IMPLEMENTATION OF DDA LINE c Program

[mohanmo]

Implementation of DDA Line:

Language:C Program

Software Requirements:c or c++ Compiler

Program Description:
                          Digital Differential Analyzer (DDA) is used for linear                    interpolation of variables over an interval between start and end point of a line

Program Code:

Code:

#include <graphics.h> /* include the necessary header files*/
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
void draw(int xa,int ya,int xb,int yb);
void main()
{
int xa,ya,xb,yb;
clrscr();
printf("Line DDA 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(int xa,int ya,int xb,int yb)
{
int xin,yin,x,y,dx,dy,steps,k;  /* request auto detection */
int gdriver=DETECT,gmode,errorcode;  /* initialize graphics and local variables */
initgraph(&gdriver,&gmode, "c:\\tc\\bgi") /* read result of initialization */
errorcode=graphresult();  /* an error occurred */
if (errorcode!=grOk)
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1);
}
dx=xb-xa;
dy=yb-ya;
if(abs(dx)>abs(dy))  /* if the condition is satisfied */
{ /* calculate the value of the condition variable*/
steps=abs(dx);
}
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 condition variable, */
{
x=x+xin; /* calculate the values of (x,y) and draw the pixel*/
y=y+yin;
putpixel(x,y,1);
} /* clean up */
getch();
closegraph();
}