ILIAS  release_5-1 Revision 5.0.0-5477-g43f3e3fab5f
module.graphic.gif.php
Go to the documentation of this file.
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.gif.php //
11// module for analyzing GIF Image files //
12// dependencies: NONE //
13// ///
15
16
17class getid3_gif
18{
19
20 function getid3_gif(&$fd, &$ThisFileInfo) {
21 $ThisFileInfo['fileformat'] = 'gif';
22 $ThisFileInfo['video']['dataformat'] = 'gif';
23 $ThisFileInfo['video']['lossless'] = true;
24 $ThisFileInfo['video']['pixel_aspect_ratio'] = (float) 1;
25
26 fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
27 $GIFheader = fread($fd, 13);
28 $offset = 0;
29
30 $ThisFileInfo['gif']['header']['raw']['identifier'] = substr($GIFheader, $offset, 3);
31 $offset += 3;
32
33 if ($ThisFileInfo['gif']['header']['raw']['identifier'] != 'GIF') {
34 $ThisFileInfo['error'][] = 'Expecting "GIF" at offset '.$ThisFileInfo['avdataoffset'].', found "'.$ThisFileInfo['gif']['header']['raw']['identifier'].'"';
35 unset($ThisFileInfo['fileformat']);
36 unset($ThisFileInfo['gif']);
37 return false;
38 }
39
40 $ThisFileInfo['gif']['header']['raw']['version'] = substr($GIFheader, $offset, 3);
41 $offset += 3;
42 $ThisFileInfo['gif']['header']['raw']['width'] = getid3_lib::LittleEndian2Int(substr($GIFheader, $offset, 2));
43 $offset += 2;
44 $ThisFileInfo['gif']['header']['raw']['height'] = getid3_lib::LittleEndian2Int(substr($GIFheader, $offset, 2));
45 $offset += 2;
46 $ThisFileInfo['gif']['header']['raw']['flags'] = getid3_lib::LittleEndian2Int(substr($GIFheader, $offset, 1));
47 $offset += 1;
48 $ThisFileInfo['gif']['header']['raw']['bg_color_index'] = getid3_lib::LittleEndian2Int(substr($GIFheader, $offset, 1));
49 $offset += 1;
50 $ThisFileInfo['gif']['header']['raw']['aspect_ratio'] = getid3_lib::LittleEndian2Int(substr($GIFheader, $offset, 1));
51 $offset += 1;
52
53 $ThisFileInfo['video']['resolution_x'] = $ThisFileInfo['gif']['header']['raw']['width'];
54 $ThisFileInfo['video']['resolution_y'] = $ThisFileInfo['gif']['header']['raw']['height'];
55 $ThisFileInfo['gif']['version'] = $ThisFileInfo['gif']['header']['raw']['version'];
56 $ThisFileInfo['gif']['header']['flags']['global_color_table'] = (bool) ($ThisFileInfo['gif']['header']['raw']['flags'] & 0x80);
57 if ($ThisFileInfo['gif']['header']['raw']['flags'] & 0x80) {
58 // Number of bits per primary color available to the original image, minus 1
59 $ThisFileInfo['gif']['header']['bits_per_pixel'] = 3 * ((($ThisFileInfo['gif']['header']['raw']['flags'] & 0x70) >> 4) + 1);
60 } else {
61 $ThisFileInfo['gif']['header']['bits_per_pixel'] = 0;
62 }
63 $ThisFileInfo['gif']['header']['flags']['global_color_sorted'] = (bool) ($ThisFileInfo['gif']['header']['raw']['flags'] & 0x40);
64 if ($ThisFileInfo['gif']['header']['flags']['global_color_table']) {
65 // the number of bytes contained in the Global Color Table. To determine that
66 // actual size of the color table, raise 2 to [the value of the field + 1]
67 $ThisFileInfo['gif']['header']['global_color_size'] = pow(2, ($ThisFileInfo['gif']['header']['raw']['flags'] & 0x07) + 1);
68 $ThisFileInfo['video']['bits_per_sample'] = ($ThisFileInfo['gif']['header']['raw']['flags'] & 0x07) + 1;
69 } else {
70 $ThisFileInfo['gif']['header']['global_color_size'] = 0;
71 }
72 if ($ThisFileInfo['gif']['header']['raw']['aspect_ratio'] != 0) {
73 // Aspect Ratio = (Pixel Aspect Ratio + 15) / 64
74 $ThisFileInfo['gif']['header']['aspect_ratio'] = ($ThisFileInfo['gif']['header']['raw']['aspect_ratio'] + 15) / 64;
75 }
76
77// if ($ThisFileInfo['gif']['header']['flags']['global_color_table']) {
78// $GIFcolorTable = fread($fd, 3 * $ThisFileInfo['gif']['header']['global_color_size']);
79// $offset = 0;
80// for ($i = 0; $i < $ThisFileInfo['gif']['header']['global_color_size']; $i++) {
81// $red = getid3_lib::LittleEndian2Int(substr($GIFcolorTable, $offset++, 1));
82// $green = getid3_lib::LittleEndian2Int(substr($GIFcolorTable, $offset++, 1));
83// $blue = getid3_lib::LittleEndian2Int(substr($GIFcolorTable, $offset++, 1));
84// $ThisFileInfo['gif']['global_color_table'][$i] = (($red << 16) | ($green << 8) | ($blue));
