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source: extensions/charlies_content/getid3/getid3/module.graphic.png.php @ 3318

Last change on this file since 3318 was 3318, checked in by vdigital, 15 years ago
+ Add Charlies' content to depository
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1	<?php
2	// +----------------------------------------------------------------------+
3	// \| PHP version 5 \|
4	// +----------------------------------------------------------------------+
5	// \| Copyright (c) 2002-2006 James Heinrich, Allan Hansen \|
6	// +----------------------------------------------------------------------+
7	// \| This source file is subject to version 2 of the GPL license, \|
8	// \| that is bundled with this package in the file license.txt and is \|
9	// \| available through the world-wide-web at the following url: \|
10	// \| http://www.gnu.org/copyleft/gpl.html \|
11	// +----------------------------------------------------------------------+
12	// \| getID3() - http://getid3.sourceforge.net or http://www.getid3.org \|
13	// +----------------------------------------------------------------------+
14	// \| Authors: James Heinrich <infoØgetid3*org> \|
15	// \| Allan Hansen <ahØartemis*dk> \|
16	// +----------------------------------------------------------------------+
17	// \| module.graphic.png.php \|
18	// \| Module for analyzing PNG graphic files. \|
19	// \| dependencies: zlib support in PHP (optional) \|
20	// +----------------------------------------------------------------------+
21	//
22	// $Id: module.graphic.png.php 3318 2009-05-20 21:54:10Z vdigital $
23
24
25
26	class getid3_png extends getid3_handler
27	{
28
29	public function Analyze() {
30
31	$getid3 = $this->getid3;
32
33	$getid3->info['png'] = array ();
34	$info_png = &$getid3->info['png'];
35
36	$getid3->info['fileformat'] = 'png';
37	$getid3->info['video']['dataformat'] = 'png';
38	$getid3->info['video']['lossless'] = false;
39
40	fseek($getid3->fp, $getid3->info['avdataoffset'], SEEK_SET);
41	$png_filedata = fread($getid3->fp, getid3::FREAD_BUFFER_SIZE);
42
43	// Magic bytes "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A"
44
45	$offset = 8;
46
47	while (((ftell($getid3->fp) - (strlen($png_filedata) - $offset)) < $getid3->info['filesize'])) {
48
49	$chunk['data_length'] = getid3_lib::BigEndian2Int(substr($png_filedata, $offset, 4));
50	$offset += 4;
51	while (((strlen($png_filedata) - $offset) < ($chunk['data_length'] + 4)) && (ftell($getid3->fp) < $getid3->info['filesize'])) {
52	$png_filedata .= fread($getid3->fp, getid3::FREAD_BUFFER_SIZE);
53	}
54
55	$chunk['type_text'] = substr($png_filedata, $offset, 4);
56	$chunk['type_raw'] = getid3_lib::BigEndian2Int($chunk['type_text']);
57	$offset += 4;
58
59	$chunk['data'] = substr($png_filedata, $offset, $chunk['data_length']);
60	$offset += $chunk['data_length'];
61
62	$chunk['crc'] = getid3_lib::BigEndian2Int(substr($png_filedata, $offset, 4));
63	$offset += 4;
64
65	$chunk['flags']['ancilliary'] = (bool)($chunk['type_raw'] & 0x20000000);
66	$chunk['flags']['private'] = (bool)($chunk['type_raw'] & 0x00200000);
67	$chunk['flags']['reserved'] = (bool)($chunk['type_raw'] & 0x00002000);
68	$chunk['flags']['safe_to_copy'] = (bool)($chunk['type_raw'] & 0x00000020);
69
70	// shortcut
71	$info_png[$chunk['type_text']] = array ();
72	$info_png_chunk_type_text = &$info_png[$chunk['type_text']];
73
74	switch ($chunk['type_text']) {
75
76	case 'IHDR': // Image Header
77	$info_png_chunk_type_text['header'] = $chunk;
78	$info_png_chunk_type_text['width'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0, 4));
79	$info_png_chunk_type_text['height'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 4, 4));
80
81	getid3_lib::ReadSequence('BigEndian2Int', $info_png_chunk_type_text['raw'], $chunk['data'], 8,
82	array (
83	'bit_depth' => 1,
84	'color_type' => 1,
85	'compression_method' => 1,
86	'filter_method' => 1,
