code: func PixbufGetFileInfo(filename string) (format interface{}, width, height int) {
  	cstr := C.CString(filename)
  	defer C.free(unsafe.Pointer(cstr))
  	var cw, ch C.gint
  	format = C.gdk_pixbuf_get_file_info((*C.gchar)(cstr), &cw, &ch)
  	// TODO: need to wrap the returned format to GdkPixbufFormat.
  	return format, int(cw), int(ch)
  }
docs: // PixbufGetFileInfo is a wrapper around gdk_pixbuf_get_file_info().
  // TODO: need to wrap the returned format to GdkPixbufFormat.