Theory :
https://pastebin.pl/view/d9b1d994

// EXP 1 To implement DDA Algorithm for drawing a line segment between two given end

#include<stdio.h>
#include<graphics.h> 
#include<math.h> 
void main()
{
float x,y,x1,y1,x2,y2,dx,dy,length; 
int i,gd,gm; clrscr();
/* Read two end points of line --
-------------------------------- */ 
printf("Enter the value of x1 
:\t"); scanf("%f",&x1); 
printf("Enter the value of y1 
:\t"); scanf("%f",&y1); 
printf("Enter the value of x2 
:\t"); scanf("%f",&x2); 
printf("Enter the value of y2 
:\t"); scanf("%f",&y2);
/* Initialise graphics mode ----------------------------------
*/
detectgraph(&gd,&gm); 
initgraph(&gd,&gm,"\\tc\\BGI");
dx=abs(x2-x1); dy=abs(y2-y1);
if (dx >= dy)
{ length = dx; }
else
{ length = dy; } dx = 
(x2-x1)/length; dy = 
(y2-y1)/length; x = 
x1 + 0.5; /* Factor 
0.5 is added to 
round the values */ 
y = y1 + 0.5; /* 
Factor 0.5 is added 
to round the values 
*/ putpixel (x, y, 
15); i = 1; /* 
Initialise loop 
counter */ while(i 
<= length)
{
x = x + dx;
y = y + dy;putpixel (x, y, 15); i = i + 1; delay(100); /*Delay is purposely 
inserted to see observe the line drawing 
process*/ 
}
getch(); 
closegraph();
}

// To implement Bresenham’s line drawing algorithm for drawing a line segment between 
two given endpoints A (x1, y2) and B(x2, y2).

#include<stdio.h>
#include<graphics.h>
#include<math.h> 
#include<conio.h> 
void main()
{
float x,y,x1,y1,x2,y2,dx,dy,e; 
int i,gd,gm; clrscr();
/* Read two end points of line --
-------------------------------- */ 
printf("Enter the value of x1 
:\t"); scanf("%f",&x1); 
printf("Enter the value of y1 
:\t"); scanf("%f",&y1); 
printf("Enter the value of x2 
:\t"); scanf("%f",&x2); 
printf("Enter the value of y2 
:\t"); scanf("%f",&y2);
/* Initialise graphics mode ----------------------------------
*/
detectgraph(&gd,&gm); 
initgraph(&gd,&gm,"c:\\tc\\BGI");
dx=abs(x2-x1); dy=abs(y2-y1);
/* Initialise starting point 
-----------------------------*/ 
x = x1; y = y1; putpixel (x, 
y, 15) ;
/* Initialise decision variable 
-------------------------------- */ e 
= 2 * dy-dx;
i = 1; /* Initialise loop counter */ do
{ while(e >= 0)
{
y = y + 1; e = 
e - 2 * dx; }
x = x + 1; e = e + 2 
* dy; i = i + 1; putpixel (x, 

y, 15); }while( i <= dx); 
getch(); closegraph();
}


// To implement area filling algorithm.

#include<stdio.h>
#include<graphics.h> 
#include<conio.h>
void flood(int, int, int, int);
void main()
{ int gd,gm;
/* Initialise graphics mode---------------------------------- */ 
detectgraph(&gd,&gm); 
initgraph(&gd,&gm,"\\tc\\bgi");
rectangle(50,50,100,100)
; flood(55,55,4,15); 
getch();
closegraph();
}
void flood(int seed_x,int seed_y,int foreground_col,int background_col)
{ if(getpixel(seed_x,seed_y)!= background_col && getpixel(seed_x,seed_y)!= 
foreground_col)
{ putpixel(seed_x,seed_y,foreground_col); 
flood(seed_x+1,seed_y,foreground_col,background_col); 
flood(seed_x-1,seed_y,foreground_col,background_col); 
flood(seed_x,seed_y+1,foreground_col,background_col); 
flood(seed_x,seed_y-1,foreground_col,background_col); 
flood(seed_x+1,seed_y+1,foreground_col,background_col); 
flood(seed_x-1,seed_y-1,foreground_col,background_col); 
flood(seed_x+1,seed_y-1,foreground_col,background_col); 
flood(seed_x-1,seed_y+1,foreground_col,background_col); }
}

