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comparison spandsp-0.0.6pre17/src/spandsp/t4_rx.h @ 4:26cd8f1ef0b1

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import spandsp-0.0.6pre17
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 15:50:58 +0200
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3:c6c5a16ce2f2 4:26cd8f1ef0b1
1 /*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * t4_rx.h - definitions for T.4 FAX receive processing
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2003 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Lesser General Public License version 2.1,
14 * as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25 * $Id: t4_rx.h,v 1.3.2.3 2009/12/21 17:18:40 steveu Exp $
26 */
27
28 /*! \file */
29
30 #if !defined(_SPANDSP_T4_RX_H_)
31 #define _SPANDSP_T4_RX_H_
32
33 /*! \page t4_page T.4 image compression and decompression
34
35 \section t4_page_sec_1 What does it do?
36 The T.4 image compression and decompression routines implement the 1D and 2D
37 encoding methods defined in ITU specification T.4. They also implement the pure
38 2D encoding method defined in T.6. These are image compression algorithms used
39 for FAX transmission.
40
41 \section t4_page_sec_1 How does it work?
42 */
43
44 typedef int (*t4_row_write_handler_t)(void *user_data, const uint8_t buf[], size_t len);
45
46 /*! Supported compression modes. */
47 typedef enum
48 {
49 /*! No compression */
50 T4_COMPRESSION_NONE = 0,
51 /*! T.1 1D compression */
52 T4_COMPRESSION_ITU_T4_1D = 1,
53 /*! T.4 2D compression */
54 T4_COMPRESSION_ITU_T4_2D = 2,
55 /*! T.6 2D compression */
56 T4_COMPRESSION_ITU_T6 = 3,
57 /*! T.85 monochrome JBIG coding */
58 T4_COMPRESSION_ITU_T85 = 4,
59 /*! T.43 colour JBIG coding */
60 T4_COMPRESSION_ITU_T43 = 5,
61 /*! T.45 run length colour compression */
62 T4_COMPRESSION_ITU_T45 = 6,
63 /*! T.81 + T.30 Annex E colour JPEG coding */
64 T4_COMPRESSION_ITU_T81 = 7,
65 /*! T.81 + T.30 Annex K colour sYCC-JPEG coding */
66 T4_COMPRESSION_ITU_SYCC_T81 = 8
67 } t4_image_compression_t;
68
69 /*! Supported X resolutions, in pixels per metre. */
70 typedef enum
71 {
72 T4_X_RESOLUTION_R4 = 4016,
73 T4_X_RESOLUTION_R8 = 8031,
74 T4_X_RESOLUTION_300 = 11811,
75 T4_X_RESOLUTION_R16 = 16063,
76 T4_X_RESOLUTION_600 = 23622,
77 T4_X_RESOLUTION_800 = 31496,
78 T4_X_RESOLUTION_1200 = 47244
79 } t4_image_x_resolution_t;
80
81 /*! Supported Y resolutions, in pixels per metre. */
82 typedef enum
83 {
84 T4_Y_RESOLUTION_STANDARD = 3850,
85 T4_Y_RESOLUTION_FINE = 7700,
86 T4_Y_RESOLUTION_300 = 11811,
87 T4_Y_RESOLUTION_SUPERFINE = 15400, /* 400 is 15748 */
88 T4_Y_RESOLUTION_600 = 23622,
89 T4_Y_RESOLUTION_800 = 31496,
90 T4_Y_RESOLUTION_1200 = 47244
91 } t4_image_y_resolution_t;
92
93 /*!
