C Programs Of Computer Graphics. In these 13 programs with Output is given.

1. 1
Program 1
WRITE A C PROGRAM TO DRAW LINE BY USING DDA AND BRESENHAM'S
ALGORITHM.
# include<stdio.h>
# include<conio.h>
# include<graphics.h>
# include<math.h>
void dda(float x1,float y1,float x2,float y2)
{
float dx,dy,x=x1,y=y1,m;
int i;
dx=x2-x1;
dy=y2-y1;
if(abs(dx)>=abs(dy))
m=abs(dx);
else
m=abs(dy);
putpixel((int)x,(int)y,15);
for(i=1;i<=m;i++)
{
x=x+dx/m;
y=y+dy/m;
putpixel((int)x,(int)y,15);
}
}
void bress(float x1,float y1,float x2,float y2)
{
int x,y,end,inc=0,p,dx=abs(x2-x1);
int dy=abs(y2-y1),c=0,current=0;
if(dx>dy)
{
p=2*dy-dx;
if(x1<x2)
{
x=x1;
y=y1;
end=x2;
if(y1<y2)
inc=1;

2. 2
if(y1>y2)
inc=-1;
}
else
{
x=x2;
y=y2;
end=x1;
if(y2<y1)
inc=1;
if(y2<y1)
inc=-1;
}
while(x<=end)
{
putpixel(x,y,15);
if(p<0)
p=p+2*dy;
else
{
y=y+inc;
p=p+2*(dy-dx);
}
x++;
if(current==0 && c==10)
{
current=1;
c=-1;
}
if(current==1 && c==6)
{
current=0;
c=-1;
}
c++;
}
}
}
void main()
{
float x1,x2,y1,y2;
int ch;
int gd=DETECT,gm=DETECT;

3. 3
initgraph(&gd,&gm," ");
printf("ENTER THE END POINTS OF LINE (x1,y1,x2,y2): ");
scanf("%f%f%f%f",&x1,&y1,&x2,&y2);
printf("CHOOSE ALGORITHM: ");
printf("n 1-DDA");
printf("n 2-BRESENHAM");
printf("n YOUR CHOICE IS: ");
scanf("%d",&ch);
if(ch==1)
dda(x1,y1,x2,y2);
if(ch==2)
bress(x1,y1,x2,y2);
getch();
closegraph();
}

4. 4
OUTPUT-1

5. 5
Program 2
WRITE A C PROGRAM TO DRAW MIDPOINT CIRCLE ALGORITHM.
# include<stdio.h>
# include<graphics.h>
# include<conio.h>
# include<math.h>
void bresenham_circle(const int h,const int k,const int r)
{
int x=0,y=r,p=(3-(2*r));
// cleardevice();
line(320,1,320,480);
line(1,240,640,240);
do
{
delay(15);
putpixel((h+x),(k+y),25);
putpixel((h+y),(k+x),15);
putpixel((h+y),(k-x),25);
putpixel((h+x),(k-y),15);
putpixel((h-x),(k-y),25);
putpixel((h-y),(k-x),15);
putpixel((h-y),(k+x),25);
putpixel((h-x),(k+y),15);
x++;
if(p<0)
p+=((4*x)+6);
else
{
y--;
p+=((4*(x-y))+10);
}
}
while(x<=y);
}
void main(void)
{
int driver=VGA,mode=VGAHI,h,k,r;

6. 6
initgraph(& driver,& mode,"c:tcbgi");
printf("n ENTER THE VALUE OF [H-COORDINATE]: ");
scanf("%d",&h);
printf("n ENTER THE VALUE OF [K-COORDINATE]: ");
scanf("%d",&k);
printf("n ENTER THE VALUE OF THE RADIUS: ");
scanf("%d",&r);
bresenham_circle(320+h,240-k,r);
do
{
r--;
bresenham_circle(320+h,240-k,r);
}while(r!=0);
getche();
}

