Page 56 - DCAP313_LAB_ON_COMPUTER_GRAPHICS

Lab on Computer Graphics

Notes y = y 1 + (dy) * (x – x 1 )/(dx)
pixel(x, y)
}
3.3.2 C Code DDA Line Algorithm
#include <graphics.h>
#include <stdio.h>
#include <conio.h>
#include <math.h>
void main()
{
int gd=DETECT,gm=DETECT,s,dx,dy,m,x 1 ,y 1 ,x 2 ,y 2 ;
fl o a t x i ,y i ,x,y;
clrscr();
printf(“Enter the sarting point x 1 & y 1n ”);
scanf(“%d%d”,&x 1 ,&y 1 );
printf(“Enter the end point x 2 & y 2n ”);
scanf(“%d%d”,&x 2 ,&y 2 );
initgraph(&gd,&gm, “”);
cleardevice();
d x = x 2 –x 1 ;
d y = y 2 –y 1 ;
if(abs(dx)>abs(dy))
s=abs(dx);
else
s=abs(dy);
x i =dx/(float)s;
y i =dy/(float)s;
x = x 1 ;
y = y 1 ;
putpixel(x 1 ,y 1 ,4);
for(m=0; m < s; m++)
{
x + = x i ;
y + = y i ;
putpixel(x,y,4);
}
getch();
}
Self Assessment Questions

6. Which one is a line algorithm for …………….. line conversion?
(a) Bresenham's (b) Beizer
(c) Both a and b (d) Midpoint

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