)+1;
twox=2*x;
twoy=2*y;
printf("n%dt%dt%dt%dt%dn",p,x,y,twox,twoy);
plotpoints(xcenter,ycenter,x,y);
}
getch();
return 0;
}
intplotpoints(intxcenter, intycenter,intx,int y) /* plot the points of the
circle as per the procedure*/
{
putpixel(xcenter+x,ycenter+y,1);
putpixel(xcenter-x,ycenter+y,1);
putpixel(xcenter+x,ycenter-y,1);
putpixel(xcenter-x,ycenter-y,1);
putpixel(xcenter+y,ycenter+x,1);
putpixel(xcenter-y,ycenter+x,1);
putpixel(xcenter+y,ycenter-x,1);
putpixel(xcenter-y,ycenter-x,1);
}
OUTPUT:

15. EXPERIMENT-5
5. Write aprogram to draw ellipse using mid-point algorithm.
CODING:
#include<stdio.h>/* include the necessary header files*/
#include<conio.h>
#include<graphics.h>
include<math.h>
#include<stdlib.h>
void plotpoints(int,int,int,int);
void main()
{
intgd=DETECT,gm;
intxcenter,ycenter,rx,ry;
intp,x,y,px,py,rx1,ry1,rx2,ry2;
initgraph(&gd,&gm,"C:TCBGI"); /*request autodetect*/
printf("n Enter the radius :"); /* get the radius and the center values*/
scanf("%d %d",&rx,&ry);
printf("n Enter the xcenter and ycenter values :");
scanf("%d %d",&xcenter,&ycenter);
ry1=ry*ry;
rx1=rx*rx;
ry2=2*ry1;
rx2=2*rx1;
/* Region1 */
x=0;
y=ry;
plotpoints(xcenter,ycenter,x,y); /*for the first region calculate the
conditionparameter*/
p=(ry1-rx1*ry+(0.25*rx1));
px=0;
py=rx2*y;
printf("nxtytptpxtpyn");
printf("n%dt%dt%dt%dt%d",x,y,p,px,py);
while(px<py) /* if this conditionis true, compute values of x and y*/
{
x=x+1;
px=px+ry2;

16. if(p>=0)
{
y=y-1;
py=py-rx2;
p=p+ry1+px-py;
}
else
p=p+ry1+px;
plotpoints(xcenter,ycenter,x,y); /*call the plotpoints function*/
printf("n%dt%dt%dt%dt%d",x,y,p,px,py);
}
/* Region2 */
printf("n%dt%dt%dt%dt%d",x,y,p,px,py);
printf("nnRegion 2n");
printf("nxtytptpxtpyn"); /* for region2 recalculate the condition
variables*/
p=(ry1*(x+0.5)*(x+0.5)+rx1*(y-1)*(y-1)-rx1*ry1);
while(y>0)
{
y=y-1;
py=py-rx2;
if(p<=0)
{
x=x+1;
px=px+ry2;
}
if(p>0)
p=p+rx1-py;
else
p=p+rx1-py+px;
plotpoints(xcenter,ycenter,x,y); /*draw the pixels for region2*/
printf("n%dt%dt%dt%dt%d",x,y,p,px,py);
}
getch();
closegraph();
}
void plotpoints(intxcenter,intycenter,intx,inty) /* plot the points of the
circle as per the procedure*/
{

17. putpixel(xcenter+x,ycenter+y,6);
putpixel(xcenter-x,ycenter+y,6);
putpixel(xcenter+x,ycenter-y,6);
putpixel(xcenter-x,ycenter-y,6);
}
Ouput:

18. EXPERIMENT-6
6. Write aprogram Rotationof Triangle.
CODING:
#include<graphics.h>
#include<stdlib.h>
#include<stdio.h>
#include<conio.h>
int x1,x2,x3,y1,y2,y3,t,tx,sx,sy,shx,shy,ch;
float rx1,rx2,rx3,ry1,ry2,ry3;
float ang,theta;
int main(void)
{
intgdriver = DETECT, gmode, errorcode;
initgraph(&gdriver, &gmode,"C:TCBGI"); /*request for auto
detection*/
errorcode= graphresult();
if(errorcode!= grOk) /* if error occours*/
{
printf("Graphics error: %sn", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1);
}
else
{
do{
printf("n1.Translationn2.Reflectionn3.Rotationn4.Scalingn5.Shearingn
");
printf("nEnter Your choice"); /* get the choice from the user*/
scanf("%d",&ch);
switch(ch)
{
printf("n Enter all coordinates values :");
scanf("%d %d %d %d %d %d",&x1,&y1,&x2,&y2,&x3,&y3);
printf("n Before Rotation "); /* get the original coordinates*/
line(x1,y1,x2,y2);
line(rx2,ry2,rx3,ry3);

