Question

Programs 1 and 2 (Line Scan Conversion)

1.Write a function to draw a line using the Basic line drawing algorithm.

The following is a function header example:

Basic-alg( int x0, int y0, int x1, int y1 )

Use this function to draw N lines (N is provided by the user) at positions (i.e., end coordinates) determined by a random number generator.

2.Write a function to draw a line using the "Bresenham" algorithm.

The following is a header example:brz ( int x0, int y0, int x1, int y1 )Use this function to draw N lines(N is provided by the user) at positions(i.e., end coordinates)determined by a random number generator.

NOTES:

Each of the line functions must handle all types of lines (horizontal, vertical,and all other line orientations)

Answer 1

1. CODE:

#include<stdio.h>
#include<time.h>
#include<stdlib.h>
#include<graphics.h>

//Function for finding absolute value
int abs (int n)
{
   return ( (n>0) ? n : ( n * (-1)));
}

//basic Function for line generation
void Basic_alg(int X0, int Y0, int X1, int Y1)
{
   // calculate dx & dy
   int dx = X1 - X0;
   int dy = Y1 - Y0;

   // calculate steps required for generating pixels
   int steps = abs(dx) > abs(dy) ? abs(dx) : abs(dy);

   // calculate increment in x & y for each steps
   float Xinc = dx / (float) steps;
   float Yinc = dy / (float) steps;

   // Put pixel for each step
   float X = X0;
   float Y = Y0;
   for (int i = 0; i <= steps; i++)
   {
       putpixel (X,Y,RED); // put pixel at (X,Y)
       X += Xinc;       // increment in x at each step
       Y += Yinc;       // increment in y at each step
       delay(10);       // for visualization of line-
                           // generation step by step
   }
}

// Driver program
int main()
{
   int gd = DETECT, gm;
   int n, i, x0, y0, x1, y1;
   printf("Enter the number of lines: ");
   scanf("%d", &n);
   // Initialize graphics function
   initgraph (&gd, &gm, "");
   for(i=0;i<n;i++){
       srand(time(NULL));
       x0 = rand()%400;
       y0 = rand()%400;
       x1 = rand()%400;
       y1 = rand()%400;
       Basic_alg(x0, y0, x1, y1);
   }
   getch();
   return 0;
}

2. CODE

#include<stdio.h>
#include<time.h>
#include<stdlib.h>
#include<graphics.h>

void brz(int x0, int y0, int x1, int y1)
{
    int dx, dy, p, x, y;

   dx=x1-x0;
   dy=y1-y0;

   x=x0;
   y=y0;

   p=2*dy-dx;

   while(x<x1)
   {
       if(p>=0)
       {
           putpixel(x,y,7);
           y=y+1;
           p=p+2*dy-2*dx;
       }
       else
       {
           putpixel(x,y,7);
           p=p+2*dy;
       }
       x=x+1;
   }
}

// Driver program
int main()
{
   int gd = DETECT, gm;
   int n, i, x0, y0, x1, y1;
   printf("Enter the number of lines: ");
   scanf("%d", &n);
   // Initialize graphics function
   initgraph (&gd, &gm, "");
   for(i=0;i<n;i++){
       srand(time(NULL));
      
      
       x0 = rand()%400;
       y0 = rand()%400;
       x1 = rand()%400;
       y1 = rand()%400;
       brz(x0, y0, x1, y1);
   }
   getch();
   return 0;
}