00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * t4.h - definitions for T.4 fax processing 00005 * 00006 * Written by Steve Underwood <steveu@coppice.org> 00007 * 00008 * Copyright (C) 2003 Steve Underwood 00009 * 00010 * All rights reserved. 00011 * 00012 * This program is free software; you can redistribute it and/or modify 00013 * it under the terms of the GNU General Public License version 2, as 00014 * published by the Free Software Foundation. 00015 * 00016 * This program is distributed in the hope that it will be useful, 00017 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00018 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00019 * GNU General Public License for more details. 00020 * 00021 * You should have received a copy of the GNU General Public License 00022 * along with this program; if not, write to the Free Software 00023 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 00024 * 00025 * $Id: t4.h,v 1.45 2007/11/26 13:58:06 steveu Exp $ 00026 */ 00027 00028 /*! \file */ 00029 00030 #if !defined(_SPANDSP_T4_H_) 00031 #define _SPANDSP_T4_H_ 00032 00033 /*! \page t4_page T.4 image compression and decompression 00034 00035 \section t4_page_sec_1 What does it do? 00036 The T.4 image compression and decompression routines implement the 1D and 2D 00037 encoding methods defined in ITU specification T.4. They also implement the pure 00038 2D encoding method defined in T.6. These are image compression algorithms used 00039 for FAX transmission. 00040 00041 \section t4_page_sec_1 How does it work? 00042 */ 00043 00044 typedef int (*t4_row_read_handler_t)(void *user_data, uint8_t buf[], size_t len); 00045 typedef int (*t4_row_write_handler_t)(void *user_data, const uint8_t buf[], size_t len); 00046 00047 typedef enum 00048 { 00049 T4_COMPRESSION_ITU_T4_1D = 1, 00050 T4_COMPRESSION_ITU_T4_2D = 2, 00051 T4_COMPRESSION_ITU_T6 = 3 00052 } t4_image_compression_t; 00053 00054 typedef enum 00055 { 00056 T4_X_RESOLUTION_R4 = 4016, 00057 T4_X_RESOLUTION_R8 = 8031, 00058 T4_X_RESOLUTION_300 = 11811, 00059 T4_X_RESOLUTION_R16 = 16063, 00060 T4_X_RESOLUTION_600 = 23622, 00061 T4_X_RESOLUTION_800 = 31496, 00062 T4_X_RESOLUTION_1200 = 47244 00063 } t4_image_x_resolution_t; 00064 00065 typedef enum 00066 { 00067 T4_Y_RESOLUTION_STANDARD = 3850, 00068 T4_Y_RESOLUTION_FINE = 7700, 00069 T4_Y_RESOLUTION_300 = 11811, 00070 T4_Y_RESOLUTION_SUPERFINE = 15400, /* 400 is 15748 */ 00071 T4_Y_RESOLUTION_600 = 23622, 00072 T4_Y_RESOLUTION_800 = 31496, 00073 T4_Y_RESOLUTION_1200 = 47244 00074 } t4_image_y_resolution_t; 00075 00076 /*! 00077 Exact widths in PELs for the difference resolutions, and page widths. 00078 Note: 00079 The A4 widths also apply to North American letter and legal. 00080 The R4 resolution widths are not supported in recent versions of T.30 00081 Only images of exactly these widths are acceptable for FAX transmisson. 00082 00083 R4 864 pels/215mm for ISO A4, North American Letter and Legal 00084 R4 1024 pels/255mm for ISO B4 00085 R4 1216 pels/303mm for ISO A3 00086 R8 1728 pels/215mm for ISO A4, North American Letter and Legal 00087 R8 2048 pels/255mm for ISO B4 00088 R8 2432 pels/303mm for ISO A3 00089 R16 3456 pels/215mm for ISO A4, North American Letter and Legal 00090 R16 4096 pels/255mm for ISO B4 00091 R16 4864 pels/303mm for ISO A3 00092 */ 00093 typedef enum 00094 { 00095 T4_WIDTH_R4_A4 = 864, 00096 T4_WIDTH_R4_B4 = 1024, 00097 T4_WIDTH_R4_A3 = 1216, 00098 T4_WIDTH_R8_A4 = 1728, 00099 T4_WIDTH_R8_B4 = 2048, 00100 T4_WIDTH_R8_A3 = 2432, 00101 T4_WIDTH_300_A4 = 2592, 00102 T4_WIDTH_300_B4 = 3072, 00103 T4_WIDTH_300_A3 = 3648, 00104 T4_WIDTH_R16_A4 = 3456, 00105 T4_WIDTH_R16_B4 = 4096, 00106 T4_WIDTH_R16_A3 = 4864, 00107 T4_WIDTH_600_A4 = 5184, 00108 T4_WIDTH_600_B4 = 6144, 00109 T4_WIDTH_600_A3 = 7296, 00110 T4_WIDTH_1200_A4 = 10368, 00111 T4_WIDTH_1200_B4 = 12288, 00112 T4_WIDTH_1200_A3 = 14592 00113 } t4_image_width_t; 00114 00115 /*! 