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1 /* |
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2 * jcparam.c |
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3 * |
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4 * Copyright (C) 1991-1998, Thomas G. Lane. |
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5 * This file is part of the Independent JPEG Group's software. |
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6 * For conditions of distribution and use, see the accompanying README file. |
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7 * |
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8 * This file contains optional default-setting code for the JPEG compressor. |
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9 * Applications do not have to use this file, but those that don't use it |
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10 * must know a lot more about the innards of the JPEG code. |
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11 */ |
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12 |
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13 #define JPEG_INTERNALS |
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14 #include "jinclude.h" |
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15 #include "jpeglib.h" |
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16 |
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17 |
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18 /* |
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19 * Quantization table setup routines |
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20 */ |
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21 |
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22 GLOBAL(void) |
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23 jpeg_add_quant_table (j_compress_ptr cinfo, int which_tbl, |
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24 const unsigned int *basic_table, |
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25 int scale_factor, boolean force_baseline) |
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26 /* Define a quantization table equal to the basic_table times |
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27 * a scale factor (given as a percentage). |
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28 * If force_baseline is TRUE, the computed quantization table entries |
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29 * are limited to 1..255 for JPEG baseline compatibility. |
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30 */ |
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31 { |
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32 JQUANT_TBL ** qtblptr; |
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33 int i; |
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34 long temp; |
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35 |
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36 /* Safety check to ensure start_compress not called yet. */ |
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37 if (cinfo->global_state != CSTATE_START) |
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38 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
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39 |
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40 if (which_tbl < 0 || which_tbl >= NUM_QUANT_TBLS) |
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41 ERREXIT1(cinfo, JERR_DQT_INDEX, which_tbl); |
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42 |
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43 qtblptr = & cinfo->quant_tbl_ptrs[which_tbl]; |
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44 |
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45 if (*qtblptr == NULL) |
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46 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) cinfo); |
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47 |
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48 for (i = 0; i < DCTSIZE2; i++) { |
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49 temp = ((long) basic_table[i] * scale_factor + 50L) / 100L; |
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50 /* limit the values to the valid range */ |
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51 if (temp <= 0L) temp = 1L; |
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52 if (temp > 32767L) temp = 32767L; /* max quantizer needed for 12 bits */ |
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53 if (force_baseline && temp > 255L) |
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54 temp = 255L; /* limit to baseline range if requested */ |
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55 (*qtblptr)->quantval[i] = (UINT16) temp; |
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56 } |
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57 |
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58 /* Initialize sent_table FALSE so table will be written to JPEG file. */ |
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59 (*qtblptr)->sent_table = FALSE; |
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60 } |
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61 |
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62 |
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63 GLOBAL(void) |
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64 jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor, |
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65 boolean force_baseline) |
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66 /* Set or change the 'quality' (quantization) setting, using default tables |
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67 * and a straight percentage-scaling quality scale. In most cases it's better |
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68 * to use jpeg_set_quality (below); this entry point is provided for |
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69 * applications that insist on a linear percentage scaling. |
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70 */ |
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71 { |
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72 /* These are the sample quantization tables given in JPEG spec section K.1. |
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73 * The spec says that the values given produce "good" quality, and |
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74 * when divided by 2, "very good" quality. |
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75 */ |
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76 static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = { |
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77 16, 11, 10, 16, 24, 40, 51, 61, |
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78 12, 12, 14, 19, 26, 58, 60, 55, |
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79 14, 13, 16, 24, 40, 57, 69, 56, |
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80 14, 17, 22, 29, 51, 87, 80, 62, |
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81 18, 22, 37, 56, 68, 109, 103, 77, |
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82 24, 35, 55, 64, 81, 104, 113, 92, |
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83 49, 64, 78, 87, 103, 121, 120, 101, |
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84 72, 92, 95, 98, 112, 100, 103, 99 |
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85 }; |
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86 static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = { |
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87 17, 18, 24, 47, 99, 99, 99, 99, |
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88 18, 21, 26, 66, 99, 99, 99, 99, |
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89 24, 26, 56, 99, 99, 99, 99, 99, |
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90 47, 66, 99, 99, 99, 99, 99, 99, |
