spandsp: t4_tx.h Source File

spandsp 0.0.6

t4_tx.h
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1/*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * t4_tx.h - definitions for T.4 FAX transmit 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
26/*! \file */
27
28#if !defined(_SPANDSP_T4_TX_H_)
29#define _SPANDSP_T4_TX_H_
30
31//#define SPANDSP_SUPPORT_TIFF_FX
32
33/*! This function is a callback from the image decoders, to read the unencoded bi-level image,
34 row by row. It is called for each row, with len set to the number of bytes per row expected.
35 \return len for OK, or zero to indicate the end of the image data. */
36 typedef int (*t4_row_read_handler_t)(void *user_data, uint8_t buf[], size_t len);
37
38#if defined(SPANDSP_SUPPORT_TIFF_FX)
39/* TIFF-FX related extensions to the tag set supported by libtiff */
40
41/*
42Indexed(346) = 0, 1. SHORT
43 0: not a palette-color image.
44 1: palette-color image.
45 This field is used to indicate that each sample value is an index
46 into an array of color values specified in the image data stream.
47 Because the color map is embedded in the image data stream, the
48 ColorMap field is not used in Profile L. Lossless color fax
49 profile supports palette-color images with the ITULAB encoding.
50 The SamplesPerPixel value must be 1.
51
52GlobalParametersIFD (400) IFD
53 An IFD containing global parameters. It is recommended that a TIFF
54 writer place this field in the first IFD, where a TIFF reader would
55 find it quickly.
56
57 Each field in the GlobalParametersIFD is a TIFF field that is legal
58 in any IFD. Required baseline fields should not be located in the
59 GlobalParametersIFD, but should be in each image IFD. If a conflict
60 exists between fields in the GlobalParametersIFD and in the image
61 IFDs, then the data in the image IFD shall prevail.
62
63 Among the GlobalParametersIFD entries is a new ProfileType field
64 which generally describes information in this IFD and in the TIFF
65 file.
66
67ProfileType(401) LONG
68 The type of image data stored in this IFD.
69 0 = Unspecified
70 1 = Group 3 fax
71 No default
72
73 The following new global fields are defined in this document as IFD
74 entries for use with fax applications.
75
76FaxProfile(402) = 0 - 6. BYTE
77 The profile that applies to this file; a profile is subset of the
78 full set of permitted fields and field values of TIFF for facsimile.
79 The currently defined values are:
80 0: does not conform to a profile defined for TIFF for facsimile
81 1: minimal black & white lossless, Profile S
82 2: extended black & white lossless, Profile F
83 3: lossless JBIG black & white, Profile J
84 4: lossy color and grayscale, Profile C
85 5: lossless color and grayscale, Profile L
86 6: Mixed Raster Content, Profile M
87
88CodingMethods(403) LONG
89 This field indicates which coding methods are used in the file. A
90 bit value of 1 indicates which of the following coding methods is
91 used:
92 Bit 0: unspecified compression,
93 Bit 1: 1-dimensional coding, ITU-T Rec. T.4 (MH - Modified Huffman),
94 Bit 2: 2-dimensional coding, ITU-T Rec. T.4 (MR - Modified Read),
95 Bit 3: 2-dimensional coding, ITU-T Rec. T.6 (MMR - Modified MR),
96 Bit 4: ITU-T Rec. T.82 coding, using ITU-T Rec. T.85 (JBIG),
97 Bit 5: ITU-T Rec. T.81 (Baseline JPEG),
98 Bit 6: ITU-T Rec. T.82 coding, using ITU-T Rec. T.43 (JBIG color),
99 Bits 7-31: reserved for future use
100 Note: There is a limit of 32 compression types to identify standard
101 compression methods.
102
103VersionYear(404) BYTE
104 Count: 4
105 The year of the standard specified by the FaxProfile field, given as
106 4 characters, e.g. '1997'; used in lossy and lossless color modes.
107
108ModeNumber (405) BYTE
109 The mode of the standard specified by the FaxProfile field. A
110 value of 0 indicates Mode 1.0; used in Mixed Raster Content mode.