00116 Length of the various supported paper sizes, in pixels at the various Y resolutions. 00117 Paper sizes are 00118 A4 (215mm x 297mm) 00119 B4 (255mm x 364mm) 00120 A3 (303mm x 418.56mm) 00121 North American Letter (215.9mm x 279.4mm) 00122 North American Legal (215.9mm x 355.6mm) 00123 Unlimited 00124 00125 T.4 does not accurately define the maximum number of scan lines in a page. A wide 00126 variety of maximum row counts are used in the real world. It is important not to 00127 set our sending limit too high, or a receiving machine might split pages. It is 00128 important not to set it too low, or we might clip pages. 00129 00130 Values seen for standard resolution A4 pages include 1037, 1045, 1109, 1126 and 1143. 00131 1109 seems the most-popular. At fine res 2150, 2196, 2200, 2237, 2252-2262, 2264, 00132 2286, and 2394 are used. 2255 seems the most popular. We try to use balanced choices 00133 here. 00134 */ 00135 typedef enum 00136 { 00137 /* A4 is 297mm long */ 00138 T4_LENGTH_STANDARD_A4 = 1143, 00139 T4_LENGTH_FINE_A4 = 2286, 00140 T4_LENGTH_300_A4 = 4665, 00141 T4_LENGTH_SUPERFINE_A4 = 4573, 00142 T4_LENGTH_600_A4 = 6998, 00143 T4_LENGTH_800_A4 = 9330, 00144 T4_LENGTH_1200_A4 = 13996, 00145 /* B4 is 364mm long */ 00146 T4_LENGTH_STANDARD_B4 = 1401, 00147 T4_LENGTH_FINE_B4 = 2802, 00148 T4_LENGTH_300_B4 = 0, 00149 T4_LENGTH_SUPERFINE_B4 = 5605, 00150 T4_LENGTH_600_B4 = 0, 00151 T4_LENGTH_800_B4 = 0, 00152 T4_LENGTH_1200_B4 = 0, 00153 /* North American letter is 279.4mm long */ 00154 T4_LENGTH_STANDARD_US_LETTER = 1075, 00155 T4_LENGTH_FINE_US_LETTER = 2151, 00156 T4_LENGTH_300_US_LETTER = 0, 00157 T4_LENGTH_SUPERFINE_US_LETTER = 4302, 00158 T4_LENGTH_600_US_LETTER = 0, 00159 T4_LENGTH_800_US_LETTER = 0, 00160 T4_LENGTH_1200_US_LETTER = 0, 00161 /* North American legal is 355.6mm long */ 00162 T4_LENGTH_STANDARD_US_LEGAL = 1369, 00163 T4_LENGTH_FINE_US_LEGAL = 2738, 00164 T4_LENGTH_300_US_LEGAL = 0, 00165 T4_LENGTH_SUPERFINE_US_LEGAL = 5476, 00166 T4_LENGTH_600_US_LEGAL = 0, 00167 T4_LENGTH_800_US_LEGAL = 0, 00168 T4_LENGTH_1200_US_LEGAL = 0 00169 } t4_image_length_t; 00170 00171 /*! 00172 T.4 FAX compression/decompression descriptor. This defines the working state 00173 for a single instance of a T.4 FAX compression or decompression channel. 00174 */ 00175 typedef struct 00176 { 00177 /* "Background" information about the FAX, which can be stored in a TIFF file. */ 00178 /*! \brief The vendor of the machine which produced the TIFF file. */ 00179 const char *vendor; 00180 /*! \brief The model of machine which produced the TIFF file. */ 00181 const char *model; 00182 /*! \brief The local ident string. */ 00183 const char *local_ident; 00184 /*! \brief The remote end's ident string. */ 00185 const char *far_ident; 00186 /*! \brief The FAX sub-address. */ 00187 const char *sub_address; 00188 /*! \brief The FAX DCS information, as an ASCII string. */ 00189 const char *dcs; 00190 /*! \brief The text which will be used in FAX page header. No text results 00191 in no header line. */ 00192 const char *header_info; 00193 00194 /*! \brief The type of