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91 99, 99, 99, 99, 99, 99, 99, 99, |
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92 99, 99, 99, 99, 99, 99, 99, 99, |
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93 99, 99, 99, 99, 99, 99, 99, 99, |
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94 99, 99, 99, 99, 99, 99, 99, 99 |
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95 }; |
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96 |
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97 /* Set up two quantization tables using the specified scaling */ |
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98 jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl, |
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99 scale_factor, force_baseline); |
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100 jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl, |
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101 scale_factor, force_baseline); |
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102 } |
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103 |
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104 |
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105 GLOBAL(int) |
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106 jpeg_quality_scaling (int quality) |
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107 /* Convert a user-specified quality rating to a percentage scaling factor |
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108 * for an underlying quantization table, using our recommended scaling curve. |
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109 * The input 'quality' factor should be 0 (terrible) to 100 (very good). |
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110 */ |
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111 { |
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112 /* Safety limit on quality factor. Convert 0 to 1 to avoid zero divide. */ |
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113 if (quality <= 0) quality = 1; |
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114 if (quality > 100) quality = 100; |
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115 |
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116 /* The basic table is used as-is (scaling 100) for a quality of 50. |
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117 * Qualities 50..100 are converted to scaling percentage 200 - 2*Q; |
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118 * note that at Q=100 the scaling is 0, which will cause jpeg_add_quant_table |
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119 * to make all the table entries 1 (hence, minimum quantization loss). |
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120 * Qualities 1..50 are converted to scaling percentage 5000/Q. |
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121 */ |
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122 if (quality < 50) |
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123 quality = 5000 / quality; |
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124 else |
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125 quality = 200 - quality*2; |
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126 |
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127 return quality; |
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128 } |
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129 |
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130 |
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131 GLOBAL(void) |
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132 jpeg_set_quality (j_compress_ptr cinfo, int quality, boolean force_baseline) |
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133 /* Set or change the 'quality' (quantization) setting, using default tables. |
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134 * This is the standard quality-adjusting entry point for typical user |
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135 * interfaces; only those who want detailed control over quantization tables |
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136 * would use the preceding three routines directly. |
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137 */ |
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138 { |
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139 /* Convert user 0-100 rating to percentage scaling */ |
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140 quality = jpeg_quality_scaling(quality); |
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141 |
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142 /* Set up standard quality tables */ |
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143 jpeg_set_linear_quality(cinfo, quality, force_baseline); |
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144 } |
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145 |
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146 |
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147 /* |
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148 * Huffman table setup routines |
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149 */ |
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150 |
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151 LOCAL(void) |
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152 add_huff_table (j_compress_ptr cinfo, |
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153 JHUFF_TBL **htblptr, const UINT8 *bits, const UINT8 *val) |
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154 /* Define a Huffman table */ |
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155 { |
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156 int nsymbols, len; |
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157 |
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158 if (*htblptr == NULL) |
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159 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); |
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160 |
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161 /* Copy the number-of-symbols-of-each-code-length counts */ |
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162 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits)); |
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163 |
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164 /* Validate the counts. We do this here mainly so we can copy the right |
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165 * number of symbols from the val[] array, without risking marching off |
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166 * the end of memory. jchuff.c will do a more thorough test later. |
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167 */ |
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168 nsymbols = 0; |
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169 for (len = 1; len <= 16; len++) |
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170 nsymbols += bits[len]; |
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171 if (nsymbols < 1 || nsymbols > 256) |
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172 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); |
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173 |
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174 MEMCOPY((*htblptr)->huffval, val, nsymbols * SIZEOF(UINT8)); |
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175 |
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176 /* Initialize sent_table FALSE so table will be written to JPEG file. */ |
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177 (*htblptr)->sent_table = FALSE; |
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178 } |
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179 |
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180 |
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181 LOCAL(void) |