7. 7
OUTPUT-2

8. 8
Program 3
WRITE A C PROGRAM OF WINDOW TO VIEW PORT.
# include<conio.h>
# include<stdio.h>
# include<graphics.h>
void image();
float wxmin,wymin,wxmax,wymax;
float vxmin,vymin,vxmax,vymax;
void main()
{
int gd,gm;
detectgraph(&gd,&gm);
initgraph(&gd,&gm,"c:tc");
printf("nt ENTER THE COORDINATES OF WINDOW: n");
printf("nt wxmin,wymin: ");
scanf("%f%f",&wxmax,&wymax);
printf("nt ENTER THE COORDINATES OF VIEW: n");
printf("nt vxmin,vymin: ");
scanf("%f%f",&vxmin,&vymin);
printf("nt vxmax,vymax: ");
scanf("%f%f",&vxmax,&vymax);
rectangle(wxmin,wymin,wxmax,wymax);
rectangle(vxmin,vymin,vxmax,vymax);
getch();
cleardevice();
image();
getch();
}
void image()
{
float x1,y1,x2,y2,vx1,vx2,vy1,vy2;
clrscr();
printf("nnt ENTER THE COORDINATES OF LINE: ");
printf("nnt X1 Y1: ");
scanf("%f%f",&x1,&y1);
printf("nnt X2 Y2: ");
scanf("%f%f",&x2,&y2);

9. 9
rectangle(wxmin,wymin,wxmax,wymax);
rectangle(vxmin,vymin,vxmax,vymax);
line(x1,y1,x2,y2);
vx1=((vxmax-vxmin)/(wxmax-wxmin))*(x1-wxmin)+vxmin;
vy1=((vxmax-vxmin)/(wxmax-wxmin))*(y1-wxmin)+vxmin;
vx2=((vxmax-vxmin)/(wxmax-wxmin))*(x2-wxmin)+vxmin;
vy2=((vxmax-vxmin)/(wxmax-wxmin))*(y2-wxmin)+vxmin;
line(vx1,vy1,vx2,vy2);
}

10. 10
OUTPUT-3

11. 11
Program 4
WRITE A C PROGRAM OF COHEN-SUTHERLAND ALGORITHM.
#include<stdio.h>
#include<graphics.h>
typedef unsigned int outcode;
enum { TOP=0x1, BOTTOM=0x2, RIGHT=0x4, LEFT=0x8 };
void lineclip(x0,y0,x1,y1,xwmin,ywmin,xwmax,ywmax )
float x0,y0,x1,y1,xwmin,ywmin,xwmax,ywmax;
{
int gd,gm;
outcode code0,code1,codeout;
int accept = 0, done=0;
code0 = calcode(x0,y0,xwmin,ywmin,xwmax,ywmax);
code1 = calcode(x1,y1,xwmin,ywmin,xwmax,ywmax);
do{
if(!(code0 | code1))
{ accept =1 ; done =1; }
else
if(code0 & code1) done = 1;
else
{
float x,y;
codeout = code0 ? code0 : code1;
if(codeout & TOP)
{
x = x0 + (x1-x0)*(ywmax-y0)/(y1-y0);
y = ywmax;
}
else
if( codeout & BOTTOM)
{
x = x0 + (x1-x0)*(ywmin-y0)/(y1-y0);
y = ywmin;
}
else

12. 12
if ( codeout & RIGHT)
{
y = y0+(y1-y0)*(xwmax-x0)/(x1-x0);
x = xwmax;
}
else
{
y = y0 + (y1-y0)*(xwmin-x0)/(x1-x0);
x = xwmin;
}
if( codeout == code0)
{
x0 = x; y0 = y;
code0=calcode(x0,y0,xwmin,ywmin,xwmax,ywmax);
}
else
{
x1 = x; y1 = y;
code1 = calcode(x1,y1,xwmin,ywmin,xwmax,ywmax);
}
}
} while( done == 0);
if(accept) line(x0,y0,x1,y1);
rectangle(xwmin,ywmin,xwmax,ywmax);
getch();
}
/*--------------------------------------------------------------------*/
int calcode (x,y,xwmin,ywmin,xwmax,ywmax)
float x,y,xwmin,ywmin,xwmax,ywmax;
{
int code =0;
if(y> ywmax)
code |=TOP;
else if( y<ywmin)
code |= BOTTOM;
else if(x > xwmax)
code |= RIGHT;
else if ( x< xwmin)