87	'interlace_method' => 1
88	)
89	);
90
91	$info_png_chunk_type_text['compression_method_text'] = getid3_png::PNGcompressionMethodLookup($info_png_chunk_type_text['raw']['compression_method']);
92	$info_png_chunk_type_text['color_type']['palette'] = (bool)($info_png_chunk_type_text['raw']['color_type'] & 0x01);
93	$info_png_chunk_type_text['color_type']['true_color'] = (bool)($info_png_chunk_type_text['raw']['color_type'] & 0x02);
94	$info_png_chunk_type_text['color_type']['alpha'] = (bool)($info_png_chunk_type_text['raw']['color_type'] & 0x04);
95
96	$getid3->info['video']['resolution_x'] = $info_png_chunk_type_text['width'];
97	$getid3->info['video']['resolution_y'] = $info_png_chunk_type_text['height'];
98
99	$getid3->info['video']['bits_per_sample'] = getid3_png::IHDRcalculateBitsPerSample($info_png_chunk_type_text['raw']['color_type'], $info_png_chunk_type_text['raw']['bit_depth']);
100	break;
101
102
103	case 'PLTE': // Palette
104	$info_png_chunk_type_text['header'] = $chunk;
105	$palette_offset = 0;
106	for ($i = 0; $i <= 255; $i++) {
107	$red = @getid3_lib::BigEndian2Int($chunk['data']{$palette_offset++});
108	$green = @getid3_lib::BigEndian2Int($chunk['data']{$palette_offset++});
109	$blue = @getid3_lib::BigEndian2Int($chunk['data']{$palette_offset++});
110	$info_png_chunk_type_text[$i] = (($red << 16) \| ($green << 8) \| ($blue));
111	}
112	break;
113
114
115	case 'tRNS': // Transparency
116	$info_png_chunk_type_text['header'] = $chunk;
117	switch ($info_png['IHDR']['raw']['color_type']) {
118	case 0:
119	$info_png_chunk_type_text['transparent_color_gray'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0, 2));
120	break;
121
122	case 2:
123	$info_png_chunk_type_text['transparent_color_red'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0, 2));
124	$info_png_chunk_type_text['transparent_color_green'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 2, 2));
125	$info_png_chunk_type_text['transparent_color_blue'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 4, 2));
126	break;
127
128	case 3:
129	for ($i = 0; $i < strlen($chunk['data']); $i++) {
130	$info_png_chunk_type_text['palette_opacity'][$i] = getid3_lib::BigEndian2Int($chunk['data'][$i]);
131	}
132	break;
133
134	case 4:
135	case 6:
136	throw new getid3_exception('Invalid color_type in tRNS chunk: '.$info_png['IHDR']['raw']['color_type']);
137
138	default:
139	$getid3->warning('Unhandled color_type in tRNS chunk: '.$info_png['IHDR']['raw']['color_type']);
140	break;
141	}
142	break;
143
144
145	case 'gAMA': // Image Gamma
146	$info_png_chunk_type_text['header'] = $chunk;
147	$info_png_chunk_type_text['gamma'] = getid3_lib::BigEndian2Int($chunk['data']) / 100000;
148	break;
149
150
151	case 'cHRM': // Primary Chromaticities
152	$info_png_chunk_type_text['header'] = $chunk;
153	$info_png_chunk_type_text['white_x'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0, 4)) / 100000;
154	$info_png_chunk_type_text['white_y'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 4, 4)) / 100000;
155	$info_png_chunk_type_text['red_y'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 8, 4)) / 100000;
156	$info_png_chunk_type_text['red_y'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 12, 4)) / 100000;
157	$info_png_chunk_type_text['green_y'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 16, 4)) / 100000;
158	$info_png_chunk_type_text['green_y'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 20, 4)) / 100000;
159	$info_png_chunk_type_text['blue_y'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 24, 4)) / 100000;
160	$info_png_chunk_type_text['blue_y'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 28, 4)) / 100000;
161	break;
162
163
164	case 'sRGB': // Standard RGB Color Space
165	$info_png_chunk_type_text['header'] = $chunk;
166	$info_png_chunk_type_text['reindering_intent'] = getid3_lib::BigEndian2Int($chunk['data']);
