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module.graphic.png.php
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1 <?php
4 // available at http://getid3.sourceforge.net //
5 // or http://www.getid3.org //
7 // See readme.txt for more details //
9 // //
10 // module.graphic.png.php //
11 // module for analyzing PNG Image files //
12 // dependencies: NONE //
13 // ///
15 
16 
17 class getid3_png
18 {
19 
20  function getid3_png(&$fd, &$ThisFileInfo) {
21 
22  // shortcut
23  $ThisFileInfo['png'] = array();
24  $thisfile_png = &$ThisFileInfo['png'];
25 
26  $ThisFileInfo['fileformat'] = 'png';
27  $ThisFileInfo['video']['dataformat'] = 'png';
28  $ThisFileInfo['video']['lossless'] = false;
29 
30  fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
31  $PNGfiledata = fread($fd, GETID3_FREAD_BUFFER_SIZE);
32  $offset = 0;
33 
34  $PNGidentifier = substr($PNGfiledata, $offset, 8); // $89 $50 $4E $47 $0D $0A $1A $0A
35  $offset += 8;
36 
37  if ($PNGidentifier != "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A") {
38  $ThisFileInfo['error'][] = 'First 8 bytes of file ('.getid3_lib::PrintHexBytes($PNGidentifier).') did not match expected PNG identifier';
39  unset($ThisFileInfo['fileformat']);
40  return false;
41  }
42 
43  while (((ftell($fd) - (strlen($PNGfiledata) - $offset)) < $ThisFileInfo['filesize'])) {
44  $chunk['data_length'] = getid3_lib::BigEndian2Int(substr($PNGfiledata, $offset, 4));
45  $offset += 4;
46  while (((strlen($PNGfiledata) - $offset) < ($chunk['data_length'] + 4)) && (ftell($fd) < $ThisFileInfo['filesize'])) {
47  $PNGfiledata .= fread($fd, GETID3_FREAD_BUFFER_SIZE);
48  }
49  $chunk['type_text'] = substr($PNGfiledata, $offset, 4);
50  $offset += 4;
51  $chunk['type_raw'] = getid3_lib::BigEndian2Int($chunk['type_text']);
52  $chunk['data'] = substr($PNGfiledata, $offset, $chunk['data_length']);
53  $offset += $chunk['data_length'];
54  $chunk['crc'] = getid3_lib::BigEndian2Int(substr($PNGfiledata, $offset, 4));
55  $offset += 4;
56 
57  $chunk['flags']['ancilliary'] = (bool) ($chunk['type_raw'] & 0x20000000);
58  $chunk['flags']['private'] = (bool) ($chunk['type_raw'] & 0x00200000);
59  $chunk['flags']['reserved'] = (bool) ($chunk['type_raw'] & 0x00002000);
60  $chunk['flags']['safe_to_copy'] = (bool) ($chunk['type_raw'] & 0x00000020);
61 
62  // shortcut
63  $thisfile_png[$chunk['type_text']] = array();
64  $thisfile_png_chunk_type_text = &$thisfile_png[$chunk['type_text']];
65 
66  switch ($chunk['type_text']) {
67 
68  case 'IHDR': // Image Header
69  $thisfile_png_chunk_type_text['header'] = $chunk;
70  $thisfile_png_chunk_type_text['width'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 4));
71  $thisfile_png_chunk_type_text['height'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 4, 4));
72  $thisfile_png_chunk_type_text['raw']['bit_depth'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 8, 1));
73  $thisfile_png_chunk_type_text['raw']['color_type'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 9, 1));
74  $thisfile_png_chunk_type_text['raw']['compression_method'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 10, 1));
75  $thisfile_png_chunk_type_text['raw']['filter_method'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 11, 1));
76  $thisfile_png_chunk_type_text['raw']['interlace_method'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 12, 1));
77 
78  $thisfile_png_chunk_type_text['compression_method_text'] = $this->PNGcompressionMethodLookup($thisfile_png_chunk_type_text['raw']['compression_method']);
79  $thisfile_png_chunk_type_text['color_type']['palette'] = (bool) ($thisfile_png_chunk_type_text['raw']['color_type'] & 0x01);
80  $thisfile_png_chunk_type_text['color_type']['true_color'] = (bool) ($thisfile_png_chunk_type_text['raw']['color_type'] & 0x02);
81  $thisfile_png_chunk_type_text['color_type']['alpha'] = (bool) ($thisfile_png_chunk_type_text['raw']['color_type'] & 0x04);
82 
83  $ThisFileInfo['video']['resolution_x'] = $thisfile_png_chunk_type_text['width'];
84  $ThisFileInfo['video']['resolution_y'] = $thisfile_png_chunk_type_text['height'];
85 
