Digital
differential analyzer (DDA) is used for linear interpolation of variables over
an interval between start and end point. DDA is used for plotting horizontal or
vertical lines. It is use to plot lines, triangles and polygons. DDA algorithm
can be described as naive line-drawing algorithm, with minor variations.
Note : You should have graphics.h header
file in the specified directory
otherwise no graphs will be displayed.
You also can copy the said file in the current
directory and declared it as #include
"graphics.h". Some of the software which meant for 64 bit system are
without any graphics utility. ‘Turbo C ‘ is providing a lots of graphics
utilities.
#include <stdio.h>
#include <conio.h>
#include<graphics.h>
void
ddaGr(int xs,int ys,int xn,int yn)
{
int
dx,dy,x=0,y=0,len,i,s,j;
if((xn-xs)>(yn-ys))
{
len=(xn-xs);
}
else
{
len=(yn-ys);
}
dx=((xn-xs)/len);
dy=((yn-ys)/len);
for(i=1;i<=len;i++)
{
x=x+dx;
y=y+dy;
putpixel(x,y,4);
if(dx>dy)
{
x++;
}
else
{
y++;
}
}
}
int main()
{
int gd,gm,x1,y1,x2,y2;
printf("\n\n\tEnter
the co-ordinates of first point : ");
scanf("%d%d",&x1,&y1);
printf("\n\n\tEnter
the co-ordinates of second point : ");
scanf("%d
%d",&x2,&y2);
detectgraph(&gm,&gd);
initgraph(&gm,&gd,"");
// mentioned proper path for bgi
ddaGr(x1,y1,x2,y2);
getch();
closegraph();
}
The Bresenham algorithm used to draw lines on a computer screen,
using only integer operation such as addition, subtraction and bit shifting. A
modified extension of the algorithm also
implemented for dawing circles.
#include <stdio.h>
#include <conio.h>
#include<graphics.h>
int main()
{
int dx,dy,x,y,t,x1,y1,x2,y2;
int
gd,gm;
printf("\n\n\tEnter
the co-ordinates of first point : ");
scanf("%d%d",&x1,&y1);
printf("\n\n\tEnter
the co-ordinates of second point : ");
scanf("%d
%d",&x2,&y2);
dx = (x2 - x1);
dy = (y2 - y1);
t = 2 * (dy) - (dx);
x = x1;
y = y1;
detectgraph(&gd,&gm);
initgraph(&gd,&gm,"");
putpixel(x,y,WHITE);
while(x
<= x2)
{
if(t < 0)
{
x=x+1;
y=y;
t = t + 2 * (dy);
}
else
{
x=x+1;
y=y+1;
t = t + 2 * (dy -
dx);
}
putpixel(x,y,WHITE);
}
getch();
closegraph();
return 0;
}
#include <stdio.h>
#include <conio.h>
#include<graphics.h>
void plot(int
x,int y,int xc,int yc)
{
putpixel(x+xc,y+yc,1);
putpixel(y+xc,x+yc,1);
putpixel(-y+xc,x+yc,1);
putpixel(-x+xc,y+yc,1);
putpixel(-x+xc,-y+yc,1);
putpixel(-y+xc,-x+yc,1);
putpixel(y+xc,-x+yc,1);
putpixel(x+xc,-y+yc,1);
}
int
main()
{
int
gdriver, gmode;
float Rad, xc,
yc, x, y, p;
printf("\n\n\tEnter
the radius : ");
scanf("%f",&Rad);
printf("\n\tEnter
the Center Point : ");
scanf("%f%f",&xc,&yc);
detectgraph(&gdriver,&gmode);
initgraph(&gdriver, &gmode, "");
detectgraph(&gdriver,&gmode);
initgraph(&gdriver, &gmode, "");
x=0;
y=Rad;
plot(x,y,xc,yc);
p=3-2*Rad;
while(x<=y)
{
if(p<0)
{
x=x+1;
plot(x,y,xc,yc);
p=p+4*x+6;
}
else
{
x=x+1;
y=y-1;
plot(x,y,xc,yc);
p=p+4*(x-y)+10;
}
}
getch();
closegraph();
return 0;
}