111
112Decode(433) SRATIONAL
113 Count = 2 * SamplesPerPixel
114 Describes how to map image sample values into the range of values
115 appropriate for the current color space. In general, the values
116 are taken in pairs and specify the minimum and maximum output
117 value for each color component. For the base color fax profile,
118 Decode has a count of 6 values and maps the unsigned ITULAB-
119 encoded sample values (Lsample, asample, bsample) to signed L*a*b*
120 values, as follows:
121 L* = Decode[0] + Lsample x (Decode[1]-Decode[0])/(2^n -1)
122 a* = Decode[2] + asample x (Decode[3]-Decode[2])/(2^n -1)
123 b* = Decode[4] + bsample x (Decode[5]-Decode[4])/(2^n -1)
124 where Decode[0], Decode[2] and Decode[4] are the minimum values
125 for L*, a*, and b*; Decode[1], Decode[3] and Decode[5] are the
126 maximum values for L*, a*, and b*; and n is the BitsPerSample.
127 When n=8,=20 L*=Decode[0] when Lsample=0 and L*=Decode[1] when
128 Lsample=255.
129
130ImageBaseColor(434) SHORT
131 Count = SamplesPerPixel
132 In areas of an image layer where no image data is available (i.e.,
133 where no strips are defined, or where the StripByteCounts entry for
134 a given strip is 0), the color specified by ImageBaseColor will be
135 used.
136
137StripRowCounts(559) LONG
138 Count = number of strips.
139 The number of scanlines stored in a strip. Profile M allows each
140 fax strip to store a different number of scanlines. For strips
141 with more than one layer, the maximum strip size is either 256
142 scanlines or full page size. The 256 maximum SHOULD be used
143 unless the capability to receive longer strips has been
144 negotiated. This field replaces RowsPerStrip for IFDs with
145 variable-size strips. Only one of the two fields, StripRowCounts
146 and RowsPerStrip, may be used in an IFD.
147
148ImageLayer(34732) LONG
149 Count = 2.
150 Image layers are defined such that layer 1 is the Background
151 layer, layer 3 is the Foreground layer, and layer 2 is the Mask
152 layer, which selects pixels from the Background and Foreground
153 layers. The ImageLayer tag contains two values, which describe
154 the layer to which the image belongs and the order in which it is
155 imaged.
156
157 ImageLayer[0] = 1, 2, 3.
158 1: Image is a Background image, i.e. the image that will appear
159 whenever the Mask contains a value of 0. Background images
160 typically contain low-resolution, continuous-tone imagery.
161 2: Image is the Mask layer. In MRC, if the Mask layer is present,
162 it must be the Primary IFD and be full page in extent.
163 3: Image is a Foreground image, i.e. the image that will appear
164 whenever the Mask contains a value of 1. The Foreground image
165 generally defines the color of text or lines but may also
166 contain high-resolution imagery.
167
168 ImageLayer[1]:
169 1: first image to be imaged in this layer
170 2: second image to be imaged in this layer
171 3: ...
172*/
173
174#define TIFFTAG_INDEXED 346
175#define TIFFTAG_GLOBALPARAMETERSIFD 400
176#define TIFFTAG_PROFILETYPE 401
177#define PROFILETYPE_UNSPECIFIED 0
178#define PROFILETYPE_G3_FAX 1
179#define TIFFTAG_FAXPROFILE 402
180#define FAXPROFILE_S 1
181#define FAXPROFILE_F 2
182#define FAXPROFILE_J 3
183#define FAXPROFILE_C 4
184#define FAXPROFILE_L 5
185#define FAXPROFILE_M 6
186#define TIFFTAG_CODINGMETHODS 403
187#define CODINGMETHODS_T4_1D (1 << 1)
188#define CODINGMETHODS_T4_2D (1 << 2)
189#define CODINGMETHODS_T6 (1 << 3)
190#define CODINGMETHODS_T85 (1 << 4)
191#define CODINGMETHODS_T42 (1 << 5)
192#define CODINGMETHODS_T43 (1 << 6)
193#define TIFFTAG_VERSIONYEAR 404
194#define TIFFTAG_MODENUMBER 405
195#define TIFFTAG_DECODE 433
196#define TIFFTAG_IMAGEBASECOLOR 434
197#define TIFFTAG_T82OPTIONS 435
198#define TIFFTAG_STRIPROWCOUNTS 559
199#define TIFFTAG_IMAGELAYER 34732
200
201#define COMPRESSION_T85 9
202#define COMPRESSION_T43 10
203#endif
204
205typedef struct t4_state_s t4_tx_state_t;
206
207#if defined(__cplusplus)
208extern "C" {
209#endif
210
211/*! \brief Prepare to send the next page of the current document.
