/**************************************************************************
*                          THE  BOLYGONES                                 *
* A "bolygone" is a mathematical equivalent of a game for kids consisting *
* in creating nice figures with a piece of string around  nails on a      *
* wooden board. Let be a circle with a radius=1, centered at point 0,0.   *
* Let us consider an angle at centre i varying from  0 to 360 degrees     *
* with a given step p. The bolygone of order n is the envelope of all the *
* cords joining each angle i to the angle n.i, where n is an integer > 1. *
* ----------------------------------------------------------------------- *
* From "Graphisme dans le plan et dans l'espace avec Turbo Pascal 4.0     *
* By R. Dony - MASSON, Paris 1990 page 49" [BIBLI 12].                    *
*                                                                         *
*             Microsoft C++ version in API WINDOWS style by J-P Moreau    *
*                  (Program to use with Bolygone.mak and Gr2D.cpp)        *
*                                 (www.jpmoreau.fr)                       *
**************************************************************************/
#include <windows.h>
#include <stdio.h>
#include <math.h>

HDC  hdc;
RECT rect;

//Functions of module Gr2D.cpp
void Fenetre(double,double,double,double); 
void Cloture(int,int,int,int); 
void Bordure();
void MoveXY(double,double);
void LineXY(double,double);


//"home made" graphic commands for hdc environment used by above functions
void DrawPixel(int ix,int iy) {
  //sorry, no other available command found
  Rectangle(hdc,rect.left+ix,rect.top+iy,
	            rect.left+ix+2,rect.top+iy+1);
}

void Swap(int *i1,int *i2) {
  int it;
  it=*i1; *i1=*i2; *i2=it;
}

void DrawLine(int ix1,int iy1,int ix2,int iy2) {
  int i,il,ix,iy;
  float dx,dy;
  if (ix2<ix1) {
	Swap(&ix1,&ix2); Swap(&iy1,&iy2);
  }
  il=(int) sqrt((ix2-ix1)*(ix2-ix1)+(iy2-iy1)*(iy2-iy1));
  dx=(float) (ix2-ix1)/il; 
  dy=(float) (iy2-iy1)/il;
  ix=ix1; iy=iy1;
  for (i=1;i<il+1; i++) {
	DrawPixel(ix,iy);
	ix=(int) (ix1+i*dx); 
	iy=(int) (iy1+i*dy);
  }
}

void OutText(int ix,int iy,char *s) {
  RECT rct;
  rct.left=ix; rct.right=ix+10*strlen(s);
  rct.top=iy; rct.bottom=iy+10;
  DrawText(hdc, s, -1, &rct,
                DT_SINGLELINE | DT_CENTER | DT_VCENTER);
}

//Draw a bolygon of order 14 with step 1 deg.
void DrawBolygon()  {
  int ordre,pas,adeg;
  double arad;
  double c,f1,f2,f3,f4;
  int c1,c2,c3,c4;
  char ch[12];

  extern int MaxX,MaxY,xgclot,xdclot,yhclot; // see Gr2d.h
  extern double pi;
    
  ordre=14; pas=1;  //these values can be changed by user
  //client drawing zone in pixels
  MaxX=(rect.right-rect.left);
  MaxY=(rect.bottom-rect.top);
  f1=-1.1; f2=-f1; f3=f1; f4=f2;
  c1=60; c2=MaxX-60; c3=10; c4=MaxY-10;
  Fenetre(f1,f2,f3,f4); // window in physical coordinates
  Cloture(c1,c2,c3,c4); // drawing zone in pixels
  Bordure();            // draw a frame around drawing zone
  adeg=0; c=pi/180.0;
  //main drawing loop
  do {
    arad=c*adeg;
    MoveXY(cos(arad),sin(arad));
    LineXY(cos(ordre*arad),sin(ordre*arad));
    adeg+=pas;
  } while (adeg < 360);
  //print titles
  OutText(xgclot+15,MaxY-yhclot+15,"BOLYGONE");
  sprintf(ch,"N = %2d",ordre);
  OutText(xgclot+xdclot-c1-60,MaxY-yhclot+15,ch);
}


//Handle window Paint and Destroy messages
long FAR PASCAL /*_export*/ WndProc(HWND hwnd,
    UINT message, UINT wParam, LONG lParam) 
{
    HPEN        hpen, hpenOld;
    PAINTSTRUCT ps;

    switch (message) {
        case WM_PAINT:
	    hdc = BeginPaint(hwnd, &ps);
	    GetClientRect(hwnd, &rect);
            hpen = CreatePen(PS_SOLID, 1, RGB(0, 0, 255));
            hpenOld = SelectObject(hdc,hpen);
               
            DrawBolygon();
               
            SelectObject(hdc,hpenOld);
            DeleteObject(hpen);
            EndPaint(hwnd, &ps);
            return 0;
        case WM_DESTROY:
            PostQuitMessage(0);
            return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}

// main program
int PASCAL WinMain(HANDLE hInstance, HANDLE hPrevInstance,
    LPSTR lpszCmdParam, int nCmdShow)
{
    static char szAppName[] = "Bolygone";
    HWND        hwnd;
    MSG         msg;
    WNDCLASS    wndclass;

    if (!hPrevInstance) {
        wndclass.style         = CS_HREDRAW | CS_VREDRAW;
        wndclass.lpfnWndProc   = WndProc;
        wndclass.cbClsExtra    = 0;
        wndclass.cbWndExtra    = 0;
        wndclass.hInstance     = hInstance;
        wndclass.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
        wndclass.hCursor       = LoadCursor(NULL, IDC_ARROW);
        wndclass.hbrBackground = GetStockObject(WHITE_BRUSH);
        wndclass.lpszMenuName  = NULL;
        wndclass.lpszClassName = szAppName;

        RegisterClass(&wndclass);
    }

    hwnd = CreateWindow(szAppName,  // window class name
        "BOLYGONE",            // window caption
        WS_OVERLAPPEDWINDOW,        // window style                       
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                      // creation parameters

   ShowWindow(hwnd, nCmdShow);
   UpdateWindow(hwnd);

   while (GetMessage(&msg, NULL, 0, 0)) {
       TranslateMessage(&msg);
       DispatchMessage(&msg);
   }
   return msg.wParam;
}

//end of file bolygone.cpp