compression used between the FAX machines. */ 00195 int line_encoding; 00196 /*! \brief The minimum number of encoded bits per row. This is a timing thing 00197 for hardware FAX machines. */ 00198 int min_row_bits; 00199 00200 /*! \brief The compression type for output to the TIFF file. */ 00201 int output_compression; 00202 /*! \brief The TIFF G3 FAX options. */ 00203 int output_t4_options; 00204 00205 /*! \brief The time at which handling of the current page began. */ 00206 time_t page_start_time; 00207 00208 /*! \brief The current number of bytes per row of uncompressed image data. */ 00209 int bytes_per_row; 00210 /*! \brief The size of the image in the image buffer, in bytes. */ 00211 int image_size; 00212 /*! \brief The current size of the image buffer. */ 00213 int image_buffer_size; 00214 uint8_t *image_buffer; 00215 00216 /*! \brief The libtiff context for the current TIFF file */ 00217 TIFF *tiff_file; 00218 /*! \brief The current file name. */ 00219 const char *file; 00220 /*! \brief The first page to transfer. -1 to start at the beginning of the file. */ 00221 int start_page; 00222 /*! \brief The last page to transfer. -1 to continue to the end of the file. */ 00223 int stop_page; 00224 00225 /*! \brief The number of pages transferred to date. */ 00226 int pages_transferred; 00227 /*! \brief The number of pages in the current TIFF file. */ 00228 int pages_in_file; 00229 /*! \brief Column-to-column (X) resolution in pixels per metre. */ 00230 int x_resolution; 00231 /*! \brief Row-to-row (Y) resolution in pixels per metre. */ 00232 int y_resolution; 00233 /*! \brief Width of the current page, in pixels. */ 00234 int image_width; 00235 /*! \brief Current pixel row number. */ 00236 int row; 00237 /*! \brief Total pixel rows in the current page. */ 00238 int image_length; 00239 /*! \brief The current number of consecutive bad rows. */ 00240 int curr_bad_row_run; 00241 /*! \brief The longest run of consecutive bad rows seen in the current page. */ 00242 int longest_bad_row_run; 00243 /*! \brief The total number of bad rows in the current page. */ 00244 int bad_rows; 00245 00246 uint32_t bits_to_date; 00247 int bits; 00248 00249 /*! \brief This variable is set if we are treating the current row as a 2D encoded 00250 one. */ 00251 int row_is_2d; 00252 /*! \brief TRUE if the current run is black */ 00253 int its_black; 00254 /*! \brief The current length of the current row. */ 00255 int row_len; 00256 /*! \brief This variable is used to record the fact we have seen at least one EOL 00257 since we started decoding. We will not try to interpret the received 00258 data as an image until we have seen the first EOL. */ 00259 int first_eol_seen; 00260 /*! \brief This variable is used to count the consecutive EOLS we have seen. If it 00261 reaches six, this is the end of the image. */ 00262 int consecutive_eols; 00263 00264 /*! \brief Black and white run-lengths for the current row. */ 00265 uint32_t *cur_runs; 00266 /*! \brief Black and white run-lengths for the reference row. */ 00267 uint32_t *ref_runs; 00268 /*! \brief The number of runs currently in the reference row. */ 00269 int ref_steps; 00270 /*! \brief The current step into the reference row run-lengths buffer. */ 00271 int b_cursor; 00272 /*! \brief The current step into the current row run-lengths buffer. */ 00273 int a_cursor; 00274 00275 /*! \brief The reference or starting changing element on the coding line. At the 00276 start of the coding line, a0 is set on an imaginary white changing element 00277 