94 Exact widths in PELs for the difference resolutions, and page widths.
95 Note:
96 The A4 widths also apply to North American letter and legal.
97 The R4 resolution widths are not supported in recent versions of T.30
98 Only images of exactly these widths are acceptable for FAX transmisson.
99
100 R4 864 pels/215mm for ISO A4, North American Letter and Legal
101 R4 1024 pels/255mm for ISO B4
102 R4 1216 pels/303mm for ISO A3
103 R8 1728 pels/215mm for ISO A4, North American Letter and Legal
104 R8 2048 pels/255mm for ISO B4
105 R8 2432 pels/303mm for ISO A3
106 R16 3456 pels/215mm for ISO A4, North American Letter and Legal
107 R16 4096 pels/255mm for ISO B4
108 R16 4864 pels/303mm for ISO A3
109 */
110 typedef enum
111 {
112 T4_WIDTH_R4_A4 = 864,
113 T4_WIDTH_R4_B4 = 1024,
114 T4_WIDTH_R4_A3 = 1216,
115 T4_WIDTH_R8_A4 = 1728,
116 T4_WIDTH_R8_B4 = 2048,
117 T4_WIDTH_R8_A3 = 2432,
118 T4_WIDTH_300_A4 = 2592,
119 T4_WIDTH_300_B4 = 3072,
120 T4_WIDTH_300_A3 = 3648,
121 T4_WIDTH_R16_A4 = 3456,
122 T4_WIDTH_R16_B4 = 4096,
123 T4_WIDTH_R16_A3 = 4864,
124 T4_WIDTH_600_A4 = 5184,
125 T4_WIDTH_600_B4 = 6144,
126 T4_WIDTH_600_A3 = 7296,
127 T4_WIDTH_1200_A4 = 10368,
128 T4_WIDTH_1200_B4 = 12288,
129 T4_WIDTH_1200_A3 = 14592
130 } t4_image_width_t;
131
132 /*!
133 Length of the various supported paper sizes, in pixels at the various Y resolutions.
134 Paper sizes are
135 A4 (215mm x 297mm)
136 B4 (255mm x 364mm)
137 A3 (303mm x 418.56mm)
138 North American Letter (215.9mm x 279.4mm)
139 North American Legal (215.9mm x 355.6mm)
140 Unlimited
141
142 T.4 does not accurately define the maximum number of scan lines in a page. A wide
143 variety of maximum row counts are used in the real world. It is important not to
144 set our sending limit too high, or a receiving machine might split pages. It is
145 important not to set it too low, or we might clip pages.
146
147 Values seen for standard resolution A4 pages include 1037, 1045, 1109, 1126 and 1143.
148 1109 seems the most-popular. At fine res 2150, 2196, 2200, 2237, 2252-2262, 2264,
149 2286, and 2394 are used. 2255 seems the most popular. We try to use balanced choices
150 here.
151 */
152 typedef enum
153 {
154 /* A4 is 297mm long */
155 T4_LENGTH_STANDARD_A4 = 1143,
156 T4_LENGTH_FINE_A4 = 2286,
157 T4_LENGTH_300_A4 = 4665,
158 T4_LENGTH_SUPERFINE_A4 = 4573,
159 T4_LENGTH_600_A4 = 6998,
160 T4_LENGTH_800_A4 = 9330,
161 T4_LENGTH_1200_A4 = 13996,
162 /* B4 is 364mm long */
163 T4_LENGTH_STANDARD_B4 = 1401,
164 T4_LENGTH_FINE_B4 = 2802,
165 T4_LENGTH_300_B4 = 0,
166 T4_LENGTH_SUPERFINE_B4 = 5605,
167 T4_LENGTH_600_B4 = 0,
168 T4_LENGTH_800_B4 = 0,
169 T4_LENGTH_1200_B4 = 0,
170 /* North American letter is 279.4mm long */
171 T4_LENGTH_STANDARD_US_LETTER = 1075,
172 T4_LENGTH_FINE_US_LETTER = 2151,
173 T4_LENGTH_300_US_LETTER = 0,
174 T4_LENGTH_SUPERFINE_US_LETTER = 4302,
175 T4_LENGTH_600_US_LETTER = 0,
176 T4_LENGTH_800_US_LETTER = 0,
177 T4_LENGTH_1200_US_LETTER = 0,
178 /* North American legal is 355.6mm long */
179 T4_LENGTH_STANDARD_US_LEGAL = 1369,
180 T4_LENGTH_FINE_US_LEGAL = 2738,
181 T4_LENGTH_300_US_LEGAL = 0,
182 T4_LENGTH_SUPERFINE_US_LEGAL = 5476,
183 T4_LENGTH_600_US_LEGAL = 0,
184 T4_LENGTH_800_US_LEGAL = 0,
185 T4_LENGTH_1200_US_LEGAL = 0
186 } t4_image_length_t;
187
188 /*!