212 \param s The T.4 context.
213 \return zero for success, -1 for failure. */
214SPAN_DECLARE(int) t4_tx_start_page(t4_tx_state_t *s);
215
216/*! \brief Prepare the current page for a resend.
217 \param s The T.4 context.
218 \return zero for success, -1 for failure. */
219SPAN_DECLARE(int) t4_tx_restart_page(t4_tx_state_t *s);
220
221/*! \brief Check for the existance of the next page, and whether its format is like the
222 current one. This information can be needed before it is determined that the current
223 page is finished with.
224 \param s The T.4 context.
225 \return 0 for next page found with the same format as the current page.
226 1 for next page found with different format from the current page.
227 -1 for no page found, or file failure. */
228SPAN_DECLARE(int) t4_tx_next_page_has_different_format(t4_tx_state_t *s);
229
230/*! \brief Complete the sending of a page.
231 \param s The T.4 context.
232 \return zero for success, -1 for failure. */
233SPAN_DECLARE(int) t4_tx_end_page(t4_tx_state_t *s);
234
235/*! \brief Return the next bit of the current document page, without actually
236 moving forward in the buffer. The document will be padded for the
237 current minimum scan line time.
238 \param s The T.4 context.
239 \return The next bit (i.e. 0 or 1). For the last bit of data, bit 1 is
240 set (i.e. the returned value is 2 or 3). */
241SPAN_DECLARE(int) t4_tx_check_bit(t4_tx_state_t *s);
242
243/*! \brief Get the next bit of the current document page. The document will
244 be padded for the current minimum scan line time.
245 \param s The T.4 context.
246 \return The next bit (i.e. 0 or 1). For the last bit of data, bit 1 is
247 set (i.e. the returned value is 2 or 3). */
248SPAN_DECLARE(int) t4_tx_get_bit(t4_tx_state_t *s);
249
250/*! \brief Get the next byte of the current document page. The document will
251 be padded for the current minimum scan line time.
252 \param s The T.4 context.
253 \return The next byte. For the last byte of data, bit 8 is
254 set. In this case, one or more bits of the byte may be padded with
255 zeros, to complete the byte. */
256SPAN_DECLARE(int) t4_tx_get_byte(t4_tx_state_t *s);
257
258/*! \brief Get the next chunk of the current document page. The document will
259 be padded for the current minimum scan line time.
260 \param s The T.4 context.
261 \param buf The buffer into which the chunk is to written.
262 \param max_len The maximum length of the chunk.
263 \return The actual length of the chunk. If this is less than max_len it
264 indicates that the end of the document has been reached. */
265SPAN_DECLARE(int) t4_tx_get_chunk(t4_tx_state_t *s, uint8_t buf[], int max_len);
266
267/*! \brief Set the encoding for the encoded data.
268 \param s The T.4 context.
269 \param encoding The encoding. */
270SPAN_DECLARE(void) t4_tx_set_tx_encoding(t4_tx_state_t *s, int encoding);
271
272/*! \brief Set the minimum number of encoded bits per row. This allows the
273 makes the encoding process to be set to comply with the minimum row
274 time specified by a remote receiving machine.
275 \param s The T.4 context.
276 \param bits The minimum number of bits per row. */
277SPAN_DECLARE(void) t4_tx_set_min_bits_per_row(t4_tx_state_t *s, int bits);
278
279/*! \brief Set the identity of the local machine, for inclusion in page headers.
280 \param s The T.4 context.
281 \param ident The identity string. */
282SPAN_DECLARE(void) t4_tx_set_local_ident(t4_tx_state_t *s, const char *ident);
283
284/*! Set the info field, included in the header line included in each page of an encoded
285 FAX. This is a string of up to 50 characters. Other information (date, local ident, etc.)
286 are automatically included in the header. If the header info is set to NULL or a zero
287 length string, no header lines will be added to the encoded FAX.
288 \brief Set the header info.
289 \param s The T.4 context.
