|
|
#include "stdafx.h"
#pragma hdrstop
/*
* jcparam.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 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. */
#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. */{ /* These are the sample quantization tables given in JPEG spec section K.1.
* 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, 10, 16, 24, 40, 51, 61, 12, 12, 14, 19, 26, 58, 60, 55, 14, 13, 16, 24, 40, 57, 69, 56, 14, 17, 22, 29, 51, 87, 80, 62, 18, 22, 37, 56, 68, 109, 103, 77, 24, 35, 55, 64, 81, 104, 113, 92, 49, 64, 78, 87, 103, 121, 120, 101, 72, 92, 95, 98, 112, 100, 103, 99 }; static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = { 17, 18, 24, 47, 99, 99, 99, 99, 18, 21, 26, 66, 99, 99, 99, 99, 24, 26, 56, 99, 99, 99, 99, 99, 47, 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 };
/* 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 jpeg_add_quant_table * to make all the table entries 1 (hence, minimum 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 */ 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
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_YCbCrA: jpeg_set_colorspace(cinfo, JCS_YCbCrA); break; case JCS_YCbCrALegacy: jpeg_set_colorspace(cinfo, JCS_YCbCrALegacy); 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:#ifdef NIFTY
cinfo->write_JFIF_header = FALSE; /* Write a JFIF marker */#else
cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */#endif
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; cinfo->num_components = 3; 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; cinfo->num_components = 4; 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; cinfo->num_components = 4; SET_COMP(0, 201, 2,2, 0, 0,0); /* YCbCr-Alpha */ SET_COMP(1, 202, 1,1, 1, 1,1); SET_COMP(2, 203, 1,1, 1, 1,1); SET_COMP(3, 204, 2,2, 0, 0,0); break; case JCS_YCbCrALegacy: cinfo->write_JFIF_header = FALSE; 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; 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;#endif
case JCS_RGB:#ifdef NIFTY
cinfo->write_Adobe_marker = FALSE; /* write Adobe marker to flag RGB */#else
cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */#endif
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:#ifdef NIFTY
cinfo->write_JFIF_header = FALSE; /* Write a JFIF marker */#else
cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */#endif
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:#ifdef NIFTY
cinfo->write_Adobe_marker = FALSE; /* write Adobe marker to flag CMYK */#else
cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */#endif
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:#ifdef NIFTY
cinfo->write_Adobe_marker = FALSE; /* write Adobe marker to flag YCCK */#else
cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */#endif
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 */
|
