BitmapHandler.php

Go to the documentation of this file.

<?php
use MediaWiki\Shell\Shell;

class BitmapHandler extends TransformationalImageHandler {

    protected function getScalerType( $dstPath, $checkDstPath = true ) {
        global $wgUseImageResize, $wgUseImageMagick, $wgCustomConvertCommand;

        if ( !$dstPath && $checkDstPath ) {
            # No output path available, client side scaling only
            $scaler = 'client';
        } elseif ( !$wgUseImageResize ) {
            $scaler = 'client';
        } elseif ( $wgUseImageMagick ) {
            $scaler = 'im';
        } elseif ( $wgCustomConvertCommand ) {
            $scaler = 'custom';
        } elseif ( function_exists( 'imagecreatetruecolor' ) ) {
            $scaler = 'gd';
        } elseif ( class_exists( 'Imagick' ) ) {
            $scaler = 'imext';
        } else {
            $scaler = 'client';
        }

        return $scaler;
    }

    public function makeParamString( $params ) {
        $res = parent::makeParamString( $params );
        if ( isset( $params['interlace'] ) && $params['interlace'] ) {
            return "interlaced-{$res}";
        } else {
            return $res;
        }
    }

    public function parseParamString( $str ) {
        $remainder = preg_replace( '/^interlaced-/', '', $str );
        $params = parent::parseParamString( $remainder );
        if ( $params === false ) {
            return false;
        }
        $params['interlace'] = $str !== $remainder;
        return $params;
    }

    public function validateParam( $name, $value ) {
        if ( $name === 'interlace' ) {
            return $value === false || $value === true;
        } else {
            return parent::validateParam( $name, $value );
        }
    }

    public function normaliseParams( $image, &$params ) {
        global $wgMaxInterlacingAreas;
        if ( !parent::normaliseParams( $image, $params ) ) {
            return false;
        }
        $mimeType = $image->getMimeType();
        $interlace = isset( $params['interlace'] ) && $params['interlace']
            && isset( $wgMaxInterlacingAreas[$mimeType] )
            && $this->getImageArea( $image ) <= $wgMaxInterlacingAreas[$mimeType];
        $params['interlace'] = $interlace;
        return true;
    }

    protected function imageMagickSubsampling( $pixelFormat ) {
        switch ( $pixelFormat ) {
            case 'yuv444':
                return [ '1x1', '1x1', '1x1' ];
            case 'yuv422':
                return [ '2x1', '1x1', '1x1' ];
            case 'yuv420':
                return [ '2x2', '1x1', '1x1' ];
            default:
                throw new MWException( 'Invalid pixel format for JPEG output' );
        }
    }

    protected function transformImageMagick( $image, $params ) {
        # use ImageMagick
        global $wgSharpenReductionThreshold, $wgSharpenParameter, $wgMaxAnimatedGifArea,
            $wgImageMagickTempDir, $wgImageMagickConvertCommand, $wgJpegPixelFormat,
            $wgJpegQuality;

        $quality = [];
        $sharpen = [];
        $scene = false;
        $animation_pre = [];
        $animation_post = [];
        $decoderHint = [];
        $subsampling = [];

