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/*
* jcdeflts.c
*
* Copyright (C) 1991, 1992, 1993, 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 optional default-setting code for the JPEG compressor.
* User interfaces do not have to use this file, but those that don't use it
* must know a lot more about the innards of the JPEG code.
*/
#include "jinclude.h"
/* Default do-nothing progress monitoring routine.
* This can be overridden by a user interface that wishes to
* provide progress monitoring; just set methods->progress_monitor
* after j_c_defaults is done. The routine will be called periodically
* during the compression process.
*
* During any one pass, loopcounter increases from 0 up to (not including)
* looplimit; the step size is not necessarily 1. Both the step size and
* the limit may differ between passes. The expected total number of passes
* is in cinfo->total_passes, and the number of passes already completed is
* in cinfo->completed_passes. Thus the fraction of work completed may be
* estimated as
* completed_passes + (loopcounter/looplimit)
* ------------------------------------------
* total_passes
* ignoring the fact that the passes may not be equal amounts of work.
*/
METHODDEF void
progress_monitor (compress_info_ptr cinfo, long loopcounter, long looplimit)
{
/* do nothing */
}
/*
* Huffman table setup routines
*/
LOCAL void
add_huff_table (compress_info_ptr cinfo,
HUFF_TBL **htblptr, const UINT8 *bits, const UINT8 *val)
/* Define a Huffman table */
{
if (*htblptr == NULL)
*htblptr = (HUFF_TBL *) (*cinfo->emethods->alloc_small) (SIZEOF(HUFF_TBL));
MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
MEMCOPY((*htblptr)->huffval, val, SIZEOF((*htblptr)->huffval));
/* Initialize sent_table FALSE so table will be written to JPEG file.
* In an application where we are writing non-interchange JPEG files,
* it might be desirable to save space by leaving default Huffman tables
* out of the file. To do that, just initialize sent_table = TRUE...
*/
(*htblptr)->sent_table = FALSE;
}
LOCAL void
std_huff_tables (compress_info_ptr cinfo)
/* Set up the standard Huffman tables (cf. JPEG standard section K.3) */
/* IMPORTANT: these are only valid for 8-bit data precision! */
{
static const UINT8 dc_luminance_bits[17] =
{ /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };
static const UINT8 dc_luminance_val[] =
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
static const UINT8 dc_chrominance_bits[17] =
{ /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
static const UINT8 dc_chrominance_val[] =
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
static const UINT8 ac_luminance_bits[17] =
{ /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };
static const UINT8 ac_luminance_val[] =
{ 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
0xf9, 0xfa };
static const UINT8 ac_chrominance_bits[17] =
{ /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };
static const UINT8 ac_chrominance_val[] =
{ 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
0xf9, 0xfa };
add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[0],
dc_luminance_bits, dc_luminance_val);
add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[0],
ac_luminance_bits, ac_luminance_val);
add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[1],
dc_chrominance_bits, dc_chrominance_val);
add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[1],
ac_chrominance_bits, ac_chrominance_val);
}
/*
* Quantization table setup routines
*/
GLOBAL void
j_add_quant_table (compress_info_ptr cinfo, int which_tbl,
const QUANT_VAL *basic_table, int scale_factor,
boolean force_baseline)
/* Define a quantization table equal to the basic_table times
* a scale factor (given as a percentage).
* If force_baseline is TRUE, the computed quantization table entries
* are limited to 1..255 for JPEG baseline compatibility.
*/
{
QUANT_TBL_PTR * qtblptr = & cinfo->quant_tbl_ptrs[which_tbl];
int i;
long temp;
if (*qtblptr == NULL)
*qtblptr = (QUANT_TBL_PTR) (*cinfo->emethods->alloc_small) (SIZEOF(QUANT_TBL));
for (i = 0; i < DCTSIZE2; i++) {
temp = ((long) basic_table[i] * scale_factor + 50L) / 100L;
/* limit the values to the valid range */
if (temp <= 0L) temp = 1L;
#ifdef EIGHT_BIT_SAMPLES
if (temp > 32767L) temp = 32767L; /* QUANT_VALs are 'short' */
#else
if (temp > 65535L) temp = 65535L; /* QUANT_VALs are 'UINT16' */
#endif
if (force_baseline && temp > 255L)
temp = 255L; /* limit to baseline range if requested */
(*qtblptr)[i] = (QUANT_VAL) temp;
}
}
GLOBAL int
j_quality_scaling (int quality)
/* Convert a user-specified quality rating to a percentage scaling factor
* for an underlying quantization table, using our recommended scaling curve.