13. 13
code |= LEFT;
return(code);
}
/*-------------------------------------------------*/
void main()
{
float x2,y2,x1,y1,xwmin,ywmin,xwmax,ywmax;
int gd,gm;
detectgraph(&gd,&gm);
initgraph(&gd,&gm,"C:TCBGI");
printf("nntEnter the co-ordinates of Line :");
printf("nntX1 Y1 : ");
scanf("%f %f",&x1,&y1);
printf("nntX2 Y2 : ");
scanf("%f %f",&x2,&y2);
printf("ntEnter the co_ordinates of window :n ");
printf("ntxwmin , ywmin : ");
scanf("%f %f",&xwmin,&ywmin);
printf("ntxwmax , ywmax : ");
scanf("%f %f",&xwmax,&ywmax);
line(x1,y1,x2,y2);
rectangle(xwmin,ywmin,xwmax,ywmax);
getch();
cleardevice();
lineclip(x1,y1,x2,y2,xwmin,ywmin,xwmax,ywmax );
getch();
closegraph();
}

14. 14
OUTPUT-4

15. 15
Program 5
WRITE A C PROGRAM TO DRAW A BEZIER – CURVE.
#include<stdio.h>
#include<graphics.h>
#include<stdlib.h>
#include<string.h>
#include<conio.h>
#include<math.h>
int *x,*y;
void bezier(int *x1,int *y1)
{
int xa,ya,za;
float u=0;
moveto(*x1,*y1);
while (u<=1)
{
xa=(*(x1+3)*pow(u,3))+(3*(*(x1+2))*pow(u,2)*(1-u))+
(3*(*(x1+1))*u*pow(1-u,2))+(*x1*pow(1-u,3));
ya=(*(y1+3)*pow(u,3))+(3*(*(y1+2))*pow(u,2)*(1-u))+
(3*(*(y1+1))*u*pow(1-u,2))+(*y1*pow(1-u,3));
lineto(xa, ya);
u += 0.01;
}
}
void main(void)
{
int gd=DETECT, gm, key, xpos, ypos, i = 0;
char xp[4], yp[4];
x = (int *)malloc(sizeof(int) * 4);
y = (int *)malloc(sizeof(int) * 4);
//registerbgidriver(EGAVGA_driver);
initgraph(&gd, &gm, "c:tcbgi");
outtextxy(10, 460, "Press Esc to exit.");
outtextxy(400, 460, "Present position : ");
moveto(getmaxx() / 2, getmaxy() / 2);
do
{

16. 16
xpos = getx();
ypos = gety();
itoa(xpos, xp, 10);
itoa(ypos,yp,10);
setviewport(550,460,639,479,1);
clearviewport();
outtextxy(0,0,xp);
outtextxy(40,0,yp);
setviewport(0,0,639,479,1);
moveto(xpos,ypos);
key=getch();
if (key==0) key=getch();
switch(key)
{
case 72 : ypos--; //up arrow
moveto(xpos,ypos);
break;
case 80 : ypos++; //down arrow
moveto(xpos,ypos);
break;
case 75 : xpos--; //left arrow
moveto(xpos,ypos);
break;
case 77 : xpos++; //right arrow
moveto(xpos,ypos);
break;
case 87 :
case 119 : ypos-=50;
moveto(xpos,ypos);
break;
case 65 :
case 97 : xpos-=50;
moveto(xpos,ypos);
break;
case 83 :
case 115 :xpos+=50;
moveto(xpos,ypos);
break;
case 90 :
case 122 :ypos+=50;
moveto(xpos,ypos);
break;
case 13 : putpixel(xpos,ypos,15);
*(x+i)=xpos;

17. 17
*(y+i)=ypos;
i++;
break;
}
if (i==4)
{
bezier(x,y);
i=0;
}
}
while(key!=27);
closegraph();
getch();
}

18. 18
Output-5

19. 19
Program 6
WRITE A C PROGRAM TO SHEAR A CUBOID.
#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<graphics.h>
void bress(float x1,float y1, float x2,float y2)
{
int x,y,end,inc=0,p,dx=abs(x2-x1),dy=abs(y2-y1),c=0,current=0;
if ( dx > dy )
{
p=2*dy-dx;
if(x1<x2)
{
x=x1;
y=y1;
end=x2;
if(y1<y2)
inc=1;
if(y1>y2)
inc=-1;
}
else
{
x=x2;
y=y2;
end=x1;
if(y2<y1)
inc=1;
if(y2>y1)
inc=-1;
}
while(x<=end)
{
putpixel(x,y,15);
if(p<0)
p=p+2*dy;
else
{

