// Листинг 1.11. Использование регионов для графических построений

RECT pRect = {-100, -100, 100, 100};
RECT pEllips = {-120, -80, 120, 80};
RECT pSm = {-60, -40, 60, 40};
const int WIDTH = 400;
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	PAINTSTRUCT ps;
	HDC hdc;
	static int sx, sy;
	HRGN hRgnEllipse;
	HRGN hRgn;
	static HBRUSH hBrush;
	switch (message)
	{
	case WM_SIZE:
		sx = LOWORD(lParam);
		sy = HIWORD(lParam);
		break;
	case WM_CREATE:
		hBrush = CreateSolidBrush(RGB(0, 0, 255));
		break;
	case WM_PAINT:
		hdc = BeginPaint(hWnd, &ps);
		SetMapMode(hdc, MM_ANISOTROPIC);	
		SetWindowExtEx(hdc, WIDTH, - WIDTH, NULL);
		SetViewportExtEx(hdc, sx, sy, NULL);
		SetViewportOrgEx(hdc, sx/2, sy/2, NULL);
		hRgn = CreateRectRgnIndirect(&pRect);
		hRgnEllipse = CreateEllipticRgnIndirect(&pEllips);
		CombineRgn(hRgn, hRgn, hRgnEllipse, RGN_DIFF);
		DeleteObject(hRgnEllipse);
		hRgnEllipse = CreateEllipticRgnIndirect(&pSm);
		CombineRgn(hRgn, hRgn, hRgnEllipse, RGN_OR);
		DeleteObject(hRgnEllipse);
		FillRgn(hdc, hRgn, hBrush);
		DeleteObject(hRgn);
		EndPaint(hWnd, &ps);
		break;
	case WM_DESTROY: PostQuitMessage(0); break;
	default: return DefWindowProc(hWnd, message, wParam, lParam);
	}
	return 0;
}