86  $ThisFileInfo['video']['bits_per_sample'] = $this->IHDRcalculateBitsPerSample($thisfile_png_chunk_type_text['raw']['color_type'], $thisfile_png_chunk_type_text['raw']['bit_depth']);
87  break;
88 
89 
90  case 'PLTE': // Palette
91  $thisfile_png_chunk_type_text['header'] = $chunk;
92  $paletteoffset = 0;
93  for ($i = 0; $i <= 255; $i++) {
94  //$thisfile_png_chunk_type_text['red'][$i] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
95  //$thisfile_png_chunk_type_text['green'][$i] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
96  //$thisfile_png_chunk_type_text['blue'][$i] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
97  $red = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
98  $green = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
99  $blue = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $paletteoffset++, 1));
100  $thisfile_png_chunk_type_text[$i] = (($red << 16) | ($green << 8) | ($blue));
101  }
102  break;
103 
104 
105  case 'tRNS': // Transparency
106  $thisfile_png_chunk_type_text['header'] = $chunk;
107  switch ($thisfile_png['IHDR']['raw']['color_type']) {
108  case 0:
109  $thisfile_png_chunk_type_text['transparent_color_gray'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 2));
110  break;
111 
112  case 2:
113  $thisfile_png_chunk_type_text['transparent_color_red'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 2));
114  $thisfile_png_chunk_type_text['transparent_color_green'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2, 2));
115  $thisfile_png_chunk_type_text['transparent_color_blue'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 4, 2));
116  break;
117 
118  case 3:
119  for ($i = 0; $i < strlen($thisfile_png_chunk_type_text['header']['data']); $i++) {
120  $thisfile_png_chunk_type_text['palette_opacity'][$i] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $i, 1));
121  }
122  break;
123 
124  case 4:
125  case 6:
126  $ThisFileInfo['error'][] = 'Invalid color_type in tRNS chunk: '.$thisfile_png['IHDR']['raw']['color_type'];
127 
128  default:
129  $ThisFileInfo['warning'][] = 'Unhandled color_type in tRNS chunk: '.$thisfile_png['IHDR']['raw']['color_type'];
130  break;
131  }
132  break;
133 
134 
135  case 'gAMA': // Image Gamma
136  $thisfile_png_chunk_type_text['header'] = $chunk;
137  $thisfile_png_chunk_type_text['gamma'] = getid3_lib::BigEndian2Int($thisfile_png_chunk_type_text['header']['data']) / 100000;
138  break;
139 
140 
141  case 'cHRM': // Primary Chromaticities
142  $thisfile_png_chunk_type_text['header'] = $chunk;
143  $thisfile_png_chunk_type_text['white_x'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 4)) / 100000;
144  $thisfile_png_chunk_type_text['white_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 4, 4)) / 100000;
145  $thisfile_png_chunk_type_text['red_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 8, 4)) / 100000;
146  $thisfile_png_chunk_type_text['red_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 12, 4)) / 100000;
147  $thisfile_png_chunk_type_text['green_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 16, 4)) / 100000;
148  $thisfile_png_chunk_type_text['green_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 20, 4)) / 100000;
149  $thisfile_png_chunk_type_text['blue_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 24, 4)) / 100000;
150  $thisfile_png_chunk_type_text['blue_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 28, 4)) / 100000;
151  break;
152 
153 
154  case 'sRGB': // Standard RGB Color Space
155  $thisfile_png_chunk_type_text['header'] = $chunk;
156  $thisfile_png_chunk_type_text['reindering_intent'] = getid3_lib::BigEndian2Int($thisfile_png_chunk_type_text['header']['data']);
157  $thisfile_png_chunk_type_text['reindering_intent_text'] = $this->PNGsRGBintentLookup($thisfile_png_chunk_type_text['reindering_intent']);
158  break;
159 
160 
161  case 'iCCP': // Embedded ICC Profile
162  $thisfile_png_chunk_type_text['header'] = $chunk;
163  list($profilename, $compressiondata) = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
164  $thisfile_png_chunk_type_text['profile_name'] = $profilename;
