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windows-nt/Source/XPSP1/NT/printscan/wia/common/jpeglib/jcparam.cpp

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2020-09-26 03:20:57 -05:00
/*
* jcparam.c
*
* Copyright (C) 1991-1995, 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.
* Applications 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.
*/
/* SCCSID = "@(#)jcparam.cc 1.4 11:43:20 09/04/96" */
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
/*
* Quantization table setup routines
*/
GLOBAL void
jpeg_add_quant_table (j_compress_ptr cinfo, int which_tbl,
const unsigned int *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.
*/
{
JQUANT_TBL ** qtblptr = & cinfo->quant_tbl_ptrs[which_tbl];
int i;
long temp;
/* Safety check to ensure start_compress not called yet. */
if (cinfo->global_state != CSTATE_START)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
if (*qtblptr == NULL) {
*qtblptr = jpeg_alloc_quant_table((j_common_ptr) cinfo);
}
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;
if (temp > 32767L) temp = 32767L; /* max quantizer needed for 12 bits */
if (force_baseline && temp > 255L)
temp = 255L; /* limit to baseline range if requested */
(*qtblptr)->quantval[i] = (UINT16) temp;
}
/* Initialize sent_table FALSE so table will be written to JPEG file. */
(*qtblptr)->sent_table = FALSE;
}
GLOBAL void
jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor,
boolean force_baseline)
/* Set or change the 'quality' (quantization) setting, using default tables
* and a straight percentage-scaling quality scale. In most cases it's better
* to use jpeg_set_quality (below); this entry point is provided for
* applications that insist on a linear percentage scaling.
*/
{
/* 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.
*/
static const unsigned int 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 unsigned int 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
};
/* Set up two quantization tables using the specified scaling */
jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
scale_factor, force_baseline);
jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
scale_factor, force_baseline);
}
GLOBAL int
jpeg_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
jpeg_set_quality (j_compress_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 three routines directly.
*/
{
/* Convert user 0-100 rating to percentage scaling */
quality = jpeg_quality_scaling(quality);
/* Set up standard quality tables */
jpeg_set_linear_quality(cinfo, quality, force_baseline);
}
/*
* Huffman table setup routines
*/
LOCAL void
add_huff_table (j_compress_ptr cinfo,
JHUFF_TBL **htblptr, const UINT8 *bits, const UINT8 *val)
/* Define a Huffman table */
{
if (*htblptr == NULL)
*htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
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. */
(*htblptr)->sent_table = FALSE;
}
LOCAL void
std_huff_tables (j_compress_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 bits_dc_luminance[17] =
{ /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };
static const UINT8 val_dc_luminance[] =
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
static const UINT8 bits_dc_chrominance[17] =
{ /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
static const UINT8 val_dc_chrominance[] =
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
static const UINT8 bits_ac_luminance[17] =
{ /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };
static const UINT8 val_ac_luminance[] =
{ 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 bits_ac_chrominance[17] =
{ /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };
static const UINT8 val_ac_chrominance[] =
{ 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],
bits_dc_luminance, val_dc_luminance);
add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[0],
bits_ac_luminance, val_ac_luminance);
add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[1],
bits_dc_chrominance, val_dc_chrominance);
add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[1],
bits_ac_chrominance, val_ac_chrominance);
}
/*
* Default parameter setup for compression.
*
* Applications 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).
*/
GLOBAL void
jpeg_set_defaults (j_compress_ptr cinfo)
{
int i;
/* Safety check to ensure start_compress not called yet. */
if (cinfo->global_state != CSTATE_START)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
/* Allocate comp_info array large enough for maximum component count.
* Array is made permanent in case application wants to compress
* multiple images at same param settings.
*/
if (cinfo->comp_info == NULL)
cinfo->comp_info = (jpeg_component_info *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
MAX_COMPONENTS * SIZEOF(jpeg_component_info));
/* Initialize everything not dependent on the color space */
cinfo->data_precision = BITS_IN_JSAMPLE;
/* Set up two quantization tables using default quality of 75 */
jpeg_set_quality(cinfo, 75, TRUE);
/* Set up two Huffman tables */
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;
}
/* Default is no multiple-scan output */
cinfo->scan_info = NULL;
cinfo->num_scans = 0;
/* Expect normal source image, not raw downsampled data */
cinfo->raw_data_in = FALSE;
/* Use Huffman coding, not arithmetic coding, by default */
cinfo->arith_code = FALSE;
/* By default, don't do extra passes to optimize entropy coding */
cinfo->optimize_coding = FALSE;
/* The standard Huffman tables are only valid for 8-bit data precision.