situated just before the first element on the line. During the coding of 00278 the coding line, the position of a0 is defined by the previous coding mode. 00279 (See 4.2.1.3.2.). */ 00280 int a0; 00281 /*! \brief The first changing element on the reference line to the right of a0 and of 00282 opposite colour to a0. */ 00283 int b1; 00284 /*! \brief The length of the in-progress run of black or white. */ 00285 int run_length; 00286 /*! \brief 2D horizontal mode control. */ 00287 int black_white; 00288 00289 uint32_t data; 00290 int data_bits; 00291 00292 /*! \brief A pointer into the image buffer indicating where the last row begins */ 00293 int last_row_starts_at; 00294 int row_starts_at; 00295 00296 /*! \brief Pointer to the buffer for the current pixel row. */ 00297 uint8_t *row_buf; 00298 00299 int bit_pos; 00300 int bit_ptr; 00301 00302 /*! \brief The maximum contiguous rows that will be 2D encoded. */ 00303 int max_rows_to_next_1d_row; 00304 /*! \brief Number of rows left that can be 2D encoded, before a 1D encoded row 00305 must be used. */ 00306 int rows_to_next_1d_row; 00307 /*! \brief The current number of bits in the current encoded row. */ 00308 int row_bits; 00309 00310 t4_row_read_handler_t row_read_handler; 00311 void *row_read_user_data; 00312 t4_row_write_handler_t row_write_handler; 00313 void *row_write_user_data; 00314 00315 /*! \brief Error and flow logging control */ 00316 logging_state_t logging; 00317 } t4_state_t; 00318 00319 /*! 00320 T.4 FAX compression/decompression statistics. 00321 */ 00322 typedef struct 00323 { 00324 /*! \brief The number of pages transferred so far. */ 00325 int pages_transferred; 00326 /*! \brief The number of pages in the file (<0 if unknown). */ 00327 int pages_in_file; 00328 /*! \brief The number of horizontal pixels in the most recent page. */ 00329 int width; 00330 /*! \brief The number of vertical pixels in the most recent page. */ 00331 int length; 00332 /*! \brief The number of bad pixel rows in the most recent page. */ 00333 int bad_rows; 00334 /*! \brief The largest number of bad pixel rows in a block in the most recent page. */ 00335 int longest_bad_row_run; 00336 /*! \brief The horizontal resolution of the page in pixels per metre */ 00337 int x_resolution; 00338 /*! \brief The vertical resolution of the page in pixels per metre */ 00339 int y_resolution; 00340 /*! \brief The type of compression used between the FAX machines */ 00341 int encoding; 00342 /*! \brief The size of the image, in bytes */ 00343 int image_size; 00344 } t4_stats_t; 00345 00346 #if defined(__cplusplus) 00347 extern "C" { 00348 #endif 00349 00350 /*! \brief Prepare for reception of a document. 00351 \param s The T.4 context. 00352 \param file The name of the file to be received. 00353 \param output_encoding The output encoding. 00354 \return A pointer to the context, or NULL if there was a problem. */ 00355 t4_state_t *t4_rx_init(t4_state_t *s, const char *file, int output_encoding); 00356 00357 /*! \brief Prepare to receive the next page of the current document. 00358 \param s The T.4 context. 00359 \return zero for success, -1 for failure. */ 00360 int t4_rx_start_page(t4_state_t *s); 00361 00362 /*! \brief Put a bit of the current document page. 00363 \param s The T.4 context. 00364 \param bit The data bit. 00365 \return TRUE when the bit ends the document page, otherwise FALSE. */ 00366 int t4_rx_put_bit(t4_state_t *s, int bit); 00367 00368 /*! \brief Put a byte of the current document page. 00369 \param s The T.4 context. 