19. line(rx3,ry3,rx1,ry1);
}
getch();
closegraph(); /* close the graph*/
return 0;
}
OUTPUT

20. EXPERIMENT-7
7. Write a program Translation of Line.
CODE
#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<graphics.h>
#include<process.h>
void draw();
void line();
int x1,x2,y1,y2;
void main(){
intgd=DETECT,gm;
initgraph(&gd,&gm,"..//bgi");
printf("n Enter the first point:");
scanf("%d%d",&x1,&y1);
printf("n Enter the Second point:");
scanf("%d%d",&x2,&y2);
cleardevice();
draw();
line();

21. getch();
}
void draw()
{
line(x1,y1,x2,y2);
}
void line()
{
intx,y,a1,a2,b1,b2;
printf("Enter the translation vectors:");
scanf("%d%d",&x,&y);
cleardevice();
a1=x1+x;
b1=y1+y;
a2=x2+x;
b2=y2+y;
line(a1,b1,a2,b2);
}
OUTPUT

23. EXPERIMENT-8
8. Write a program to perform scaling ofline.
CODE
#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<graphics.h>
#include<process.h>
void draw();
void tri();
int x1,x2,x3,y3,y1,y2,mx,my;
void main(){
intgd=DETECT,gm;
initgraph(&gd,&gm,"..//bgi");
printf("n Enter the firstpoint for the triangle:");
scanf("%d%d",&x1,&y1);
printf("n Enter the Second point for the
triangle:");
scanf("%d%d",&x2,&y2);
printf("n Enter the Third point for the
triangle:");
scanf("%d%d",&x3,&y3);

24. cleardevice();
draw();
scale();
getch();
}
void draw()
{
line(x1,y1,x2,y2);
line(x2,y2,x3,y3);
line(x3,y3,x1,y1);
}
void scale()
{
intx,y,a1,a2,b1,b2,a3,b3;
intmx,my;
printf("Enter the scaling coordinates:");
scanf("%d%d",&x,&y);
mx=(x1+x2+x3)/3;
my=(y1+y2+y3)/3;

25. cleardevice();
a1=mx+(x1-mx)*x;
b1=my+(y1-my)*y;
a2=mx+(x2-mx)*x;
b2=my+(y2-my)*y;
a3=mx+(x3-mx)*x;
b3=my+(y3-my)*y;
line(a1,b1,a2,b2);
line(a2,b2,a3,b3);
line(a3,b3,a1,b1);
draw();
}
OUTPUT

26. EXPERIMENT-9
9. Write a program shearing of Rectangle.
CODE
#include<graphics.h>
#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
int x1,y1,x2,y2,x,y;
int main(void){
intgd=DETECT,gm;
clrscr();
initgraph(&gd,&gm,"..//bgi");
printf("ntENter the top left coordinate:");
scanf("%d%d",&x1,&y1);
printf("ntENter the bottom right coordinate:");
scanf("%d%d",&x2,&y2);
printf("n Enter the value of shearing coordinate for x shear:n");
scanf("%d",&x);
printf("n Enter the value of shearing coordinate for y shear:n");
scanf("%d",&y);
cleardevice();
rectangle(x1,y1,x2,y2);

27. printf("n Now press a key to see shear in x-axis");
getch();
rectangle(x1,y1,x2*x,y2);
printf("n Now press a key to see shear in y-axis");
rectangle(x1,y1,x2,y2*y);
getch();
closegraph();
getch();
}
Output:

28. EXPERIMENT-10
10.Write aprogramto implement boundary –fill algorithm
include<graphics.h>
#include<dos.h>
void fill_right(intx,int y);
void fill_left(intx,int y);
void main()
{
intgd=DETECT,gm,x,y,n,i;
clrscr();
initgraph(&gd,&gm,"c:turboc3bgi");
printf("*** Boundary Fill algorithm ***");
line (50,50,200,50);
line (200,50,200,300);
line (200,300,50,300);
line (50,300,50,50);
x=100; y=100;
fill_right(x,y);
fill_left(x-1,y);
getch();
}
void fill_right(intx,int y)
{
{

