// Листинг 1.7. Построение кардиоиды

#define _USE_MATH_DEFINES
#include <cmath>
const int R = 100;
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
   PAINTSTRUCT ps;
   HDC hdc;
   static int sx, sy;
   int a, b, x, y;		//Экранные координаты
   double angle;		//Физические координаты
   switch(message)
   {
   case WM_SIZE:
      sx = LOWORD(lParam);	//Ширина окна
      sy = HIWORD(lParam);	//Высота окна
      break;
   case WM_PAINT:
      hdc = BeginPaint(hWnd, &ps);
      a = sx/2;
      b = sy/2;
      MoveToEx(hdc, 0, b, NULL);
      LineTo(hdc, sx, b);
      MoveToEx(hdc, a, 0, NULL);
      LineTo(hdc, a, sy);
      MoveToEx(hdc, a, b, NULL);
      for (angle = 0.0; angle < 2*M_PI; angle += 0.1)
      {
         x = a + R*(1 - cos(angle))*cos(angle);
         y = b - R*(1 - cos(angle))*sin(angle);
         LineTo(hdc, x, y);
      }
      EndPaint(hWnd, &ps);
      break;
   case WM_DESTROY: PostQuitMessage(0); break;
   default: return DefWindowProc(hWnd, message, wParam, lParam);
   }
   return 0;
}