* The input 'quality' factor should be 0 (terrible) to 100 (very good).
*/
{
/* Safety limit on quality factor. Convert 0 to 1 to avoid zero divide. */
if (quality <= 0) quality = 1;
if (quality > 100) quality = 100;
/* The basic table is used as-is (scaling 100) for a quality of 50.
* Qualities 50..100 are converted to scaling percentage 200 - 2*Q;
* note that at Q=100 the scaling is 0, which will cause j_add_quant_table
* to make all the table entries 1 (hence, no quantization loss).
* Qualities 1..50 are converted to scaling percentage 5000/Q.
*/
if (quality < 50)
quality = 5000 / quality;
else
quality = 200 - quality*2;
return quality;
}
GLOBAL void
j_set_quality (compress_info_ptr cinfo, int quality, boolean force_baseline)
/* Set or change the 'quality' (quantization) setting, using default tables.
* This is the standard quality-adjusting entry point for typical user
* interfaces; only those who want detailed control over quantization tables
* would use the preceding two routines directly.
*/
{
/* This is the sample quantization table given in the JPEG spec section K.1,
* but expressed in zigzag order (as are all of our quant. tables).
* The spec says that the values given produce "good" quality, and
* when divided by 2, "very good" quality. (These two settings are
* selected by quality=50 and quality=75 respectively.)
*/
static const QUANT_VAL std_luminance_quant_tbl[DCTSIZE2] = {
16, 11, 12, 14, 12, 10, 16, 14,
13, 14, 18, 17, 16, 19, 24, 40,
26, 24, 22, 22, 24, 49, 35, 37,
29, 40, 58, 51, 61, 60, 57, 51,
56, 55, 64, 72, 92, 78, 64, 68,
87, 69, 55, 56, 80, 109, 81, 87,
95, 98, 103, 104, 103, 62, 77, 113,
121, 112, 100, 120, 92, 101, 103, 99
};
static const QUANT_VAL std_chrominance_quant_tbl[DCTSIZE2] = {
17, 18, 18, 24, 21, 24, 47, 26,
26, 47, 99, 66, 56, 66, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99
};
/* Convert user 0-100 rating to percentage scaling */
quality = j_quality_scaling(quality);
/* Set up two quantization tables using the specified quality scaling */
j_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
quality, force_baseline);
j_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
quality, force_baseline);
}
/* Default parameter setup for compression.
*
* User interfaces that don't choose to use this routine must do their
* own setup of all these parameters. Alternately, you can call this
* to establish defaults and then alter parameters selectively. This
* is the recommended approach since, if we add any new parameters,
* your code will still work (they'll be set to reasonable defaults).
*
* See above for the meaning of the 'quality' and 'force_baseline' parameters.
* Typically, the application's default quality setting will be passed to this
* routine. A later call on j_set_quality() can be used to change to a
* user-specified quality setting.
*
* This routine sets up for a color image; to output a grayscale image,
* do this first and call j_monochrome_default() afterwards.
* (The latter can be called within c_ui_method_selection, so the
* choice can depend on the input file header.)
* Note that if you want a JPEG colorspace other than GRAYSCALE or YCbCr,
* you should also change the component ID codes, and you should NOT emit
* a JFIF header (set write_JFIF_header = FALSE).
*
* CAUTION: if you want to compress multiple images per run, it's necessary
* to call j_c_defaults before *each* call to jpeg_compress, since subsidiary
* structures like the Huffman tables are automatically freed during cleanup.