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182 std_huff_tables (j_compress_ptr cinfo) |
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183 /* Set up the standard Huffman tables (cf. JPEG standard section K.3) */ |
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184 /* IMPORTANT: these are only valid for 8-bit data precision! */ |
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185 { |
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186 static const UINT8 bits_dc_luminance[17] = |
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187 { /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 }; |
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188 static const UINT8 val_dc_luminance[] = |
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189 { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 }; |
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190 |
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191 static const UINT8 bits_dc_chrominance[17] = |
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192 { /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 }; |
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193 static const UINT8 val_dc_chrominance[] = |
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194 { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 }; |
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195 |
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196 static const UINT8 bits_ac_luminance[17] = |
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197 { /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d }; |
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198 static const UINT8 val_ac_luminance[] = |
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199 { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, |
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200 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, |
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201 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, |
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202 0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0, |
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203 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16, |
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204 0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28, |
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205 0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, |
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206 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, |
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207 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, |
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208 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, |
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209 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, |
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210 0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, |
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211 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, |
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212 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, |
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213 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, |
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214 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, |
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215 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, |
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216 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2, |
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217 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, |
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218 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, |
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219 0xf9, 0xfa }; |
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220 |
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221 static const UINT8 bits_ac_chrominance[17] = |
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222 { /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 }; |
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223 static const UINT8 val_ac_chrominance[] = |
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224 { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, |
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225 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, |
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226 0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91, |
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227 0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0, |
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228 0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34, |
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229 0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26, |
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230 0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38, |
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231 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, |
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232 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, |
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233 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, |
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234 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, |
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235 0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, |
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236 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, |
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237 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, |
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238 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, |
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239 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, |
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240 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, |
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241 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, |
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242 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, |
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243 0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, |
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244 0xf9, 0xfa }; |
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245 |
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246 add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[0], |
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247 bits_dc_luminance, val_dc_luminance); |
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248 add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[0], |
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249 bits_ac_luminance, val_ac_luminance); |
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250 add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[1], |
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251 bits_dc_chrominance, val_dc_chrominance); |
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252 add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[1], |
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253 bits_ac_chrominance, val_ac_chrominance); |
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254 } |
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255 |
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256 |
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257 /* |
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258 * Default parameter setup for compression. |