* If the precision is higher, force optimization on so that usable
* tables will be computed. This test can be removed if default tables
* are supplied that are valid for the desired precision.
*/
if (cinfo->data_precision > 8)
cinfo->optimize_coding = TRUE;
/* By default, use the simpler non-cosited sampling alignment */
cinfo->CCIR601_sampling = FALSE;
/* No input smoothing */
cinfo->smoothing_factor = 0;
/* DCT algorithm preference */
cinfo->dct_method = JDCT_DEFAULT;
/* No restart markers */
cinfo->restart_interval = 0;
cinfo->restart_in_rows = 0;
/* Fill in default JFIF marker parameters. Note that whether the marker
* will actually be written is determined by jpeg_set_colorspace.
*/
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;
#ifdef NIFTY
/* bytes_in_buffer is none */
/* it's not at all clear that this is the correct place
to do this, but why not??? */
cinfo->bytes_in_buffer = 0;
#endif
/* Choose JPEG colorspace based on input space, set defaults accordingly */
jpeg_default_colorspace(cinfo);
}
/*
* Select an appropriate JPEG colorspace for in_color_space.
*/
GLOBAL void
jpeg_default_colorspace (j_compress_ptr cinfo)
{
switch (cinfo->in_color_space) {
case JCS_GRAYSCALE:
jpeg_set_colorspace(cinfo, JCS_GRAYSCALE);
break;
case JCS_RGB:
jpeg_set_colorspace(cinfo, JCS_YCbCr);
break;
case JCS_YCbCr:
jpeg_set_colorspace(cinfo, JCS_YCbCr);
break;
case JCS_CMYK:
jpeg_set_colorspace(cinfo, JCS_CMYK); /* By default, no translation */
break;
case JCS_YCCK:
jpeg_set_colorspace(cinfo, JCS_YCCK);
break;
#ifdef NIFTY
/* support for various NIFTY colorspaces. */
case JCS_YCC:
jpeg_set_colorspace(cinfo, JCS_YCC);
break;
case JCS_YCCA:
jpeg_set_colorspace(cinfo, JCS_YCCA);
break;
case JCS_RGBA:
jpeg_set_colorspace(cinfo, JCS_YCbCrA);
break;
case JCS_RGBA_LEGACY:
jpeg_set_colorspace(cinfo, JCS_YCbCrA_LEGACY);
break;
case JCS_YCbCrA:
jpeg_set_colorspace(cinfo, JCS_YCbCrA);
break;
case JCS_YCbCrA_LEGACY:
/* JCS_YCbCrA_LEGACY is only allowed as a JPEG colorspace.
NEVER as an input colorspace. */
ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
break;
#endif
case JCS_UNKNOWN:
jpeg_set_colorspace(cinfo, JCS_UNKNOWN);
break;
default:
ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
}
}
/*
* Set the JPEG colorspace, and choose colorspace-dependent default values.
*/
GLOBAL void
jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace)
{
jpeg_component_info * compptr;
int ci;
#define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl) \
(compptr = &cinfo->comp_info[index], \
compptr->component_id = (id), \
compptr->h_samp_factor = (hsamp), \
compptr->v_samp_factor = (vsamp), \
compptr->quant_tbl_no = (quant), \
compptr->dc_tbl_no = (dctbl), \
compptr->ac_tbl_no = (actbl) )
/* Safety check to ensure start_compress not called yet. */
if (cinfo->global_state != CSTATE_START)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
/* For all colorspaces, we use Q and Huff tables 0 for luminance components,
* tables 1 for chrominance components.
*/
cinfo->jpeg_color_space = colorspace;
cinfo->write_JFIF_header = FALSE; /* No marker for non-JFIF colorspaces */
cinfo->write_Adobe_marker = FALSE; /* write no Adobe marker by default */
switch (colorspace) {
case JCS_GRAYSCALE:
cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
cinfo->num_components = 1;
/* JFIF specifies component ID 1 */
SET_COMP(0, 1, 1,1, 0, 0,0);
break;
#ifdef NIFTY
case JCS_YCC:
cinfo->write_JFIF_header = FALSE; /* don't write a JFIF marker. */
cinfo->num_components = 3;
/* NOTE:
these component numbers MUST BE UNIQUE!!!
so YCC was changed to YCc.
