d7248d63fb
The functions returning null or the class property is set explict null. Some function should not accept null or return null. Found by phan strict checks Change-Id: Ie50f23249282cdb18caa332f562a3945a58d86ff
293 lines
8.5 KiB
PHP
293 lines
8.5 KiB
PHP
<?php
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/**
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* Handler for Google's WebP format <https://developers.google.com/speed/webp/>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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* @ingroup Media
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*/
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/**
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* Handler for Google's WebP format <https://developers.google.com/speed/webp/>
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*
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* @ingroup Media
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*/
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class WebPHandler extends BitmapHandler {
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/**
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* Value to store in img_metadata if there was an error extracting metadata
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*/
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private const BROKEN_FILE = '0';
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/**
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* Minimum chunk header size to be able to read all header types
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*/
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private const MINIMUM_CHUNK_HEADER_LENGTH = 18;
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/**
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* Version of the metadata stored in db records
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*/
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private const _MW_WEBP_VERSION = 1;
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private const VP8X_ICC = 32;
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private const VP8X_ALPHA = 16;
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private const VP8X_EXIF = 8;
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private const VP8X_XMP = 4;
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private const VP8X_ANIM = 2;
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public function getSizeAndMetadata( $state, $filename ) {
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$parsedWebPData = self::extractMetadata( $filename );
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if ( !$parsedWebPData ) {
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return [ 'metadata' => [ '_error' => self::BROKEN_FILE ] ];
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}
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$parsedWebPData['metadata']['_MW_WEBP_VERSION'] = self::_MW_WEBP_VERSION;
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$info = [
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'width' => $parsedWebPData['width'],
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'height' => $parsedWebPData['height'],
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'metadata' => $parsedWebPData
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];
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return $info;
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}
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public function getMetadataType( $image ) {
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return 'parsed-webp';
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}
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public function isFileMetadataValid( $image ) {
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$data = $image->getMetadataArray();
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if ( $data === [ '_error' => self::BROKEN_FILE ] ) {
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// Do not repetitivly regenerate metadata on broken file.
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return self::METADATA_GOOD;
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}
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if ( !$data || !isset( $data['_error'] ) ) {
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wfDebug( __METHOD__ . " invalid WebP metadata" );
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return self::METADATA_BAD;
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}
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if ( !isset( $data['metadata']['_MW_WEBP_VERSION'] )
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|| $data['metadata']['_MW_WEBP_VERSION'] != self::_MW_WEBP_VERSION
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) {
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wfDebug( __METHOD__ . " old but compatible WebP metadata" );
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return self::METADATA_COMPATIBLE;
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}
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return self::METADATA_GOOD;
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}
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/**
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* Extracts the image size and WebP type from a file
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*
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* @param string $filename
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* @return array|bool Header data array with entries 'compression', 'width' and 'height',
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* where 'compression' can be 'lossy', 'lossless', 'animated' or 'unknown'. False if
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* file is not a valid WebP file.
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*/
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public static function extractMetadata( $filename ) {
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wfDebugLog( 'WebP', __METHOD__ . ": Extracting metadata from $filename" );
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$info = RiffExtractor::findChunksFromFile( $filename, 100 );
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if ( $info === false ) {
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wfDebugLog( 'WebP', __METHOD__ . ": Not a valid RIFF file" );
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return false;
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}
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if ( $info['fourCC'] != 'WEBP' ) {
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wfDebugLog( 'WebP', __METHOD__ . ': FourCC was not WEBP: ' .
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bin2hex( $info['fourCC'] ) );
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return false;
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}
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$metadata = self::extractMetadataFromChunks( $info['chunks'], $filename );
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if ( !$metadata ) {
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wfDebugLog( 'WebP', __METHOD__ . ": No VP8 chunks found" );
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return false;
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}
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return $metadata;
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}
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/**
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* Extracts the image size and WebP type from a file based on the chunk list
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* @param array[] $chunks Chunks as extracted by RiffExtractor
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* @param string $filename
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* @return array Header data array with entries 'compression', 'width' and 'height', where
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* 'compression' can be 'lossy', 'lossless', 'animated' or 'unknown'
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*/
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public static function extractMetadataFromChunks( $chunks, $filename ) {
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$vp8Info = [];
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foreach ( $chunks as $chunk ) {
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if ( !in_array( $chunk['fourCC'], [ 'VP8 ', 'VP8L', 'VP8X' ] ) ) {
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// Not a chunk containing interesting metadata
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continue;
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}
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$chunkHeader = file_get_contents( $filename, false, null,
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$chunk['start'], self::MINIMUM_CHUNK_HEADER_LENGTH );
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wfDebugLog( 'WebP', __METHOD__ . ": {$chunk['fourCC']}" );
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switch ( $chunk['fourCC'] ) {
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case 'VP8 ':
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return array_merge( $vp8Info,
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self::decodeLossyChunkHeader( $chunkHeader ) );
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case 'VP8L':
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return array_merge( $vp8Info,
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self::decodeLosslessChunkHeader( $chunkHeader ) );
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case 'VP8X':
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$vp8Info = array_merge( $vp8Info,
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self::decodeExtendedChunkHeader( $chunkHeader ) );
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// Continue looking for other chunks to improve the metadata
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break;
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}
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}
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return $vp8Info;
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}
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/**
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* Decodes a lossy chunk header
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* @param string $header First few bytes of the header, expected to be at least 18 bytes long
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* @return bool|array See WebPHandler::decodeHeader
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*/
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protected static function decodeLossyChunkHeader( $header ) {
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// Bytes 0-3 are 'VP8 '
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// Bytes 4-7 are the VP8 stream size
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// Bytes 8-10 are the frame tag
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// Bytes 11-13 are 0x9D 0x01 0x2A called the sync code
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$syncCode = substr( $header, 11, 3 );
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if ( $syncCode != "\x9D\x01\x2A" ) {
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wfDebugLog( 'WebP', __METHOD__ . ': Invalid sync code: ' .
