368 lines
14 KiB
C
368 lines
14 KiB
C
/*
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* jcdeflts.c
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*
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* Copyright (C) 1991, Thomas G. Lane.
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* This file is part of the Independent JPEG Group's software.
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* For conditions of distribution and use, see the accompanying README file.
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*
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* This file contains optional default-setting code for the JPEG compressor.
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* User interfaces do not have to use this file, but those that don't use it
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* must know a lot more about the innards of the JPEG code.
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*/
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#include "jinclude.h"
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LOCAL void
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add_huff_table (compress_info_ptr cinfo,
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HUFF_TBL **htblptr, const UINT8 *bits, const UINT8 *val)
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/* Define a Huffman table */
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{
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if (*htblptr == NULL)
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*htblptr = (HUFF_TBL *) (*cinfo->emethods->alloc_small) (SIZEOF(HUFF_TBL));
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memcpy((void *) (*htblptr)->bits, (const void *) bits,
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SIZEOF((*htblptr)->bits));
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memcpy((void *) (*htblptr)->huffval, (const void *) val,
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SIZEOF((*htblptr)->huffval));
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/* Initialize sent_table FALSE so table will be written to JPEG file.
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* In an application where we are writing non-interchange JPEG files,
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* it might be desirable to save space by leaving default Huffman tables
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* out of the file. To do that, just initialize sent_table = TRUE...
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*/
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(*htblptr)->sent_table = FALSE;
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}
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LOCAL void
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std_huff_tables (compress_info_ptr cinfo)
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/* Set up the standard Huffman tables (cf. JPEG-8-R8 section 13.3) */
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{
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static const UINT8 dc_luminance_bits[17] =
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{ /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };
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static const UINT8 dc_luminance_val[] =
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{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
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static const UINT8 dc_chrominance_bits[17] =
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{ /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
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static const UINT8 dc_chrominance_val[] =
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{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
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static const UINT8 ac_luminance_bits[17] =
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{ /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };
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static const UINT8 ac_luminance_val[] =
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{ 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
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0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
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0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
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0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
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0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
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0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
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0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
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0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
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0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
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0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
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0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
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0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
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0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
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0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
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0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
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0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
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0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
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0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
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0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
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0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
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0xf9, 0xfa };
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static const UINT8 ac_chrominance_bits[17] =
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{ /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };
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static const UINT8 ac_chrominance_val[] =
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{ 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
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0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
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0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
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0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
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0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
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0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
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0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
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0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
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0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
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0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
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0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
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0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
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0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
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0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
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0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
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0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
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0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
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0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
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0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
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0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
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0xf9, 0xfa };
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add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[0],
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dc_luminance_bits, dc_luminance_val);
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add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[0],
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ac_luminance_bits, ac_luminance_val);
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add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[1],
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dc_chrominance_bits, dc_chrominance_val);
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add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[1],
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ac_chrominance_bits, ac_chrominance_val);
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}
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/* This is the sample quantization table given in JPEG-8-R8 sec 13.1,
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* but expressed in zigzag order (as are all of our quant. tables).
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* The spec says that the values given produce "good" quality, and
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* when divided by 2, "very good" quality. (These two settings are
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* selected by quality=50 and quality=75 in j_set_quality, below.)
