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/src/FreeImage/Source/LibJPEG/jcapistd.c

https://bitbucket.org/cabalistic/ogredeps/
C | 161 lines | 68 code | 23 blank | 70 comment | 18 complexity | 98951837a74c22f4fe7bb1ff6c320116 MD5 | raw file
  1/*
  2 * jcapistd.c
  3 *
  4 * Copyright (C) 1994-1996, 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.
  7 *
  8 * This file contains application interface code for the compression half
  9 * of the JPEG library.  These are the "standard" API routines that are
 10 * used in the normal full-compression case.  They are not used by a
 11 * transcoding-only application.  Note that if an application links in
 12 * jpeg_start_compress, it will end up linking in the entire compressor.
 13 * We thus must separate this file from jcapimin.c to avoid linking the
 14 * whole compression library into a transcoder.
 15 */
 16
 17#define JPEG_INTERNALS
 18#include "jinclude.h"
 19#include "jpeglib.h"
 20
 21
 22/*
 23 * Compression initialization.
 24 * Before calling this, all parameters and a data destination must be set up.
 25 *
 26 * We require a write_all_tables parameter as a failsafe check when writing
 27 * multiple datastreams from the same compression object.  Since prior runs
 28 * will have left all the tables marked sent_table=TRUE, a subsequent run
 29 * would emit an abbreviated stream (no tables) by default.  This may be what
 30 * is wanted, but for safety's sake it should not be the default behavior:
 31 * programmers should have to make a deliberate choice to emit abbreviated
 32 * images.  Therefore the documentation and examples should encourage people
 33 * to pass write_all_tables=TRUE; then it will take active thought to do the
 34 * wrong thing.
 35 */
 36
 37GLOBAL(void)
 38jpeg_start_compress (j_compress_ptr cinfo, boolean write_all_tables)
 39{
 40  if (cinfo->global_state != CSTATE_START)
 41    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
 42
 43  if (write_all_tables)
 44    jpeg_suppress_tables(cinfo, FALSE);	/* mark all tables to be written */
 45
 46  /* (Re)initialize error mgr and destination modules */
 47  (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
 48  (*cinfo->dest->init_destination) (cinfo);
 49  /* Perform master selection of active modules */
 50  jinit_compress_master(cinfo);
 51  /* Set up for the first pass */
 52  (*cinfo->master->prepare_for_pass) (cinfo);
 53  /* Ready for application to drive first pass through jpeg_write_scanlines
 54   * or jpeg_write_raw_data.
 55   */
 56  cinfo->next_scanline = 0;
 57  cinfo->global_state = (cinfo->raw_data_in ? CSTATE_RAW_OK : CSTATE_SCANNING);
 58}
 59
 60
 61/*
 62 * Write some scanlines of data to the JPEG compressor.
 63 *
 64 * The return value will be the number of lines actually written.
 65 * This should be less than the supplied num_lines only in case that
 66 * the data destination module has requested suspension of the compressor,
 67 * or if more than image_height scanlines are passed in.
 68 *
 69 * Note: we warn about excess calls to jpeg_write_scanlines() since
 70 * this likely signals an application programmer error.  However,
 71 * excess scanlines passed in the last valid call are *silently* ignored,
 72 * so that the application need not adjust num_lines for end-of-image
 73 * when using a multiple-scanline buffer.
 74 */
 75
 76GLOBAL(JDIMENSION)
 77jpeg_write_scanlines (j_compress_ptr cinfo, JSAMPARRAY scanlines,
 78		      JDIMENSION num_lines)
 79{
 80  JDIMENSION row_ctr, rows_left;
 81
 82  if (cinfo->global_state != CSTATE_SCANNING)
 83    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
 84  if (cinfo->next_scanline >= cinfo->image_height)
 85    WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
 86
 87  /* Call progress monitor hook if present */
 88  if (cinfo->progress != NULL) {
 89    cinfo->progress->pass_counter = (long) cinfo->next_scanline;
 90    cinfo->progress->pass_limit = (long) cinfo->image_height;
 91    (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
 92  }
 93
 94  /* Give master control module another chance if this is first call to
 95   * jpeg_write_scanlines.  This lets output of the frame/scan headers be
 96   * delayed so that application can write COM, etc, markers between
 97   * jpeg_start_compress and jpeg_write_scanlines.
 98   */
 99  if (cinfo->master->call_pass_startup)
100    (*cinfo->master->pass_startup) (cinfo);
101
102  /* Ignore any extra scanlines at bottom of image. */
103  rows_left = cinfo->image_height - cinfo->next_scanline;
104  if (num_lines > rows_left)
105    num_lines = rows_left;
106
107  row_ctr = 0;
108  (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, num_lines);
109  cinfo->next_scanline += row_ctr;
110  return row_ctr;
111}
112
113
114/*
115 * Alternate entry point to write raw data.
116 * Processes exactly one iMCU row per call, unless suspended.
117 */
118
119GLOBAL(JDIMENSION)
120jpeg_write_raw_data (j_compress_ptr cinfo, JSAMPIMAGE data,
121		     JDIMENSION num_lines)
122{
123  JDIMENSION lines_per_iMCU_row;
124
125  if (cinfo->global_state != CSTATE_RAW_OK)
126    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
127  if (cinfo->next_scanline >= cinfo->image_height) {
128    WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
129    return 0;
130  }
131
132  /* Call progress monitor hook if present */
133  if (cinfo->progress != NULL) {
134    cinfo->progress->pass_counter = (long) cinfo->next_scanline;
135    cinfo->progress->pass_limit = (long) cinfo->image_height;
136    (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
137  }
138
139  /* Give master control module another chance if this is first call to
140   * jpeg_write_raw_data.  This lets output of the frame/scan headers be
141   * delayed so that application can write COM, etc, markers between
142   * jpeg_start_compress and jpeg_write_raw_data.
143   */
144  if (cinfo->master->call_pass_startup)
145    (*cinfo->master->pass_startup) (cinfo);
146
147  /* Verify that at least one iMCU row has been passed. */
148  lines_per_iMCU_row = cinfo->max_v_samp_factor * DCTSIZE;
149  if (num_lines < lines_per_iMCU_row)
150    ERREXIT(cinfo, JERR_BUFFER_SIZE);
151
152  /* Directly compress the row. */
153  if (! (*cinfo->coef->compress_data) (cinfo, data)) {
154    /* If compressor did not consume the whole row, suspend processing. */
155    return 0;
156  }
157
158  /* OK, we processed one iMCU row. */
159  cinfo->next_scanline += lines_per_iMCU_row;
160  return lines_per_iMCU_row;
161}