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259 * |
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260 * Applications that don't choose to use this routine must do their |
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261 * own setup of all these parameters. Alternately, you can call this |
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262 * to establish defaults and then alter parameters selectively. This |
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263 * is the recommended approach since, if we add any new parameters, |
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264 * your code will still work (they'll be set to reasonable defaults). |
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265 */ |
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266 |
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267 GLOBAL(void) |
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268 jpeg_set_defaults (j_compress_ptr cinfo) |
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269 { |
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270 int i; |
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271 |
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272 /* Safety check to ensure start_compress not called yet. */ |
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273 if (cinfo->global_state != CSTATE_START) |
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274 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
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275 |
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276 /* Allocate comp_info array large enough for maximum component count. |
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277 * Array is made permanent in case application wants to compress |
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278 * multiple images at same param settings. |
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279 */ |
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280 if (cinfo->comp_info == NULL) |
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281 cinfo->comp_info = (jpeg_component_info *) |
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282 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, |
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283 MAX_COMPONENTS * SIZEOF(jpeg_component_info)); |
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284 |
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285 /* Initialize everything not dependent on the color space */ |
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286 |
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287 cinfo->data_precision = BITS_IN_JSAMPLE; |
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288 /* Set up two quantization tables using default quality of 75 */ |
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289 jpeg_set_quality(cinfo, 75, TRUE); |
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290 /* Set up two Huffman tables */ |
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291 std_huff_tables(cinfo); |
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292 |
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293 /* Initialize default arithmetic coding conditioning */ |
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294 for (i = 0; i < NUM_ARITH_TBLS; i++) { |
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295 cinfo->arith_dc_L[i] = 0; |
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296 cinfo->arith_dc_U[i] = 1; |
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297 cinfo->arith_ac_K[i] = 5; |
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298 } |
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299 |
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300 /* Default is no multiple-scan output */ |
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301 cinfo->scan_info = NULL; |
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302 cinfo->num_scans = 0; |
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303 |
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304 /* Expect normal source image, not raw downsampled data */ |
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305 cinfo->raw_data_in = FALSE; |
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306 |
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307 /* Use Huffman coding, not arithmetic coding, by default */ |
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308 cinfo->arith_code = FALSE; |
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309 |
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310 /* By default, don't do extra passes to optimize entropy coding */ |
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311 cinfo->optimize_coding = FALSE; |
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312 /* The standard Huffman tables are only valid for 8-bit data precision. |
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313 * If the precision is higher, force optimization on so that usable |
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314 * tables will be computed. This test can be removed if default tables |
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315 * are supplied that are valid for the desired precision. |
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316 */ |
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317 if (cinfo->data_precision > 8) |
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318 cinfo->optimize_coding = TRUE; |
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319 |
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320 /* By default, use the simpler non-cosited sampling alignment */ |
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321 cinfo->CCIR601_sampling = FALSE; |
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322 |
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323 /* No input smoothing */ |
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324 cinfo->smoothing_factor = 0; |
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325 |
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326 /* DCT algorithm preference */ |
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327 cinfo->dct_method = JDCT_DEFAULT; |
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328 |
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329 /* No restart markers */ |
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330 cinfo->restart_interval = 0; |
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331 cinfo->restart_in_rows = 0; |
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332 |
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333 /* Fill in default JFIF marker parameters. Note that whether the marker |
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334 * will actually be written is determined by jpeg_set_colorspace. |
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335 * |
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336 * By default, the library emits JFIF version code 1.01. |
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337 * An application that wants to emit JFIF 1.02 extension markers should set |
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338 * JFIF_minor_version to 2. We could probably get away with just defaulting |
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339 * to 1.02, but there may still be some decoders in use that will complain |
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340 * about that; saying 1.01 should minimize compatibility problems. |
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341 */ |
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342 cinfo->JFIF_major_version = 1; /* Default JFIF version = 1.01 */ |
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343 cinfo->JFIF_minor_version = 1; |
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344 cinfo->density_unit = 0; /* Pixel size is unknown by default */ |
