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git.saurik.com Git - wxWidgets.git/blob - src/jpeg/jcapimin.c
4 * Copyright (C) 1994-1998, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
8 * This file contains application interface code for the compression half
9 * of the JPEG library. These are the "minimum" API routines that may be
10 * needed in either the normal full-compression case or the transcoding-only
13 * Most of the routines intended to be called directly by an application
14 * are in this file or in jcapistd.c. But also see jcparam.c for
15 * parameter-setup helper routines, jcomapi.c for routines shared by
16 * compression and decompression, and jctrans.c for the transcoding case.
19 #define JPEG_INTERNALS
25 * Initialization of a JPEG compression object.
26 * The error manager must already be set up (in case memory manager fails).
30 jpeg_CreateCompress (j_compress_ptr cinfo
, int version
, size_t structsize
)
34 /* Guard against version mismatches between library and caller. */
35 cinfo
->mem
= NULL
; /* so jpeg_destroy knows mem mgr not called */
36 if (version
!= JPEG_LIB_VERSION
)
37 ERREXIT2(cinfo
, JERR_BAD_LIB_VERSION
, JPEG_LIB_VERSION
, version
);
38 if (structsize
!= SIZEOF(struct jpeg_compress_struct
))
39 ERREXIT2(cinfo
, JERR_BAD_STRUCT_SIZE
,
40 (int) SIZEOF(struct jpeg_compress_struct
), (int) structsize
);
42 /* For debugging purposes, we zero the whole master structure.
43 * But the application has already set the err pointer, and may have set
44 * client_data, so we have to save and restore those fields.
45 * Note: if application hasn't set client_data, tools like Purify may
49 struct jpeg_error_mgr
* err
= cinfo
->err
;
50 void * client_data
= cinfo
->client_data
; /* ignore Purify complaint here */
51 MEMZERO(cinfo
, SIZEOF(struct jpeg_compress_struct
));
53 cinfo
->client_data
= client_data
;
55 cinfo
->is_decompressor
= FALSE
;
57 /* Initialize a memory manager instance for this object */
58 jinit_memory_mgr((j_common_ptr
) cinfo
);
60 /* Zero out pointers to permanent structures. */
61 cinfo
->progress
= NULL
;
64 cinfo
->comp_info
= NULL
;
66 for (i
= 0; i
< NUM_QUANT_TBLS
; i
++)
67 cinfo
->quant_tbl_ptrs
[i
] = NULL
;
69 for (i
= 0; i
< NUM_HUFF_TBLS
; i
++) {
70 cinfo
->dc_huff_tbl_ptrs
[i
] = NULL
;
71 cinfo
->ac_huff_tbl_ptrs
[i
] = NULL
;
74 cinfo
->script_space
= NULL
;
76 cinfo
->input_gamma
= 1.0; /* in case application forgets */
79 cinfo
->global_state
= CSTATE_START
;
84 * Destruction of a JPEG compression object
88 jpeg_destroy_compress (j_compress_ptr cinfo
)
90 jpeg_destroy((j_common_ptr
) cinfo
); /* use common routine */
95 * Abort processing of a JPEG compression operation,
96 * but don't destroy the object itself.
100 jpeg_abort_compress (j_compress_ptr cinfo
)
102 jpeg_abort((j_common_ptr
) cinfo
); /* use common routine */
107 * Forcibly suppress or un-suppress all quantization and Huffman tables.
108 * Marks all currently defined tables as already written (if suppress)
109 * or not written (if !suppress). This will control whether they get emitted
110 * by a subsequent jpeg_start_compress call.
112 * This routine is exported for use by applications that want to produce
113 * abbreviated JPEG datastreams. It logically belongs in jcparam.c, but
114 * since it is called by jpeg_start_compress, we put it here --- otherwise
115 * jcparam.o would be linked whether the application used it or not.
119 jpeg_suppress_tables (j_compress_ptr cinfo
, wxjpeg_boolean suppress
)
125 for (i
= 0; i
< NUM_QUANT_TBLS
; i
++) {
126 if ((qtbl
= cinfo
->quant_tbl_ptrs
[i
]) != NULL
)
127 qtbl
->sent_table
= suppress
;
130 for (i
= 0; i
< NUM_HUFF_TBLS
; i
++) {
131 if ((htbl
= cinfo
->dc_huff_tbl_ptrs
[i
]) != NULL
)
132 htbl
->sent_table
= suppress
;
133 if ((htbl
= cinfo
->ac_huff_tbl_ptrs
[i
]) != NULL
)
134 htbl
->sent_table
= suppress
;
140 * Finish JPEG compression.
142 * If a multipass operating mode was selected, this may do a great deal of
143 * work including most of the actual output.
