250 lines
10 KiB
C
250 lines
10 KiB
C
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/*
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* jcinit.c
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*
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* Copyright (C) 1991-1997, Thomas G. Lane.
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* Modified 2003-2017 by Guido Vollbeding.
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* This file is part of the Independent JPEG Group's software.
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* For conditions of distribution and use, see the accompanying README file.
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*
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* This file contains initialization logic for the JPEG compressor.
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* This routine is in charge of selecting the modules to be executed and
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* making an initialization call to each one.
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*
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* Logically, this code belongs in jcmaster.c. It's split out because
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* linking this routine implies linking the entire compression library.
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* For a transcoding-only application, we want to be able to use jcmaster.c
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* without linking in the whole library.
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*/
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#define JPEG_INTERNALS
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#include "jinclude.h"
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#include "jpeglib.h"
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/*
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* Compute JPEG image dimensions and related values.
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* NOTE: this is exported for possible use by application.
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* Hence it mustn't do anything that can't be done twice.
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*/
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GLOBAL(void)
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jpeg_calc_jpeg_dimensions (j_compress_ptr cinfo)
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/* Do computations that are needed before master selection phase */
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{
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/* Sanity check on input image dimensions to prevent overflow in
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* following calculations.
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* We do check jpeg_width and jpeg_height in initial_setup in jcmaster.c,
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* but image_width and image_height can come from arbitrary data,
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* and we need some space for multiplication by block_size.
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*/
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if (((long) cinfo->image_width >> 24) || ((long) cinfo->image_height >> 24))
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ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
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#ifdef DCT_SCALING_SUPPORTED
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/* Compute actual JPEG image dimensions and DCT scaling choices. */
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if (cinfo->scale_num >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/1 scaling */
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cinfo->jpeg_width = cinfo->image_width * cinfo->block_size;
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cinfo->jpeg_height = cinfo->image_height * cinfo->block_size;
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cinfo->min_DCT_h_scaled_size = 1;
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cinfo->min_DCT_v_scaled_size = 1;
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} else if (cinfo->scale_num * 2 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/2 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 2L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 2L);
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cinfo->min_DCT_h_scaled_size = 2;
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cinfo->min_DCT_v_scaled_size = 2;
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} else if (cinfo->scale_num * 3 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/3 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 3L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 3L);
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cinfo->min_DCT_h_scaled_size = 3;
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cinfo->min_DCT_v_scaled_size = 3;
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} else if (cinfo->scale_num * 4 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/4 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 4L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 4L);
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cinfo->min_DCT_h_scaled_size = 4;
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cinfo->min_DCT_v_scaled_size = 4;
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} else if (cinfo->scale_num * 5 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/5 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 5L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 5L);
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cinfo->min_DCT_h_scaled_size = 5;
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cinfo->min_DCT_v_scaled_size = 5;
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} else if (cinfo->scale_num * 6 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/6 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 6L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 6L);
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cinfo->min_DCT_h_scaled_size = 6;
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cinfo->min_DCT_v_scaled_size = 6;
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} else if (cinfo->scale_num * 7 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/7 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 7L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 7L);
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cinfo->min_DCT_h_scaled_size = 7;
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cinfo->min_DCT_v_scaled_size = 7;
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} else if (cinfo->scale_num * 8 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/8 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 8L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 8L);
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cinfo->min_DCT_h_scaled_size = 8;
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cinfo->min_DCT_v_scaled_size = 8;
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} else if (cinfo->scale_num * 9 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/9 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 9L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 9L);
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cinfo->min_DCT_h_scaled_size = 9;
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cinfo->min_DCT_v_scaled_size = 9;
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} else if (cinfo->scale_num * 10 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/10 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 10L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 10L);
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cinfo->min_DCT_h_scaled_size = 10;
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cinfo->min_DCT_v_scaled_size = 10;
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} else if (cinfo->scale_num * 11 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/11 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 11L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 11L);
