internal static extern bool DeleteDC(HDC hdc);
internal static extern int SetStretchBltMode(HDC hdc, int iStretchMode);
internal static extern HDC CreateCompatibleDC(HDC hdc);
internal static extern HBITMAP SelectObject(HDC hdc, HBITMAP hgdiobj);
internal static extern HBITMAP CreateCompatibleBitmap(HDC hdc, int nWidth, int nHeight);
internal static extern HDC ReleaseDC(HWND hwnd, HDC hdc);