Program to draw a polygon by accepting vertex coordinates and perform basic transformations (translation, scaling, rotation) about a given point based on user’s choice. - MASTER GUIDE

Program to draw a polygon by accepting vertex coordinates and perform basic transformations (translation, scaling, rotation) about a given point based on user’s choice. 

 #include<stdio.h>

#include<conio.h>

#include<graphics.h>

#include<math.h>

void input();

void drawobj();

void translation();

void scaling();

void rotation();

int n,i,ch;

float x[10],y[10],tx,ty,sx,sy,xt,yt,r,px,py;

int maxx=640,maxy=480,midx=320,midy=240;

void input()

{

printf("Enter the number of vertices : ");

scanf("%d",&n);

printf("Enter %d x-y co-ordinates\n",n);

for(i=0;i<n;i++)

{

  printf("Enter the x and y coordinates : ");

  scanf("%f%f",&x[i],&y[i]);

}

printf("Original Object\n");

setcolor(WHITE);

line(midx,0,midx,maxy);

line(0,midy,maxx,midy);

outtextxy(midx-2,midy+2,"0,0");

drawobj();

getch();

}

void drawobj()

{

for(i=0;i<n-1;i++)

line(midx+x[i],midy-y[i],midx+x[i+1],midy-y[i+1]);

line(midx+x[i],midy-y[i],midx+x[0],midy-y[0]);

}

void translation()

{

printf("\nEnter the translation unit tx,ty : ");

scanf("%f%f",&tx,&ty);

printf("After translation");

for(i=0;i<n;i++)

{

x[i]=x[i]+tx;

y[i]=y[i]+ty;

}

setcolor(RED);

drawobj();

getch();

}

void scaling()

{

printf("Enter scaling unit sx,sy : ");

scanf("%f%f",&sx,&sy);

printf("Enter the fixedpoint px and py : ");

scanf("%f%f",&px,&py);

printf("After scaling");

for(i=0;i<n;i++)

{

x[i]=x[i]*sx + px*(1-sx);

  y[i]=y[i]*sy + py*(1-sy);

}

setcolor(RED);

drawobj();

getch();

}

void rotation()

{

int xshift,yshift;

printf("Enter angle of rotation : ");

scanf("%f",&r);

r=r*(3.1415/180);

printf("Enter the pivot point px and py : ");

scanf("%f%f",&px,&py);

printf("After rotation\n");

for(i=0;i<n;i++)

{

xshift=x[i]-px;

yshift=y[i]-py;

x[i]=px+ (xshift)*cos(r) - (yshift) * sin(r);

y[i]=py+ (xshift) * sin(r) + (yshift) *cos(r);

}

setcolor(RED);

drawobj();

getch();

}

void main()

{

int gd=DETECT,gm;

initgraph(&gd,&gm,"C:\\TURBOC3\\BGI");

while(1)

{

clrscr();

cleardevice();

printf("Menu\n");

printf("1:Translation\n2:Scaling\n3:Rotation\n4:Exit\n");

printf("Enter your choice : ");

scanf("%d",&ch);

switch(ch)

{

case 1:

input();

translation();

break;

case 2:

input();

scaling();

break;

case 3:

input();

rotation();

break;

case 4: closegraph();

exit();

} 

}

}

OUTPUT: