/*******************************************************************
*                   DEMO OF MODULE GRAPH2D.CPP                     *
* ---------------------------------------------------------------- *
* This program demonstrates the use of the module graph2d to draw  *
* a 2D curve with automatic scaling.                               *
*                                                                  *
*                        Visual C++ version by J-P Moreau, Paris   *
*                        (use with grafdemo.mak and graph2d.cpp)   *
*                                  (www.jpmoreau.fr)               *
*******************************************************************/
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

HDC  hdc;
RECT rect;
HPEN hpen, hpenOld;

//Functions used here of Graph2D.cpp
void Initwindow(int,double,double,double,double);
void MoveXY(double,double);
void LineXY(double,double);
void Legendes (int,char *,char *,char *,int,int,char *,int,int,char *);

//"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;
  double dx,dy;
  if (ix2<ix1) {
    Swap(&ix1,&ix2); Swap(&iy1,&iy2);
  }
  il=(int) sqrt((ix2-ix1)*(ix2-ix1)+(iy2-iy1)*(iy2-iy1));
  dx=(double) (ix2-ix1)/il; 
  dy=(double) (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-5; rct.bottom=iy+15;
  DrawText(hdc, s, -1, &rct,
                DT_SINGLELINE | DT_CENTER | DT_VCENTER);
}


//Draw curve y=sin(x) from x=0 with a dx step of 0.1 (250 pts)
void Graph_demo() {
  extern MaxX, MaxY;
  double dx=0.1,x=0;
  int i,nwin=10;
  //client drawing zone in pixels
  MaxX=(rect.right-rect.left);
  MaxY=(rect.bottom-rect.top);
  //open graphic zone n° 10 (physical coordinates)
  Initwindow(nwin,0,10,-1,1);
  //main drawing loop
  MoveXY(x,sin(x));
  for (i=1; i<=250; i++) {
    x+=dx;
    LineXY(x,sin(x));
  }
  //write captions
  Legendes(nwin," FUNCTION  Y = SIN(X) ","X","Y",MaxX-150,40,"250 points",0,0,"");
}


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

            Graph_demo();
               
            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[] = "Grafdemo";
    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
        " DEMO GRAPH 2D",           // 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 grafdemo.cpp