167	$info_png_chunk_type_text['reindering_intent_text'] = getid3_png::PNGsRGBintentLookup($info_png_chunk_type_text['reindering_intent']);
168	break;
169
170
171	case 'iCCP': // Embedded ICC Profile
172	$info_png_chunk_type_text['header'] = $chunk;
173	list($profilename, $compressiondata) = explode("\x00", $chunk['data'], 2);
174	$info_png_chunk_type_text['profile_name'] = $profilename;
175	$info_png_chunk_type_text['compression_method'] = getid3_lib::BigEndian2Int($compressiondata[0]);
176	$info_png_chunk_type_text['compression_profile'] = substr($compressiondata, 1);
177	$info_png_chunk_type_text['compression_method_text'] = getid3_png::PNGcompressionMethodLookup($info_png_chunk_type_text['compression_method']);
178	break;
179
180
181	case 'tEXt': // Textual Data
182	$info_png_chunk_type_text['header'] = $chunk;
183	list($keyword, $text) = explode("\x00", $chunk['data'], 2);
184	$info_png_chunk_type_text['keyword'] = $keyword;
185	$info_png_chunk_type_text['text'] = $text;
186
187	$info_png['comments'][$info_png_chunk_type_text['keyword']][] = $info_png_chunk_type_text['text'];
188	break;
189
190
191	case 'zTXt': // Compressed Textual Data
192	$info_png_chunk_type_text['header'] = $chunk;
193	list($keyword, $otherdata) = explode("\x00", $chunk['data'], 2);
194	$info_png_chunk_type_text['keyword'] = $keyword;
195	$info_png_chunk_type_text['compression_method'] = getid3_lib::BigEndian2Int(substr($otherdata, 0, 1));
196	$info_png_chunk_type_text['compressed_text'] = substr($otherdata, 1);
197	$info_png_chunk_type_text['compression_method_text'] = getid3_png::PNGcompressionMethodLookup($info_png_chunk_type_text['compression_method']);
198
199	if ($info_png_chunk_type_text['compression_method'] != 0) {
200	// unknown compression method
201	break;
202	}
203
204	if (function_exists('gzuncompress')) {
205	$info_png_chunk_type_text['text'] = gzuncompress($info_png_chunk_type_text['compressed_text']);
206	}
207	else {
208	if (!@$this->zlib_warning) {
209	$getid3->warning('PHP does not have --with-zlib support - cannot gzuncompress()');
210	}
211	$this->zlib_warning = true;
212	}
213
214
215	if (isset($info_png_chunk_type_text['text'])) {
216	$info_png['comments'][$info_png_chunk_type_text['keyword']][] = $info_png_chunk_type_text['text'];
217	}
218	break;
219
220
221	case 'iTXt': // International Textual Data
222	$info_png_chunk_type_text['header'] = $chunk;
223	list($keyword, $otherdata) = explode("\x00", $chunk['data'], 2);
224	$info_png_chunk_type_text['keyword'] = $keyword;
225	$info_png_chunk_type_text['compression'] = (bool)getid3_lib::BigEndian2Int(substr($otherdata, 0, 1));
226	$info_png_chunk_type_text['compression_method'] = getid3_lib::BigEndian2Int($otherdata[1]);
227	$info_png_chunk_type_text['compression_method_text'] = getid3_png::PNGcompressionMethodLookup($info_png_chunk_type_text['compression_method']);
228	list($languagetag, $translatedkeyword, $text) = explode("\x00", substr($otherdata, 2), 3);
229	$info_png_chunk_type_text['language_tag'] = $languagetag;
230	$info_png_chunk_type_text['translated_keyword'] = $translatedkeyword;
231
232	if ($info_png_chunk_type_text['compression']) {
233
234	switch ($info_png_chunk_type_text['compression_method']) {
235	case 0:
236	if (function_exists('gzuncompress')) {
237	$info_png_chunk_type_text['text'] = gzuncompress($text);
238	}
239	else {
240	if (!@$this->zlib_warning) {
241	$getid3->warning('PHP does not have --with-zlib support - cannot gzuncompress()');
242	}
243	$this->zlib_warning = true;
244	}
245	break;
246
247	default:
248	// unknown compression method
249	break;
250	}
251
252	} else {
253
254	$info_png_chunk_type_text['text'] = $text;
255
256	}
257
258	if (isset($info_png_chunk_type_text['text'])) {
259	$info_png['comments'][$info_png_chunk_type_text['keyword']][] = $info_png_chunk_type_text['text'];
260	}
261	break;
262
263
264	case 'bKGD': // Background Color
265	$info_png_chunk_type_text['header'] = $chunk;
