Practical

Computer Graphics Assignment 1

Write C++ program to draw a concave polygon and fill it with desired colour using scan fill algorithm. Apply
the concept of inheritance.

Code:

#include <conio.h>
#include <iostream>
#include <graphics.h>
#include <stdlib.h>
using namespace std;
class point
{
public:
int x,y;
};
class poly
{
private:
point p[20];
int inter[20],x,y;
int v,xmin,ymin,xmax,ymax;
public:
int c;
void read();
void calcs();
void display();
void ints(float);
void sort(int);
};
void poly::read()
{
int i;
cout<<"\n Scan Fill Algorithm ";
cout<<"\n Enter Number Of Vertices Of Polygon: ";
cin>>v;
if(v>2)
{
for(i=0;i<v; i++) //ACCEPT THE VERTICES
{
cout<<"\nEnter co-ordinate no. "<<i+1<<" : ";
cout<<"\n\tx"<<(i+1)<<"=";
cin>>p[i].x;
cout<<"\n\ty"<<(i+1)<<"=";
cin>>p[i].y;
}
p[i].x=p[0].x;
p[i].y=p[0].y;
xmin=xmax=p[0].x;
ymin=ymax=p[0].y;
}
else
cout<<"\n Enter valid no. of vertices.";
}
void poly::calcs()
{
for(int i=0;i<v;i++)
{
if(xmin>p[i].x)
xmin=p[i].x;
if(xmax<p[i].x)
xmax=p[i].x;
if(ymin>p[i].y)
ymin=p[i].y;
if(ymax<p[i].y)
ymax=p[i].y;
}
}
void poly::display()
{
int ch1;
char ch='y';
float s,s2;
do
{
cout<<"\n\nMENU:";
cout<<"\n\n\t1 . Scan line Fill ";
cout<<"\n\n\t2 . Exit ";
cout<<"\n\nEnter your choice:";
cin>>ch1;
switch(ch1)
{
case 1:
s=ymin+0.01;
delay(100);
cleardevice();
while(s<=ymax)
{
ints(s);
sort(s);
s++;
}
break;
case 2:
exit(0);
}
cout<<"Do you want to continue?: ";
cin>>ch;
}while(ch=='y' || ch=='Y');
}
void poly::ints(float z)
{
int x1,x2,y1,y2,temp;
c=0;
for(int i=0;i<v;i++)
{
x1=p[i].x;
y1=p[i].y;
x2=p[i+1].x;
y2=p[i+1].y;
if(y2<y1)
{
temp=x1;
x1=x2;
x2=temp;
 temp=y1;
y1=y2;
y2=temp;
}
if(z<=y2&&z>=y1)
{
if((y1-y2)==0)
x=x1;
else
{
x=((x2-x1)*(z-y1))/(y2-y1);
x=x+x1;
}
if(x<=xmax && x>=xmin)
inter[c++]=x;
}
}
}
void poly::sort(int z) // sorting
{
int temp,j,i;
for(i=0;i<v;i++)
{
line(p[i].x,p[i].y,p[i+1].x,p[i+1].y);
}
delay(100);
for(i=0; i<c;i+=2)
{
delay(100);
line(inter[i],z,inter[i+1],z);
}
}
int main() //main
{
int cl;
initwindow(500,600);
cleardevice();
poly x;
x.read();
x.calcs();
cleardevice();
cout<<"\n\tEnter The Color You Want :(In Range 0 To 15 )->"; //selecting color
cin>>cl;
setcolor(cl);
x.display();

closegraph(); //closing graph

getch();
return 0;
}

Input :

Number of Vertices : 4

Cordinates 1st :
x1= 200
y1= 200
Cordinates 2st :
x2= 200
y2= 400

Cordinates 3st :
x3= 400
y3= 200

Cordinates 4st :
x4= 400
y4= 400

Output:
 Practical

Computer Graphics Assignment 2

Write C++ program to implement Cohen Southerland line clipping algorithm.

