/* * jcparam.c * * This file was part of the Independent JPEG Group's software: * Copyright (C) 1991-1998, Thomas G. Lane. * Modified 2003-2008 by Guido Vollbeding. * Lossless JPEG Modifications: * Copyright (C) 1999, Ken Murchison. * libjpeg-turbo Modifications: * Copyright (C) 2009-2011, 2018, 2023, D. R. Commander. * For conditions of distribution and use, see the accompanying README.ijg * 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" #include "jstdhuff.c" /* * 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 Annex K (Clause K.1) of * Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994. * 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 }; #if JPEG_LIB_VERSION >= 70 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); } #endif 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); } /* * 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 */ #if JPEG_LIB_VERSION >= 70 cinfo->scale_num = 1; /* 1:1 scaling */ cinfo->scale_denom = 1; #endif /* Set up two quantization tables using default quality of 75 */ jpeg_set_quality(cinfo, 75, TRUE); /* Set up two Huffman tables */ std_huff_tables((j_common_ptr)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 == 12 && !cinfo->arith_code) cinfo->optimize_coding = TRUE; /* By default, use the simpler non-cosited sampling alignment */ cinfo->CCIR601_sampling = FALSE; #if JPEG_LIB_VERSION >= 70 /* By default, apply fancy downsampling */ cinfo->do_fancy_downsampling = TRUE; #endif /* 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: case JCS_EXT_RGB: case JCS_EXT_RGBX: case JCS_EXT_BGR: case JCS_EXT_BGRX: case JCS_EXT_XBGR: case JCS_EXT_XRGB: case JCS_EXT_RGBA: case JCS_EXT_BGRA: case JCS_EXT_ABGR: case JCS_EXT_ARGB: if (cinfo->master->lossless) jpeg_set_colorspace(cinfo, JCS_RGB); else 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); if (cinfo->master->lossless) { cinfo->master->lossless = FALSE; jpeg_default_colorspace(cinfo); } /* 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 */ #ifdef C_LOSSLESS_SUPPORTED /* * Enable lossless mode. */ GLOBAL(void) jpeg_enable_lossless(j_compress_ptr cinfo, int predictor_selection_value, int point_transform) { /* Safety check to ensure start_compress not called yet. */ if (cinfo->global_state != CSTATE_START) ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); cinfo->master->lossless = TRUE; cinfo->Ss = predictor_selection_value; cinfo->Se = 0; cinfo->Ah = 0; cinfo->Al = point_transform; /* The JPEG spec simply gives the range 0..15 for Al (Pt), but that seems * wrong: the upper bound ought to depend on data precision. Perhaps they * really meant 0..N-1 for N-bit precision, which is what we allow here. * Values greater than or equal to the data precision will result in a blank * image. */ if (cinfo->Ss < 1 || cinfo->Ss > 7 || cinfo->Al < 0 || cinfo->Al >= cinfo->data_precision) ERREXIT4(cinfo, JERR_BAD_PROGRESSION, cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al); } #endif /* C_LOSSLESS_SUPPORTED */