MediaWiki master
WebPHandler.php
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1<?php
33 private const BROKEN_FILE = '0';
37 private const MINIMUM_CHUNK_HEADER_LENGTH = 18;
41 private const _MW_WEBP_VERSION = 1;
42
43 private const VP8X_ICC = 32;
44 private const VP8X_ALPHA = 16;
45 private const VP8X_EXIF = 8;
46 private const VP8X_XMP = 4;
47 private const VP8X_ANIM = 2;
48
49 public function getSizeAndMetadata( $state, $filename ) {
50 $parsedWebPData = self::extractMetadata( $filename );
51 if ( !$parsedWebPData ) {
52 return [ 'metadata' => [ '_error' => self::BROKEN_FILE ] ];
53 }
54
55 $parsedWebPData['metadata']['_MW_WEBP_VERSION'] = self::_MW_WEBP_VERSION;
56 $info = [
57 'width' => $parsedWebPData['width'],
58 'height' => $parsedWebPData['height'],
59 'metadata' => $parsedWebPData
60 ];
61 return $info;
62 }
63
64 public function getMetadataType( $image ) {
65 return 'parsed-webp';
66 }
67
68 public function isFileMetadataValid( $image ) {
69 $data = $image->getMetadataArray();
70 if ( $data === [ '_error' => self::BROKEN_FILE ] ) {
71 // Do not repetitivly regenerate metadata on broken file.
73 }
74
75 if ( !$data || !isset( $data['_error'] ) ) {
76 wfDebug( __METHOD__ . " invalid WebP metadata" );
77
78 return self::METADATA_BAD;
79 }
80
81 if ( !isset( $data['metadata']['_MW_WEBP_VERSION'] )
82 || $data['metadata']['_MW_WEBP_VERSION'] != self::_MW_WEBP_VERSION
83 ) {
84 wfDebug( __METHOD__ . " old but compatible WebP metadata" );
85
87 }
89 }
90
99 public static function extractMetadata( $filename ) {
100 wfDebugLog( 'WebP', __METHOD__ . ": Extracting metadata from $filename" );
101
102 $info = RiffExtractor::findChunksFromFile( $filename, 100 );
103 if ( $info === false ) {
104 wfDebugLog( 'WebP', __METHOD__ . ": Not a valid RIFF file" );
105 return false;
106 }
107
108 if ( $info['fourCC'] !== 'WEBP' ) {
109 wfDebugLog( 'WebP', __METHOD__ . ': FourCC was not WEBP: ' .
110 bin2hex( $info['fourCC'] ) );
111 return false;
112 }
113
114 $metadata = self::extractMetadataFromChunks( $info['chunks'], $filename );
115 if ( !$metadata ) {
116 wfDebugLog( 'WebP', __METHOD__ . ": No VP8 chunks found" );
117 return false;
118 }
119
120 return $metadata;
121 }
122
130 public static function extractMetadataFromChunks( $chunks, $filename ) {
131 $vp8Info = [];
132
133 foreach ( $chunks as $chunk ) {
134 if ( !in_array( $chunk['fourCC'], [ 'VP8 ', 'VP8L', 'VP8X' ] ) ) {
135 // Not a chunk containing interesting metadata
136 continue;
137 }
138
139 $chunkHeader = file_get_contents( $filename, false, null,
140 $chunk['start'], self::MINIMUM_CHUNK_HEADER_LENGTH );
141 wfDebugLog( 'WebP', __METHOD__ . ": {$chunk['fourCC']}" );
142
143 switch ( $chunk['fourCC'] ) {
144 case 'VP8 ':
145 return array_merge( $vp8Info,
146 self::decodeLossyChunkHeader( $chunkHeader ) );
147 case 'VP8L':
148 return array_merge( $vp8Info,
149 self::decodeLosslessChunkHeader( $chunkHeader ) );
150 case 'VP8X':
151 $vp8Info = array_merge( $vp8Info,
152 self::decodeExtendedChunkHeader( $chunkHeader ) );
153 // Continue looking for other chunks to improve the metadata
154 break;
155 }
156 }
157 return $vp8Info;
158 }
159
165 protected static function decodeLossyChunkHeader( $header ) {
166 // Bytes 0-3 are 'VP8 '
167 // Bytes 4-7 are the VP8 stream size
168 // Bytes 8-10 are the frame tag
169 // Bytes 11-13 are 0x9D 0x01 0x2A called the sync code
170 $syncCode = substr( $header, 11, 3 );
171 if ( $syncCode !== "\x9D\x01\x2A" ) {
172 wfDebugLog( 'WebP', __METHOD__ . ': Invalid sync code: ' .