189 T.4 FAX compression/decompression descriptor. This defines the working state
190 for a single instance of a T.4 FAX compression or decompression channel.
191 */
192 typedef struct t4_state_s t4_state_t;
193
194 /*!
195 T.4 FAX compression/decompression statistics.
196 */
197 typedef struct
198 {
199 /*! \brief The number of pages transferred so far. */
200 int pages_transferred;
201 /*! \brief The number of pages in the file (<0 if unknown). */
202 int pages_in_file;
203 /*! \brief The number of horizontal pixels in the most recent page. */
204 int width;
205 /*! \brief The number of vertical pixels in the most recent page. */
206 int length;
207 /*! \brief The number of bad pixel rows in the most recent page. */
208 int bad_rows;
209 /*! \brief The largest number of bad pixel rows in a block in the most recent page. */
210 int longest_bad_row_run;
211 /*! \brief The horizontal resolution of the page in pixels per metre */
212 int x_resolution;
213 /*! \brief The vertical resolution of the page in pixels per metre */
214 int y_resolution;
215 /*! \brief The type of compression used between the FAX machines */
216 int encoding;
217 /*! \brief The size of the image on the line, in bytes */
218 int line_image_size;
219 } t4_stats_t;
220
221 #if defined(__cplusplus)
222 extern "C" {
223 #endif
224
225 /*! \brief Prepare for reception of a document.
226 \param s The T.4 context.
227 \param file The name of the file to be received.
228 \param output_encoding The output encoding.
229 \return A pointer to the context, or NULL if there was a problem. */
230 SPAN_DECLARE(t4_state_t *) t4_rx_init(t4_state_t *s, const char *file, int output_encoding);
231
232 /*! \brief Prepare to receive the next page of the current document.
233 \param s The T.4 context.
234 \return zero for success, -1 for failure. */
235 SPAN_DECLARE(int) t4_rx_start_page(t4_state_t *s);
236
237 /*! \brief Put a bit of the current document page.
238 \param s The T.4 context.
239 \param bit The data bit.
240 \return TRUE when the bit ends the document page, otherwise FALSE. */
241 SPAN_DECLARE(int) t4_rx_put_bit(t4_state_t *s, int bit);
242
243 /*! \brief Put a byte of the current document page.
244 \param s The T.4 context.
245 \param byte The data byte.
246 \return TRUE when the byte ends the document page, otherwise FALSE. */
247 SPAN_DECLARE(int) t4_rx_put_byte(t4_state_t *s, uint8_t byte);
248
249 /*! \brief Put a byte of the current document page.
250 \param s The T.4 context.
251 \param buf The buffer containing the chunk.
252 \param len The length of the chunk.
253 \return TRUE when the byte ends the document page, otherwise FALSE. */
254 SPAN_DECLARE(int) t4_rx_put_chunk(t4_state_t *s, const uint8_t buf[], int len);
255
256 /*! \brief Complete the reception of a page.
257 \param s The T.4 receive context.
258 \return 0 for success, otherwise -1. */
259 SPAN_DECLARE(int) t4_rx_end_page(t4_state_t *s);
260
261 /*! \brief End reception of a document. Tidy up and close the file.
262 This should be used to end T.4 reception started with
263 t4_rx_init.
264 \param s The T.4 receive context.