266	switch ($info_png['IHDR']['raw']['color_type']) {
267	case 0:
268	case 4:
269	$info_png_chunk_type_text['background_gray'] = getid3_lib::BigEndian2Int($chunk['data']);
270	break;
271
272	case 2:
273	case 6:
274	$info_png_chunk_type_text['background_red'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0 * $info_png['IHDR']['raw']['bit_depth'], $info_png['IHDR']['raw']['bit_depth']));
275	$info_png_chunk_type_text['background_green'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 1 * $info_png['IHDR']['raw']['bit_depth'], $info_png['IHDR']['raw']['bit_depth']));
276	$info_png_chunk_type_text['background_blue'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 2 * $info_png['IHDR']['raw']['bit_depth'], $info_png['IHDR']['raw']['bit_depth']));
277	break;
278
279	case 3:
280	$info_png_chunk_type_text['background_index'] = getid3_lib::BigEndian2Int($chunk['data']);
281	break;
282
283	default:
284	break;
285	}
286	break;
287
288
289	case 'pHYs': // Physical Pixel Dimensions
290	$info_png_chunk_type_text['header'] = $chunk;
291	$info_png_chunk_type_text['pixels_per_unit_x'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0, 4));
292	$info_png_chunk_type_text['pixels_per_unit_y'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 4, 4));
293	$info_png_chunk_type_text['unit_specifier'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 8, 1));
294	$info_png_chunk_type_text['unit'] = getid3_png::PNGpHYsUnitLookup($info_png_chunk_type_text['unit_specifier']);
295	break;
296
297
298	case 'sBIT': // Significant Bits
299	$info_png_chunk_type_text['header'] = $chunk;
300	switch ($info_png['IHDR']['raw']['color_type']) {
301	case 0:
302	$info_png_chunk_type_text['significant_bits_gray'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0, 1));
303	break;
304
305	case 2:
306	case 3:
307	$info_png_chunk_type_text['significant_bits_red'] = getid3_lib::BigEndian2Int($chunk['data'][0]);
308	$info_png_chunk_type_text['significant_bits_green'] = getid3_lib::BigEndian2Int($chunk['data'][1]);
309	$info_png_chunk_type_text['significant_bits_blue'] = getid3_lib::BigEndian2Int($chunk['data'][2]);
310	break;
311
312	case 4:
313	$info_png_chunk_type_text['significant_bits_gray'] = getid3_lib::BigEndian2Int($chunk['data'][0]);
314	$info_png_chunk_type_text['significant_bits_alpha'] = getid3_lib::BigEndian2Int($chunk['data'][1]);
315	break;
316
317	case 6:
318	$info_png_chunk_type_text['significant_bits_red'] = getid3_lib::BigEndian2Int($chunk['data'][0]);
319	$info_png_chunk_type_text['significant_bits_green'] = getid3_lib::BigEndian2Int($chunk['data'][1]);
320	$info_png_chunk_type_text['significant_bits_blue'] = getid3_lib::BigEndian2Int($chunk['data'][2]);
321	$info_png_chunk_type_text['significant_bits_alpha'] = getid3_lib::BigEndian2Int($chunk['data'][3]);
322	break;
323
324	default:
325	break;
326	}
327	break;
328
329
330	case 'sPLT': // Suggested Palette
331	$info_png_chunk_type_text['header'] = $chunk;
332
333	list($palettename, $otherdata) = explode("\x00", $chunk['data'], 2);
334	$info_png_chunk_type_text['palette_name'] = $palettename;
335
336	$info_png_chunk_type_text['sample_depth_bits'] = getid3_lib::BigEndian2Int($otherdata[0]);
337	$info_png_chunk_type_text['sample_depth_bytes'] = $info_png_chunk_type_text['sample_depth_bits'] / 8;
338
339	$s_plt_offset = 1;
340	$paletteCounter = 0;
341	while ($s_plt_offset < strlen($otherdata)) {
342
343	$info_png_chunk_type_text['red'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $s_plt_offset, $info_png_chunk_type_text['sample_depth_bytes']));
344	$s_plt_offset += $info_png_chunk_type_text['sample_depth_bytes'];
345
346	$info_png_chunk_type_text['green'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $s_plt_offset, $info_png_chunk_type_text['sample_depth_bytes']));
347	$s_plt_offset += $info_png_chunk_type_text['sample_depth_bytes'];
348