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cinfo->min_DCT_h_scaled_size = 11;
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cinfo->min_DCT_v_scaled_size = 11;
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} else if (cinfo->scale_num * 12 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/12 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 12L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 12L);
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cinfo->min_DCT_h_scaled_size = 12;
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cinfo->min_DCT_v_scaled_size = 12;
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} else if (cinfo->scale_num * 13 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/13 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 13L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 13L);
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cinfo->min_DCT_h_scaled_size = 13;
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cinfo->min_DCT_v_scaled_size = 13;
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} else if (cinfo->scale_num * 14 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/14 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 14L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 14L);
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cinfo->min_DCT_h_scaled_size = 14;
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cinfo->min_DCT_v_scaled_size = 14;
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} else if (cinfo->scale_num * 15 >= cinfo->scale_denom * cinfo->block_size) {
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/* Provide block_size/15 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 15L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 15L);
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cinfo->min_DCT_h_scaled_size = 15;
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cinfo->min_DCT_v_scaled_size = 15;
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} else {
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/* Provide block_size/16 scaling */
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cinfo->jpeg_width = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 16L);
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cinfo->jpeg_height = (JDIMENSION)
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jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 16L);
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cinfo->min_DCT_h_scaled_size = 16;
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cinfo->min_DCT_v_scaled_size = 16;
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}
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#else /* !DCT_SCALING_SUPPORTED */
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/* Hardwire it to "no scaling" */
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cinfo->jpeg_width = cinfo->image_width;
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cinfo->jpeg_height = cinfo->image_height;
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cinfo->min_DCT_h_scaled_size = DCTSIZE;
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cinfo->min_DCT_v_scaled_size = DCTSIZE;
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#endif /* DCT_SCALING_SUPPORTED */
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}
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/*
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* Master selection of compression modules.
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* This is done once at the start of processing an image. We determine
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* which modules will be used and give them appropriate initialization calls.
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*/
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GLOBAL(void)
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jinit_compress_master (j_compress_ptr cinfo)
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{
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long samplesperrow;
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JDIMENSION jd_samplesperrow;
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/* For now, precision must match compiled-in value... */
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if (cinfo->data_precision != BITS_IN_JSAMPLE)
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ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
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/* Sanity check on input image dimensions */
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if (cinfo->image_height <= 0 || cinfo->image_width <= 0 ||
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cinfo->input_components <= 0)
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ERREXIT(cinfo, JERR_EMPTY_IMAGE);
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/* Width of an input scanline must be representable as JDIMENSION. */
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samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
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jd_samplesperrow = (JDIMENSION) samplesperrow;
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if ((long) jd_samplesperrow != samplesperrow)
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ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
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/* Compute JPEG image dimensions and related values. */
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jpeg_calc_jpeg_dimensions(cinfo);
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/* Initialize master control (includes parameter checking/processing) */
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jinit_c_master_control(cinfo, FALSE /* full compression */);
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/* Preprocessing */
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if (! cinfo->raw_data_in) {
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jinit_color_converter(cinfo);
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jinit_downsampler(cinfo);
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jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
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}
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/* Forward DCT */
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jinit_forward_dct(cinfo);
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/* Entropy encoding: either Huffman or arithmetic coding. */
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if (cinfo->arith_code)
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jinit_arith_encoder(cinfo);
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else {
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jinit_huff_encoder(cinfo);
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}
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/* Need a full-image coefficient buffer in any multi-pass mode. */
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jinit_c_coef_controller(cinfo,
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(boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding));
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jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
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jinit_marker_writer(cinfo);
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/* We can now tell the memory manager to allocate virtual arrays. */
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(*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
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/* Write the datastream header (SOI) immediately.
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* Frame and scan headers are postponed till later.
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* This lets application insert special markers after the SOI.
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*/
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(*cinfo->marker->write_file_header) (cinfo);
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}
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