85// }
86// }
87//
88// // Image Descriptor
89// while (!feof($fd)) {
90// $NextBlockTest = fread($fd, 1);
91// switch ($NextBlockTest) {
92//
93// case ',': // ',' - Image separator character
94//
95// $ImageDescriptorData = $NextBlockTest.fread($fd, 9);
96// $ImageDescriptor = array();
97// $ImageDescriptor['image_left'] = getid3_lib::LittleEndian2Int(substr($ImageDescriptorData, 1, 2));
98// $ImageDescriptor['image_top'] = getid3_lib::LittleEndian2Int(substr($ImageDescriptorData, 3, 2));
99// $ImageDescriptor['image_width'] = getid3_lib::LittleEndian2Int(substr($ImageDescriptorData, 5, 2));
100// $ImageDescriptor['image_height'] = getid3_lib::LittleEndian2Int(substr($ImageDescriptorData, 7, 2));
101// $ImageDescriptor['flags_raw'] = getid3_lib::LittleEndian2Int(substr($ImageDescriptorData, 9, 1));
102// $ImageDescriptor['flags']['use_local_color_map'] = (bool) ($ImageDescriptor['flags_raw'] & 0x80);
103// $ImageDescriptor['flags']['image_interlaced'] = (bool) ($ImageDescriptor['flags_raw'] & 0x40);
104// $ThisFileInfo['gif']['image_descriptor'][] = $ImageDescriptor;
105//
106// if ($ImageDescriptor['flags']['use_local_color_map']) {
107//
108// $ThisFileInfo['warning'][] = 'This version of getID3() cannot parse local color maps for GIFs';
109// return true;
110//
111// }
112//echo 'Start of raster data: '.ftell($fd).'<BR>';
113// $RasterData = array();
114// $RasterData['code_size'] = getid3_lib::LittleEndian2Int(fread($fd, 1));
115// $RasterData['block_byte_count'] = getid3_lib::LittleEndian2Int(fread($fd, 1));
116// $ThisFileInfo['gif']['raster_data'][count($ThisFileInfo['gif']['image_descriptor']) - 1] = $RasterData;
117//
118// $CurrentCodeSize = $RasterData['code_size'] + 1;
119// for ($i = 0; $i < pow(2, $RasterData['code_size']); $i++) {
120// $DefaultDataLookupTable[$i] = chr($i);
121// }
122// $DefaultDataLookupTable[pow(2, $RasterData['code_size']) + 0] = ''; // Clear Code
123// $DefaultDataLookupTable[pow(2, $RasterData['code_size']) + 1] = ''; // End Of Image Code
124//
125//
126// $NextValue = $this->GetLSBits($fd, $CurrentCodeSize);
127// echo 'Clear Code: '.$NextValue.'<BR>';
128//
129// $NextValue = $this->GetLSBits($fd, $CurrentCodeSize);
130// echo 'First Color: '.$NextValue.'<BR>';
131//
132// $Prefix = $NextValue;
133//$i = 0;
134// while ($i++ < 20) {
135// $NextValue = $this->GetLSBits($fd, $CurrentCodeSize);
136// echo $NextValue.'<BR>';
137// }
138//return true;
139// break;
140//
141// case '!':
142// // GIF Extension Block
143// $ExtensionBlockData = $NextBlockTest.fread($fd, 2);
144// $ExtensionBlock = array();
145// $ExtensionBlock['function_code'] = getid3_lib::LittleEndian2Int(substr($ExtensionBlockData, 1, 1));
146// $ExtensionBlock['byte_length'] = getid3_lib::LittleEndian2Int(substr($ExtensionBlockData, 2, 1));
147// $ExtensionBlock['data'] = fread($fd, $ExtensionBlock['byte_length']);
148// $ThisFileInfo['gif']['extension_blocks'][] = $ExtensionBlock;
149// break;
150//
151// case ';':
152// $ThisFileInfo['gif']['terminator_offset'] = ftell($fd) - 1;
153// // GIF Terminator
154// break;
155//
156// default:
157// break;
158//
159//
160// }
161// }
162
163 return true;
164 }
165
166
167 function GetLSBits($fd, $bits) {
168 static $bitbuffer = '';
169 while (strlen($bitbuffer) < $bits) {
170//echo 'Read another byte: '.ftell($fd).'<BR>';
171 $bitbuffer = str_pad(decbin(ord(fread($fd, 1))), 8, '0', STR_PAD_LEFT).$bitbuffer;
172 }
173
174 $value = bindec(substr($bitbuffer, 0 - $bits));
175 $bitbuffer = substr($bitbuffer, 0, 0 - $bits);
176
177 return $value;
178 }
179
180}
181
182
183?>
getid3_gif
getID3() by James Heinrich info@getid3.org //
Definition: module.graphic.gif.php:18
getid3_gif\GetLSBits
GetLSBits($fd, $bits)
Definition: module.graphic.gif.php:167
getid3_gif\getid3_gif
getid3_gif(&$fd, &$ThisFileInfo)
Definition: module.graphic.gif.php:20
getid3_handler\fseek
fseek($bytes, $whence=SEEK_SET)
Definition: getid3.php:1697
getid3_handler\fread
fread($bytes)
Definition: getid3.php:1685
getid3_lib\LittleEndian2Int
LittleEndian2Int($byteword, $signed=false)
Definition: getid3.lib.php:266