/*  2. felev, uj tematika, C nyelv          grafika 2.,
       7.gyak, MENEDZSER                    transzformaciok sikban
*/

//Grafikus transzformacio demo program
//Kezeles a numerikus tasztaturaval, NumLock legyen bekapcsolva!!!

#include <stdio.h>
#include <conio.h>
#include <math.h>
#include <graphics.h>

int gd,gm;
double Lx,Ly,x1Gl,y1Gl,x2Gl,y2Gl;

//fuggveny prototipusok:
void GrStart(double x1,double y1,double x2,double y2);
int XK(double x);
int YK(double y);
void Elt(double x0, double y0, double dx, double dy, double* x1, double* y1);
void Forg(double x0, double y0, double alfa, double* x1, double* y1);
void Zoom(double x0, double y0, double kx, double ky, double* x1, double* y1);

void main()
{ double P1x,P1y,P2x,P2y,P3x,P3y; //haromszogcsucsok a Vilag KR-ben
  double dx,dy,kx,ky, alfa, dalfa; //dalfa a szoglepes forgatashoz
  char bill;

  clrscr(); puts("Transzformacio-demo\n");
  puts("Add meg a Vilag-koordinatatartomany hatarait!");
  puts("Celszeruen fogjak kozre a nullat, hogy lassuk a");
  puts(" Vilag-koordinatarendszer tengelyeit is!\n");
  printf("x1 (-120) ="); scanf("%lf",&x1Gl);
  printf("y1 ( -90) ="); scanf("%lf",&y1Gl);
  printf("x2 ( 120) ="); scanf("%lf",&x2Gl);
  printf("y2 (  90) ="); scanf("%lf",&y2Gl);
  puts("\n A demoban egy haromszoget lehet eltolni, forgatni, nagyitani.");
  puts("A P1 csucspontot kis kor jelzi.");
  puts("Add meg a haromszog csucsainak koordinatait a Vilag-KR-ben:\n");
  printf("P1x  (20)= "); scanf("%lf",&P1x);
  printf("P1y  (20)= "); scanf("%lf",&P1y);
  printf("P2x  (-15)= "); scanf("%lf",&P2x);
  printf("P2y  (-18)= "); scanf("%lf",&P2y);
  printf("P3x  ( 27)= "); scanf("%lf",&P3x);
  printf("P3y  (-21)= "); scanf("%lf",&P3y);
  puts("\nKezeles a numerikus tasztatura szamaival,");
  puts("-,+ forgat, K kicsinyit, N nagyit, V kilep");
  puts("\nIndulashoz nyomj Entert!");
  getch();
  dx= sqrt((P2x-P1x)*(P2x-P1x)+(P2y-P1y)*(P2y-P1y))/20.0; dy= dx;
  kx=0.9; ky= kx; dalfa= M_PI/20.0;
  GrStart(x1Gl,y1Gl,x2Gl,y2Gl);
  if (P1x==P2x) {if (P2y>P1y) alfa=M_PI/2.0;
		 else alfa= -M_PI/2.0;
		}
  else {alfa= atan((P2y-P1y)/(P2x-P1x));
	if (P1x>P2x)  alfa= M_PI - alfa;
       }
  do
  {
   setcolor(WHITE);
   line(XK(x1Gl),YK(0.0),XK(x2Gl),YK(0.0)); //Koordinatatengelyek
   line(XK(0.0),YK(y1Gl),XK(0.0),YK(y2Gl));
   line(XK(P1x),YK(P1y),XK(P2x),YK(P2y));
   circle(XK(P1x),YK(P1y),3);//nullkor P1 korul
   setcolor(YELLOW);
   line(XK(P2x),YK(P2y),XK(P3x),YK(P3y));
