+/**
+ * Sets the given area to be decoded. This function should be called right after opj_read_header and before any tile header reading.
+ *
+ * @param p_codec the jpeg2000 codec.
+ * @param p_start_x the left position of the rectangle to decode (in image coordinates).
+ * @param p_end_x the right position of the rectangle to decode (in image coordinates).
+ * @param p_start_y the up position of the rectangle to decode (in image coordinates).
+ * @param p_end_y the bottom position of the rectangle to decode (in image coordinates).
+ *
+ * @return true if the area could be set.
+ */
+OPJ_API opj_bool OPJ_CALLCONV opj_set_decode_area( opj_codec_t *p_codec,
+ OPJ_INT32 p_start_x, OPJ_INT32 p_start_y,
+ OPJ_INT32 p_end_x, OPJ_INT32 p_end_y );
+
+/**
+ * Reads a tile header. This function is compulsory and allows one to know the size of the tile thta will be decoded.
+ * The user may need to refer to the image got by opj_read_header to understand the size being taken by the tile.
+ *
+ * @param p_codec the jpeg2000 codec.
+ * @param p_tile_index pointer to a value that will hold the index of the tile being decoded, in case of success.
+ * @param p_data_size pointer to a value that will hold the maximum size of the decoded data, in case of success. In case
+ * of truncated codestreams, the actual number of bytes decoded may be lower. The computation of the size is the same
+ * as depicted in opj_write_tile.
+ * @param p_tile_x0 pointer to a value that will hold the x0 pos of the tile (in the image).
+ * @param p_tile_y0 pointer to a value that will hold the y0 pos of the tile (in the image).
+ * @param p_tile_x1 pointer to a value that will hold the x1 pos of the tile (in the image).
+ * @param p_tile_y1 pointer to a value that will hold the y1 pos of the tile (in the image).
+ * @param p_nb_comps pointer to a value that will hold the number of components in the tile.
+ * @param p_should_go_on pointer to a boolean that will hold the fact that the decoding should go on. In case the
+ * codestream is over at the time of the call, the value will be set to false. The user should then stop
+ * the decoding.
+ * @param p_stream the stream to decode.
+ * @return true if the tile header could be decoded. In case the decoding should end, the returned value is still true.
+ * returning false may be the result of a shortage of memory or an internal error.
+ */
+OPJ_API opj_bool OPJ_CALLCONV opj_read_tile_header( opj_codec_t *p_codec,
+ opj_stream_t * p_stream,
+ OPJ_UINT32 * p_tile_index,
+ OPJ_UINT32 * p_data_size,
+ OPJ_INT32 * p_tile_x0, OPJ_INT32 * p_tile_y0,
+ OPJ_INT32 * p_tile_x1, OPJ_INT32 * p_tile_y1,
+ OPJ_UINT32 * p_nb_comps,
+ opj_bool * p_should_go_on );
+