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Diffstat (limited to 'src/jpeg-8c/jcparam.c')
| -rw-r--r-- | src/jpeg-8c/jcparam.c | 632 |
1 files changed, 632 insertions, 0 deletions
diff --git a/src/jpeg-8c/jcparam.c b/src/jpeg-8c/jcparam.c new file mode 100644 index 00000000..c5e85dda --- /dev/null +++ b/src/jpeg-8c/jcparam.c @@ -0,0 +1,632 @@ +/* + * jcparam.c + * + * Copyright (C) 1991-1998, Thomas G. Lane. + * Modified 2003-2008 by Guido Vollbeding. + * 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; + 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 (which_tbl < 0 || which_tbl >= NUM_QUANT_TBLS) + ERREXIT1(cinfo, JERR_DQT_INDEX, which_tbl); + + qtblptr = & cinfo->quant_tbl_ptrs[which_tbl]; + + 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; +} + + +/* 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 +}; + + +GLOBAL(void) +jpeg_default_qtables (j_compress_ptr cinfo, boolean force_baseline) +/* Set or change the 'quality' (quantization) setting, using default tables + * and straight percentage-scaling quality scales. + * This entry point allows different scalings for luminance and chrominance. + */ +{ + /* Set up two quantization tables using the specified scaling */ + jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl, + cinfo->q_scale_factor[0], force_baseline); + jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl, + cinfo->q_scale_factor[1], force_baseline); +} + + +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. + */ +{ + /* 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 */ +{ + int nsymbols, len; + + if (*htblptr == NULL) + *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); + + /* Copy the number-of-symbols-of-each-code-length counts */ + MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits)); + + /* Validate the counts. We do this here mainly so we can copy the right + * number of symbols from the val[] array, without risking marching off + * the end of memory. jchuff.c will do a more thorough test later. + */ + nsymbols = 0; + for (len = 1; len <= 16; len++) + nsymbols += bits[len]; + if (nsymbols < 1 || nsymbols > 256) + ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); + + MEMCOPY((*htblptr)->huffval, val, nsymbols * SIZEOF(UINT8)); + + /* 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->scale_num = 1; /* 1:1 scaling */ + cinfo->scale_denom = 1; + 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; + + /* By default, apply fancy downsampling */ + cinfo->do_fancy_downsampling = TRUE; + + /* 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. + * + * By default, the library emits JFIF version code 1.01. + * An application that wants to emit JFIF 1.02 extension markers should set + * JFIF_minor_version to 2. We could probably get away with just defaulting + * to 1.02, but there may still be some decoders in use that will complain + * about that; saying 1.01 should minimize compatibility problems. + */ + cinfo->JFIF_major_version = 1; /* Default JFIF version = 1.01 */ + cinfo->JFIF_minor_version = 1; + 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; + + /* 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; + 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; + 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 need to put it in the permanent pool in case the application performs + * multiple compressions without changing the settings. To avoid a memory + * leak if jpeg_simple_progression is called repeatedly for the same JPEG + * object, we try to re-use previously allocated space, and we allocate + * enough space to handle YCbCr even if initially asked for grayscale. + */ + if (cinfo->script_space == NULL || cinfo->script_space_size < nscans) { + cinfo->script_space_size = MAX(nscans, 10); + cinfo->script_space = (jpeg_scan_info *) + (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, + cinfo->script_space_size * SIZEOF(jpeg_scan_info)); + } + scanptr = cinfo->script_space; + 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 */ |