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bin2hex( $syncCode ) );
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return [];
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}
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// Bytes 14-17 are image size
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$imageSize = unpack( 'v2', substr( $header, 14, 4 ) );
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// Image sizes are 14 bit, 2 MSB are scaling parameters which are ignored here
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return [
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'compression' => 'lossy',
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'width' => $imageSize[1] & 0x3FFF,
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'height' => $imageSize[2] & 0x3FFF
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];
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}
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/**
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* Decodes a lossless chunk header
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* @param string $header First few bytes of the header, expected to be at least 13 bytes long
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* @return bool|array See WebPHandler::decodeHeader
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*/
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public static function decodeLosslessChunkHeader( $header ) {
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// Bytes 0-3 are 'VP8L'
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// Bytes 4-7 are chunk stream size
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// Byte 8 is 0x2F called the signature
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if ( $header[8] != "\x2F" ) {
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wfDebugLog( 'WebP', __METHOD__ . ': Invalid signature: ' .
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bin2hex( $header[8] ) );
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return [];
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}
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// Bytes 9-12 contain the image size
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// Bits 0-13 are width-1; bits 15-27 are height-1
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$imageSize = unpack( 'C4', substr( $header, 9, 4 ) );
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return [
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'compression' => 'lossless',
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'width' => ( $imageSize[1] | ( ( $imageSize[2] & 0x3F ) << 8 ) ) + 1,
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'height' => ( ( ( $imageSize[2] & 0xC0 ) >> 6 ) |
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( $imageSize[3] << 2 ) | ( ( $imageSize[4] & 0x03 ) << 10 ) ) + 1
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];
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}
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/**
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* Decodes an extended chunk header
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* @param string $header First few bytes of the header, expected to be at least 18 bytes long
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* @return bool|array See WebPHandler::decodeHeader
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*/
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public static function decodeExtendedChunkHeader( $header ) {
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// Bytes 0-3 are 'VP8X'
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// Byte 4-7 are chunk length
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// Byte 8-11 are a flag bytes
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$flags = unpack( 'c', substr( $header, 8, 1 ) );
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// Byte 12-17 are image size (24 bits)
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$width = unpack( 'V', substr( $header, 12, 3 ) . "\x00" );
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$height = unpack( 'V', substr( $header, 15, 3 ) . "\x00" );
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return [
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'compression' => 'unknown',
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'animated' => ( $flags[1] & self::VP8X_ANIM ) == self::VP8X_ANIM,
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'transparency' => ( $flags[1] & self::VP8X_ALPHA ) == self::VP8X_ALPHA,
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'width' => ( $width[1] & 0xFFFFFF ) + 1,
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'height' => ( $height[1] & 0xFFFFFF ) + 1
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];
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}
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/**
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* @param File $file
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* @return bool True, not all browsers support WebP
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*/
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public function mustRender( $file ) {
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return true;
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}
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/**
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* @param File $file
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* @return bool False if we are unable to render this image
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*/
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public function canRender( $file ) {
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if ( self::isAnimatedImage( $file ) ) {
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return false;
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}
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return true;
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}
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/**
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* @param File $image
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* @return bool
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*/
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public function isAnimatedImage( $image ) {
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$metadata = $image->getMetadataArray();
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if ( isset( $metadata['animated'] ) && $metadata['animated'] === true ) {
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return true;
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}
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return false;
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}
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public function canAnimateThumbnail( $file ) {
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return false;
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}
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/**
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* Render files as PNG
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*
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* @param string $ext
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* @param string $mime
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* @param array|null $params
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* @return array
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*/
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public function getThumbType( $ext, $mime, $params = null ) {
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return [ 'png', 'image/png' ];
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}
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/**
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* Must use "im" for XCF
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*
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* @param string|null $dstPath
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* @param bool $checkDstPath
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* @return string
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*/
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protected function getScalerType( $dstPath, $checkDstPath = true ) {
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return 'im';
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}
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}
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