165  $thisfile_png_chunk_type_text['compression_method'] = getid3_lib::BigEndian2Int(substr($compressiondata, 0, 1));
166  $thisfile_png_chunk_type_text['compression_profile'] = substr($compressiondata, 1);
167 
168  $thisfile_png_chunk_type_text['compression_method_text'] = $this->PNGcompressionMethodLookup($thisfile_png_chunk_type_text['compression_method']);
169  break;
170 
171 
172  case 'tEXt': // Textual Data
173  $thisfile_png_chunk_type_text['header'] = $chunk;
174  list($keyword, $text) = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
175  $thisfile_png_chunk_type_text['keyword'] = $keyword;
176  $thisfile_png_chunk_type_text['text'] = $text;
177 
178  $thisfile_png['comments'][$thisfile_png_chunk_type_text['keyword']][] = $thisfile_png_chunk_type_text['text'];
179  break;
180 
181 
182  case 'zTXt': // Compressed Textual Data
183  $thisfile_png_chunk_type_text['header'] = $chunk;
184  list($keyword, $otherdata) = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
185  $thisfile_png_chunk_type_text['keyword'] = $keyword;
186  $thisfile_png_chunk_type_text['compression_method'] = getid3_lib::BigEndian2Int(substr($otherdata, 0, 1));
187  $thisfile_png_chunk_type_text['compressed_text'] = substr($otherdata, 1);
188  $thisfile_png_chunk_type_text['compression_method_text'] = $this->PNGcompressionMethodLookup($thisfile_png_chunk_type_text['compression_method']);
189  switch ($thisfile_png_chunk_type_text['compression_method']) {
190  case 0:
191  $thisfile_png_chunk_type_text['text'] = gzuncompress($thisfile_png_chunk_type_text['compressed_text']);
192  break;
193 
194  default:
195  // unknown compression method
196  break;
197  }
198 
199  if (isset($thisfile_png_chunk_type_text['text'])) {
200  $thisfile_png['comments'][$thisfile_png_chunk_type_text['keyword']][] = $thisfile_png_chunk_type_text['text'];
201  }
202  break;
203 
204 
205  case 'iTXt': // International Textual Data
206  $thisfile_png_chunk_type_text['header'] = $chunk;
207  list($keyword, $otherdata) = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
208  $thisfile_png_chunk_type_text['keyword'] = $keyword;
209  $thisfile_png_chunk_type_text['compression'] = (bool) getid3_lib::BigEndian2Int(substr($otherdata, 0, 1));
210  $thisfile_png_chunk_type_text['compression_method'] = getid3_lib::BigEndian2Int(substr($otherdata, 1, 1));
211  $thisfile_png_chunk_type_text['compression_method_text'] = $this->PNGcompressionMethodLookup($thisfile_png_chunk_type_text['compression_method']);
212  list($languagetag, $translatedkeyword, $text) = explode("\x00", substr($otherdata, 2), 3);
213  $thisfile_png_chunk_type_text['language_tag'] = $languagetag;
214  $thisfile_png_chunk_type_text['translated_keyword'] = $translatedkeyword;
215 
216  if ($thisfile_png_chunk_type_text['compression']) {
217 
218  switch ($thisfile_png_chunk_type_text['compression_method']) {
219  case 0:
220  $thisfile_png_chunk_type_text['text'] = gzuncompress($text);
221  break;
222 
223  default:
224  // unknown compression method
225  break;
226  }
227 
228  } else {
229 
230  $thisfile_png_chunk_type_text['text'] = $text;
231 
232  }
233 
234  if (isset($thisfile_png_chunk_type_text['text'])) {
235  $thisfile_png['comments'][$thisfile_png_chunk_type_text['keyword']][] = $thisfile_png_chunk_type_text['text'];
236  }
237  break;
238 
239 
240  case 'bKGD': // Background Color
241  $thisfile_png_chunk_type_text['header'] = $chunk;
242  switch ($thisfile_png['IHDR']['raw']['color_type']) {
243  case 0:
244  case 4:
245  $thisfile_png_chunk_type_text['background_gray'] = getid3_lib::BigEndian2Int($thisfile_png_chunk_type_text['header']['data']);
246  break;
247 
248  case 2:
249  case 6:
250  $thisfile_png_chunk_type_text['background_red'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0 * $thisfile_png['IHDR']['raw']['bit_depth'], $thisfile_png['IHDR']['raw']['bit_depth']));
251  $thisfile_png_chunk_type_text['background_green'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 1 * $thisfile_png['IHDR']['raw']['bit_depth'], $thisfile_png['IHDR']['raw']['bit_depth']));
252  $thisfile_png_chunk_type_text['background_blue'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2 * $thisfile_png['IHDR']['raw']['bit_depth'], $thisfile_png['IHDR']['raw']['bit_depth']));