290 \param info A string, of up to 50 bytes, which will form the info field. */
291SPAN_DECLARE(void) t4_tx_set_header_info(t4_tx_state_t *s, const char *info);
292
293/*! Set the time zone for the time stamp in page header lines. If this function is not used
294 the current time zone of the program's environment is used.
295 \brief Set the header timezone.
296 \param s The T.4 context.
297 \param tz A time zone descriptor. */
298SPAN_DECLARE(void) t4_tx_set_header_tz(t4_tx_state_t *s, tz_t *tz);
299
300/*! \brief Set the row read handler for a T.4 transmit context.
301 \param s The T.4 transmit context.
302 \param handler A pointer to the handler routine.
303 \param user_data An opaque pointer passed to the handler routine.
304 \return 0 for success, otherwise -1. */
305SPAN_DECLARE(int) t4_tx_set_row_read_handler(t4_tx_state_t *s, t4_row_read_handler_t handler, void *user_data);
306
307/*! \brief Get the row-to-row (y) resolution of the current page.
308 \param s The T.4 context.
309 \return The resolution, in pixels per metre. */
310SPAN_DECLARE(int) t4_tx_get_y_resolution(t4_tx_state_t *s);
311
312/*! \brief Get the column-to-column (x) resolution of the current page.
313 \param s The T.4 context.
314 \return The resolution, in pixels per metre. */
315SPAN_DECLARE(int) t4_tx_get_x_resolution(t4_tx_state_t *s);
316
317/*! \brief Get the width of the current page, in pixel columns.
318 \param s The T.4 context.
319 \return The number of columns. */
320SPAN_DECLARE(int) t4_tx_get_image_width(t4_tx_state_t *s);
321
322/*! \brief Get the number of pages in the file.
323 \param s The T.4 context.
324 \return The number of pages, or -1 if there is an error. */
325SPAN_DECLARE(int) t4_tx_get_pages_in_file(t4_tx_state_t *s);
326
327/*! \brief Get the currnet page number in the file.
328 \param s The T.4 context.
329 \return The page number, or -1 if there is an error. */
330SPAN_DECLARE(int) t4_tx_get_current_page_in_file(t4_tx_state_t *s);
331
332/*! Get the current image transfer statistics.
333 \brief Get the current transfer statistics.
334 \param s The T.4 context.
335 \param t A pointer to a statistics structure. */
336SPAN_DECLARE(void) t4_tx_get_transfer_statistics(t4_tx_state_t *s, t4_stats_t *t);
337
338/*! \brief Prepare for transmission of a document.
339 \param s The T.4 context.
340 \param file The name of the file to be sent.
341 \param start_page The first page to send. -1 for no restriction.
342 \param stop_page The last page to send. -1 for no restriction.
343 \return A pointer to the context, or NULL if there was a problem. */
344SPAN_DECLARE(t4_tx_state_t *) t4_tx_init(t4_tx_state_t *s, const char *file, int start_page, int stop_page);
345
346/*! \brief End the transmission of a document. Tidy up and close the file.
347 This should be used to end T.4 transmission started with t4_tx_init.
348 \param s The T.4 context.
349 \return 0 for success, otherwise -1. */
350SPAN_DECLARE(int) t4_tx_release(t4_tx_state_t *s);
351
352/*! \brief End the transmission of a document. Tidy up, close the file and
353 free the context. This should be used to end T.4 transmission
354 started with t4_tx_init.
355 \param s The T.4 context.
356 \return 0 for success, otherwise -1. */
357SPAN_DECLARE(int) t4_tx_free(t4_tx_state_t *s);
358
359#if defined(__cplusplus)
360}
361#endif
362
363#endif
364/*- End of file ------------------------------------------------------------*/
t4_state_s
Definition private/t4_tx.h:36
t4_state_s::tz
struct tz_s * tz
Optional per instance time zone for the FAX page header timestamp.
Definition private/t4_tx.h:51
t4_stats_t
Definition t4_rx.h:213
tz_s
Definition private/timezone.h:82
t4_tx_next_page_has_different_format
int t4_tx_next_page_has_different_format(t4_tx_state_t *s)
Check for the existance of the next page, and whether its format is like the current one....
Definition t4_tx.c:1328
t4_tx_init
t4_tx_state_t * t4_tx_init(t4_tx_state_t *s, const char *file, int start_page, int stop_page)
Prepare for transmission of a document.
