/*-----------------------------------------
   SINEWAVE.C -- Sine Wave Using Polyline
                 (c) Charles Petzold, 1996
  -----------------------------------------*/

#include <windows.h>
#include <math.h>

#define NUM    1000
#define TWOPI  (2 * 3.14159)

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
     {
     static char szAppName[] = "SineWave" ;
     HWND        hwnd ;
     MSG         msg ;
     WNDCLASSEX  wndclass ;

     wndclass.cbSize        = sizeof (wndclass) ;
     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 = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
     wndclass.lpszMenuName  = NULL ;
     wndclass.lpszClassName = szAppName ;
     wndclass.hIconSm       = LoadIcon (NULL, IDI_APPLICATION) ;

     RegisterClassEx (&wndclass) ;

     hwnd = CreateWindow (szAppName, "Sine Wave Using Polyline",
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          NULL, NULL, hInstance, NULL) ;

     ShowWindow (hwnd, iCmdShow) ;
     UpdateWindow (hwnd) ;

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

LRESULT CALLBACK WndProc (HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
     {
     static int  cxClient, cyClient ;
     HDC         hdc ;
     int         i ;
     PAINTSTRUCT ps ;
     POINT       pt [NUM] ;

     switch (iMsg)
          {
          case WM_SIZE:
               cxClient = LOWORD (lParam) ;
               cyClient = HIWORD (lParam) ;
               return 0 ;

          case WM_PAINT:
               hdc = BeginPaint (hwnd, &ps) ;

               MoveToEx (hdc, 0,        cyClient / 2, NULL) ;
               LineTo   (hdc, cxClient, cyClient / 2) ;

               for (i = 0 ; i < NUM ; i++)
                    {
                    pt[i].x = i * cxClient / NUM ;
                    pt[i].y = (int) (cyClient / 2 *
                                    (1 - sin (TWOPI * i / NUM))) ;
                    }

               Polyline (hdc, pt, NUM) ;

               return 0 ;

          case WM_DESTROY:
               PostQuitMessage (0) ;
               return 0 ;
          }

     return DefWindowProc (hwnd, iMsg, wParam, lParam) ;
     }