265 \return 0 for success, otherwise -1. */
266 SPAN_DECLARE(int) t4_rx_release(t4_state_t *s);
267
268 /*! \brief End reception of a document. Tidy up, close the file and
269 free the context. This should be used to end T.4 reception
270 started with t4_rx_init.
271 \param s The T.4 receive context.
272 \return 0 for success, otherwise -1. */
273 SPAN_DECLARE(int) t4_rx_free(t4_state_t *s);
274
275 /*! \brief Set the row write handler for a T.4 receive context.
276 \param s The T.4 receive context.
277 \param handler A pointer to the handler routine.
278 \param user_data An opaque pointer passed to the handler routine.
279 \return 0 for success, otherwise -1. */
280 SPAN_DECLARE(int) t4_rx_set_row_write_handler(t4_state_t *s, t4_row_write_handler_t handler, void *user_data);
281
282 /*! \brief Set the encoding for the received data.
283 \param s The T.4 context.
284 \param encoding The encoding. */
285 SPAN_DECLARE(void) t4_rx_set_rx_encoding(t4_state_t *s, int encoding);
286
287 /*! \brief Set the expected width of the received image, in pixel columns.
288 \param s The T.4 context.
289 \param width The number of pixels across the image. */
290 SPAN_DECLARE(void) t4_rx_set_image_width(t4_state_t *s, int width);
291
292 /*! \brief Set the row-to-row (y) resolution to expect for a received image.
293 \param s The T.4 context.
294 \param resolution The resolution, in pixels per metre. */
295 SPAN_DECLARE(void) t4_rx_set_y_resolution(t4_state_t *s, int resolution);
296
297 /*! \brief Set the column-to-column (x) resolution to expect for a received image.
298 \param s The T.4 context.
299 \param resolution The resolution, in pixels per metre. */
300 SPAN_DECLARE(void) t4_rx_set_x_resolution(t4_state_t *s, int resolution);
301
302 /*! \brief Set the DCS information of the fax, for inclusion in the file.
303 \param s The T.4 context.
304 \param dcs The DCS information, formatted as an ASCII string. */
305 SPAN_DECLARE(void) t4_rx_set_dcs(t4_state_t *s, const char *dcs);
306
307 /*! \brief Set the sub-address of the fax, for inclusion in the file.
308 \param s The T.4 context.
309 \param sub_address The sub-address string. */
310 SPAN_DECLARE(void) t4_rx_set_sub_address(t4_state_t *s, const char *sub_address);
311
312 /*! \brief Set the identity of the remote machine, for inclusion in the file.
313 \param s The T.4 context.
314 \param ident The identity string. */
315 SPAN_DECLARE(void) t4_rx_set_far_ident(t4_state_t *s, const char *ident);
316
317 /*! \brief Set the vendor of the remote machine, for inclusion in the file.
318 \param s The T.4 context.
319 \param vendor The vendor string, or NULL. */
320 SPAN_DECLARE(void) t4_rx_set_vendor(t4_state_t *s, const char *vendor);
321
322 /*! \brief Set the model of the remote machine, for inclusion in the file.
323 \param s The T.4 context.
324 \param model The model string, or NULL. */
325 SPAN_DECLARE(void) t4_rx_set_model(t4_state_t *s, const char *model);
326
327 /*! Get the current image transfer statistics.
328 \brief Get the current transfer statistics.
329 \param s The T.4 context.
330 \param t A pointer to a statistics structure. */
331 SPAN_DECLARE(void) t4_get_transfer_statistics(t4_state_t *s, t4_stats_t *t);
332
333 /*! Get the short text name of an encoding format.
334 \brief Get the short text name of an encoding format.
335 \param encoding The encoding type.
336 \return A pointer to the string. */
337 SPAN_DECLARE(const char *) t4_encoding_to_str(int encoding);
338
339 #if defined(__cplusplus)
340 }
341 #endif
342
343 #endif
344 /*- End of file ------------------------------------------------------------*/

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