/* THIS PROGRAM IS TO TRANSLATE , ROTATE & SCALE THE FIGURE */
	    /* ABOUT ANY ARBITARY  POINT ON THE SCREEN */

#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<graphics.h>
#define pi 3.14
#define maxsize 3

float xa,ya,xb,yb,xc,yc;
float xa1,ya1,xb1,yb1,xc1,yc1;
float xr,yr,sa,sb;
float a[3][3],b[3][3],c[3][3],d[3][3],e[3][3],f[3][3],ra,r;
float g[3][3],h[3][3],q[3][3],z[3][3],w[3][3],sx,sy,sum;
float identity[3][3];
void multiply(float [3][3],float[3][3]);

 main()
 {
  int i,j;
  int gm=DETECT,gd=DETECT;
  initgraph(&gm,&gd,"c:\\turboc\\bgi");
  clrscr();

  printf(" ENTER THE FIRST POINT : ");
  scanf("%f%f",&xa,&ya);
  printf(" ENTER THE SECOND POINT : ");
  scanf("%f%f",&xb,&yb);
  printf(" ENTER THE THIRD POINT : ");
  scanf("%f%f",&xc,&yc);
  clrscr();

  line(xa,ya,xb,yb);
  line(xb,yb,xc,yc);
  line(xc,yc,xa,ya);
  getche();

  printf(" * ENTER THE POINTS FROM WHICH THE TRIANGLE HAS TO ROTATE : ");
  scanf("%f%f",&xr,&yr);
  printf(" * ENTER THE ANGLE THROUGH WHICH YOU WANT TO ROTATE THE TRIANGLE : ");
  scanf("%f",&r);
  printf(" * ENTER THE POINTS OF SCALING : ");
  scanf("%f %f",&sa,&sb);
  printf("\n ENTER THE SCALING PARAMETERS i.e Sx and Sy :");
  scanf("%f%f",&sx,&sy);
  ra=(r*pi)/180.0;

  set_identity(a);
  a[0][0]=cos(ra);
  a[0][1]=-sin(ra);
  a[1][0]=sin(ra);
  a[1][1]=cos(ra);

  set_identity(b);
  b[0][2]= -xr;
  b[1][2]= -yr;

  multiply(a,b);

  set_identity(c);
  c[0][2]=xr;
  c[1][2]=yr;

  multiply(c,d);

  set_identity(z);
  z[0][2]=-sa;
  z[1][2]=-sb;

  multiply(z,d);

  set_identity(q);
  q[0][0]=sx;
  q[1][1]=sy;

  multiply(q,d);

  set_identity(w);
  w[0][2]=sa;
  w[1][2]=sb;

  multiply(w,d);

   for(i=0;i<3;i++)
  {
   for(j=0;j<3;j++)
   {
    e[i][j]=d[i][j];
   }
  }

  set_identity(f);
  f[0][0]=xa;
  f[1][0]=ya;
  f[2][0]=1;

  multiply(e,f);
  xa1=d[0][0];
  ya1=d[1][0];

  set_identity(g);
  g[0][0]=xb;
  g[1][0]=yb;
  g[2][0]=1;

  multiply(e,g);
  xb1=d[0][0];
  yb1=d[1][0];

  set_identity(h);
  h[0][0]=xc;
  h[1][0]=yc;
  h[2][0]=1;

  multiply(e,h);
  xc1=d[0][0];
  yc1=d[1][0];

  clrscr();

  line(xa,ya,xb,yb);
  line(xb,yb,xc,yc);
  line(xc,yc,xa,ya);

  line(xa1,ya1,xb1,yb1);
  line(xb1,yb1,xc1,yc1);
  line(xc1,yc1,xa1,ya1);

  getch();
 }

 void multiply(float a[3][3],float b[3][3])
 {
  int i,j,k;
  for(i=0;i<3;i++)
  {
   for(j=0;j<3;j++)
   {
    sum=0;
    for(k=0;k<3;k++)
     {
      sum=sum+a[i][k]*b[k][j];
     }
    d[i][j] = sum;
   }
  }
 }


 set_identity(float a[3][3])
 {
  int i,j;
  for(i=0;i<maxsize;i++)
  {
   for(j=0;j<maxsize;j++)
   {
     a[i][j] = (i==j);/*? 1:0;*/
   }
  }
 }