Code:

#include<iostream>
#include<stdlib.h>
#include<math.h>
#include<graphics.h>
#include<dos.h>
using namespace std;
class Coordinate
{
public:
int x,y;
char code[4];
};
class Lineclip
{
public:
Coordinate PT;
void drawwindow();
void drawline(Coordinate p1,Coordinate p2);
Coordinate setcode(Coordinate p);
int visibility(Coordinate p1,Coordinate p2);
Coordinate resetendpt(Coordinate p1,Coordinate p2);
};
int main()
{
Lineclip lc;
int gd = DETECT,v,gm;
Coordinate p1,p2,p3,p4,ptemp;

cout<<"\n Enter x1 and y1\n";

cin>>p1.x>>p1.y;
cout<<"\n Enter x2 and y2\n";
cin>>p2.x>>p2.y;

initgraph(&gd,&gm,"");
lc.drawwindow();
delay(2000);

lc.drawline (p1,p2);
delay(2000);
cleardevice();

delay(2000);
p1=lc.setcode(p1);
p2=lc.setcode(p2);
v=lc.visibility(p1,p2);
 delay(2000);

switch(v)
{
case 0: lc.drawwindow();
delay(2000);
lc.drawline(p1,p2);
break;
case 1:lc.drawwindow();
delay(2000);
break;
case 2:p3=lc.resetendpt(p1,p2);
p4=lc.resetendpt(p2,p1);
lc.drawwindow();
delay(2000);
lc.drawline(p3,p4);
break;

}
delay(2000);
closegraph();
}

void Lineclip::drawwindow()
{
line(150,100,450,100);
line(450,100,450,350);
line(450,350,150,350);
line(150,350,150,100);

void Lineclip::drawline(Coordinate p1,Coordinate p2)

{
line(p1.x,p1.y,p2.x,p2.y);
}

Coordinate Lineclip::setcode(Coordinate p)

{
Coordinate ptemp;

if(p.y<100)
ptemp.code[0]='1';
else
ptemp.code[0]='0';

if(p.y>350)
ptemp.code[1]='1';
else
ptemp.code[1]='0';

if(p.x>450)
ptemp.code[2]='1';
else
ptemp.code[2]='0';
 if(p.x<150)
ptemp.code[3]='1';
else
ptemp.code[3]='0';

ptemp.x=p.x;
ptemp.y=p.y;

return(ptemp);

};

int Lineclip:: visibility(Coordinate p1,Coordinate p2)

{
int i,flag=0;

for(i=0;i<4;i++)
{
if(p1.code[i]!='0' || (p2.code[i]=='1'))
flag='0';
}

if(flag==0)
return(0);

for(i=0;i<4;i++)
{
if(p1.code[i]==p2.code[i] && (p2.code[i]=='1'))
flag='0';
}

if(flag==0)
return(1);

return(2);
}

Coordinate Lineclip::resetendpt(Coordinate p1,Coordinate p2)

{
Coordinate temp;
int x,y,i;
float m,k;

if(p1.code[3]=='1')
x=150;
if(p1.code[2]=='1')
x=450;
if((p1.code[3]=='1') || (p1.code[2])=='1')
{

m=(float)(p2.y-p1.y)/(p2.x-p1.x);
k=(p1.y+(m*(x-p1.x)));
 temp.y=k;
temp.x=x;

for(i=0;i<4;i++)
temp.code[i]=p1.code[i];

if(temp.y<=350 && temp.y>=100)

return (temp);
}

if(p1.code[0]=='1')
y=100;
if(p1.code[1]=='1')
y=350;
if((p1.code[1]=='1') || (p1.code[1]=='1'))
{
m=(float)(p2.y-p1.y)/(p2.x-p1.x);
k=(float)p1.x+(float)(y-p1.y)/m;
temp.x=k;
temp.y=y;

for(i=0;i<4;i++)
temp.code[i]=p1.code[i];

return(temp);

}
else
return(p1);

Input :

X1 , Y1:
100
200

X2, Y2 :
500
100
Output:
 Practical

Computer Graphics Assignment 3

Write C++ program to draw the following pattern. Use DDA and Bresenham‘s Line drawing

algorithm. Apply concept of encapsulation.