29. if((getpixel(x,y) != WHITE)&&(getpixel(x,y) !=RED)
{
putpixel(x,y,RED);
fill_right(++x,y); x=x-1;
fill_right(x,y-1);
fill_right(x,y+1);
}
delay(1);
}
void fill_left(intx,int y)
{
if((getpixel(x,y) != WHITE)&&(getpixel(x,y) !=RED))
{
putpixel(x,y,RED);
fill_left(--x,y); x=x+1;
fill_left(x,y-1);
fill_left(x,y+1);
}delay(1);
OUTPUT

30. EXPERIMENT-11
11. Write a program toimplement flood–fill algorithm.
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
void boundfill(intxc,intyc,intr,intb)
{
int cur;
cur=getpixel(xc,yc);
if(cur!=b && cur!=r)
{
putpixel(xc,yc,r);
delay(1);
boundfill(xc+1,yc,r,b);
boundfill(xc-1,yc,r,b);
boundfill(xc,yc+1,r,b);
boundfill(xc,yc-1,r,b);
}
}
void main()
{
intgd=DETECT,gm;
initgraph(&gd,&gm,"..bgi");

31. rectangle(100,100,300,300);
boundfill(105,105,4,WHITE);
getch();
closegraph();
}
getch();
}
OUTPUT:

32. EXPERIMENT-12
12. Write a program toimplement Bezier curve using four control points.
#include <stdio.h>
#include <stdlib.h>
#include <graphics.h>
#include <math.h>
void bezier (intx[4], int y[4])
{
intgd = DETECT, gm; inti;
double t;
initgraph (&gd, &gm, "..bgi");
for (t = 0.0; t < 1.0; t += 0.0005)
{
double xt = pow (1-t, 3) * x[0] + 3 * t * pow (1-t, 2) * x[1] + 3 * pow (t, 2) *
(1-t) * x[2] + pow (t, 3) * x[3];
double yt = pow (1-t, 3) * y[0] + 3 * t * pow (1-t, 2) * y[1] + 3 * pow
(t, 2) * (1-t) * y[2] + pow (t, 3) * y[3];
putpixel (xt, yt, WHITE);
}
for (i=0; i<4; i++)
putpixel (x[i], y[i], YELLOW);
getch();
closegraph();
return;
}

33. void main()
{
intx[4], y[4]; inti;
printf ("Enter the x- and y-coordinates of the four control points.n");
for (i=0; i<4; i++) scanf ("%d%d", &x[i], &y[i]); bezier (x, y);
}
closegraph();
}
getch();
}
OUTPUT

34. EXPERIMENT-13
13. Write a program toimplement CohenSutherlandline clipping
algorithm.
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
void clip(float,float,float);
inti,j=0,n;
int rx1,rx2,ry1,ry2;
float x1[8],y1[8];
void main()
{
intgd=DETECT,gm;
inti,n;
float x[8],y[8],m;
clrscr();
initgraph(&gd,&gm,"");
printf("coordinates for rectangle : ");
scanf("%d%d%d%d",&rx1,&ry1,&rx2,&ry2);
printf("no. of sides for polygon : ");
scanf("%d",&n);
printf("coordinates : ");

35. for(i=0;i<n;i++)
{
scanf("%f%f",&x[i],&y[i]);
}
cleardevice();
outtextxy(10,10,"Beforeclipping");
outtextxy(10,470,"Pressany key....");
rectangle(rx1,ry1,rx2,ry2);
for(i=0;i<n-1;i++)
line(x[i],y[i],x[i+1],y[i+1]);
line(x[i],y[i],x[0],y[0]);
getch();
cleardevice();
for(i=0;i<n-1;i++)
{
m=(y[i+1]-y[i])/(x[i+1]-x[i]);
clip(x[i],y[i],m);
}
clip(x[0],y[0],m);
outtextxy(10,10,"After clipping");
outtextxy(10,470,"Pressany key....");
rectangle(rx1,ry1,rx2,ry2);
for(i=0;i<j-1;i++)