        if ( $params['mimeType'] == 'image/jpeg' ) {
            $qualityVal = isset( $params['quality'] ) ? (string)$params['quality'] : null;
            $quality = [ '-quality', $qualityVal ?: (string)$wgJpegQuality ]; // 80% by default
            if ( $params['interlace'] ) {
                $animation_post = [ '-interlace', 'JPEG' ];
            }
            # Sharpening, see T8193
            if ( ( $params['physicalWidth'] + $params['physicalHeight'] )
                / ( $params['srcWidth'] + $params['srcHeight'] )
                < $wgSharpenReductionThreshold
            ) {
                $sharpen = [ '-sharpen', $wgSharpenParameter ];
            }
            if ( version_compare( $this->getMagickVersion(), "6.5.6" ) >= 0 ) {
                // JPEG decoder hint to reduce memory, available since IM 6.5.6-2
                $decoderHint = [ '-define', "jpeg:size={$params['physicalDimensions']}" ];
            }
            if ( $wgJpegPixelFormat ) {
                $factors = $this->imageMagickSubsampling( $wgJpegPixelFormat );
                $subsampling = [ '-sampling-factor', implode( ',', $factors ) ];
            }
        } elseif ( $params['mimeType'] == 'image/png' ) {
            $quality = [ '-quality', '95' ]; // zlib 9, adaptive filtering
            if ( $params['interlace'] ) {
                $animation_post = [ '-interlace', 'PNG' ];
            }
        } elseif ( $params['mimeType'] == 'image/webp' ) {
            $quality = [ '-quality', '95' ]; // zlib 9, adaptive filtering
        } elseif ( $params['mimeType'] == 'image/gif' ) {
            if ( $this->getImageArea( $image ) > $wgMaxAnimatedGifArea ) {
                // Extract initial frame only; we're so big it'll
                // be a total drag. :P
                $scene = 0;
            } elseif ( $this->isAnimatedImage( $image ) ) {
                // Coalesce is needed to scale animated GIFs properly (T3017).
                $animation_pre = [ '-coalesce' ];
                // We optimize the output, but -optimize is broken,
                // use optimizeTransparency instead (T13822)
                if ( version_compare( $this->getMagickVersion(), "6.3.5" ) >= 0 ) {
                    $animation_post = [ '-fuzz', '5%', '-layers', 'optimizeTransparency' ];
                }
            }
            if ( $params['interlace'] && version_compare( $this->getMagickVersion(), "6.3.4" ) >= 0
                && !$this->isAnimatedImage( $image ) ) { // interlacing animated GIFs is a bad idea
                $animation_post[] = '-interlace';
                $animation_post[] = 'GIF';
            }
        } elseif ( $params['mimeType'] == 'image/x-xcf' ) {
            // Before merging layers, we need to set the background
            // to be transparent to preserve alpha, as -layers merge
            // merges all layers on to a canvas filled with the
            // background colour. After merging we reset the background
            // to be white for the default background colour setting
            // in the PNG image (which is used in old IE)
            $animation_pre = [
                '-background', 'transparent',
                '-layers', 'merge',
                '-background', 'white',
            ];
            Wikimedia\suppressWarnings();
            $xcfMeta = unserialize( $image->getMetadata() );
            Wikimedia\restoreWarnings();
            if ( $xcfMeta
                && isset( $xcfMeta['colorType'] )
                && $xcfMeta['colorType'] === 'greyscale-alpha'
                && version_compare( $this->getMagickVersion(), "6.8.9-3" ) < 0
            ) {
                // T68323 - Greyscale images not rendered properly.
                // So only take the "red" channel.
                $channelOnly = [ '-channel', 'R', '-separate' ];
                $animation_pre = array_merge( $animation_pre, $channelOnly );
            }
        }

        // Use one thread only, to avoid deadlock bugs on OOM
        $env = [ 'OMP_NUM_THREADS' => 1 ];
        if ( strval( $wgImageMagickTempDir ) !== '' ) {
            $env['MAGICK_TMPDIR'] = $wgImageMagickTempDir;
        }

        $rotation = isset( $params['disableRotation'] ) ? 0 : $this->getRotation( $image );
        list( $width, $height ) = $this->extractPreRotationDimensions( $params, $rotation );

        $cmd = Shell::escape( ...array_merge(
            [ $wgImageMagickConvertCommand ],
            $quality,
            // Specify white background color, will be used for transparent images
            // in Internet Explorer/Windows instead of default black.
            [ '-background', 'white' ],
            $decoderHint,
            [ $this->escapeMagickInput( $params['srcPath'], $scene ) ],
            $animation_pre,
            // For the -thumbnail option a "!" is needed to force exact size,
            // or ImageMagick may decide your ratio is wrong and slice off
            // a pixel.
            [ '-thumbnail', "{$width}x{$height}!" ],
            // Add the source url as a comment to the thumb, but don't add the flag if there's no comment
            ( $params['comment'] !== ''
                ? [ '-set', 'comment', $this->escapeMagickProperty( $params['comment'] ) ]
                : [] ),
            // T108616: Avoid exposure of local file path
            [ '+set', 'Thumb::URI' ],
            [ '-depth', 8 ],
            $sharpen,
            [ '-rotate', "-$rotation" ],
            $subsampling,
            $animation_post,
            [ $this->escapeMagickOutput( $params['dstPath'] ) ] ) );

        wfDebug( __METHOD__ . ": running ImageMagick: $cmd\n" );
        $retval = 0;
        $err = wfShellExecWithStderr( $cmd, $retval, $env );

        if ( $retval !== 0 ) {
            $this->logErrorForExternalProcess( $retval, $err, $cmd );

            return $this->getMediaTransformError( $params, "$err\nError code: $retval" );
        }

        return false; # No error
    }

    protected function transformImageMagickExt( $image, $params ) {
        global $wgSharpenReductionThreshold, $wgSharpenParameter, $wgMaxAnimatedGifArea,
            $wgJpegPixelFormat, $wgJpegQuality;

        try {
            $im = new Imagick();
            $im->readImage( $params['srcPath'] );