Code :

#include <iostream>
# include <graphics.h>
# include <stdlib.h>
using namespace std;
class dcircle
{
private: int x0, y0;
public:
dcircle()
{
x0=0;
y0=0;
}
void setoff(int xx, int yy)
{
x0=xx;
y0=yy;
}
void drawc(int x1, int y1, int r)
{
float d;
int x,y;
x=0;
y=r;
d=3-2*r;
do
{
putpixel(x1+x0+x, y0+y-y1, 15);
putpixel(x1+x0+y, y0+x-y1,15);
putpixel(x1+x0+y, y0-x-y1,15);
putpixel(x1+x0+x,y0-y-y1,15);
putpixel(x1+x0-x,y0-y-y1,15);
putpixel(x1+x0-y, y0-x-y1,15);
putpixel(x1+x0-y, y0+x-y1,15);
putpixel(x1+x0-x, y0+y-y1,15);
if (d<=0)
{
d = d+4*x+6;
}
else
{
d=d+4*(x-y)+10;
y=y-1;
}
x=x+1;
}
while(x<y);
}
};

class pt
{
protected: int xco, yco,color;
public:
pt()
{
xco=0,yco=0,color=15;
}
void setco(int x, int y)
{
xco=x;
yco=y;
}
void setcolor(int c)
{
color=c;
}
void draw()
{
putpixel(xco,yco,color);
}
};
class dline:public pt
{
private: int x2, y2;
public:
dline():pt()
{
x2=0;
y2=0;
}
void setline(int x, int y, int xx, int yy)
{
pt::setco(x,y);
x2=xx;
y2=yy;
}
void drawl( int colour)
{
float x,y,dx,dy,length;
int i;
pt::setcolor(colour);
dx= abs(x2-xco);
dy=abs(y2-yco);
if(dx>=dy)
{
length= dx;
}
else
{
length= dy;
}
dx=(x2-xco)/length;
dy=(y2-yco)/length;
x=xco+0.5;
y=yco+0.5;
i=1;
while(i<=length)
{
pt::setco(x,y);
pt::draw();
x=x+dx;
y=y+dy;
i=i+1;
}
pt::setco(x,y);
pt::draw();
}
};
int main()
{
int gd=DETECT, gm;
initgraph(&gd, &gm, NULL);
int x,y,r, x1, x2, y1, y2, xmax, ymax, xmid, ymid, n, i;
dcircle c;
cout<<"\nenter coordinates of centre of circle : ";
cout<<"\n enter the value of x : ";
cin>>x;
cout<<"\nenter the value of y : ";
cin>>y;
cout<<"\nenter the value of radius : ";
cin>>r;
xmax= getmaxx();
ymax=getmaxy();
xmid=xmax/2;
ymid=ymax/2;
setcolor(1);
c.setoff(xmid,ymid);
line(xmid, 0, xmid, ymax);
line(0,ymid,xmax,ymid);
setcolor(15);
c.drawc(x,y,r);
pt p1;
p1.setco(100,100);
p1.setcolor(14);
dline l;
l.setline(x1+xmid, ymid-y1, x2+xmid, ymid-y2);
cout<<"Enter Total Number of lines : ";
cin>>n;
for(i=0;i<n;i++)
{
cout<<"Enter co-ordinates of point x1 : ";
cin>>x1;
cout<<"enter coordinates of point y1 : ";
cin>>y1;
cout<<"Enter co-ordinates of point x2 : ";
cin>>x2;
cout<<"enter coordinates of point y2 : ";
cin>>y2;
l.setline(x1+xmid, ymid-y1, x2+xmid, ymid-y2);
l.drawl(15);
}
cout<<"\nEnter coordinates of centre of circle : ";
cout<<"\n Enter the value of x : ";
cin>>x;
cout<<"\nEnter the value of y : ";
cin>>y;
cout<<"\nEnter the value of radius : ";
cin>>r;
setcolor(5);
c.drawc(x,y,r);
getch();
delay(200);
closegraph();
return 0;
}

Input :

Value Of X : 100
Value Of Y : 70
Value Of R : 30

Next Inputs In Image Given Below.

