1 /* 2 * jcinit.c 3 * 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 file. 7 * 8 * This file contains initialization logic for the JPEG compressor. 9 * This routine is in charge of selecting the modules to be executed and 10 * making an initialization call to each one. 11 * 12 * Logically, this code belongs in jcmaster.c. It's split out because 13 * linking this routine implies linking the entire compression library. 14 * For a transcoding-only application, we want to be able to use jcmaster.c 15 * without linking in the whole library. 16 */ 17 18 #define JPEG_INTERNALS 19 #include "jinclude.h" 20 #include "jpeglib.h" 21 22 23 /* 24 * Master selection of compression modules. 25 * This is done once at the start of processing an image. We determine 26 * which modules will be used and give them appropriate initialization calls. 27 */ 28 29 GLOBAL(void) jinit_compress_master(j_compress_ptr cinfo)30jinit_compress_master (j_compress_ptr cinfo) 31 { 32 /* Initialize master control (includes parameter checking/processing) */ 33 jinit_c_master_control(cinfo, FALSE /* full compression */); 34 35 /* Preprocessing */ 36 if (! cinfo->raw_data_in) { 37 jinit_color_converter(cinfo); 38 jinit_downsampler(cinfo); 39 jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */); 40 } 41 /* Forward DCT */ 42 jinit_forward_dct(cinfo); 43 /* Entropy encoding: either Huffman or arithmetic coding. */ 44 if (cinfo->arith_code) 45 jinit_arith_encoder(cinfo); 46 else { 47 jinit_huff_encoder(cinfo); 48 } 49 50 /* Need a full-image coefficient buffer in any multi-pass mode. */ 51 jinit_c_coef_controller(cinfo, 52 (boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding)); 53 jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */); 54 55 jinit_marker_writer(cinfo); 56 57 /* We can now tell the memory manager to allocate virtual arrays. */ 58 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); 59 60 /* Write the datastream header (SOI) immediately. 61 * Frame and scan headers are postponed till later. 62 * This lets application insert special markers after the SOI. 63 */ 64 (*cinfo->marker->write_file_header) (cinfo); 65 } 66