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345 cinfo->X_density = 1; /* Pixel aspect ratio is square by default */ |
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346 cinfo->Y_density = 1; |
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347 |
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348 /* Choose JPEG colorspace based on input space, set defaults accordingly */ |
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349 |
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350 jpeg_default_colorspace(cinfo); |
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351 } |
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352 |
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353 |
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354 /* |
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355 * Select an appropriate JPEG colorspace for in_color_space. |
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356 */ |
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357 |
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358 GLOBAL(void) |
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359 jpeg_default_colorspace (j_compress_ptr cinfo) |
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360 { |
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361 switch (cinfo->in_color_space) { |
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362 case JCS_GRAYSCALE: |
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363 jpeg_set_colorspace(cinfo, JCS_GRAYSCALE); |
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364 break; |
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365 case JCS_RGB: |
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366 jpeg_set_colorspace(cinfo, JCS_YCbCr); |
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367 break; |
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368 case JCS_YCbCr: |
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369 jpeg_set_colorspace(cinfo, JCS_YCbCr); |
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370 break; |
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371 case JCS_CMYK: |
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372 jpeg_set_colorspace(cinfo, JCS_CMYK); /* By default, no translation */ |
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373 break; |
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374 case JCS_YCCK: |
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375 jpeg_set_colorspace(cinfo, JCS_YCCK); |
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376 break; |
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377 case JCS_UNKNOWN: |
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378 jpeg_set_colorspace(cinfo, JCS_UNKNOWN); |
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379 break; |
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380 default: |
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381 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE); |
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382 } |
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383 } |
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384 |
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385 |
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386 /* |
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387 * Set the JPEG colorspace, and choose colorspace-dependent default values. |
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388 */ |
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389 |
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390 GLOBAL(void) |
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391 jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace) |
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392 { |
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393 jpeg_component_info * compptr; |
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394 int ci; |
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395 |
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396 #define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl) \ |
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397 (compptr = &cinfo->comp_info[index], \ |
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398 compptr->component_id = (id), \ |
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399 compptr->h_samp_factor = (hsamp), \ |
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400 compptr->v_samp_factor = (vsamp), \ |
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401 compptr->quant_tbl_no = (quant), \ |
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402 compptr->dc_tbl_no = (dctbl), \ |
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403 compptr->ac_tbl_no = (actbl) ) |
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404 |
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405 /* Safety check to ensure start_compress not called yet. */ |
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406 if (cinfo->global_state != CSTATE_START) |
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407 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
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408 |
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409 /* For all colorspaces, we use Q and Huff tables 0 for luminance components, |
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410 * tables 1 for chrominance components. |
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411 */ |
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412 |
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413 cinfo->jpeg_color_space = colorspace; |
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414 |
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415 cinfo->write_JFIF_header = FALSE; /* No marker for non-JFIF colorspaces */ |
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416 cinfo->write_Adobe_marker = FALSE; /* write no Adobe marker by default */ |
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417 |
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418 switch (colorspace) { |
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419 case JCS_GRAYSCALE: |
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420 cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */ |
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421 cinfo->num_components = 1; |
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422 /* JFIF specifies component ID 1 */ |
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423 SET_COMP(0, 1, 1,1, 0, 0,0); |
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424 break; |
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425 case JCS_RGB: |
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426 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */ |
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427 cinfo->num_components = 3; |
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428 SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0); |
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429 SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0); |
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430 SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0); |
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431 break; |
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432 case JCS_YCbCr: |
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433 cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */ |
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434 cinfo->num_components = 3; |
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435 /* JFIF specifies component IDs 1,2,3 */ |
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436 /* We default to 2x2 subsamples of chrominance */ |
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437 SET_COMP(0, 1, 2,2, 0, 0,0); |
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438 SET_COMP(1, 2, 1,1, 1, 1,1); |
