DirectFB Reference Manual
IDirectFBSurface   DrawGlyph

Draw a single glyph specified by its Unicode index at the specified position with the given color following the specified flags.

DrawGlyph (
	IDirectFBSurface		*	thiz,
	unsigned int			index,
	int			x,
	int			y,
	DFBSurfaceTextFlags			flags
);

If font was loaded with the DFFA_NOCHARMAP flag, index specifies the raw glyph index in the font.

You need to set a font using the SetFont() method before calling this function.