253  break;
254 
255  case 3:
256  $thisfile_png_chunk_type_text['background_index'] = getid3_lib::BigEndian2Int($thisfile_png_chunk_type_text['header']['data']);
257  break;
258 
259  default:
260  break;
261  }
262  break;
263 
264 
265  case 'pHYs': // Physical Pixel Dimensions
266  $thisfile_png_chunk_type_text['header'] = $chunk;
267  $thisfile_png_chunk_type_text['pixels_per_unit_x'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 4));
268  $thisfile_png_chunk_type_text['pixels_per_unit_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 4, 4));
269  $thisfile_png_chunk_type_text['unit_specifier'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 8, 1));
270  $thisfile_png_chunk_type_text['unit'] = $this->PNGpHYsUnitLookup($thisfile_png_chunk_type_text['unit_specifier']);
271  break;
272 
273 
274  case 'sBIT': // Significant Bits
275  $thisfile_png_chunk_type_text['header'] = $chunk;
276  switch ($thisfile_png['IHDR']['raw']['color_type']) {
277  case 0:
278  $thisfile_png_chunk_type_text['significant_bits_gray'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
279  break;
280 
281  case 2:
282  case 3:
283  $thisfile_png_chunk_type_text['significant_bits_red'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
284  $thisfile_png_chunk_type_text['significant_bits_green'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 1, 1));
285  $thisfile_png_chunk_type_text['significant_bits_blue'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2, 1));
286  break;
287 
288  case 4:
289  $thisfile_png_chunk_type_text['significant_bits_gray'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
290  $thisfile_png_chunk_type_text['significant_bits_alpha'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 1, 1));
291  break;
292 
293  case 6:
294  $thisfile_png_chunk_type_text['significant_bits_red'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
295  $thisfile_png_chunk_type_text['significant_bits_green'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 1, 1));
296  $thisfile_png_chunk_type_text['significant_bits_blue'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2, 1));
297  $thisfile_png_chunk_type_text['significant_bits_alpha'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 3, 1));
298  break;
299 
300  default:
301  break;
302  }
303  break;
304 
305 
306  case 'sPLT': // Suggested Palette
307  $thisfile_png_chunk_type_text['header'] = $chunk;
308  list($palettename, $otherdata) = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
309  $thisfile_png_chunk_type_text['palette_name'] = $palettename;
310  $sPLToffset = 0;
311  $thisfile_png_chunk_type_text['sample_depth_bits'] = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, 1));
312  $sPLToffset += 1;
313  $thisfile_png_chunk_type_text['sample_depth_bytes'] = $thisfile_png_chunk_type_text['sample_depth_bits'] / 8;
314  $paletteCounter = 0;
315  while ($sPLToffset < strlen($otherdata)) {
316  $thisfile_png_chunk_type_text['red'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, $thisfile_png_chunk_type_text['sample_depth_bytes']));
317  $sPLToffset += $thisfile_png_chunk_type_text['sample_depth_bytes'];
318  $thisfile_png_chunk_type_text['green'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, $thisfile_png_chunk_type_text['sample_depth_bytes']));
319  $sPLToffset += $thisfile_png_chunk_type_text['sample_depth_bytes'];
320  $thisfile_png_chunk_type_text['blue'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, $thisfile_png_chunk_type_text['sample_depth_bytes']));
321  $sPLToffset += $thisfile_png_chunk_type_text['sample_depth_bytes'];
322  $thisfile_png_chunk_type_text['alpha'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, $thisfile_png_chunk_type_text['sample_depth_bytes']));
323  $sPLToffset += $thisfile_png_chunk_type_text['sample_depth_bytes'];
324  $thisfile_png_chunk_type_text['frequency'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $sPLToffset, 2));
325  $sPLToffset += 2;
326  $paletteCounter++;
327  }
328  break;
329 
330 
331  case 'hIST': // Palette Histogram