*/
GLOBAL void
j_c_defaults (compress_info_ptr cinfo, int quality, boolean force_baseline)
/* NB: the external methods must already be set up. */
{
short i;
jpeg_component_info * compptr;
/* Initialize pointers as needed to mark stuff unallocated. */
cinfo->comp_info = NULL;
for (i = 0; i < NUM_QUANT_TBLS; i++)
cinfo->quant_tbl_ptrs[i] = NULL;
for (i = 0; i < NUM_HUFF_TBLS; i++) {
cinfo->dc_huff_tbl_ptrs[i] = NULL;
cinfo->ac_huff_tbl_ptrs[i] = NULL;
}
cinfo->data_precision = BITS_IN_JSAMPLE; /* default; can be overridden by input_init */
cinfo->density_unit = 0; /* Pixel size is unknown by default */
cinfo->X_density = 1; /* Pixel aspect ratio is square by default */
cinfo->Y_density = 1;
cinfo->input_gamma = 1.0; /* no gamma correction by default */
cinfo->write_JFIF_header = TRUE; /* write a JFIF marker */
cinfo->comment_text = NULL; /* but no COM block */
/* Prepare three color components; first is luminance which is also usable */
/* for grayscale. The others are assumed to be UV or similar chrominance. */
cinfo->jpeg_color_space = CS_YCbCr;
cinfo->num_components = 3;
cinfo->comp_info = (jpeg_component_info *)
(*cinfo->emethods->alloc_small) (4 * SIZEOF(jpeg_component_info));
/* Note: we allocate a 4-entry comp_info array so that user interface can
* easily change over to CMYK color space if desired.
*/
compptr = &cinfo->comp_info[0];
compptr->component_index = 0;
compptr->component_id = 1; /* JFIF specifies IDs 1,2,3 */
compptr->h_samp_factor = 2; /* default to 2x2 subsamples of chrominance */
compptr->v_samp_factor = 2;
compptr->quant_tbl_no = 0; /* use tables 0 for luminance */
compptr->dc_tbl_no = 0;
compptr->ac_tbl_no = 0;
compptr = &cinfo->comp_info[1];
compptr->component_index = 1;
compptr->component_id = 2;
compptr->h_samp_factor = 1;
compptr->v_samp_factor = 1;
compptr->quant_tbl_no = 1; /* use tables 1 for chrominance */
compptr->dc_tbl_no = 1;
compptr->ac_tbl_no = 1;
compptr = &cinfo->comp_info[2];
compptr->component_index = 2;
compptr->component_id = 3;
compptr->h_samp_factor = 1;
compptr->v_samp_factor = 1;
compptr->quant_tbl_no = 1; /* use tables 1 for chrominance */
compptr->dc_tbl_no = 1;
compptr->ac_tbl_no = 1;
/* Set up two quantization tables using the specified quality scaling */
j_set_quality(cinfo, quality, force_baseline);
/* Set up two Huffman tables in case user interface wants Huffman coding */
std_huff_tables(cinfo);
/* Initialize default arithmetic coding conditioning */
for (i = 0; i < NUM_ARITH_TBLS; i++) {
cinfo->arith_dc_L[i] = 0;
cinfo->arith_dc_U[i] = 1;
cinfo->arith_ac_K[i] = 5;
}
/* Use Huffman coding, not arithmetic coding, by default */
cinfo->arith_code = FALSE;
/* Color images are interleaved by default */
cinfo->interleave = TRUE;
/* By default, don't do extra passes to optimize entropy coding */
cinfo->optimize_coding = FALSE;
/* By default, use the simpler non-cosited sampling alignment */
cinfo->CCIR601_sampling = FALSE;
/* No input smoothing */
cinfo->smoothing_factor = 0;
/* No restart markers */
cinfo->restart_interval = 0;
cinfo->restart_in_rows = 0;
/* Install default do-nothing progress monitoring method. */
cinfo->methods->progress_monitor = progress_monitor;
}
GLOBAL void
j_monochrome_default (compress_info_ptr cinfo)
/* Change the j_c_defaults() values to emit a monochrome JPEG file. */
{
jpeg_component_info * compptr;
cinfo->jpeg_color_space = CS_GRAYSCALE;
cinfo->num_components = 1;
/* Set single component to 1x1 subsampling */
compptr = &cinfo->comp_info[0];
compptr->h_samp_factor = 1;
compptr->v_samp_factor = 1;
}
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