JCINIT.C
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上传日期:2007-01-08
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- ////////////////////////////////////////////////////////////////////////
- //
- // Note : this file is included as part of the Smaller Animals Software
- // JpegFile package. Though this file has not been modified from it's
- // original IJG 6a form, it is not the responsibility on the Independent
- // JPEG Group to answer questions regarding this code.
- //
- // Any questions you have about this code should be addressed to :
- //
- // CHRISDL@PAGESZ.NET - the distributor of this package.
- //
- // Remember, by including this code in the JpegFile package, Smaller
- // Animals Software assumes all responsibilities for answering questions
- // about it. If we (SA Software) can't answer your questions ourselves, we
- // will direct you to people who can.
- //
- // Thanks, CDL.
- //
- ////////////////////////////////////////////////////////////////////////
- /*
- * jcinit.c
- *
- * Copyright (C) 1991-1996, Thomas G. Lane.
- * This file is part of the Independent JPEG Group's software.
- * For conditions of distribution and use, see the accompanying README file.
- *
- * This file contains initialization logic for the JPEG compressor.
- * This routine is in charge of selecting the modules to be executed and
- * making an initialization call to each one.
- *
- * Logically, this code belongs in jcmaster.c. It's split out because
- * linking this routine implies linking the entire compression library.
- * For a transcoding-only application, we want to be able to use jcmaster.c
- * without linking in the whole library.
- */
- #define JPEG_INTERNALS
- #include "jinclude.h"
- #include "jpeglib.h"
- /*
- * Master selection of compression modules.
- * This is done once at the start of processing an image. We determine
- * which modules will be used and give them appropriate initialization calls.
- */
- GLOBAL(void)
- jinit_compress_master (j_compress_ptr cinfo)
- {
- /* Initialize master control (includes parameter checking/processing) */
- jinit_c_master_control(cinfo, FALSE /* full compression */);
- /* Preprocessing */
- if (! cinfo->raw_data_in) {
- jinit_color_converter(cinfo);
- jinit_downsampler(cinfo);
- jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
- }
- /* Forward DCT */
- jinit_forward_dct(cinfo);
- /* Entropy encoding: either Huffman or arithmetic coding. */
- if (cinfo->arith_code) {
- ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
- } else {
- if (cinfo->progressive_mode) {
- #ifdef C_PROGRESSIVE_SUPPORTED
- jinit_phuff_encoder(cinfo);
- #else
- ERREXIT(cinfo, JERR_NOT_COMPILED);
- #endif
- } else
- jinit_huff_encoder(cinfo);
- }
- /* Need a full-image coefficient buffer in any multi-pass mode. */
- jinit_c_coef_controller(cinfo,
- (cinfo->num_scans > 1 || cinfo->optimize_coding));
- jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
- jinit_marker_writer(cinfo);
- /* We can now tell the memory manager to allocate virtual arrays. */
- (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
- /* Write the datastream header (SOI) immediately.
- * Frame and scan headers are postponed till later.
- * This lets application insert special markers after the SOI.
- */
- (*cinfo->marker->write_file_header) (cinfo);
- }