//To implement Bit Map method for given character generation 

#include<stdio.h>
#include<conio.h> 
#include<graphics.h> 
void main()
{ int gd=DETECT,gm,i,j; int 
a[20][20]=
{{0,0,0,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,0,0},
{0,0,1,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,1,0},
{0,1,0,0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0},
{1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0},
{1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,1,1,1,1,0},
{1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,1,0},
{0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,1,0},
{0,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,1,0,0}, 
{0,0,0,1,1,1,0,0,0,0,0,0,0,1,1,1,1,0,0,0}}; 
initgraph(&gd,&gm,"c:\\tc\\bgi"); 
for(i=0;i<19;i++)
{ for(j=0;j<19;j++)
{
if(a[i][j]==1)
 putpixel(100+j,200+i,WHITE);
}
}
getch();
}


//: To apply the basic 2D transformations such as translation, Scaling, Rotation for a 
given 2D object

include<graphics.h>
#include<conio.h>
#include<math.h> 
#include<stdio.h> 
int main()
{
int i, x, y, tx, ty, sx, sy, angle=10, xmax, ymax, xmid, ymid, op; 
int gd,gm; float p1[10]={50,50,
 100,50,
 100,100,
 50,100,
 50,50,}; 
int pi[10]; float 
b[3][3]={1,0,0,
 0,1,0,
 0,0,1}; int c[1][1]; float 
a[1][1]; printf("\nSelect the transformation 
: "); printf("\n1 : Traslation"); printf("\n2 : 
Rotation"); printf("\n3 : Scaling"); 
printf("\n4 : Rotation about arbitrary 
point"); printf( "\nEnter the option : "); 
scanf("%d",&op); switch(op)
{
case 1: 
printf("\nEnter x traslation : "); 
scanf("%d",&tx); 
printf("\nEnter y traslation : "); 
scanf("%d",&ty);
b[0][0] = 1; 
b[0][1] = 0; 
b[0][2] = 0;
b[1][0] = 0; 
b[1][1] = 1; 
b[1][2] = 0;
b[2][0] = tx; 
b[2][1] = ty; 
b[2][2] = 1; 
break;
case 2: 
printf("\nEnter Rotation angle : "); 
scanf("%d",&angle);
b[0][0] =cos(angle*3.142/180); 
b[0][1] =sin(angle*3.142/180); 
b[0][2] = 0;
b[1][0] =-sin(angle*3.142/180); 
b[1][1] = cos(angle*3.142/180); 
b[1][2] = 0;
b[2][0] = 0; 
b[2][1] = 0; 
b[2][2] = 1; 
break;
case 3: 
printf("\nEnter x scaling : "); 
scanf("%d",&sx); 
printf("\nEnter y scaling : "); 
scanf("%d",&sy);
b[0][0] = sx; 
b[0][1] = 0;
b[0][2] = 0;
b[1][0] = 0; 
b[1][1] = sy; 
b[1][2] = 0;
b[2][0] = 0; 
b[2][1] = 0; 
b[2][2] = 1; 
break;

case 4: 
printf("\nEnter x coordinate of arbitrary point : 
"); scanf("%d",&x); printf("\nEnter y coordinate 
of arbitrary point : "); scanf("%d",&y); 
printf("\nEnter Rotation angle : "); 
scanf("%d",&angle);
tx = x; 
ty = y; 
b[0][0] 
=cos(an
gle*3.1
42/180)
; b[0][1] 
=sin(an
gle*3.1
42/180)
; b[0][2] 
= 0;
b[1][0] =-sin(angle*3.142/180); 
b[1][1] = cos(angle*3.142/180); 
b[1][2] = 0;
b[2][0] = -tx* cos(angle*3.142/180) + ty*sin(angle*3.142/180)+tx; 
b[2][1] = -tx* sin(angle*3.142/180) - ty*cos(angle*3.142/180)+ty; 
b[2][2] = 1;
} detectgraph(&gd,&gm); 
initgraph(&gd,&gm,"\\tc\\bgi"); // Initialize 
graphics
xmax = getmaxx(); // Get maximum x 
coordinate
ymax = getmaxy(); // Get maximum y 
coordinate
xmid = xmax/2; // Get the center x 
coordinate