00370 \param byte The data byte. 00371 \return TRUE when the byte ends the document page, otherwise FALSE. */ 00372 int t4_rx_put_byte(t4_state_t *s, uint8_t byte); 00373 00374 /*! \brief Put a byte of the current document page. 00375 \param s The T.4 context. 00376 \param buf The buffer containing the chunk. 00377 \param len The length of the chunk. 00378 \return TRUE when the byte ends the document page, otherwise FALSE. */ 00379 int t4_rx_put_chunk(t4_state_t *s, const uint8_t buf[], int len); 00380 00381 /*! \brief Complete the reception of a page. 00382 \param s The T.4 receive context. 00383 \return 0 for success, otherwise -1. */ 00384 int t4_rx_end_page(t4_state_t *s); 00385 00386 /*! \brief End reception of a document. Tidy up, close the file and 00387 free the context. This should be used to end T.4 reception 00388 started with t4_rx_init. 00389 \param s The T.4 receive context. 00390 \return 0 for success, otherwise -1. */ 00391 int t4_rx_delete(t4_state_t *s); 00392 00393 /*! \brief End reception of a document. Tidy up and close the file. 00394 This should be used to end T.4 reception started with 00395 t4_rx_init. 00396 \param s The T.4 context. 00397 \return 0 for success, otherwise -1. */ 00398 int t4_rx_end(t4_state_t *s); 00399 00400 int t4_rx_set_row_write_handler(t4_state_t *s, t4_row_write_handler_t handler, void *user_data); 00401 00402 /*! \brief Set the encoding for the received data. 00403 \param s The T.4 context. 00404 \param encoding The encoding. */ 00405 void t4_rx_set_rx_encoding(t4_state_t *s, int encoding); 00406 00407 /*! \brief Set the expected width of the received image, in pixel columns. 00408 \param s The T.4 context. 00409 \param columns The number of pixels across the image. */ 00410 void t4_rx_set_image_width(t4_state_t *s, int width); 00411 00412 /*! \brief Set the row-to-row (y) resolution to expect for a received image. 00413 \param s The T.4 context. 00414 \param resolution The resolution, in pixels per metre. */ 00415 void t4_rx_set_y_resolution(t4_state_t *s, int resolution); 00416 00417 /*! \brief Set the column-to-column (x) resolution to expect for a received image. 00418 \param s The T.4 context. 00419 \param resolution The resolution, in pixels per metre. */ 00420 void t4_rx_set_x_resolution(t4_state_t *s, int resolution); 00421 00422 /*! \brief Set the DCS information of the fax, for inclusion in the file. 00423 \param s The T.4 context. 00424 \param dcs The DCS information, formatted as an ASCII string. */ 00425 void t4_rx_set_dcs(t4_state_t *s, const char *dcs); 00426 00427 /*! \brief Set the sub-address of the fax, for inclusion in the file. 00428 \param s The T.4 context. 00429 \param sub_address The sub-address string. */ 00430 void t4_rx_set_sub_address(t4_state_t *s, const char *sub_address); 00431 00432 /*! \brief Set the identity of the remote machine, for inclusion in the file. 00433 \param s The T.4 context. 00434 \param ident The identity string. */ 00435 void t4_rx_set_far_ident(t4_state_t *s, const char *ident); 00436 00437 /*! \brief Set the vendor of the remote machine, for inclusion in the file. 00438 \param s The T.4 context. 00439 \param vendor The vendor string, or NULL. */ 00440 void t4_rx_set_vendor(t4_state_t *s, const char *vendor); 00441 00442 /*! \brief Set the model of the remote machine, for inclusion in the file. 00443 \param s The T.4 context. 00444 \param model The model string, or NULL. */ 00445 void t4_rx_set_model(t4_state_t *s, const char *model); 00446 00447 /*! \brief Prepare for transmission of a document. 