1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
|
/*
* jcapistd.c
*
* Copyright (C) 1994-1996, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README.ijg
* file.
*
* This file contains application interface code for the compression half
* of the JPEG library. These are the "standard" API routines that are
* used in the normal full-compression case. They are not used by a
* transcoding-only application. Note that if an application links in
* jpeg_start_compress, it will end up linking in the entire compressor.
* We thus must separate this file from jcapimin.c to avoid linking the
* whole compression library into a transcoder.
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
/*
* Compression initialization.
* Before calling this, all parameters and a data destination must be set up.
*
* We require a write_all_tables parameter as a failsafe check when writing
* multiple datastreams from the same compression object. Since prior runs
* will have left all the tables marked sent_table=TRUE, a subsequent run
* would emit an abbreviated stream (no tables) by default. This may be what
* is wanted, but for safety's sake it should not be the default behavior:
* programmers should have to make a deliberate choice to emit abbreviated
* images. Therefore the documentation and examples should encourage people
* to pass write_all_tables=TRUE; then it will take active thought to do the
* wrong thing.
*/
GLOBAL(void)
jpeg_start_compress (j_compress_ptr cinfo, boolean write_all_tables)
{
if (cinfo->global_state != CSTATE_START)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
if (write_all_tables)
jpeg_suppress_tables(cinfo, FALSE); /* mark all tables to be written */
/* (Re)initialize error mgr and destination modules */
(*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
(*cinfo->dest->init_destination) (cinfo);
/* Perform master selection of active modules */
jinit_compress_master(cinfo);
/* Set up for the first pass */
(*cinfo->master->prepare_for_pass) (cinfo);
/* Ready for application to drive first pass through jpeg_write_scanlines
* or jpeg_write_raw_data.
*/
cinfo->next_scanline = 0;
cinfo->global_state = (cinfo->raw_data_in ? CSTATE_RAW_OK : CSTATE_SCANNING);
}
/*
* Write some scanlines of data to the JPEG compressor.
*
* The return value will be the number of lines actually written.
* This should be less than the supplied num_lines only in case that
* the data destination module has requested suspension of the compressor,
* or if more than image_height scanlines are passed in.
*
* Note: we warn about excess calls to jpeg_write_scanlines() since
* this likely signals an application programmer error. However,
* excess scanlines passed in the last valid call are *silently* ignored,
* so that the application need not adjust num_lines for end-of-image
* when using a multiple-scanline buffer.
*/
GLOBAL(JDIMENSION)
jpeg_write_scanlines (j_compress_ptr cinfo, JSAMPARRAY scanlines,
JDIMENSION num_lines)
{
JDIMENSION row_ctr, rows_left;
if (cinfo->global_state != CSTATE_SCANNING)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
if (cinfo->next_scanline >= cinfo->image_height)
WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
/* Call progress monitor hook if present */
if (cinfo->progress != NULL) {
cinfo->progress->pass_counter = (long) cinfo->next_scanline;
cinfo->progress->pass_limit = (long) cinfo->image_height;
(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
}
/* Give master control module another chance if this is first call to
* jpeg_write_scanlines. This lets output of the frame/scan headers be
* delayed so that application can write COM, etc, markers between
* jpeg_start_compress and jpeg_write_scanlines.
*/
if (cinfo->master->call_pass_startup)
(*cinfo->master->pass_startup) (cinfo);
/* Ignore any extra scanlines at bottom of image. */
rows_left = cinfo->image_height - cinfo->next_scanline;
if (num_lines > rows_left)
num_lines = rows_left;
row_ctr = 0;
(*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, num_lines);
cinfo->next_scanline += row_ctr;
return row_ctr;
}
/*
* Alternate entry point to write raw data.
* Processes exactly one iMCU row per call, unless suspended.
*/
GLOBAL(JDIMENSION)
jpeg_write_raw_data (j_compress_ptr cinfo, JSAMPIMAGE data,
JDIMENSION num_lines)
{
JDIMENSION lines_per_iMCU_row;
if (cinfo->global_state != CSTATE_RAW_OK)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
if (cinfo->next_scanline >= cinfo->image_height) {
WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
return 0;
}
/* Call progress monitor hook if present */
if (cinfo->progress != NULL) {
cinfo->progress->pass_counter = (long) cinfo->next_scanline;
cinfo->progress->pass_limit = (long) cinfo->image_height;
(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
}
/* Give master control module another chance if this is first call to
* jpeg_write_raw_data. This lets output of the frame/scan headers be
* delayed so that application can write COM, etc, markers between
* jpeg_start_compress and jpeg_write_raw_data.
*/
if (cinfo->master->call_pass_startup)
(*cinfo->master->pass_startup) (cinfo);
/* Verify that at least one iMCU row has been passed. */
lines_per_iMCU_row = cinfo->max_v_samp_factor * DCTSIZE;
if (num_lines < lines_per_iMCU_row)
ERREXIT(cinfo, JERR_BUFFER_SIZE);
/* Directly compress the row. */
if (! (*cinfo->coef->compress_data) (cinfo, data)) {
/* If compressor did not consume the whole row, suspend processing. */
return 0;
}
/* OK, we processed one iMCU row. */
cinfo->next_scanline += lines_per_iMCU_row;
return lines_per_iMCU_row;
}
|
