C++输出透明背景字体

void printtptext(HWND hwnd, int x, int y, int cHeight, int cWidth, LPCWSTR lpString, COLORREF color, LPCWSTR pszFaceName)
{
  	HDC hdc = GetDC(hwnd);//获取设备上下文的句柄 
	SetBkMode(hdc, TRANSPARENT);
	SetTextColor(hdc, color);
	HFONT font = CreateFont(cHeight, cWidth, 0, 0, FW_NORMAL, FALSE, FALSE,  0, ANSI_CHARSET, OUT_DEFAULT_PRECIS,  CLIP_DEFAULT_PRECIS,  DEFAULT_QUALITY, DEFAULT_PITCH | FF_SWISS,  pszFaceName);
  	SelectObject(hdc, font);
  	TextOut(hdc, x, y, lpString, wcslen(lpString)); 
}