00448 \param s The T.4 context. 00449 \param file The name of the file to be sent. 00450 \param start_page The first page to send. -1 for no restriction. 00451 \param stop_page The last page to send. -1 for no restriction. 00452 \return A pointer to the context, or NULL if there was a problem. */ 00453 t4_state_t *t4_tx_init(t4_state_t *s, const char *file, int start_page, int stop_page); 00454 00455 /*! \brief Prepare to send the next page of the current document. 00456 \param s The T.4 context. 00457 \return zero for success, -1 for failure. */ 00458 int t4_tx_start_page(t4_state_t *s); 00459 00460 /*! \brief Prepare the current page for a resend. 00461 \param s The T.4 context. 00462 \return zero for success, -1 for failure. */ 00463 int t4_tx_restart_page(t4_state_t *s); 00464 00465 /*! \brief Check for the existance of the next page. This information can 00466 be needed before it is determined that the current page is finished with. 00467 \param s The T.4 context. 00468 \return zero for next page found, -1 for failure. */ 00469 int t4_tx_more_pages(t4_state_t *s); 00470 00471 /*! \brief Complete the sending of a page. 00472 \param s The T.4 context. 00473 \return zero for success, -1 for failure. */ 00474 int t4_tx_end_page(t4_state_t *s); 00475 00476 /*! \brief Get the next bit of the current document page. The document will 00477 be padded for the current minimum scan line time. If the 00478 file does not contain an RTC (return to control) code at 00479 the end of the page, one will be added where appropriate. 00480 \param s The T.4 context. 00481 \return The next bit (i.e. 0 or 1). For the last bit of data, bit 1 is 00482 set (i.e. the returned value is 2 or 3). */ 00483 int t4_tx_get_bit(t4_state_t *s); 00484 00485 /*! \brief Get the next byte of the current document page. The document will 00486 be padded for the current minimum scan line time. If the 00487 file does not contain an RTC (return to control) code at 00488 the end of the page, one will be added where appropriate. 00489 \param s The T.4 context. 00490 \return The next byte. For the last byte of data, bit 8 is 00491 set. In this case, one or more bits of the byte may be padded with 00492 zeros, to complete the byte. */ 00493 int t4_tx_get_byte(t4_state_t *s); 00494 00495 /*! \brief Get the next chunk of the current document page. The document will 00496 be padded for the current minimum scan line time. If the 00497 file does not contain an RTC (return to control) code at 00498 the end of the page, one will be added where appropriate. 00499 \param s The T.4 context. 00500 \param buf The buffer into which the chunk is to written. 00501 \param max_len The maximum length of the chunk. 00502 \return The actual length of the chunk. If this is less than max_len it 00503 indicates that the end of the document has been reached. */ 00504 int t4_tx_get_chunk(t4_state_t *s, uint8_t buf[], int max_len); 00505 00506 /*! \brief Return the next bit of the current document page, without actually 00507 moving forward in the buffer. The document will be padded for the 00508 current minimum scan line time. If the file does not contain an 00509 RTC (return to control) code at the end of the page, one will be 00510 added. 00511 \param s The T.4 context. 00512 \return The next bit (i.e. 0 or 1). For the last bit of data, bit 1 is 00513 set (i.e. the returned value is 2 or 3). */ 00514 int t4_tx_check_bit(t4_state_t *s); 00515 00516 /*! \brief End the transmission of a document. Tidy up, close the file and 00517 free the context. This should be used to end T.4 transmission 00518 started with t4_tx_init. 00519 \param s The T.4 context. 