| 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 | |
| 37 | GLOBAL(void) |
| 38 | jpeg_start_compress (j_compress_ptr cinfo, wxjpeg_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 | |
| 76 | GLOBAL(JDIMENSION) |
| 77 | jpeg_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 | |
| 119 | GLOBAL(JDIMENSION) |
| 120 | jpeg_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 | } |