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439 SET_COMP(2, 3, 1,1, 1, 1,1); |
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440 break; |
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441 case JCS_CMYK: |
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442 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */ |
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443 cinfo->num_components = 4; |
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444 SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0); |
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445 SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0); |
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446 SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0); |
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447 SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0); |
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448 break; |
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449 case JCS_YCCK: |
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450 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */ |
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451 cinfo->num_components = 4; |
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452 SET_COMP(0, 1, 2,2, 0, 0,0); |
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453 SET_COMP(1, 2, 1,1, 1, 1,1); |
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454 SET_COMP(2, 3, 1,1, 1, 1,1); |
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455 SET_COMP(3, 4, 2,2, 0, 0,0); |
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456 break; |
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457 case JCS_UNKNOWN: |
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458 cinfo->num_components = cinfo->input_components; |
|
459 if (cinfo->num_components < 1 || cinfo->num_components > MAX_COMPONENTS) |
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460 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, |
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461 MAX_COMPONENTS); |
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462 for (ci = 0; ci < cinfo->num_components; ci++) { |
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463 SET_COMP(ci, ci, 1,1, 0, 0,0); |
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464 } |
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465 break; |
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466 default: |
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467 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); |
|
468 } |
|
469 } |
|
470 |
|
471 |
|
472 #ifdef C_PROGRESSIVE_SUPPORTED |
|
473 |
|
474 LOCAL(jpeg_scan_info *) |
|
475 fill_a_scan (jpeg_scan_info * scanptr, int ci, |
|
476 int Ss, int Se, int Ah, int Al) |
|
477 /* Support routine: generate one scan for specified component */ |
|
478 { |
|
479 scanptr->comps_in_scan = 1; |
|
480 scanptr->component_index[0] = ci; |
|
481 scanptr->Ss = Ss; |
|
482 scanptr->Se = Se; |
|
483 scanptr->Ah = Ah; |
|
484 scanptr->Al = Al; |
|
485 scanptr++; |
|
486 return scanptr; |
|
487 } |
|
488 |
|
489 LOCAL(jpeg_scan_info *) |
|
490 fill_scans (jpeg_scan_info * scanptr, int ncomps, |
|
491 int Ss, int Se, int Ah, int Al) |
|
492 /* Support routine: generate one scan for each component */ |
|
493 { |
|
494 int ci; |
|
495 |
|
496 for (ci = 0; ci < ncomps; ci++) { |
|
497 scanptr->comps_in_scan = 1; |
|
498 scanptr->component_index[0] = ci; |
|
499 scanptr->Ss = Ss; |
|
500 scanptr->Se = Se; |
|
501 scanptr->Ah = Ah; |
|
502 scanptr->Al = Al; |
|
503 scanptr++; |
|
504 } |
|
505 return scanptr; |
|
506 } |
|
507 |
|
508 LOCAL(jpeg_scan_info *) |
|
509 fill_dc_scans (jpeg_scan_info * scanptr, int ncomps, int Ah, int Al) |
|
510 /* Support routine: generate interleaved DC scan if possible, else N scans */ |
|
511 { |
|
512 int ci; |
|
513 |
|
514 if (ncomps <= MAX_COMPS_IN_SCAN) { |
|
515 /* Single interleaved DC scan */ |
|
516 scanptr->comps_in_scan = ncomps; |
|
517 for (ci = 0; ci < ncomps; ci++) |
|
518 scanptr->component_index[ci] = ci; |
|
519 scanptr->Ss = scanptr->Se = 0; |
|
520 scanptr->Ah = Ah; |
|
521 scanptr->Al = Al; |
|
522 scanptr++; |
|
523 } else { |
|
524 /* Noninterleaved DC scan for each component */ |
|
525 scanptr = fill_scans(scanptr, ncomps, 0, 0, Ah, Al); |
|
526 } |
|
527 return scanptr; |
|
528 } |
|
529 |
|
530 |
|
531 /* |
|
532 * Create a recommended progressive-JPEG script. |
|
533 * cinfo->num_components and cinfo->jpeg_color_space must be correct. |
|
534 */ |
|
535 |
|
536 GLOBAL(void) |
|
537 jpeg_simple_progression (j_compress_ptr cinfo) |
|
538 { |
|
539 int ncomps = cinfo->num_components; |
|
540 int nscans; |
|
541 jpeg_scan_info * scanptr; |
|
542 |
|
543 /* Safety check to ensure start_compress not called yet. */ |
|
544 if (cinfo->global_state != CSTATE_START) |
|
545 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
|
546 |
|
547 /* Figure space needed for script. Calculation must match code below! */ |
|
548 if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) { |
|
549 /* Custom script for YCbCr color images. */ |
|
550 nscans = 10; |
|
551 } else { |
|
552 /* All-purpose script for other color spaces. */ |
|
553 if (ncomps > MAX_COMPS_IN_SCAN) |
|
554 nscans = 6 * ncomps; /* 2 DC + 4 AC scans per component */ |
|
555 else |
|
556 nscans = 2 + 4 * ncomps; /* 2 DC scans; 4 AC scans per component */ |
|
557 } |
|
558 |
|
559 /* Allocate space for script. |
|
560 * We need to put it in the permanent pool in case the application performs |
|
561 * multiple compressions without changing the settings. To avoid a memory |
|
562 * leak if jpeg_simple_progression is called repeatedly for the same JPEG |
|
563 * object, we try to re-use previously allocated space, and we allocate |
|
564 * enough space to handle YCbCr even if initially asked for grayscale. |
|
565 */ |
|
566 if (cinfo->script_space == NULL || cinfo->script_space_size < nscans) { |
|
567 cinfo->script_space_size = MAX(nscans, 10); |
|
568 cinfo->script_space = (jpeg_scan_info *) |
|
569 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, |
|
570 cinfo->script_space_size * SIZEOF(jpeg_scan_info)); |
|
571 } |
|
572 scanptr = cinfo->script_space; |
|
573 cinfo->scan_info = scanptr; |
|
574 cinfo->num_scans = nscans; |
|
575 |
|
576 if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) { |
|
577 /* Custom script for YCbCr color images. */ |
|
578 /* Initial DC scan */ |
|
579 scanptr = fill_dc_scans(scanptr, ncomps, 0, 1); |
|
580 /* Initial AC scan: get some luma data out in a hurry */ |
|
581 scanptr = fill_a_scan(scanptr, 0, 1, 5, 0, 2); |
|
582 /* Chroma data is too small to be worth expending many scans on */ |
|
583 scanptr = fill_a_scan(scanptr, 2, 1, 63, 0, 1); |
|
584 scanptr = fill_a_scan(scanptr, 1, 1, 63, 0, 1); |
|
585 /* Complete spectral selection for luma AC */ |
|
586 scanptr = fill_a_scan(scanptr, 0, 6, 63, 0, 2); |
|
587 /* Refine next bit of luma AC */ |
|
588 scanptr = fill_a_scan(scanptr, 0, 1, 63, 2, 1); |
|
589 /* Finish DC successive approximation */ |
|
590 scanptr = fill_dc_scans(scanptr, ncomps, 1, 0); |
|
591 /* Finish AC successive approximation */ |
|
592 scanptr = fill_a_scan(scanptr, 2, 1, 63, 1, 0); |
|
593 scanptr = fill_a_scan(scanptr, 1, 1, 63, 1, 0); |
|
594 /* Luma bottom bit comes last since it's usually largest scan */ |
|
595 scanptr = fill_a_scan(scanptr, 0, 1, 63, 1, 0); |
|
596 } else { |
|
597 /* All-purpose script for other color spaces. */ |
|
598 /* Successive approximation first pass */ |
|
599 scanptr = fill_dc_scans(scanptr, ncomps, 0, 1); |
|
600 scanptr = fill_scans(scanptr, ncomps, 1, 5, 0, 2); |
|
601 scanptr = fill_scans(scanptr, ncomps, 6, 63, 0, 2); |
|
602 /* Successive approximation second pass */ |
|
603 scanptr = fill_scans(scanptr, ncomps, 1, 63, 2, 1); |
|
604 /* Successive approximation final pass */ |
|
605 scanptr = fill_dc_scans(scanptr, ncomps, 1, 0); |
|
606 scanptr = fill_scans(scanptr, ncomps, 1, 63, 1, 0); |
|
607 } |
|
608 } |
|
609 |
|
610 #endif /* C_PROGRESSIVE_SUPPORTED */ |