4 * Copyright (C) 1991-1997, 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.ijg
9 * This file contains initialization logic for the JPEG compressor.
10 * This routine is in charge of selecting the modules to be executed and
11 * making an initialization call to each one.
13 * Logically, this code belongs in jcmaster.c. It's split out because
14 * linking this routine implies linking the entire compression library.
15 * For a transcoding-only application, we want to be able to use jcmaster.c
16 * without linking in the whole library.
19 #define JPEG_INTERNALS
25 * Master selection of compression modules.
26 * This is done once at the start of processing an image. We determine
27 * which modules will be used and give them appropriate initialization calls.
31 jinit_compress_master(j_compress_ptr cinfo)
33 /* Initialize master control (includes parameter checking/processing) */
34 jinit_c_master_control(cinfo, FALSE /* full compression */);
37 if (!cinfo->raw_data_in) {
38 jinit_color_converter(cinfo);
39 jinit_downsampler(cinfo);
40 jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
43 jinit_forward_dct(cinfo);
44 /* Entropy encoding: either Huffman or arithmetic coding. */
45 if (cinfo->arith_code) {
46 #ifdef C_ARITH_CODING_SUPPORTED
47 jinit_arith_encoder(cinfo);
49 ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
52 if (cinfo->progressive_mode) {
53 #ifdef C_PROGRESSIVE_SUPPORTED
54 jinit_phuff_encoder(cinfo);
56 ERREXIT(cinfo, JERR_NOT_COMPILED);
59 jinit_huff_encoder(cinfo);
62 /* Need a full-image coefficient buffer in any multi-pass mode. */
63 jinit_c_coef_controller(cinfo, (boolean)(cinfo->num_scans > 1 ||
64 cinfo->optimize_coding));
65 jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
67 jinit_marker_writer(cinfo);
69 /* We can now tell the memory manager to allocate virtual arrays. */
70 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr)cinfo);
72 /* Write the datastream header (SOI) immediately.
73 * Frame and scan headers are postponed till later.
74 * This lets application insert special markers after the SOI.
76 (*cinfo->marker->write_file_header) (cinfo);