And it wasn't an easy bug to find, either!!!! rgvb. */
SET_COMP(0, 0x59 /* 'Y' */, 2,2, 0, 0,0); /* Photo YCC */
SET_COMP(1, 0x43 /* 'C' */, 1,1, 1, 1,1);
SET_COMP(2, 0x63 /* 'c' */, 1,1, 1, 1,1);
break;
case JCS_YCCA:
cinfo->write_JFIF_header = FALSE; /* don't write a JFIF marker. */
cinfo->num_components = 4;
/* NOTE:
these component numbers MUST BE UNIQUE!!!
so YCC was changed to YCc.
And it wasn't an easy bug to find, either!!!! rgvb. */
SET_COMP(0, 0x59 /* 'Y' */, 2,2, 0, 0,0); /* PhotoYCC-Alpha */
SET_COMP(1, 0x43 /* 'C' */, 1,1, 1, 1,1);
SET_COMP(2, 0x63 /* 'c' */, 1,1, 1, 1,1);
SET_COMP(3, 0x41 /* 'A' */, 2,2, 0, 0,0);
break;
case JCS_YCbCrA:
cinfo->write_JFIF_header = FALSE; /* don't write a JFIF marker. */
cinfo->num_components = 4;
SET_COMP(0, 1, 2,2, 0, 0,0); /* YCbCr-Alpha */
SET_COMP(1, 2, 1,1, 1, 1,1);
SET_COMP(2, 3, 1,1, 1, 1,1);
SET_COMP(3, 4, 2,2, 0, 0,0);
break;
case JCS_RGBA:
cinfo->write_JFIF_header = FALSE; /* don't write a JFIF marker. */
cinfo->num_components = 4;
SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0); /* RGB-Alpha Straight through */
SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0);
SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0);
SET_COMP(3, 0x41 /* 'A' */, 1,1, 0, 0,0);
break;
case JCS_YCbCrA_LEGACY:
cinfo->write_JFIF_header = FALSE; /* don't write a JFIF marker. */
cinfo->num_components = 4;
SET_COMP(0, 1, 2,2, 0, 0,0); /* YCbCr-Alpha */
SET_COMP(1, 2, 1,1, 1, 1,1);
SET_COMP(2, 3, 1,1, 1, 1,1);
SET_COMP(3, 4, 2,2, 0, 0,0);
break;
/* JCS_RGBA_LEGACY should NEVER appear as a JPEG colorspace. It
is only valid as an input color on compression and an output
color on decompression. */
case JCS_RGBA_LEGACY:
ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
break;
#endif
case JCS_RGB:
cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */
cinfo->num_components = 3;
SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0);
SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0);
SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0);
break;
case JCS_YCbCr:
cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
cinfo->num_components = 3;
/* JFIF specifies component IDs 1,2,3 */
/* We default to 2x2 subsamples of chrominance */
SET_COMP(0, 1, 2,2, 0, 0,0);
SET_COMP(1, 2, 1,1, 1, 1,1);
SET_COMP(2, 3, 1,1, 1, 1,1);
break;
case JCS_CMYK:
cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */
cinfo->num_components = 4;
SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0);
SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0);
SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0);
SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0);
break;
case JCS_YCCK:
cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */
cinfo->num_components = 4;
SET_COMP(0, 1, 2,2, 0, 0,0);
SET_COMP(1, 2, 1,1, 1, 1,1);
SET_COMP(2, 3, 1,1, 1, 1,1);
SET_COMP(3, 4, 2,2, 0, 0,0);
break;
case JCS_UNKNOWN:
cinfo->num_components = cinfo->input_components;
if (cinfo->num_components < 1 || cinfo->num_components > MAX_COMPONENTS)
ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
MAX_COMPONENTS);
for (ci = 0; ci < cinfo->num_components; ci++) {
SET_COMP(ci, ci, 1,1, 0, 0,0);
}
break;
default:
ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
}
}
#ifdef C_PROGRESSIVE_SUPPORTED
LOCAL jpeg_scan_info *
fill_a_scan (jpeg_scan_info * scanptr, int ci,
int Ss, int Se, int Ah, int Al)
/* Support routine: generate one scan for specified component */
{
scanptr->comps_in_scan = 1;
scanptr->component_index[0] = ci;
scanptr->Ss = Ss;
scanptr->Se = Se;
scanptr->Ah = Ah;
scanptr->Al = Al;
