| /* |
| * jcdeflts.c |
| * |
| * Copyright (C) 1991, 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. |
| */ |
| |
| #include "jinclude.h" |
| |
| |
| 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 = (*cinfo->emethods->alloc_small) (SIZEOF(HUFF_TBL)); |
| |
| memcpy((void *) (*htblptr)->bits, (void *) bits, |
| SIZEOF((*htblptr)->bits)); |
| memcpy((void *) (*htblptr)->huffval, (void *) 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-8-R8 section 13.3) */ |
| { |
| 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); |
| } |
| |
| |
| /* This is the sample quantization table given in JPEG-8-R8 sec 13.1, |
| * 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 in j_set_quality, below.) |
| */ |
| |
| |
| 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 |
| }; |
| |
| |
| LOCAL void |
| 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) */ |
| { |
| QUANT_TBL_PTR * qtblptr = & cinfo->quant_tbl_ptrs[which_tbl]; |
| int i; |
| long temp; |
| |
| if (*qtblptr == NULL) |
| *qtblptr = (*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 void |
| j_set_quality (compress_info_ptr cinfo, int quality, boolean force_baseline) |
| /* Set or change the 'quality' (quantization) setting. */ |
| /* The 'quality' factor should be 0 (terrible) to 100 (very good). */ |
| /* Quality 50 corresponds to the JPEG basic tables given above; */ |
| /* quality 100 results in no quantization scaling at all. */ |
| /* If force_baseline is TRUE, quantization table entries are limited */ |
| /* to 0..255 for JPEG baseline compatibility; this is only an issue */ |
| /* for quality settings below 24. */ |
| { |
| /* Safety limit on quality factor. Convert 0 to 1 to avoid zero divide. */ |
| if (quality <= 0) quality = 1; |
| if (quality > 100) quality = 100; |
| |
| /* Convert quality rating to a percentage scaling of the basic tables. |
| * 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 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; |
| |
| /* Set up two quantization tables using the specified quality scaling */ |
| add_quant_table(cinfo, 0, std_luminance_quant_tbl, quality, force_baseline); |
| 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. |
| * |
| * See above for the meaning of the 'quality' parameter. 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 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 safest |
| * to call j_default_compression before *each* call to jpeg_compress (and |
| * j_free_defaults afterwards). If this isn't practical, you'll have to |
| * be careful to reset any individual parameters that may change during |
| * the compression run. The main thing you need to worry about as this |
| * is written is that the sent_table boolean in each Huffman table must |
| * be reset to FALSE before each compression; otherwise, Huffman tables |
| * won't get emitted for the second and subsequent images. |
| */ |
| |
| GLOBAL void |
| j_default_compression (compress_info_ptr cinfo, int quality) |
| /* 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 = 8; /* 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 */ |
| |
| /* Prepare three color components; first is luminance which is also usable */ |
| /* for grayscale. The others are assumed to be UV or similar chrominance. */ |
| cinfo->write_JFIF_header = TRUE; |
| cinfo->jpeg_color_space = CS_YCbCr; |
| cinfo->num_components = 3; |
| cinfo->comp_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 */ |
| /* Baseline compatibility is forced (a nonissue for reasonable defaults) */ |
| j_set_quality(cinfo, quality, TRUE); |
| |
| /* 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 restart markers */ |
| cinfo->restart_interval = 0; |
| } |
| |
| |
| |
| GLOBAL void |
| j_monochrome_default (compress_info_ptr cinfo) |
| /* Change the j_default_compression() 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; |
| } |
| |
| |
| |
| /* This routine releases storage allocated by j_default_compression. |
| * Note that freeing the method pointer structs and the compress_info_struct |
| * itself are the responsibility of the user interface. |
| */ |
| |
| GLOBAL void |
| j_free_defaults (compress_info_ptr cinfo) |
| { |
| short i; |
| |
| #define FREE(ptr) if ((ptr) != NULL) \ |
| (*cinfo->emethods->free_small) ((void *) ptr) |
| |
| FREE(cinfo->comp_info); |
| for (i = 0; i < NUM_QUANT_TBLS; i++) |
| FREE(cinfo->quant_tbl_ptrs[i]); |
| for (i = 0; i < NUM_HUFF_TBLS; i++) { |
| FREE(cinfo->dc_huff_tbl_ptrs[i]); |
| FREE(cinfo->ac_huff_tbl_ptrs[i]); |
| } |
| } |