[WinAPI] Rysowanie figur

case WM_LBUTTONDOWN:
{
    RECT WindowRect;
    GetWindowRect( hwnd, & WindowRect );
    const int W = WindowRect.right - WindowRect.left;
    const int H = WindowRect.bottom - WindowRect.top;
    HDC hdc = GetDC( hwnd );
    RECT Rect = { 0, 0, W, H };
    FillRect( hdc, & Rect, CreateSolidBrush( 0xFFFFFF ) );
   
    for( int i = 0; i < W; i += 10 )
    {
        MoveToEx( hdc, i, 0,( LPPOINT ) NULL );
        LineTo( hdc, i, H );
    }
    for( int i = 0; i < H; i += 10 )
    {
        MoveToEx( hdc, 0, i,( LPPOINT ) NULL );
        LineTo( hdc, W, i );
    }
    break;
}

case WM_RBUTTONDOWN:
{
    RECT Okno;
    GetWindowRect( hwnd, & Okno );
    const int W = Okno.right - Okno.left;
    const int H = Okno.bottom - Okno.top;
    HDC hdc = GetDC( hwnd );
    RECT Rect = { 0, 0, W, H };
    FillRect( hdc, & Rect, CreateSolidBrush( 0xFFFFFF ) );
    int szer = H;
    int i = 0;
    do
    {
        Ellipse( hdc, i, i, szer, szer );
        szer -= 10;
        i += 10;
    } while( i < H / 2 );
   
    break;
}