36. line(x1[i],y1[i],x1[i+1],y1[i+1]);
getch();
}
void clip(float e,floatf,floatm)
{
while(e<rx1 e>rx2 f<ry1 f>ry2)
{
if(e<rx1)
{
f+=m*(rx1-e);
e=rx1;
}
else if(e>rx2)
{
f+=m*(rx2-e);
e=rx1;
}
if(f<ry1)
{
e+=(ry1-f)/m;
f=ry1;
}
else if(f>ry2)

37. {
e+=(ry2-f)/m;
f=ry2;
}
x1[j]=e;
y1[j]=f;
j++;
}
}
OUTPUT

38. EXPERIMENT-14
14. Write a program toimplement Liang Barsky line clipping algorithm.
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
Void main
{
float x1,y1,x2,y2,xmin,xmax,ymin,ymax,dx,dy;
float p[4],q[4],r[4];
float max,min,u1,u2;
float xi,xii,yi,yii;
int gd,gm,i;
gd=DETECT;
initgraph(&gd,&gm,"c:tcbgi");
clrscr();
printf("n enter the line co-ordinates");
printf("n enter 1stx=");
scanf("%f",&x1);
printf("t1sty=");
scanf("%f",&y1);
printf("n enter 2nd x=");
scanf("%f",&x2);
printf("t2nd y=");

39. scanf("%f",&y2);
printf("n enter window boundry");
printf("n xmin=");
scanf("%f",&xmin);
printf("n ymin=");
scanf("%f",&ymin);
printf("n xmax=");
scanf("%f",&xmax);
printf("n ymax=");
scanf("%f",&ymax)
dx=x2-x1;
dy=y2-y1;
cleardevice();
line(x1,y1,x2,y2);
rectangle(xmin,ymin,xmax,ymax);
p[0]=-dx;
q[0]=x1-xmin;
p[1]=dx;
q[1]=xmax-x1;
p[2]=-dy;
p[2]=-dy;
q[2]=y1-ymin;
p[3]=dy;
q[3]=ymax-y1;
for(i=0;i<4;i++)

40. {
if(p[i]==0 && q[i]<0)
{
printf("Lineis outside the boundry,itis not a clipping candidaten");
getch();
exit(0);
}
}
for(i=0;i<4;i++)
{
r[i]=q[i]/p[i];
printf("n r[%d]=%f",i,r[i]);
}
max=0;min=1;
for(i=0;i<4;i++)
if(p[i]<0)
{
if(r[i]>max)
max=r[i];
}
else
{
if(r[i]<min)
min=r[i];
}

41. u1=max;
u2=min;
printf("n u1=%f",u1);
printf("n u2=%f",u2);
if(u1>u2)
{
printf("n line is completely outside");
getch();
exit(0);
}
xi=x1+(u1*dx);
yi=y1+(u1*dy);
xii=x1+(u2*dx);
yii=y1+(u2*dy);
rectangle (xmin, ymin, xmax, ymax);
sector(5);
line(xi,yi,xii,yii);
getch();
closegraph();
}

43. EXPERIMENT-15
15. Write a program toimplement face of a cartoon.
# include <graphics.h>
# include<conio.h>
#include <stdlib.h>
main()
{
intgd= DETECT, gm,area, temp1, temp2, left=25, top=75;
void*p;
initgraph(&gd, &gm,”C:TCBGI”);
Setcolor(YELLOW);
Circle(50, 100,25);
Sefillstyle(SOLID__FILL,YELLOW);
floodfill(50,100, YELLOW);
Setcolor(BLACK);
Sefillstyle(SOLID__FILL,BLACK);
fillellipse(44, 85, 2, 6);
fillellipse(56, 85, 2, 6);
ellipse(50, 100, 205, 335, 20,9);
ellipse(50, 100, 205, 335, 20,10);
ellipse(50, 100, 205, 335, 20,11);
area= imagesize(left, top, left+ 50, top+50);
p= malloc(area);
setcolor(WHITE);
settextstyle(SANS_SERIF_FONT, HORIZ_DIR,2);
outtextxy(155, 451, “Smiling Face Animation”);
setcolor(BLUE);
rectangle(0,0 , 639,449);
while(!kbhit())
{
Temp1= 1+ randam(588);

44. {
Temp1= 1+ randam(380);
{
Getimage(left, top, left+ 50, top+ 50);
putimage(left, top, p, XOR_PUT);
putimage(temp1, temp2, p, XOR_PUT);
delay(100);
left= temp1;
top = temp2;
}
getch();
closegraph();
return();
}
OUTPUT