static extern int FT_Get_Kerning(IntPtr face, uint left, uint right, uint kern_mode, out FT_Vector kerning);
static extern int FT_Get_Kerning (IntPtr face, uint left, uint right, uint kern_mode, out FT_Vector kerning);
public static extern void FT_Get_Kerning(IntPtr face, int left, int right, int kernmode, out FT_Vector kerning);