20. 20
y=y+inc;
p=p+2*(dy-dx);
}
x++;
if(current==0 && c==10)
{
current=1;
c=-1;
}
if(current==1 && c==6)
{
current=0;
c=-1;
}
c++;
}
}
else
{
p=2*dx-dy;
if(y1<y2)
{
x=x1;
y=y1;
end=y2;
if(x1<x2)
inc=1;
if(x1>x2)
inc=-1;
}
else
{
x=x2;
y=y2;
end=y1;
if(x2<x1)
inc=1;
if(x2>x1)
inc=-1;
}
while(y<=end)
{
putpixel(x,y,15);
if(p<0)

21. 21
p=p+2*dx;
else
{
x=x+inc;
p=p+2*(dx-dy);
}
y++;
if(current==0 && c==10)
{
current=1;
c=-1;
}
if(current==1 && c==6)
{
current=0;
c=-1;
}
c++;
}
}
}
void main()
{
float x1,x2,a,b,c,d,y1,y2;
double ch;
int t=30;
int gd=DETECT,gm=DETECT;
initgraph(&gd,&gm,"c:tcbgi");
printf("Enter the end pts of the line(x,y)");
scanf("%f%f%f%f",&x1,&y1,&x2,&y2);
bress(x1,y1,x2,y1);
bress(x2,y1,x2,y2);
bress(x1,y2,x2,y2);
bress(x1,y2,x1,y1);
bress(x1+t,y1+t,x2+t,y1+t);
bress(x2+t,y1+t,x2+t,y2+t);
bress(x1+t,y2+t,x2+t,y2+t);
bress(x1+t,y2+t,x1+t,y1+t);
bress(x1,y1,x1+t,y1+t);
bress(x2,y1,x2+t,y1+t);

22. 22
bress(x1,y2,x1+t,y2+t);
bress(x2,y2,x2+t,y2+t);
/*
a=x1+(10*y1);
b=x2+(10*y1);
c=(10*x1)+y1;
d=(10*x2)+y1;*/
bress(x1+50,y1+40,x2+50,y1+40);
bress(x1+t,y2+t,x1+50,y1+40);
bress(x2+t,y2+t,x2+50,y1+40);
bress(x1+50,y1+40,x1,y1);
bress(x2+50,y1+40,x2,y1);
getch();
closegraph();
}

23. 23
OUTPUT-6

24. 24
Program 7
WRITE A C PROGRAM TO DRAW A POLYGON AND PERFORM THE FOLLOWING
OPERATIONS:-
ROTATION
TRANSLATION
SCALING.
#include<stdio.h>
#include<graphics.h>
#include<stdlib.h>
#include<conio.h>
#include<math.h>
int *x,*y,i,nin;
float x1,y1,theta;
void drawpolygon(int *x,int *y)
{
int gd=DETECT,gm,ch=0,x1,y1,theta;
//registerbgidriver(EGAVGA_driver);
initgraph(&gd,&gm,"");
for (i=0;i<(nin-1);i++)
line(*(x+i),*(y+i),*(x+i+1),*(y+i+1));
line(*(x+nin-1),*(y+nin-1),*x,*y);
getch();
closegraph();
}
void translate(float x1,float y1)
{
for (i=0;i<nin;i++)
{
*(x+i)+=x1;
*(y+i)+=y1;
}
}
void scale(float x1,float y1)
{
int a,b;
a=*x;

25. 25
b=*y;
translate(-a,-b);
for (i=0;i<nin;i++)
{
*(x+i)*=x1;
*(y+i)*=y1;
}
translate(a,b);
}
void rotate(float theta)
{
int a,b,c,d;
c=*x;
d=*y;
translate(-c,-d);
for (i=0;i<nin;i++)
{
a=(*(x+i)*cos(theta))-(*(y+i)*sin(theta));
b=(*(x+i)*sin(theta))+(*(y+i)*cos(theta));
*(x+i)=a;
*(y+i)=b;
}
translate(c,d);
}
void main(void)
{
int ch;
x=(int *)malloc(sizeof(int)*10);
y=(int *)malloc(sizeof(int)*10);
clrscr();
printf("ENTER NUMBER OF SIDES IN POLYGON : ");
scanf("%d",&nin);
printf("ENTER THE COORDINATES OF THE VERTICES (x,y) :n");
for (i=0;i<nin;i++)
{
printf("(i+1) : ");
scanf("%d%d",&(*(x+i)),&(*(y+i)));
}
drawpolygon(x,y);
while (ch!=4)
{
printf("YOUR OPTIONS :n");