147 jpeg_finish_compress (j_compress_ptr cinfo
)
151 if (cinfo
->global_state
== CSTATE_SCANNING
||
152 cinfo
->global_state
== CSTATE_RAW_OK
) {
153 /* Terminate first pass */
154 if (cinfo
->next_scanline
< cinfo
->image_height
)
155 ERREXIT(cinfo
, JERR_TOO_LITTLE_DATA
);
156 (*cinfo
->master
->finish_pass
) (cinfo
);
157 } else if (cinfo
->global_state
!= CSTATE_WRCOEFS
)
158 ERREXIT1(cinfo
, JERR_BAD_STATE
, cinfo
->global_state
);
159 /* Perform any remaining passes */
160 while (! cinfo
->master
->is_last_pass
) {
161 (*cinfo
->master
->prepare_for_pass
) (cinfo
);
162 for (iMCU_row
= 0; iMCU_row
< cinfo
->total_iMCU_rows
; iMCU_row
++) {
163 if (cinfo
->progress
!= NULL
) {
164 cinfo
->progress
->pass_counter
= (long) iMCU_row
;
165 cinfo
->progress
->pass_limit
= (long) cinfo
->total_iMCU_rows
;
166 (*cinfo
->progress
->progress_monitor
) ((j_common_ptr
) cinfo
);
168 /* We bypass the main controller and invoke coef controller directly;
169 * all work is being done from the coefficient buffer.
171 if (! (*cinfo
->coef
->compress_data
) (cinfo
, (JSAMPIMAGE
) NULL
))
172 ERREXIT(cinfo
, JERR_CANT_SUSPEND
);
174 (*cinfo
->master
->finish_pass
) (cinfo
);
176 /* Write EOI, do final cleanup */
177 (*cinfo
->marker
->write_file_trailer
) (cinfo
);
178 (*cinfo
->dest
->term_destination
) (cinfo
);
179 /* We can use jpeg_abort to release memory and reset global_state */
180 jpeg_abort((j_common_ptr
) cinfo
);
185 * Write a special marker.
186 * This is only recommended for writing COM or APPn markers.
187 * Must be called after jpeg_start_compress() and before
188 * first call to jpeg_write_scanlines() or jpeg_write_raw_data().
192 jpeg_write_marker (j_compress_ptr cinfo
, int marker
,
193 const JOCTET
*dataptr
, unsigned int datalen
)
195 JMETHOD(void, write_marker_byte
, (j_compress_ptr info
, int val
));
197 if (cinfo
->next_scanline
!= 0 ||
198 (cinfo
->global_state
!= CSTATE_SCANNING
&&
199 cinfo
->global_state
!= CSTATE_RAW_OK
&&
200 cinfo
->global_state
!= CSTATE_WRCOEFS
))
201 ERREXIT1(cinfo
, JERR_BAD_STATE
, cinfo
->global_state
);
203 (*cinfo
->marker
->write_marker_header
) (cinfo
, marker
, datalen
);
204 write_marker_byte
= cinfo
->marker
->write_marker_byte
; /* copy for speed */
206 (*write_marker_byte
) (cinfo
, *dataptr
);
211 /* Same, but piecemeal. */
214 jpeg_write_m_header (j_compress_ptr cinfo
, int marker
, unsigned int datalen
)
216 if (cinfo
->next_scanline
!= 0 ||
217 (cinfo
->global_state
!= CSTATE_SCANNING
&&
218 cinfo
->global_state
!= CSTATE_RAW_OK
&&
219 cinfo
->global_state
!= CSTATE_WRCOEFS
))
220 ERREXIT1(cinfo
, JERR_BAD_STATE
, cinfo
->global_state
);
222 (*cinfo
->marker
->write_marker_header
) (cinfo
, marker
, datalen
);
226 jpeg_write_m_byte (j_compress_ptr cinfo
, int val
)
228 (*cinfo
->marker
->write_marker_byte
) (cinfo
, val
);
233 * Alternate compression function: just write an abbreviated table file.
234 * Before calling this, all parameters and a data destination must be set up.
236 * To produce a pair of files containing abbreviated tables and abbreviated
237 * image data, one would proceed as follows:
239 * initialize JPEG object
240 * set JPEG parameters
241 * set destination to table file
242 * jpeg_write_tables(cinfo);
243 * set destination to image file
244 * jpeg_start_compress(cinfo, FALSE);
246 * jpeg_finish_compress(cinfo);
248 * jpeg_write_tables has the side effect of marking all tables written
249 * (same as jpeg_suppress_tables(..., TRUE)). Thus a subsequent start_compress
250 * will not re-emit the tables unless it is passed write_all_tables=TRUE.
254 jpeg_write_tables (j_compress_ptr cinfo
)
256 if (cinfo
->global_state
!= CSTATE_START
)
257 ERREXIT1(cinfo
, JERR_BAD_STATE
, cinfo
->global_state
);
259 /* (Re)initialize error mgr and destination modules */
260 (*cinfo
->err
->reset_error_mgr
) ((j_common_ptr
) cinfo
);
261 (*cinfo
->dest
->init_destination
) (cinfo
);
262 /* Initialize the marker writer ... bit of a crock to do it here. */
263 jinit_marker_writer(cinfo
);
264 /* Write them tables! */
265 (*cinfo
->marker
->write_tables_only
) (cinfo
);
267 (*cinfo
->dest
->term_destination
) (cinfo
);
269 * In library releases up through v6a, we called jpeg_abort() here to free
270 * any working memory allocated by the destination manager and marker
271 * writer. Some applications had a problem with that: they allocated space
272 * of their own from the library memory manager, and didn't want it to go
273 * away during write_tables. So now we do nothing. This will cause a
274 * memory leak if an app calls write_tables repeatedly without doing a full
275 * compression cycle or otherwise resetting the JPEG object. However, that
276 * seems less bad than unexpectedly freeing memory in the normal case.
277 * An app that prefers the old behavior can call jpeg_abort for itself after
278 * each call to jpeg_write_tables().