Definition t4_tx.c:1493
t4_tx_set_local_ident
void t4_tx_set_local_ident(t4_tx_state_t *s, const char *ident)
Set the identity of the local machine, for inclusion in page headers.
Definition t4_tx.c:1423
t4_tx_set_row_read_handler
int t4_tx_set_row_read_handler(t4_tx_state_t *s, t4_row_read_handler_t handler, void *user_data)
Set the row read handler for a T.4 transmit context.
Definition t4_tx.c:1213
t4_tx_free
int t4_tx_free(t4_tx_state_t *s)
End the transmission of a document. Tidy up, close the file and free the context. This should be used...
Definition t4_tx.c:1585
t4_tx_set_header_tz
void t4_tx_set_header_tz(t4_tx_state_t *s, tz_t *tz)
Set the header timezone.
Definition t4_tx.c:1435
t4_tx_restart_page
int t4_tx_restart_page(t4_tx_state_t *s)
Prepare the current page for a resend.
Definition t4_tx.c:1347
t4_tx_start_page
int t4_tx_start_page(t4_tx_state_t *s)
Prepare to send the next page of the current document.
Definition t4_tx.c:1221
t4_tx_get_transfer_statistics
void t4_tx_get_transfer_statistics(t4_tx_state_t *s, t4_stats_t *t)
Get the current transfer statistics.
Definition t4_tx.c:1478
t4_tx_check_bit
int t4_tx_check_bit(t4_tx_state_t *s)
Return the next bit of the current document page, without actually moving forward in the buffer....
Definition t4_tx.c:1398
t4_tx_get_bit
int t4_tx_get_bit(t4_tx_state_t *s)
Get the next bit of the current document page. The document will be padded for the current minimum sc...
Definition t4_tx.c:1362
t4_tx_get_y_resolution
int t4_tx_get_y_resolution(t4_tx_state_t *s)
Get the row-to-row (y) resolution of the current page.
Definition t4_tx.c:1441
t4_tx_set_min_bits_per_row
void t4_tx_set_min_bits_per_row(t4_tx_state_t *s, int bits)
Set the minimum number of encoded bits per row. This allows the makes the encoding process to be set ...
Definition t4_tx.c:1417
t4_tx_get_byte
int t4_tx_get_byte(t4_tx_state_t *s)
Get the next byte of the current document page. The document will be padded for the current minimum s...
Definition t4_tx.c:1378
t4_tx_get_image_width
int t4_tx_get_image_width(t4_tx_state_t *s)
Get the width of the current page, in pixel columns.
Definition t4_tx.c:1453
t4_tx_release
int t4_tx_release(t4_tx_state_t *s)
End the transmission of a document. Tidy up and close the file. This should be used to end T....
Definition t4_tx.c:1574
t4_tx_get_x_resolution
int t4_tx_get_x_resolution(t4_tx_state_t *s)
Get the column-to-column (x) resolution of the current page.
Definition t4_tx.c:1447
t4_tx_set_header_info
void t4_tx_set_header_info(t4_tx_state_t *s, const char *info)
Set the header info.
Definition t4_tx.c:1429
t4_tx_end_page
int t4_tx_end_page(t4_tx_state_t *s)
Complete the sending of a page.
Definition t4_tx.c:1355
t4_row_read_handler_t
int(* t4_row_read_handler_t)(void *user_data, uint8_t buf[], size_t len)
Definition t4_tx.h:36
t4_tx_set_tx_encoding
void t4_tx_set_tx_encoding(t4_tx_state_t *s, int encoding)
Set the encoding for the encoded data.
Definition t4_tx.c:1409
t4_tx_get_current_page_in_file
int t4_tx_get_current_page_in_file(t4_tx_state_t *s)
Get the currnet page number in the file.
Definition t4_tx.c:1472
t4_tx_get_pages_in_file
int t4_tx_get_pages_in_file(t4_tx_state_t *s)
Get the number of pages in the file.
Definition t4_tx.c:1459
t4_tx_get_chunk
int t4_tx_get_chunk(t4_tx_state_t *s, uint8_t buf[], int max_len)
Get the next chunk of the current document page. The document will be padded for the current minimum ...
Definition t4_tx.c:1386