Grphics c codings for MM lab

//Ellips draing using midpoint algorithm


#include<stdio.h>
//#include<conio.h>
#include<graphics.h>
#include<math.h>
void disp();
float x,y;
int xc,yc;
void main()
{
int gd=DETECT,gm;
int a,b;
float p1,p2;
//clrscr();
initgraph(&gd,&gm,"");
scanf("%d%d",&xc,&yc);
scanf("%d%d",&a,&b);
x=0;y=b;
disp();
p1=(b*b)-(a*a*b)+(a*a)/4;
while((2.0*b*b*x)<=(2.0*a*a*y))
{
x++;
if(p1<=0)
p1=p1+(2.0*b*b*x)+(b*b);
else
{
y--;
p1=p1+(2.0*b*b*x)+(b*b)-(2.0*a*a*y);
}
disp();
x=-x;
disp();
x=-x;
}
x=a;
y=0;
disp();
p2=(a*a)+2.0*(b*b*a)+(b*b)/4;
while((2.0*b*b*x)>(2.0*a*a*y))
{
y++;
if(p2>0)
p2=p2+(a*a)-(2.0*a*a*y);
else
{
x--;
p2=p2+(2.0*b*b*x)-(2.0*a*a*y)+(a*a);
}
disp();
y=-y;
disp();
y=-y;
}
//getch();
closegraph();
}
void disp()
{
putpixel(xc+x,yc+y,10);
putpixel(xc-x,yc+y,10);
putpixel(xc+x,yc-y,10);
putpixel(xc+x,yc-y,10);
}





//Line Drawing Algorithm - Bresenham

#include<stdio.h>
#include<conio.h>
#include<graphics.h>
void main()
{
      int gd = DETECT, gm;
      int dx, dy, p, end;
      float x1, x2, y1, y2, x, y;
      initgraph(&gd, &gm, "c:\tc\bgi");
      printf("Enter Value of X1: ");
      scanf("%f", &x1);
      printf("Enter Value of Y1: ");
      scanf("%f", &y1);
      printf("Enter Value of X2: ");
      scanf("%f", &x2);
      printf("Enter Value of Y2: ");
      scanf("%f", &y2);
      dx = abs(x1 - x2);
      dy = abs(y1 - y2);
      p = 2 * dy - dx;
      if(x1 > x2)
      {
            x = x2;
            y = y2;
            end = x1;
      }
      else
      {
            x = x1;
            y = y1;
            end = x2;
      }
      putpixel(x, y, 10);
      while(x < end)
      {
            x = x + 1;
            if(p < 0)
            {
                  p = p + 2 * dy;
            }
            else
            {
                  y = y + 1;
                  p = p + 2 * (dy - dx);
            }
            putpixel(x, y, 10);
      }
      getch();
      closegraph();
}







// circle drawing algorithm-midpoint

#include<stdio.h>
#include<conio.h>
#include<graphics.h>
int x,y,p,r,d,a,b;
void mid();
void pixel(int a,int b);
void main()
{
int gm,gr;
clrscr();
detectgraph(&gm,&gr);
initgraph(&gm,&gr,"d:\\tc\\BGI");
printf("Enter the center point:\n");
scanf("%d%d",&a,&b);
printf("Enter the radius:\n");
scanf("%d",&r);
mid();
getch();
}
void mid()
{
x=0;
y=r;
p=1-r;
while(x<y)
{
pixel(a,b);
if(p<0)
x=x+1;
else
{
x=x+1;
y=y-1;
}
if(p<0)
p=p+2*x+1;
else
p=p+2*(x-y)+1;
}
}
void pixel(int a,int b)
{
putpixel(a+x,b+y,10);
putpixel(a-x,b+y,10);
putpixel(a+x,b-y,10);
putpixel(a-x,b-y,10);
putpixel(a+y,b+x,10);
putpixel(a-y,b-x,10);
putpixel(a+y,b-x,10);
putpixel(a-y,b+x,10);
}