Step by Step ALGORITHM

1. Include the graphics header file and obtain graphics mode and driver.

2. Get the co-ordinates of two end points of a line (x1,y1) & (x2,y2) and store left end point in (x1,y1).

3. Load (x1,y1) into frame buffer that means plot the first point.

4. Calculate constants dx,dy,2dy,2dy-2dx and obtain value for decision parameter p=2dy-dx.

5. At each x along the line perform the test if p<0, next point to plot is (x+1,y) and p+1=p+2dy otherwise (x+1,y+1) & p+1=p+2dy-2dx 6. Repeat steps dx times. 7. Display a line. |BresenHam’s Line Drawing Algorithm computer Graphics Source Code Programming in Computer Graphics #include<stdio.h>

#include<conio.h>

#include<graphics.h>

void main()

{

int x,y,x1,y1,x2,y2,gx,gy,dx,dy,m,i,p;

clrscr();

printf("Enter the starting point of line\n");

scanf("%d%d",&x1,&y1);

printf("Enter the end point of the line\n");

scanf("%d%d",&x2,&y2);

detectgraph(&gx,&gy);

initgraph(&gx,&gy,"d:\\tc\\bgi");

dx=x2-x1;

dy=y2-y1;

p=(2*dy)-dx;

for(i=1;i<dx;i++)

{

if(p<0)

{

x=x1++;

y=y1;

putpixel(x,y,30);

p=p+(2*dy);}

else

{

x=x1++;

y=y1++;

putpixel(x,y,30);

p=p+(2*dy)-(2*dx);

}

}

getch();

}

Example Result OUTPUT | BRESENHAM’S LINE DRAWING ALGORITHM

Enter the starting point of line

0

0

Enter the end point of the line

200

200