26. 26
printf("1)TRANSLATEn");
printf("2)SCALEn");
printf("3)ROTATEn");
printf("4)EXITn");
printf("nYOUR CHOICE : ");
scanf("%d",&ch);
clrscr();
switch(ch)
{
case 1:printf("TRANSLATION IN X-DIRECTION : ");
scanf("%d",&x1);
printf("TRANSLATION IN Y-DIRECTION : ");
scanf("%d",&y1);
translate(x1,y1);
drawpolygon(x,y);
break;
case 2:printf("SCALING IN X-DIRECTION : ");
scanf("%f",&x1);
printf("SCALING IN Y-DIRECTION : ");
scanf("%f",&y1);
scale(x1,y1);
drawpolygon(x,y);
break;
case 3:printf("ANGLE OF ROTATION(ANTI-CLOCKWISE IS POSITIVE) : ");
scanf("%f",&theta);
theta*=3.1415/180;
rotate(-theta);
drawpolygon(x,y);
break;
case 4:exit(0);
}
}
}

27. 27
Output-7
After translation
After scaling

28. 28
After Rotation

29. 29
Program 8
WRITE A C PROGRAM TO DRAW A RECTANGLE BY USING BRESENHAM AND DDA
ALGORITHM.
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
void dda(float x1,float y1,float x2,float y2)
{
float dx,dy,x=x1,y=y1,m;
int i;
dx=x2-x1;
dy=y2-y1;
if(abs(dx)>=abs(dy))
m=abs(dx);
else m=abs(dy);
putpixel((int)x,(int)y,15);
for(i=1;i<m;i++)
{
x=x+dx/m;
y=y+dy/m;
putpixel((int)x,(int)y,15);
}
}
void bress(float x1,float y1,float x2,float y2)
{
int x,y,end,inc=0,p,dx=abs(x2-x1),dy=abs(y2-y1),c=0,current=0;
if(dx>dy)
{
p=2*dy-dx;
if(x1<x2)
{
x=x1;y=y1;end=x2;
}
if(y1<y2)
inc=1;
if(y1>y2)
inc=-1;
}
else
{
x=x2;y=y2;end=x1;
if(y2<y1)

30. 30
inc=1;
if(y2>y1)
inc=-1;
}
while(x<=end)
{
putpixel(x,y,15);
if(p<0)
p=p+2*dy;
else
{
y=y+inc;p=p+2*(dy-dx);
}
x++;
if(current==0&&c==10)
{
current=1;
c=-1;
}
if(current==1&&c==6)
{
current=0;
c=-1;
}
c++;
}
}
void main()
{
float x1,x2,y1,y2,x3,y3,x4,y4;
int ch;
int gdriver=DETECT, gmode=DETECT;
initgraph(&gdriver, &gmode, "c:tcBGI");
printf("Enter end points of line (x1,y1,x2,y2)");
scanf("%f %f %f %f %f %f %f %f",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4);
printf("Choose algorithm(1-DDA 2-BRESENHAM)");
scanf("%d",&ch);
bress(x1,y1,x2,y2);
dda(x2,y2,x3,y3);
bress(x4,y4,x3,y3);
dda(x4,y4,x1,y1);
getch();
closegraph();
}

31. 31
OUTPUT-8

32. 32
Program 9
WRITE A C PROGRAM TO DRAW A SOLID AND FIND ITS VANISHING POINT.
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
void createsolid();
void main()
{
int gd = DETECT,gm = DETECT;
initgraph(&gd,&gm,"c:tcbgi");
clrscr();
createsolid();
getch();
closegraph();
}
void createsolid()
{
//The coordinates of first rectangle
line(250,200,370,200);
line(370,200,370,320);
line(370,320,250,320);
line(250,200,250,320);
//The coordinates of scond rectangle
line(280,150,400,150);
line(400,150,400,270);
line(400,270,280,270);
line(280,150,280,270);
//The coordinates of the lines
line(250,200,280,150);
line(370,200,400,150);
line(370,320,400,270);
line(250,320,280,270);
//The coordinates of the X,Y and Z axis
line(320,300,600,300);
line(320,50,320,300);
line(320,300,170,450);
//Coordinates for vanishing point
putpixel(190,430,RED);
}