ymid = ymax/2; 
setcolor(1);
// Get the center y 
coordinate
line(xmid,0,xmid,ymax); // Draw y coordinate
line(0, ymid, xmax, ymid); // Draw x coordinate
setcolor(4); for 
(i=0; i<8;i=i+2)
{ line(p1[i]+xmid,ymid-p1[i+1],xmid+p1[i+2],ymid-p1[i+3]);
}
for(i=0;i<9;i=i+2)
{
a[0][0]=p1[i]; a[0][1]=p1[i+1]; c[0][0] = 
a[0][0]*b[0][0]+a[0][1]*b[1][0]+b[2][0]; c[0][1] = 
a[0][0]*b[0][1]+a[0][1]*b[1][1]+b[2][1]; 
pi[i]=c[0][0]; pi[i+1]=c[0][1];
}
setcolor(15); for 
(i=0; i<8;i=i+2)
{ line(xmid+pi[i],ymid-pi[i+1],xmid+pi[i+2],ymid-pi[i+3]);
}
getch(); 
closegraph(); 
return 0;
}

// To implement Bezier curve.

#include <stdio.h>
#include <graphics.h>
#include <conio.h>
#include<stdio.h> 
#include<process.h> 
int gd,gm,maxx,maxy; 
float xxx[4][2];
/* Function to draw line from relative position specified in array xxx-----------------------*/ 
void line1(float x2,float y2)
{ line(xxx[0][0],xxx[0][1],x2,y2);
xxx[0][0]=x2; xxx[0][1]=y2;
}
/* Bezier function-------------------- */
void bezier(float xb,float yb,float xc,float yc,float xd,float yd,int n)
{ float xab,yab,xbc,ybc,xcd,ycd; 
float xabc,yabc,xbcd,ybcd; 
float xabcd,yabcd;
if (n==0)
{
line1(xb,yb); 
line1(xc,yc);
line1(xd,yd); }
else
{ xab = (xxx[0][0]+xb)/2; yab = 
(xxx[0][1]+yb)/2; xbc = (xb+xc)/2; ybc = 
(yb+yc)/2; xcd = (xc+xd)/2; ycd = 
(yc+yd)/2; xabc = (xab+xbc)/2; yabc = 
(yab+ybc)/2; xbcd = (xbc+xcd)/2; ybcd = 
(ybc+ycd)/2; xabcd = (xabc+xbcd)/2; 
yabcd = (yabc+ybcd)/2; n=n-1; 
bezier(xab,yab,xabc,yabc,xabcd,yabcd,n);
bezier(xbcd,ybcd,xcd,ycd,xd,yd,n);
}
}
/* Function to initialise graphics----------------------------------- */ void 
igraph()
{ detectgraph(&gd,&gm);
if(gd<0)
{ puts("CANNOT DETECT A GRAPHICS CARD");
exit(1); 
}
initgraph(&gd,&gm,"\\tc\\bgi");
} void 
main()
{
int i;
float temp1,temp2; 
igraph();
/*Read two end points and two control points of the curve*/ 
for(i=0;i<4;i++)
{
printf("Enter (x,y) coordinates of point%d : ",i+1);
scanf("%f,%f",&temp1,&temp2);
xxx[i][0] = temp1; xxx[i][1] 
= temp2;
}
bezier(xxx[1][0],xxx[1][1],xxx[2][0],xxx[2][1],xxx[3][0],xxx[3][1],8); getch();
closegraph();
}