   line(XK(P3x),YK(P3y),XK(P1x),YK(P1y));
   do
   {do ; while (!kbhit()); bill= toupper(getch());
   }while (bill!='2' && bill!='4' && bill!='6' && bill!='8' && bill!='+' &&
	   bill!='-' && bill!='N' && bill!='K' && bill!='V');
   setcolor(BLACK); //feketevel felulrajyol, torol
   line(XK(P1x),YK(P1y),XK(P2x),YK(P2y));
   circle(XK(P1x),YK(P1y),3);//nullkor P1 korul
   line(XK(P2x),YK(P2y),XK(P3x),YK(P3y));
   line(XK(P3x),YK(P3y),XK(P1x),YK(P1y));
   switch (bill)
   {case '2': Elt(P1x,P1y,0.0,-dy,&P1x,&P1y);
	      Elt(P2x,P2y,0.0,-dy,&P2x,&P2y);
	      Elt(P3x,P3y,0.0,-dy,&P3x,&P3y); break;
    case '4': Elt(P1x,P1y,-dx,0.0,&P1x,&P1y);
	      Elt(P2x,P2y,-dx,0.0,&P2x,&P2y);
	      Elt(P3x,P3y,-dx,0.0,&P3x,&P3y); break;
    case '6': Elt(P1x,P1y,dx,0.0,&P1x,&P1y);
	      Elt(P2x,P2y,dx,0.0,&P2x,&P2y);
	      Elt(P3x,P3y,dx,0.0,&P3x,&P3y); break;
    case '8': Elt(P1x,P1y,0.0,dy,&P1x,&P1y);
	      Elt(P2x,P2y,0.0,dy,&P2x,&P2y);
	      Elt(P3x,P3y,0.0,dy,&P3x,&P3y); break;
    case 'K': if (sqrt((P2x-P1x)*(P2x-P1x)+(P2y-P2x)*(P2y-P2x))>10e-8)
	      {Zoom(P1x,P1y,kx,ky,&P1x,&P1y);
	       Zoom(P2x,P2y,kx,ky,&P2x,&P2y);
	       Zoom(P3x,P3y,kx,ky,&P3x,&P3y);
	      }
	      break;
    case 'N': if (sqrt((P2x-P1x)*(P2x-P1x)+(P2y-P2x)*(P2y-P2x))<10e6)
	      {Zoom(P1x,P1y,1/kx,1/ky,&P1x,&P1y);
	       Zoom(P2x,P2y,1/kx,1/ky,&P2x,&P2y);
	       Zoom(P3x,P3y,1/kx,1/ky,&P3x,&P3y);
	      }
	      break;
    case '-': alfa -= dalfa;
	      Forg(P1x,P1y,-dalfa,&P1x,&P1y);
	      Forg(P2x,P2y,-dalfa,&P2x,&P2y);
	      Forg(P3x,P3y,-dalfa,&P3x,&P3y); break;
    case '+': alfa += dalfa;
	      Forg(P1x,P1y,dalfa,&P1x,&P1y);
	      Forg(P2x,P2y,dalfa,&P2x,&P2y);
	      Forg(P3x,P3y,dalfa,&P3x,&P3y); break;
   }
  } while (bill!='V');
  closegraph();
}

//fuggveny definiciok:
void GrStart(double x1,double y1,double x2,double y2)
{x1Gl=x1; y1Gl=y1; x2Gl=x2; y2Gl=y2;
 detectgraph(&gd,&gm); initgraph(&gd,&gm,"O:\\BC\\BGI");
 Lx=getmaxx()/(x2-x1); Ly=getmaxy()/(y2-y1);
}

int XK(double x)
{return floor(Lx*(x-x1Gl)+0.5);  //+0.5 kerekites miatt
}

int YK(double y)
{return floor(Ly*(y2Gl-y)+0.5);  //+0.5 kerekites miatt
}

void Elt(double x0, double y0, double dx, double dy, double* x1, double* y1)
{*x1= x0+dx; *y1= y0+dy;
}

void Forg(double x0, double y0, double alfa, double* x1, double* y1)
{*x1= x0*cos(alfa)-y0*sin(alfa);
 *y1= x0*sin(alfa)+y0*cos(alfa);
}

void Zoom(double x0, double y0, double kx, double ky, double* x1, double* y1)
{*x1= kx*x0; *y1= ky*y0;
}