33. 33
OUTPUT-9

34. 34
Program 10
WRITE A C PROGRAM TO TRANSLATE A LINE BY USING DDA ALGORITHM.
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
void dda(float x1,float y1,float x2,float y2)
{
float dx,dy,x=x1,y=y1,m;
int i;
dx=x2-x1;
dy=y2-y1;
if(abs(dx)>=abs(dy))
m=abs(dx);
else
m=abs(dy);
putpixel((int)x,(int)y,15);
for(i=1;i<=m;i++)
{ x=x+dx/m;
y=y+dy/m;
putpixel((int)x,(int)y,15);
}
}
void main()
{
float x11,x12,y11,y12, x21, x22, y21, y22;
float nw;
int gd=DETECT,gm=DETECT;
initgraph(&gd,&gm,"c:tcbin");
printf("enter endpoints of line(x1,y1,x2,y2)");
scanf("%f%f%f%f",&x11,&x12,&y11,&y12);
dda(x11,x12,y11,y12);
printf("Please enter new position");
scanf("%f",&nw);
x21=x11+nw;
y21=y11+nw;
x22=x12+nw;
y22=y12+nw;
dda(x21,x22,y21,y22);
getch();
closegraph();
}

35. 35
OUTPUT-10

36. 36
Program 11
WRITE A C PROGRAM TO ROTATE A TRIANGLE.
#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<graphics.h>
void bress(float x1,float y1, float x2,float y2)
{
int x,y,end,inc=0,p,dx=abs(x2-x1),dy=abs(y2-y1),c=0,current=0;
if ( dx > dy )
{
p=2*dy-dx;
if(x1<x2)
{
x=x1;
y=y1;
end=x2;
if(y1<y2)
inc=1;
if(y1>y2)
inc=-1;
}
else
{
x=x2;
y=y2;
end=x1;
if(y2<y1)
inc=1;
if(y2>y1)
inc=-1;
}
while(x<=end)
{
putpixel(x,y,15);
if(p<0)
p=p+2*dy;
else
{
y=y+inc;
p=p+2*(dy-dx);

37. 37
}
x++;
if(current==0 && c==10)
{
current=1;
c=-1;
}
if(current==1 && c==6)
{
current=0;
c=-1;
}
c++;
}
}
else
{
p=2*dx-dy;
if(y1<y2)
{
x=x1;
y=y1;
end=y2;
if(x1<x2)
inc=1;
if(x1>x2)
inc=-1;
}
else
{
x=x2;
y=y2;
end=y1;
if(x2<x1)
inc=1;
if(x2>x1)
inc=-1;
}
while(y<=end)
{
putpixel(x,y,15);
if(p<0)
p=p+2*dx;
else

38. 38
{
x=x+inc;
p=p+2*(dx-dy);
}
y++;
if(current==0 && c==10)
{
current=1;
c=-1;
}
if(current==1 && c==6)
{
current=0;
c=-1;
}
c++;
}
}
}
void main()
{
float a[3][3],b[3][3],c[3][3],i,j,k;
float r=(3.14*45)/180;
int gd=DETECT,gm=DETECT;
clrscr();
initgraph(&gd,&gm,"c:tcbgi");
//IMAGE(triangle)
bress(0,0,100,100);
bress(100,100,500,200);
bress(500,200,0,0);
a[0][0]=0;
a[0][1]=0;
a[0][2]=1;
a[1][0]=100;
a[1][1]=100;
a[1][2]=1;
a[2][0]=500;
a[2][1]=200;
a[2][2]=1;
b[0][0]=cos(r);

39. 39
b[0][1]=sin(r);
b[0][2]=0;
b[1][0]=-sin(r);
b[1][1]=cos(r);
b[1][2]=0;
b[2][0]=0;
b[2][1]=0;
b[2][2]=1;
//MATRIX MULTIPLICATION
for(i=0;i<3;i++)
for(j=0;j<3;j++)
{
c[i][j]=0;
for(k=0;k<3;k++)
{
c[i][j]+=a[i][k]*b[k][j];
}
}
//AFTER ROTATION
line(c[0][0],c[0][1],c[1][0],c[1][1]);
line(c[1][0],c[1][1],c[2][0],c[2][1]);
line(c[2][0],c[2][1],c[0][0] ,c[0][1]);
getch();
}

