+ * @brief Dump a buffer.
+ * @details
+ * The filename will includes the buffer information. (width, height, format)
+ * @param[in] buffer A TDM buffer
+ * @param[in] file The path of file.
+ */
+void
+tdm_helper_dump_buffer_str(tbm_surface_h buffer, char *dir, char *str);
+
+/**
+ * @brief fill a buffer with 0 for given pos.
+ * @details
+ * This function supports only if a buffer has below formats.
+ * - TBM_FORMAT_ARGB8888
+ * - TBM_FORMAT_XRGB8888
+ * @param[in] buffer A TDM buffer
+ */
+void
+tdm_helper_clear_buffer_pos(tbm_surface_h buffer, tdm_pos *pos);
+
+/**
+ * @brief fill a buffer with 0 for given pos.
+ * @details
+ * This function supports only if a buffer has below formats.
+ * - TBM_FORMAT_ARGB8888
+ * - TBM_FORMAT_XRGB8888
+ * @param[in] buffer A TDM buffer
+ */
+void
+tdm_helper_clear_buffer_color(tbm_surface_h buffer, tdm_pos *pos, unsigned int color);
+
+/**