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*/
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static const QUANT_VAL std_luminance_quant_tbl[DCTSIZE2] = {
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16, 11, 12, 14, 12, 10, 16, 14,
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13, 14, 18, 17, 16, 19, 24, 40,
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26, 24, 22, 22, 24, 49, 35, 37,
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29, 40, 58, 51, 61, 60, 57, 51,
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56, 55, 64, 72, 92, 78, 64, 68,
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87, 69, 55, 56, 80, 109, 81, 87,
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95, 98, 103, 104, 103, 62, 77, 113,
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121, 112, 100, 120, 92, 101, 103, 99
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};
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static const QUANT_VAL std_chrominance_quant_tbl[DCTSIZE2] = {
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17, 18, 18, 24, 21, 24, 47, 26,
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26, 47, 99, 66, 56, 66, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99
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};
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LOCAL void
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add_quant_table (compress_info_ptr cinfo, int which_tbl,
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const QUANT_VAL *basic_table, int scale_factor,
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boolean force_baseline)
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/* Define a quantization table equal to the basic_table times */
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/* a scale factor (given as a percentage) */
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{
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QUANT_TBL_PTR * qtblptr = & cinfo->quant_tbl_ptrs[which_tbl];
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int i;
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long temp;
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if (*qtblptr == NULL)
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*qtblptr = (QUANT_TBL_PTR) (*cinfo->emethods->alloc_small) (SIZEOF(QUANT_TBL));
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for (i = 0; i < DCTSIZE2; i++) {
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temp = ((long) basic_table[i] * scale_factor + 50L) / 100L;
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/* limit the values to the valid range */
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if (temp <= 0L) temp = 1L;
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#ifdef EIGHT_BIT_SAMPLES
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if (temp > 32767L) temp = 32767L; /* QUANT_VALs are 'short' */
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#else
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if (temp > 65535L) temp = 65535L; /* QUANT_VALs are 'UINT16' */
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#endif
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if (force_baseline && temp > 255L)
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temp = 255L; /* limit to baseline range if requested */
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(*qtblptr)[i] = (QUANT_VAL) temp;
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}
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}
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GLOBAL void
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j_set_quality (compress_info_ptr cinfo, int quality, boolean force_baseline)
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/* Set or change the 'quality' (quantization) setting. */
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/* The 'quality' factor should be 0 (terrible) to 100 (very good). */
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/* Quality 50 corresponds to the JPEG basic tables given above; */
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/* quality 100 results in no quantization scaling at all. */
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/* If force_baseline is TRUE, quantization table entries are limited */
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/* to 0..255 for JPEG baseline compatibility; this is only an issue */
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/* for quality settings below 24. */
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{
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/* Safety limit on quality factor. Convert 0 to 1 to avoid zero divide. */
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if (quality <= 0) quality = 1;
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if (quality > 100) quality = 100;
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/* Convert quality rating to a percentage scaling of the basic tables.
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* The basic table is used as-is (scaling 100) for a quality of 50.
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* Qualities 50..100 are converted to scaling percentage 200 - 2*Q;
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* note that at Q=100 the scaling is 0, which will cause add_quant_table
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* to make all the table entries 1 (hence, no quantization loss).
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* Qualities 1..50 are converted to scaling percentage 5000/Q.
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*/
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if (quality < 50)
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quality = 5000 / quality;
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else
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quality = 200 - quality*2;
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/* Set up two quantization tables using the specified quality scaling */
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add_quant_table(cinfo, 0, std_luminance_quant_tbl, quality, force_baseline);
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add_quant_table(cinfo, 1, std_chrominance_quant_tbl, quality, force_baseline);
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}
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/* Default parameter setup for compression.
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*
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* User interfaces that don't choose to use this routine must do their
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* own setup of all these parameters. Alternately, you can call this
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* to establish defaults and then alter parameters selectively. This
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* is the recommended approach since, if we add any new parameters,
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* your code will still work (they'll be set to reasonable defaults).
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*
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* See above for the meaning of the 'quality' and 'force_baseline' parameters.
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* Typically, the application's default quality setting will be passed to this
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* routine. A later call on j_set_quality() can be used to change to a
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* user-specified quality setting.
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*
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* This routine sets up for a color image; to output a grayscale image,
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* do this first and call j_monochrome_default() afterwards.
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* (The latter can be called within c_ui_method_selection, so the
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* choice can depend on the input file header.)
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* Note that if you want a JPEG colorspace other than GRAYSCALE or YCbCr,
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* you should also change the component ID codes, and you should NOT emit
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* a JFIF header (set write_JFIF_header = FALSE).
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*
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* CAUTION: if you want to compress multiple images per run, it's safest
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* to call j_c_defaults before *each* call to jpeg_compress (and
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* j_c_free_defaults afterwards). If this isn't practical, you'll have to
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* be careful to reset any individual parameters that may change during
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* the compression run. The main thing you need to worry about at present
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* is that the sent_table boolean in each Huffman table must be reset to
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* FALSE before each compression; otherwise, Huffman tables won't get
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* emitted for the second and subsequent images.