332  $thisfile_png_chunk_type_text['header'] = $chunk;
333  $hISTcounter = 0;
334  while ($hISTcounter < strlen($thisfile_png_chunk_type_text['header']['data'])) {
335  $thisfile_png_chunk_type_text[$hISTcounter] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $hISTcounter / 2, 2));
336  $hISTcounter += 2;
337  }
338  break;
339 
340 
341  case 'tIME': // Image Last-Modification Time
342  $thisfile_png_chunk_type_text['header'] = $chunk;
343  $thisfile_png_chunk_type_text['year'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 2));
344  $thisfile_png_chunk_type_text['month'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2, 1));
345  $thisfile_png_chunk_type_text['day'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 3, 1));
346  $thisfile_png_chunk_type_text['hour'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 4, 1));
347  $thisfile_png_chunk_type_text['minute'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 5, 1));
348  $thisfile_png_chunk_type_text['second'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 6, 1));
349  $thisfile_png_chunk_type_text['unix'] = gmmktime($thisfile_png_chunk_type_text['hour'], $thisfile_png_chunk_type_text['minute'], $thisfile_png_chunk_type_text['second'], $thisfile_png_chunk_type_text['month'], $thisfile_png_chunk_type_text['day'], $thisfile_png_chunk_type_text['year']);
350  break;
351 
352 
353  case 'oFFs': // Image Offset
354  $thisfile_png_chunk_type_text['header'] = $chunk;
355  $thisfile_png_chunk_type_text['position_x'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 4), false, true);
356  $thisfile_png_chunk_type_text['position_y'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 4, 4), false, true);
357  $thisfile_png_chunk_type_text['unit_specifier'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 8, 1));
358  $thisfile_png_chunk_type_text['unit'] = $this->PNGoFFsUnitLookup($thisfile_png_chunk_type_text['unit_specifier']);
359  break;
360 
361 
362  case 'pCAL': // Calibration Of Pixel Values
363  $thisfile_png_chunk_type_text['header'] = $chunk;
364  list($calibrationname, $otherdata) = explode("\x00", $thisfile_png_chunk_type_text['header']['data'], 2);
365  $thisfile_png_chunk_type_text['calibration_name'] = $calibrationname;
366  $pCALoffset = 0;
367  $thisfile_png_chunk_type_text['original_zero'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $pCALoffset, 4), false, true);
368  $pCALoffset += 4;
369  $thisfile_png_chunk_type_text['original_max'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $pCALoffset, 4), false, true);
370  $pCALoffset += 4;
371  $thisfile_png_chunk_type_text['equation_type'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $pCALoffset, 1));
372  $pCALoffset += 1;
373  $thisfile_png_chunk_type_text['equation_type_text'] = $this->PNGpCALequationTypeLookup($thisfile_png_chunk_type_text['equation_type']);
374  $thisfile_png_chunk_type_text['parameter_count'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], $pCALoffset, 1));
375  $pCALoffset += 1;
376  $thisfile_png_chunk_type_text['parameters'] = explode("\x00", substr($thisfile_png_chunk_type_text['header']['data'], $pCALoffset));
377  break;
378 
379 
380  case 'sCAL': // Physical Scale Of Image Subject
381  $thisfile_png_chunk_type_text['header'] = $chunk;
382  $thisfile_png_chunk_type_text['unit_specifier'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
383  $thisfile_png_chunk_type_text['unit'] = $this->PNGsCALUnitLookup($thisfile_png_chunk_type_text['unit_specifier']);
384  list($pixelwidth, $pixelheight) = explode("\x00", substr($thisfile_png_chunk_type_text['header']['data'], 1));
385  $thisfile_png_chunk_type_text['pixel_width'] = $pixelwidth;
386  $thisfile_png_chunk_type_text['pixel_height'] = $pixelheight;
387  break;
388 
389 
390  case 'gIFg': // GIF Graphic Control Extension
391  $gIFgCounter = 0;
392  if (isset($thisfile_png_chunk_type_text) && is_array($thisfile_png_chunk_type_text)) {
393  $gIFgCounter = count($thisfile_png_chunk_type_text);
394  }
395  $thisfile_png_chunk_type_text[$gIFgCounter]['header'] = $chunk;
396  $thisfile_png_chunk_type_text[$gIFgCounter]['disposal_method'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 0, 1));