Output:
 Practical

Computer Graphics Assignment 5

Write C++ Program To Generate Fractal Patterns By Using Koch Curves

Code :

#include <iostream>
#include <math.h>
#include <graphics.h>
using namespace std;
class kochCurve
{
public:
void koch(int it,int x1,int y1,int x5,int y5)
{
int x2,y2,x3,y3,x4,y4;
int dx,dy;
if (it==0)
{
line(x1,y1,x5,y5);
}
else
{
delay(10);
dx=(x5-x1)/3;
dy=(y5-y1)/3;
x2=x1+dx;
y2=y1+dy;
x3=(int)(0.5*(x1+x5)+sqrt(3)*(y1-y5)/6);
y3=(int)(0.5*(y1+y5)+sqrt(3)*(x5-x1)/6);
x4=2*dx+x1;
y4=2*dy+y1;
koch(it-1,x1,y1,x2,y2);
koch(it-1,x2,y2,x3,y3);
koch(it-1,x3,y3,x4,y4);
koch(it-1,x4,y4,x5,y5);
}
}
};
int main()
{
kochCurve k;
int it;
cout<<"Enter Number Of Iterations : "<<endl;
cin>>it;
int gd=DETECT,gm;
initgraph(&gd,&gm,NULL);
k.koch(it,150,20,20,280);
k.koch(it,280,280,150,20);
k.koch(it,20,280,280,280);
getch();
closegraph();
return 0;
}

Output:
 Practical

Computer Graphics Assignment 4

Write C++ program to draw 2-D object and perform following basic transformation

a) Scaling

b) Translation

c) Rotation

Apply the concept of operator overloading.

Code :

#include<iostream>
#include<graphics.h>
#include<math.h>
using namespace std;
class transform
{
public:
int m,a[20][20],c[20][20];
int i,j,k;
public:

void object();
void accept();
void operator *(float b[20][20])
{
for(int i=0;i<m;i++)
{
for(int j=0;j<m;j++)
{
c[i][j]=0;
for(int k=0;k<m;k++)
{
c[i][j]=c[i][j]+(a[i][k]*b[k][j]);
}
}
}
}
};
void transform::object()
{
int gd,gm;
gd=DETECT;
initgraph(&gd,&gm,NULL);
line(300,0,300,600);
 line(0,300,600,300);
for( i=0;i<m-1;i++)
{
line(300+a[i][0],300-a[i][1],300+a[i+1][0],300-a[i+1][1]);
}
line(300+a[0][0],300-a[0][1],300+a[i][0],300-a[i][1]);
for( i=0;i<m-1;i++)
{

line(300+c[i][0],300-c[i][1],300+c[i+1][0],300-c[i+1][1]);
}
line(300+c[0][0],300-c[0][1],300+c[i][0],300-c[i][1]);
int temp;
cout << "Press 1 to continue";
cin >> temp;
closegraph();
}
void transform::accept()
{
cout<<"\n";
cout<<"Enter the Number Of Edges:";
cin>>m;
cout<<"\nEnter The Coordinates :";
for(int i=0;i<m;i++)
{
for(int j=0;j<3;j++)
{
if(j>=2)
a[i][j]=1;
else
cin>>a[i][j];
}
}
}
int main()
{
int ch,tx,ty,sx,sy;
float deg,theta,b[20][20];
transform t;
t.accept();

cout<<"\nEnter your choice";

cout<<"\n1.Translation"
"\n2.Scaling"
"\n3.Rotation";
cin>>ch;
switch(ch)
{
case 1: cout<<"\nTRANSLATION OPERATION\n";
cout<<"Enter value for tx and ty:";
cin>>tx>>ty;
b[0][0]=b[2][2]=b[1][1]=1;
b[0][1]=b[0][2]=b[1][0]=b[1][2]=0;
b[2][0]=tx;
b[2][1]=ty;
t * b;

t.object();
 break;
case 2: cout<<"\nSCALING OPERATION\n";
cout<<"Enter value for sx,sy:";
cin>>sx>>sy;
b[0][0]=sx;
b[1][1]=sy;
b[0][1]=b[0][2]=b[1][0]=b[1][2]=0;
b[2][0]=b[2][1]=0;
b[2][2] = 1;
t * b;
t.object();
break;
case 3: cout<<"\nROTATION OPERATION\n";
cout<<"Enter value for angle:";
cin>>deg;
theta=deg*(3.14/100);
b[0][0]=b[1][1]=cos(theta);
b[0][1]=sin(theta);
b[1][0]=sin(-theta);
b[0][2]=b[1][2]=b[2][0]=b[2][1]=0;
b[2][2]=1;
t * b;
t.object();
break;
default:
cout<<"\nInvalid choice";

getch();

return 0;
}

Input :

Provided In Image Given Below

Output :
For Tranlation :
For Scaling :

For Rotation :