00520 \return 0 for success, otherwise -1. */ 00521 int t4_tx_delete(t4_state_t *s); 00522 00523 /*! \brief End the transmission of a document. Tidy up and close the file. 00524 This should be used to end T.4 transmission started with t4_tx_init. 00525 \param s The T.4 context. 00526 \return 0 for success, otherwise -1. */ 00527 int t4_tx_end(t4_state_t *s); 00528 00529 /*! \brief Set the encoding for the encoded data. 00530 \param s The T.4 context. 00531 \param encoding The encoding. */ 00532 void t4_tx_set_tx_encoding(t4_state_t *s, int encoding); 00533 00534 /*! \brief Set the minimum number of encoded bits per row. This allows the 00535 makes the encoding process to be set to comply with the minimum row 00536 time specified by a remote receiving machine. 00537 \param s The T.4 context. 00538 \param bits The minimum number of bits per row. */ 00539 void t4_tx_set_min_row_bits(t4_state_t *s, int bits); 00540 00541 /*! \brief Set the identity of the local machine, for inclusion in page headers. 00542 \param s The T.4 context. 00543 \param ident The identity string. */ 00544 void t4_tx_set_local_ident(t4_state_t *s, const char *ident); 00545 00546 /*! Set the info field, included in the header line included in each page of an encoded 00547 FAX. This is a string of up to 50 characters. Other information (date, local ident, etc.) 00548 are automatically included in the header. If the header info is set to NULL or a zero 00549 length string, no header lines will be added to the encoded FAX. 00550 \brief Set the header info. 00551 \param s The T.4 context. 00552 \param info A string, of up to 50 bytes, which will form the info field. */ 00553 void t4_tx_set_header_info(t4_state_t *s, const char *info); 00554 00555 int t4_tx_set_row_read_handler(t4_state_t *s, t4_row_read_handler_t handler, void *user_data); 00556 00557 /*! \brief Get the row-to-row (y) resolution of the current page. 00558 \param s The T.4 context. 00559 \return The resolution, in pixels per metre. */ 00560 int t4_tx_get_y_resolution(t4_state_t *s); 00561 00562 /*! \brief Get the column-to-column (x) resolution of the current page. 00563 \param s The T.4 context. 00564 \return The resolution, in pixels per metre. */ 00565 int t4_tx_get_x_resolution(t4_state_t *s); 00566 00567 /*! \brief Get the width of the current page, in pixel columns. 00568 \param s The T.4 context. 00569 \return The number of columns. */ 00570 int t4_tx_get_image_width(t4_state_t *s); 00571 00572 /*! \brief Get the number of pages in the file. 00573 \param s The T.4 context. 00574 \return The number of pages, or -1 if there is an error. */ 00575 int t4_tx_get_pages_in_file(t4_state_t *s); 00576 00577 /*! Get the current image transfer statistics. 00578 \brief Get the current transfer statistics. 00579 \param s The T.4 context. 00580 \param t A pointer to a statistics structure. */ 00581 void t4_get_transfer_statistics(t4_state_t *s, t4_stats_t *t); 00582 00583 /*! Get the short text name of an encoding format. 00584 \brief Get the short text name of an encoding format. 00585 \param encoding The encoding type. 00586 \return A pointer to the string. */ 00587 const char *t4_encoding_to_str(int encoding); 00588 00589 #if defined(__cplusplus) 00590 } 00591 #endif 00592 00593 #endif 00594 /*- End of file ------------------------------------------------------------*/