349	$info_png_chunk_type_text['blue'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $s_plt_offset, $info_png_chunk_type_text['sample_depth_bytes']));
350	$s_plt_offset += $info_png_chunk_type_text['sample_depth_bytes'];
351
352	$info_png_chunk_type_text['alpha'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $s_plt_offset, $info_png_chunk_type_text['sample_depth_bytes']));
353	$s_plt_offset += $info_png_chunk_type_text['sample_depth_bytes'];
354
355	$info_png_chunk_type_text['frequency'][$paletteCounter] = getid3_lib::BigEndian2Int(substr($otherdata, $s_plt_offset, 2));
356	$s_plt_offset += 2;
357
358	$paletteCounter++;
359	}
360	break;
361
362
363	case 'hIST': // Palette Histogram
364	$info_png_chunk_type_text['header'] = $chunk;
365	$h_ist_counter = 0;
366	while ($h_ist_counter < strlen($chunk['data'])) {
367	$info_png_chunk_type_text[$h_ist_counter] = getid3_lib::BigEndian2Int(substr($chunk['data'], $h_ist_counter / 2, 2));
368	$h_ist_counter += 2;
369	}
370	break;
371
372
373	case 'tIME': // Image Last-Modification Time
374	$info_png_chunk_type_text['header'] = $chunk;
375	$info_png_chunk_type_text['year'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0, 2));
376	$info_png_chunk_type_text['month'] = getid3_lib::BigEndian2Int($chunk['data']{2});
377	$info_png_chunk_type_text['day'] = getid3_lib::BigEndian2Int($chunk['data']{3});
378	$info_png_chunk_type_text['hour'] = getid3_lib::BigEndian2Int($chunk['data']{4});
379	$info_png_chunk_type_text['minute'] = getid3_lib::BigEndian2Int($chunk['data']{5});
380	$info_png_chunk_type_text['second'] = getid3_lib::BigEndian2Int($chunk['data']{6});
381	$info_png_chunk_type_text['unix'] = gmmktime($info_png_chunk_type_text['hour'], $info_png_chunk_type_text['minute'], $info_png_chunk_type_text['second'], $info_png_chunk_type_text['month'], $info_png_chunk_type_text['day'], $info_png_chunk_type_text['year']);
382	break;
383
384
385	case 'oFFs': // Image Offset
386	$info_png_chunk_type_text['header'] = $chunk;
387	$info_png_chunk_type_text['position_x'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0, 4), false, true);
388	$info_png_chunk_type_text['position_y'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 4, 4), false, true);
389	$info_png_chunk_type_text['unit_specifier'] = getid3_lib::BigEndian2Int($chunk['data'][8]);
390	$info_png_chunk_type_text['unit'] = getid3_png::PNGoFFsUnitLookup($info_png_chunk_type_text['unit_specifier']);
391	break;
392
393
394	case 'pCAL': // Calibration Of Pixel Values
395	$info_png_chunk_type_text['header'] = $chunk;
396	list($calibrationname, $otherdata) = explode("\x00", $chunk['data'], 2);
397	$info_png_chunk_type_text['calibration_name'] = $calibrationname;
398	$info_png_chunk_type_text['original_zero'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0, 4), false, true);
399	$info_png_chunk_type_text['original_max'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 4, 4), false, true);
400	$info_png_chunk_type_text['equation_type'] = getid3_lib::BigEndian2Int($chunk['data'][8]);
401	$info_png_chunk_type_text['equation_type_text'] = getid3_png::PNGpCALequationTypeLookup($info_png_chunk_type_text['equation_type']);
402	$info_png_chunk_type_text['parameter_count'] = getid3_lib::BigEndian2Int($chunk['data'][9]);
403	$info_png_chunk_type_text['parameters'] = explode("\x00", substr($chunk['data'], 10));
404	break;
405
406
407	case 'sCAL': // Physical Scale Of Image Subject
408	$info_png_chunk_type_text['header'] = $chunk;
409	$info_png_chunk_type_text['unit_specifier'] = getid3_lib::BigEndian2Int(substr($chunk['data'], 0, 1));
410	$info_png_chunk_type_text['unit'] = getid3_png::PNGsCALUnitLookup($info_png_chunk_type_text['unit_specifier']);
411	list($info_png_chunk_type_text['pixel_width'], $info_png_chunk_type_text['pixel_height']) = explode("\x00", substr($chunk['data'], 1));
412	break;
413
414
415	case 'gIFg': // GIF Graphic Control Extension
416	$gIFg_counter = 0;