40. 40
OUTPUT-11

41. 41
Program 12
WRITE A C PROGRAM TO DRAW BEZIER – SURFACE.
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
void main()
{
int gd,gm, x1,x2,x3,x4,y1,y2,y3,y4,y11,y22,y33,y44,i;
gd=DETECT,gm=DETECT;
clrscr();
initgraph(&gd,&gm,"c:tcbgi");
x1=100;x2=130;x3=170;x4=200;y1=150;y2=16 ;y3=160;x4=165;
line(x1,y1,x2,y2);
line(x2,y2,x3,y3);
line(x3,y3,x4,y4);
y11=y1;
y22=y2;
y33=y3;
y44=y4;
for(i=0;i<5;i++)
{
y11=y11+10;
y22=y22+10;
y33=y33+10;
y44=y44+10;
line(x1,y11,x2,y22);
line(x2,y22,x3,y33);
line(x3,y33,x4,y44);
}
line(x1,y1,x1,y11);
line(x2,y2,x2,y22);
line(x3,y3,x3,y33);
line(x4,y4,x4,y44);
getch();
closegraph();
}

42. 42
OUTPUT-12

43. 43
Program 13
WRITE A C PROGRAM TO CONVERT WINDOW COORDINATES IN TO VIEW PORT.
#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<graphics.h>
void bress(float x1,float y1, float x2,float y2)
{
int x,y,end,inc=0,p,dx=abs(x2-x1),dy=abs(y2-y1),c=0,current=0;
if ( dx > dy )
{
p=2*dy-dx;
if(x1<x2)
{
x=x1;
y=y1;
end=x2;
if(y1<y2)
inc=1;
if(y1>y2)
inc=-1;
}
else
{
x=x2;
y=y2;
end=x1;
if(y2<y1)
inc=1;
if(y2>y1)
inc=-1;
}
while(x<=end)
{
putpixel(x,y,15);
if(p<0)
p=p+2*dy;
else
{
y=y+inc;
p=p+2*(dy-dx);

44. 44
}
x++;
if(current==0 && c==10)
{
current=1;
c=-1;
}
if(current==1 && c==6)
{
current=0;
c=-1;
}
c++;
}
}
else
{
p=2*dx-dy;
if(y1<y2)
{
x=x1;
y=y1;
end=y2;
if(x1<x2)
inc=1;
if(x1>x2)
inc=-1;
}
else
{
x=x2;
y=y2;
end=y1;
if(x2<x1)
inc=1;
if(x2>x1)
inc=-1;
}
while(y<=end)
{
putpixel(x,y,15);
if(p<0)
p=p+2*dx;
else

45. 45
{
x=x+inc;
p=p+2*(dx-dy);
}
y++;
if(current==0 && c==10)
{
current=1;
c=-1;
}
if(current==1 && c==6)
{
current=0;
c=-1;
}
c++;
}
}
}
void main()
{
float x1,x2,x3,x4,y1,y2,y3,y4;
double ch;
int t;
float vx,vy,vx1,vx2,vy2;
int gd=DETECT,gm=DETECT;
initgraph(&gd,&gm,"c:tcbgi");
outtextxy(250,190,"World coordinates");
bress(200,200,400,200);
bress(200,200,200,400);
bress(400,200,400,400);
bress(200,400,400,400);
outtextxy(23,10,"View port");
bress(20,20,100,20);
bress(20,20,20,100);
bress(100,20,100,100);
bress(20,100,100,100);
//IMAGE(triangle)
bress(250,250,350,250);

46. 46
bress(250,250,300,300);
bress(350,250,300,300);
//TRANSFORMATION
vx=(((100-20)*(250-200))/(400-200))+20;
vy=(((100-20)*(250-200))/(400-200))+20;
vx1=(((100-20)*(350-200))/(400-200))+20;
vx2=(((100-20)*(300-200))/(400-200))+20;
vy2=(((100-20)*(300-200))/(400-200))+20;
//TRANSFORMED IMAGE
bress(vx,vy,vx1,vy);
bress(vx,vy,vx2,vy2);
bress(vx1,vy,vx2,vy2);
getch();
}

47. 47
OUTPUT-13