173 bin2hex( $syncCode ) );
174 return [];
175 }
176 // Bytes 14-17 are image size
177 $imageSize = unpack( 'v2', substr( $header, 14, 4 ) );
178 // Image sizes are 14 bit, 2 MSB are scaling parameters which are ignored here
179 return [
180 'compression' => 'lossy',
181 'width' => $imageSize[1] & 0x3FFF,
182 'height' => $imageSize[2] & 0x3FFF
183 ];
184 }
185
191 public static function decodeLosslessChunkHeader( $header ) {
192 // Bytes 0-3 are 'VP8L'
193 // Bytes 4-7 are chunk stream size
194 // Byte 8 is 0x2F called the signature
195 if ( $header[8] !== "\x2F" ) {
196 wfDebugLog( 'WebP', __METHOD__ . ': Invalid signature: ' .
197 bin2hex( $header[8] ) );
198 return [];
199 }
200 // Bytes 9-12 contain the image size
201 // Bits 0-13 are width-1; bits 15-27 are height-1
202 $imageSize = unpack( 'C4', substr( $header, 9, 4 ) );
203 return [
204 'compression' => 'lossless',
205 'width' => ( $imageSize[1] | ( ( $imageSize[2] & 0x3F ) << 8 ) ) + 1,
206 'height' => ( ( ( $imageSize[2] & 0xC0 ) >> 6 ) |
207 ( $imageSize[3] << 2 ) | ( ( $imageSize[4] & 0x03 ) << 10 ) ) + 1
208 ];
209 }
210
216 public static function decodeExtendedChunkHeader( $header ) {
217 // Bytes 0-3 are 'VP8X'
218 // Byte 4-7 are chunk length
219 // Byte 8-11 are a flag bytes
220 $flags = unpack( 'c', substr( $header, 8, 1 ) );
221
222 // Byte 12-17 are image size (24 bits)
223 $width = unpack( 'V', substr( $header, 12, 3 ) . "\x00" );
224 $height = unpack( 'V', substr( $header, 15, 3 ) . "\x00" );
225
226 return [
227 'compression' => 'unknown',
228 'animated' => ( $flags[1] & self::VP8X_ANIM ) === self::VP8X_ANIM,
229 'transparency' => ( $flags[1] & self::VP8X_ALPHA ) === self::VP8X_ALPHA,
230 'width' => ( $width[1] & 0xFFFFFF ) + 1,
231 'height' => ( $height[1] & 0xFFFFFF ) + 1
232 ];
233 }
234
239 public function mustRender( $file ) {
240 return true;
241 }
242
247 public function canRender( $file ) {
248 if ( $this->isAnimatedImage( $file ) ) {
249 return false;
250 }
251 return true;
252 }
253
258 public function isAnimatedImage( $image ) {
259 $metadata = $image->getMetadataArray();
260 if ( isset( $metadata['animated'] ) && $metadata['animated'] === true ) {
261 return true;
262 }
263
264 return false;
265 }
266
267 public function canAnimateThumbnail( $file ) {
268 return false;
269 }
270
279 public function getThumbType( $ext, $mime, $params = null ) {
280 return [ 'png', 'image/png' ];
281 }
282
290 protected function getScalerType( $dstPath, $checkDstPath = true ) {
291 return 'im';
292 }
293}
wfDebug( $text, $dest='all', array $context=[])
Sends a line to the debug log if enabled or, optionally, to a comment in output.
wfDebugLog( $logGroup, $text, $dest='all', array $context=[])
Send a line to a supplementary debug log file, if configured, or main debug log if not.
Generic handler for bitmap images.
const METADATA_COMPATIBLE
const METADATA_GOOD
static findChunksFromFile( $filename, $maxChunks=-1)
Handler for Google's WebP format https://developers.google.com/speed/webp/
mustRender( $file)
canAnimateThumbnail( $file)
If the material is animated, we can animate the thumbnail.
isFileMetadataValid( $image)
Check if the metadata is valid for this handler.
static extractMetadataFromChunks( $chunks, $filename)
Extracts the image size and WebP type from a file based on the chunk list.
isAnimatedImage( $image)
getScalerType( $dstPath, $checkDstPath=true)
Must use "im" for XCF.
static decodeLossyChunkHeader( $header)
Decodes a lossy chunk header.
getSizeAndMetadata( $state, $filename)
Get image size information and metadata array.
canRender( $file)
getThumbType( $ext, $mime, $params=null)
Render files as PNG.
static decodeLosslessChunkHeader( $header)
Decodes a lossless chunk header.
getMetadataType( $image)
Get a string describing the type of metadata, for display purposes.
static extractMetadata( $filename)
Extracts the image size and WebP type from a file.
static decodeExtendedChunkHeader( $header)
Decodes an extended chunk header.
$header