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*/
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GLOBAL void
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j_c_defaults (compress_info_ptr cinfo, int quality, boolean force_baseline)
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/* NB: the external methods must already be set up. */
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{
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short i;
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jpeg_component_info * compptr;
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/* Initialize pointers as needed to mark stuff unallocated. */
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cinfo->comp_info = NULL;
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for (i = 0; i < NUM_QUANT_TBLS; i++)
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cinfo->quant_tbl_ptrs[i] = NULL;
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for (i = 0; i < NUM_HUFF_TBLS; i++) {
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cinfo->dc_huff_tbl_ptrs[i] = NULL;
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cinfo->ac_huff_tbl_ptrs[i] = NULL;
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}
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cinfo->data_precision = 8; /* default; can be overridden by input_init */
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cinfo->density_unit = 0; /* Pixel size is unknown by default */
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cinfo->X_density = 1; /* Pixel aspect ratio is square by default */
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cinfo->Y_density = 1;
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cinfo->input_gamma = 1.0; /* no gamma correction by default */
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/* Prepare three color components; first is luminance which is also usable */
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/* for grayscale. The others are assumed to be UV or similar chrominance. */
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cinfo->write_JFIF_header = TRUE;
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cinfo->jpeg_color_space = CS_YCbCr;
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cinfo->num_components = 3;
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cinfo->comp_info = (jpeg_component_info *)
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(*cinfo->emethods->alloc_small) (4 * SIZEOF(jpeg_component_info));
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/* Note: we allocate a 4-entry comp_info array so that user interface can
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* easily change over to CMYK color space if desired.
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*/
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compptr = &cinfo->comp_info[0];
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compptr->component_index = 0;
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compptr->component_id = 1; /* JFIF specifies IDs 1,2,3 */
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compptr->h_samp_factor = 2; /* default to 2x2 subsamples of chrominance */
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compptr->v_samp_factor = 2;
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compptr->quant_tbl_no = 0; /* use tables 0 for luminance */
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compptr->dc_tbl_no = 0;
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compptr->ac_tbl_no = 0;
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compptr = &cinfo->comp_info[1];
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compptr->component_index = 1;
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compptr->component_id = 2;
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compptr->h_samp_factor = 1;
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compptr->v_samp_factor = 1;
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compptr->quant_tbl_no = 1; /* use tables 1 for chrominance */
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compptr->dc_tbl_no = 1;
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compptr->ac_tbl_no = 1;
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compptr = &cinfo->comp_info[2];
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compptr->component_index = 2;
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compptr->component_id = 3;
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compptr->h_samp_factor = 1;
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compptr->v_samp_factor = 1;
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compptr->quant_tbl_no = 1; /* use tables 1 for chrominance */
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compptr->dc_tbl_no = 1;
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compptr->ac_tbl_no = 1;
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/* Set up two quantization tables using the specified quality scaling */
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j_set_quality(cinfo, quality, force_baseline);
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/* Set up two Huffman tables in case user interface wants Huffman coding */
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std_huff_tables(cinfo);
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/* Initialize default arithmetic coding conditioning */
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for (i = 0; i < NUM_ARITH_TBLS; i++) {
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cinfo->arith_dc_L[i] = 0;
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cinfo->arith_dc_U[i] = 1;
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cinfo->arith_ac_K[i] = 5;
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}
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/* Use Huffman coding, not arithmetic coding, by default */
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cinfo->arith_code = FALSE;
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/* Color images are interleaved by default */
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cinfo->interleave = TRUE;
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/* By default, don't do extra passes to optimize entropy coding */
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cinfo->optimize_coding = FALSE;
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/* By default, use the simpler non-cosited sampling alignment */
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cinfo->CCIR601_sampling = FALSE;
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/* No restart markers */
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cinfo->restart_interval = 0;
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}
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GLOBAL void
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j_monochrome_default (compress_info_ptr cinfo)
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/* Change the j_c_defaults() values to emit a monochrome JPEG file. */
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{
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jpeg_component_info * compptr;
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cinfo->jpeg_color_space = CS_GRAYSCALE;
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cinfo->num_components = 1;
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/* Set single component to 1x1 subsampling */
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compptr = &cinfo->comp_info[0];
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compptr->h_samp_factor = 1;
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compptr->v_samp_factor = 1;
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}
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/* This routine releases storage allocated by j_c_defaults.
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* Note that freeing the method pointer structs and the compress_info_struct
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* itself are the responsibility of the user interface.
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*/
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GLOBAL void
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j_c_free_defaults (compress_info_ptr cinfo)
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{
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short i;
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#define FREE(ptr) if ((ptr) != NULL) \
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(*cinfo->emethods->free_small) ((void *) ptr)
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FREE(cinfo->comp_info);
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for (i = 0; i < NUM_QUANT_TBLS; i++)
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FREE(cinfo->quant_tbl_ptrs[i]);
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for (i = 0; i < NUM_HUFF_TBLS; i++) {
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FREE(cinfo->dc_huff_tbl_ptrs[i]);
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FREE(cinfo->ac_huff_tbl_ptrs[i]);
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}
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}
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