Practical 5 Computer Graphics

#include<iostream>
#include<stdlib.h>
#include<graphics.h>
using namespace std;

float dda(float x1, float y1, float x2, float y2)
{
     float dx,dy,x,y,length,h,my,mx,ix,iy;
     float signdx, signdy;
     int i;
     
     dx = x2-x1;
     dy = y2-y1;
     
     if(dx>0)
       signdx = 1;
     else if(dx == 0)  
       signdx = 0;
     else
       signdx = -1;  
     
     if(dy>0)
       signdy = 1;
     else if(dy == 0)  
       signdy = 0;
     else
       signdy = -1; 
       
       if(dx<dy)
           length=dy;
       else 
           length=dx;
           
        ix = dx/length;
        iy = dy/length;        
        
        x = x1+(0.5*signdx);
        y = y1+(0.5*signdy);
        
        putpixel(x,y,RED);
        for(i=0;i<=length;i++)
        {
            x = x+ix;
            y = y+iy;
            putpixel(x,y,RED);   
            delay(35);
        }
}

int Circle(int xc, int yc, int x, int y)
{
     putpixel(xc+x,yc+y,RED);
     putpixel(xc-x,yc+y,RED);
     putpixel(xc+x,yc-y,RED);
     putpixel(xc-x,yc-y,RED);
     putpixel(xc+y,yc-x,RED);
     putpixel(xc-y,yc+x,RED);
     putpixel(xc+y,yc+x,RED);
     putpixel(xc-y,yc-x,RED);
}

int circle_bres(int xc, int yc, int r)
{
    int x = 0;
    int y = r;
    
    int d = 3-2*r;
    
    Circle(xc,yc,x,y);
    
    do
    {
       if(d<0)
          d+= 4*x + 6;
       else 
       {
           d += 4*(x-y)+10;
           y--;
       }   
       x++;
       
       Circle(xc,yc,x,y);
    }while(x<=y);
}

int main()
{
  int gd=DETECT,gm; 
 int x,y,r;
      
   
   cout<<"\n Enter the centre point of circle: ";
   cin>>x>>y;
   cout<<"\n Enter the radius of the circle: ";
   cin>>r;   
   
   initgraph(&gd,&gm,NULL);     
   
   circle_bres(x,y,r*2); 
   circle_bres(x,y,r);
   
   dda(x,y-r*2,x-1.73*r,y+r); 
   dda(x-1.73*r,y+r,x+1.73*r,y+r);
   dda(x,y-r*2,x+1.73*r,y+r);
 
   
   delay(1000);
   closegraph();

  return 0; 

} 

 

   PRACTICAL NO. 3
   
   TITLE:  Write C++/Java program to draw 2-D object and perform following basic transformations,
           a) Scaling
           b) Translation
           c) Rotation
           Use operator overloading.
#include<iostream>
#include<graphics.h>
#include<math.h>
using namespace std;

void Display(int n,float c[10][3])
{
	float maxx,maxy;
	int i;
	maxx=getmaxx();
	maxy=getmaxy();
	maxx=maxx/2;
	maxy=maxy/2;
	i=0;
	
	while(i<n-1)
	{
		line(maxx+c[i][0],maxy-c[i][1],maxx+c[i+1][0],maxy-c[i+1][1]);
		i++;
	}
	
	i=n-1;
	
	line(maxx+c[i][0],maxy-c[i][1],maxx+c[0][0],maxy-c[0][1]);
	
	line(0,maxy,maxx*2,maxy);
	line(maxx,0,maxx,maxy*2);
}

void Multi(int n,float b[10][3],float c[10][3],float a[10][3])
{
	int i,j,k;
	
	for(i=0;i<n;i++)
	{
		for(j=0;j<3;j++)
		{
		   a[i][j]=0;
	        }
        }
        for(i=0;i<n;i++)
	{
		for(j=0;j<3;j++)
		{
			for(k=0;k<3;k++)
			{
				
				a[i][j]=a[i][j]+(c[i][k]*b[k][j]);
			}
		}
	}

}	 			

void Translation(int n,float c[][3],float tx,float ty)
{
	float b[10][3],a[10][3];
	int i=0,j;
	
	for(i=0;i<3;i++)
	{
		for(j=0;j<3;j++)
		{
			b[i][j]=0;
		}
	}
	
	b[0][0]=1;
	b[1][1]=1;
	b[2][0]=tx;
	b[2][1]=ty;
	b[2][2]=1;
	
	Multi(n,b,c,a);
	Display(n,a);
	delay(5000);
}

void Scaling(int n,float c[][3],float sx,float sy)
{
	float b[10][3],a[10][3];
	int i=0,j;
	
	for(i=0;i<3;i++)
	{
		for(j=0;j<3;j++)
		{
			b[i][j]=0;
		}
	}
	
	b[0][0]=sx;
	b[1][1]=1;
	b[0][1]=sy;
	b[0][2]=1;
	