417	if (isset($info_png_chunk_type_text) && is_array($info_png_chunk_type_text)) {
418	$gIFg_counter = count($info_png_chunk_type_text);
419	}
420	$info_png_chunk_type_text[$gIFg_counter]['header'] = $chunk;
421	$info_png_chunk_type_text[$gIFg_counter]['disposal_method'] = getid3_lib::BigEndian2Int($chunk['data'][0]);
422	$info_png_chunk_type_text[$gIFg_counter]['user_input_flag'] = getid3_lib::BigEndian2Int($chunk['data'][1]);
423	$info_png_chunk_type_text[$gIFg_counter]['delay_time'] = getid3_lib::BigEndian2Int($chunk['data'][2]);
424	break;
425
426
427	case 'gIFx': // GIF Application Extension
428	$gIFx_counter = 0;
429	if (isset($info_png_chunk_type_text) && is_array($info_png_chunk_type_text)) {
430	$gIFx_counter = count($info_png_chunk_type_text);
431	}
432	$info_png_chunk_type_text[$gIFx_counter]['header'] = $chunk;
433	$info_png_chunk_type_text[$gIFx_counter]['application_identifier'] = substr($chunk['data'], 0, 8);
434	$info_png_chunk_type_text[$gIFx_counter]['authentication_code'] = substr($chunk['data'], 8, 3);
435	$info_png_chunk_type_text[$gIFx_counter]['application_data'] = substr($chunk['data'], 11);
436	break;
437
438
439	case 'IDAT': // Image Data
440	$idat_information_field_index = 0;
441	if (isset($info_png['IDAT']) && is_array($info_png['IDAT'])) {
442	$idat_information_field_index = count($info_png['IDAT']);
443	}
444	unset($chunk['data']);
445	$info_png_chunk_type_text[$idat_information_field_index]['header'] = $chunk;
446	break;
447
448
449	case 'IEND': // Image Trailer
450	$info_png_chunk_type_text['header'] = $chunk;
451	break;
452
453
454	default:
455	$info_png_chunk_type_text['header'] = $chunk;
456	$getid3->warning('Unhandled chunk type: '.$chunk['type_text']);
457	break;
458	}
459	}
460
461	return true;
462	}
463
464
465
466	public static function PNGsRGBintentLookup($sRGB) {
467
468	static $lookup = array (
469	0 => 'Perceptual',
470	1 => 'Relative colorimetric',
471	2 => 'Saturation',
472	3 => 'Absolute colorimetric'
473	);
474	return (isset($lookup[$sRGB]) ? $lookup[$sRGB] : 'invalid');
475	}
476
477
478
479	public static function PNGcompressionMethodLookup($compression_method) {
480
481	return ($compression_method == 0 ? 'deflate/inflate' : 'invalid');
482	}
483
484
485
486	public static function PNGpHYsUnitLookup($unit_id) {
487
488	static $lookup = array (
489	0 => 'unknown',
490	1 => 'meter'
491	);
492	return (isset($lookup[$unit_id]) ? $lookup[$unit_id] : 'invalid');
493	}
494
495
496
497	public static function PNGoFFsUnitLookup($unit_id) {
498
499	static $lookup = array (
500	0 => 'pixel',
501	1 => 'micrometer'
502	);
503	return (isset($lookup[$unit_id]) ? $lookup[$unit_id] : 'invalid');
504	}
505
506
507
508	public static function PNGpCALequationTypeLookup($equation_type) {
509
510	static $lookup = array (
511	0 => 'Linear mapping',
512	1 => 'Base-e exponential mapping',
513	2 => 'Arbitrary-base exponential mapping',
514	3 => 'Hyperbolic mapping'
515	);
516	return (isset($lookup[$equation_type]) ? $lookup[$equation_type] : 'invalid');
517	}
518
519
520
521	public static function PNGsCALUnitLookup($unit_id) {
522
523	static $lookup = array (
524	0 => 'meter',
525	1 => 'radian'
526	);
527	return (isset($lookup[$unit_id]) ? $lookup[$unit_id] : 'invalid');
528	}
529
530
531
532	public static function IHDRcalculateBitsPerSample($color_type, $bit_depth) {
533
534	switch ($color_type) {
535	case 0: // Each pixel is a grayscale sample.
536	return $bit_depth;
537
538	case 2: // Each pixel is an R,G,B triple
539	return 3 * $bit_depth;
540
541	case 3: // Each pixel is a palette index; a PLTE chunk must appear.
542	return $bit_depth;
543
544	case 4: // Each pixel is a grayscale sample, followed by an alpha sample.
545	return 2 * $bit_depth;
546
547	case 6: // Each pixel is an R,G,B triple, followed by an alpha sample.
548	return 4 * $bit_depth;
549	}
550	return false;
551	}
552
553	}
554
555
556	?>

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