397  $thisfile_png_chunk_type_text[$gIFgCounter]['user_input_flag'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 1, 1));
398  $thisfile_png_chunk_type_text[$gIFgCounter]['delay_time'] = getid3_lib::BigEndian2Int(substr($thisfile_png_chunk_type_text['header']['data'], 2, 2));
399  break;
400 
401 
402  case 'gIFx': // GIF Application Extension
403  $gIFxCounter = 0;
404  if (isset($thisfile_png_chunk_type_text) && is_array($thisfile_png_chunk_type_text)) {
405  $gIFxCounter = count($thisfile_png_chunk_type_text);
406  }
407  $thisfile_png_chunk_type_text[$gIFxCounter]['header'] = $chunk;
408  $thisfile_png_chunk_type_text[$gIFxCounter]['application_identifier'] = substr($thisfile_png_chunk_type_text['header']['data'], 0, 8);
409  $thisfile_png_chunk_type_text[$gIFxCounter]['authentication_code'] = substr($thisfile_png_chunk_type_text['header']['data'], 8, 3);
410  $thisfile_png_chunk_type_text[$gIFxCounter]['application_data'] = substr($thisfile_png_chunk_type_text['header']['data'], 11);
411  break;
412 
413 
414  case 'IDAT': // Image Data
415  $idatinformationfieldindex = 0;
416  if (isset($thisfile_png['IDAT']) && is_array($thisfile_png['IDAT'])) {
417  $idatinformationfieldindex = count($thisfile_png['IDAT']);
418  }
419  unset($chunk['data']);
420  $thisfile_png_chunk_type_text[$idatinformationfieldindex]['header'] = $chunk;
421  break;
422 
423 
424  case 'IEND': // Image Trailer
425  $thisfile_png_chunk_type_text['header'] = $chunk;
426  break;
427 
428 
429  default:
430  //unset($chunk['data']);
431  $thisfile_png_chunk_type_text['header'] = $chunk;
432  $ThisFileInfo['warning'][] = 'Unhandled chunk type: '.$chunk['type_text'];
433  break;
434  }
435  }
436 
437  return true;
438  }
439 
440  function PNGsRGBintentLookup($sRGB) {
441  static $PNGsRGBintentLookup = array(
442  0 => 'Perceptual',
443  1 => 'Relative colorimetric',
444  2 => 'Saturation',
445  3 => 'Absolute colorimetric'
446  );
447  return (isset($PNGsRGBintentLookup[$sRGB]) ? $PNGsRGBintentLookup[$sRGB] : 'invalid');
448  }
449 
450  function PNGcompressionMethodLookup($compressionmethod) {
451  static $PNGcompressionMethodLookup = array(
452  0 => 'deflate/inflate'
453  );
454  return (isset($PNGcompressionMethodLookup[$compressionmethod]) ? $PNGcompressionMethodLookup[$compressionmethod] : 'invalid');
455  }
456 
457  function PNGpHYsUnitLookup($unitid) {
458  static $PNGpHYsUnitLookup = array(
459  0 => 'unknown',
460  1 => 'meter'
461  );
462  return (isset($PNGpHYsUnitLookup[$unitid]) ? $PNGpHYsUnitLookup[$unitid] : 'invalid');
463  }
464 
465  function PNGoFFsUnitLookup($unitid) {
466  static $PNGoFFsUnitLookup = array(
467  0 => 'pixel',
468  1 => 'micrometer'
469  );
470  return (isset($PNGoFFsUnitLookup[$unitid]) ? $PNGoFFsUnitLookup[$unitid] : 'invalid');
471  }
472 
473  function PNGpCALequationTypeLookup($equationtype) {
474  static $PNGpCALequationTypeLookup = array(
475  0 => 'Linear mapping',
476  1 => 'Base-e exponential mapping',
477  2 => 'Arbitrary-base exponential mapping',
478  3 => 'Hyperbolic mapping'
479  );
480  return (isset($PNGpCALequationTypeLookup[$equationtype]) ? $PNGpCALequationTypeLookup[$equationtype] : 'invalid');
481  }
482 
483  function PNGsCALUnitLookup($unitid) {
484  static $PNGsCALUnitLookup = array(
485  0 => 'meter',
486  1 => 'radian'
487  );
488  return (isset($PNGsCALUnitLookup[$unitid]) ? $PNGsCALUnitLookup[$unitid] : 'invalid');
489  }
490 
491  function IHDRcalculateBitsPerSample($color_type, $bit_depth) {
492  switch ($color_type) {
493  case 0: // Each pixel is a grayscale sample.
494  return $bit_depth;
495  break;
496 
497  case 2: // Each pixel is an R,G,B triple
498  return 3 * $bit_depth;
499  break;
500 
501  case 3: // Each pixel is a palette index; a PLTE chunk must appear.
502  return $bit_depth;
503  break;
504 
505  case 4: // Each pixel is a grayscale sample, followed by an alpha sample.
506  return 2 * $bit_depth;
507  break;
508 
509  case 6: // Each pixel is an R,G,B triple, followed by an alpha sample.
510  return 4 * $bit_depth;
511  break;
512  }
513  return false;
514  }
515 
516 }
517 
518 
519 ?>