	Multi(n,b,c,a);
	Display(n,a);
	delay(5000);

}		

void Rotation(int n,float c[][3],float ra)
{
 int i=0,j;
 float b[10][3],xp,yp,a[10][3];
 xp=c[0][0];
 yp=c[0][1];
 for(i=0;i<3;i++)
 {
   for(j=0;j<3;j++)
   {
     b[i][j]=0;
   }
 }   
    b[0][0]=b[1][1]=cos(ra*3.14/180);
    b[0][0]=sin(ra*3.14/180);
    b[1][0]=-sin(ra*3.14/180);
    b[2][0]=(-xp*cos(ra*3.14/180))+(yp*sin(ra*3.14/180))+xp;
    b[2][1]=(-xp*sin(ra*3.14/180))-(yp*cos(ra*3.14/180))+yp;
    b[2][2]=1;
    
    Multi(n,b,c,a);
    Display(n,a);
    delay(5000);
}

int main()
{
	int i,j,k,iCh,gd=DETECT,n,gm,ch,a;
	float c[10][3],tx,ty,sx,sy,R,ra;
	
	cout<<"\n Enter number of co-ordinates :";
	cin>>n;	
	
	for(i=0;i<n;i++)
	{
		cout<<"\n Enter the co-ordinates of  vertex:";
		cin>>c[i][0]>>c[i][1];
		c[i][2]=1;
	}
	initgraph(&gd,&gm,NULL);
	Display(n,c);
	delay(5000);
	closegraph();
	do
	{
		
		cout<<"*********************MENU**********************";
		cout<<"\n1. Translation...";
		cout<<"\n2. Scaling...";
		cout<<"\n3. Rotation...";
		cout<<"\n4. Exit...";
		cout<<"\nEnter your choice: ";
		cin>>ch;
		
	switch(ch)
	{
	case 1:
	cout<<"\n Enter the translation factor for x and y axis:";
	cin>>tx>>ty;
	initgraph(&gd,&gm,NULL);
	Translation(n,c,tx,ty);
	delay(5000);
	closegraph();
	break;
	
	case 2:
	cout<<"\n Enter the scaling factor for x and y axis:";
	cin>>sx>>sy;
	initgraph(&gd,&gm,NULL);
        Scaling(n,c,sx,sy);
        delay(5000);
        closegraph();
	break;
	
	case 3:
	cout<<"\n Enter the angle of rotation:";
	cin>>ra;
	initgraph(&gd,&gm,NULL);
	Rotation(n,c,ra);
	delay(5000);
	closegraph();
	break;
	
	case 4:
        exit(0);
	break;
	}
	
}while(ch!=4);
	
    closegraph();
    delay(5000);
    return 0;
	
}

/*
  PRACTICAL NO. 2
  
  TITLE : Write C++/Java program to draw circle using Bresenham‘s algorithm. Inherit pixel class.
*/

#include<iostream>
#include<graphics.h>
using namespace std;
class Pixel
{
   public:
     void pixel(int X,int Y,int x,int y)
      {
          putpixel(X+x, Y+y, RED); 
          putpixel(X-x, Y+y, RED); 
          putpixel(X+x, Y-y, RED); 
          putpixel(X-x, Y-y, RED); 
          putpixel(X+y, Y+x, RED); 
          putpixel(X-y, Y+x, RED); 
          putpixel(X+y, Y-x, RED); 
          putpixel(X-y, Y-x, RED); 
      }
      
};
class Bresenham : public Pixel
{
   public:
     void Bres_algo(int X,int Y,int r)
      {
         int x=0;
         int y=r;
         
         int d = 3-(2*r);
         
         pixel(X,Y,x,y);
         
         do
         {
            if(d<0)
            {
               d = d+(4*x)+6;
            }
            else
            {
               d = d+4*(x-y)+10;
               y--;
            }
            x++;
            pixel(X,Y,x,y);
         }while(x<=y);
      }
};
int main()
{
   int X,Y,r;
   
   Bresenham b;
   
   cout<<"\nBRESENHAM CIRCLE DRAWING.....";
   cout<<"\n Enter the co-ordinates (X,Y) :";
   cin>>X>>Y;
   cout<<"\n Enter the Radius :";
   cin>>r;
   
   int gd = DETECT, gm;
   initgraph(&gd,&gm,NULL);
   b.Bres_algo(X,Y,r);
   
    getch();
    delay(100000);
    closegraph();    
    return 0; 
   
} 


//bresenham s algorithm
draw circle using bresenham s algorithm
java program to draw circle