scanptr++;
return scanptr;
}
LOCAL jpeg_scan_info *
fill_scans (jpeg_scan_info * scanptr, int ncomps,
int Ss, int Se, int Ah, int Al)
/* Support routine: generate one scan for each component */
{
int ci;
for (ci = 0; ci < ncomps; ci++) {
scanptr->comps_in_scan = 1;
scanptr->component_index[0] = ci;
scanptr->Ss = Ss;
scanptr->Se = Se;
scanptr->Ah = Ah;
scanptr->Al = Al;
scanptr++;
}
return scanptr;
}
LOCAL jpeg_scan_info *
fill_dc_scans (jpeg_scan_info * scanptr, int ncomps, int Ah, int Al)
/* Support routine: generate interleaved DC scan if possible, else N scans */
{
int ci;
if (ncomps <= MAX_COMPS_IN_SCAN) {
/* Single interleaved DC scan */
scanptr->comps_in_scan = ncomps;
for (ci = 0; ci < ncomps; ci++)
scanptr->component_index[ci] = ci;
scanptr->Ss = scanptr->Se = 0;
scanptr->Ah = Ah;
scanptr->Al = Al;
scanptr++;
} else {
/* Noninterleaved DC scan for each component */
scanptr = fill_scans(scanptr, ncomps, 0, 0, Ah, Al);
}
return scanptr;
}
/*
* Create a recommended progressive-JPEG script.
* cinfo->num_components and cinfo->jpeg_color_space must be correct.
*/
GLOBAL void
jpeg_simple_progression (j_compress_ptr cinfo)
{
int ncomps = cinfo->num_components;
int nscans;
jpeg_scan_info * scanptr;
/* Safety check to ensure start_compress not called yet. */
if (cinfo->global_state != CSTATE_START)
ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
/* Figure space needed for script. Calculation must match code below! */
if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
/* Custom script for YCbCr color images. */
nscans = 10;
} else {
/* All-purpose script for other color spaces. */
if (ncomps > MAX_COMPS_IN_SCAN)
nscans = 6 * ncomps; /* 2 DC + 4 AC scans per component */
else
nscans = 2 + 4 * ncomps; /* 2 DC scans; 4 AC scans per component */
}
/* Allocate space for script. */
/* We use permanent pool just in case application re-uses script. */
scanptr = (jpeg_scan_info *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
nscans * SIZEOF(jpeg_scan_info));
cinfo->scan_info = scanptr;
cinfo->num_scans = nscans;
if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
/* Custom script for YCbCr color images. */
/* Initial DC scan */
scanptr = fill_dc_scans(scanptr, ncomps, 0, 1);
/* Initial AC scan: get some luma data out in a hurry */
scanptr = fill_a_scan(scanptr, 0, 1, 5, 0, 2);
/* Chroma data is too small to be worth expending many scans on */
scanptr = fill_a_scan(scanptr, 2, 1, 63, 0, 1);
scanptr = fill_a_scan(scanptr, 1, 1, 63, 0, 1);
/* Complete spectral selection for luma AC */
scanptr = fill_a_scan(scanptr, 0, 6, 63, 0, 2);
/* Refine next bit of luma AC */
scanptr = fill_a_scan(scanptr, 0, 1, 63, 2, 1);
/* Finish DC successive approximation */
scanptr = fill_dc_scans(scanptr, ncomps, 1, 0);
/* Finish AC successive approximation */
scanptr = fill_a_scan(scanptr, 2, 1, 63, 1, 0);
scanptr = fill_a_scan(scanptr, 1, 1, 63, 1, 0);
/* Luma bottom bit comes last since it's usually largest scan */
scanptr = fill_a_scan(scanptr, 0, 1, 63, 1, 0);
} else {
/* All-purpose script for other color spaces. */
/* Successive approximation first pass */
scanptr = fill_dc_scans(scanptr, ncomps, 0, 1);
scanptr = fill_scans(scanptr, ncomps, 1, 5, 0, 2);
scanptr = fill_scans(scanptr, ncomps, 6, 63, 0, 2);
/* Successive approximation second pass */
scanptr = fill_scans(scanptr, ncomps, 1, 63, 2, 1);
/* Successive approximation final pass */
scanptr = fill_dc_scans(scanptr, ncomps, 1, 0);
scanptr = fill_scans(scanptr, ncomps, 1, 63, 1, 0);
}
}
#endif /* C_PROGRESSIVE_SUPPORTED */
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