            if ( $params['mimeType'] == 'image/jpeg' ) {
                // Sharpening, see T8193
                if ( ( $params['physicalWidth'] + $params['physicalHeight'] )
                    / ( $params['srcWidth'] + $params['srcHeight'] )
                    < $wgSharpenReductionThreshold
                ) {
                    // Hack, since $wgSharpenParameter is written specifically for the command line convert
                    list( $radius, $sigma ) = explode( 'x', $wgSharpenParameter );
                    $im->sharpenImage( $radius, $sigma );
                }
                $qualityVal = isset( $params['quality'] ) ? (string)$params['quality'] : null;
                $im->setCompressionQuality( $qualityVal ?: $wgJpegQuality );
                if ( $params['interlace'] ) {
                    $im->setInterlaceScheme( Imagick::INTERLACE_JPEG );
                }
                if ( $wgJpegPixelFormat ) {
                    $factors = $this->imageMagickSubsampling( $wgJpegPixelFormat );
                    $im->setSamplingFactors( $factors );
                }
            } elseif ( $params['mimeType'] == 'image/png' ) {
                $im->setCompressionQuality( 95 );
                if ( $params['interlace'] ) {
                    $im->setInterlaceScheme( Imagick::INTERLACE_PNG );
                }
            } elseif ( $params['mimeType'] == 'image/gif' ) {
                if ( $this->getImageArea( $image ) > $wgMaxAnimatedGifArea ) {
                    // Extract initial frame only; we're so big it'll
                    // be a total drag. :P
                    $im->setImageScene( 0 );
                } elseif ( $this->isAnimatedImage( $image ) ) {
                    // Coalesce is needed to scale animated GIFs properly (T3017).
                    $im = $im->coalesceImages();
                }
                // GIF interlacing is only available since 6.3.4
                $v = Imagick::getVersion();
                preg_match( '/ImageMagick ([0-9]+\.[0-9]+\.[0-9]+)/', $v['versionString'], $v );

                if ( $params['interlace'] && version_compare( $v[1], '6.3.4' ) >= 0 ) {
                    $im->setInterlaceScheme( Imagick::INTERLACE_GIF );
                }
            }

            $rotation = isset( $params['disableRotation'] ) ? 0 : $this->getRotation( $image );
            list( $width, $height ) = $this->extractPreRotationDimensions( $params, $rotation );

            $im->setImageBackgroundColor( new ImagickPixel( 'white' ) );

            // Call Imagick::thumbnailImage on each frame
            foreach ( $im as $i => $frame ) {
                if ( !$frame->thumbnailImage( $width, $height, /* fit */ false ) ) {
                    return $this->getMediaTransformError( $params, "Error scaling frame $i" );
                }
            }
            $im->setImageDepth( 8 );

            if ( $rotation && !$im->rotateImage( new ImagickPixel( 'white' ), 360 - $rotation ) ) {
                return $this->getMediaTransformError( $params, "Error rotating $rotation degrees" );
            }

            if ( $this->isAnimatedImage( $image ) ) {
                wfDebug( __METHOD__ . ": Writing animated thumbnail\n" );
                // This is broken somehow... can't find out how to fix it
                $result = $im->writeImages( $params['dstPath'], true );
            } else {
                $result = $im->writeImage( $params['dstPath'] );
            }
            if ( !$result ) {
                return $this->getMediaTransformError( $params,
                    "Unable to write thumbnail to {$params['dstPath']}" );
            }
        } catch ( ImagickException $e ) {
            return $this->getMediaTransformError( $params, $e->getMessage() );
        }

        return false;
    }

    protected function transformCustom( $image, $params ) {
        # Use a custom convert command
        global $wgCustomConvertCommand;

        # Variables: %s %d %w %h
        $src = Shell::escape( $params['srcPath'] );
        $dst = Shell::escape( $params['dstPath'] );
        $cmd = $wgCustomConvertCommand;
        $cmd = str_replace( '%s', $src, str_replace( '%d', $dst, $cmd ) ); # Filenames
        $cmd = str_replace( '%h', Shell::escape( $params['physicalHeight'] ),
            str_replace( '%w', Shell::escape( $params['physicalWidth'] ), $cmd ) ); # Size
        wfDebug( __METHOD__ . ": Running custom convert command $cmd\n" );
        $retval = 0;
        $err = wfShellExecWithStderr( $cmd, $retval );

        if ( $retval !== 0 ) {
            $this->logErrorForExternalProcess( $retval, $err, $cmd );

            return $this->getMediaTransformError( $params, $err );
        }

        return false; # No error
    }

    protected function transformGd( $image, $params ) {
        # Use PHP's builtin GD library functions.
        # First find out what kind of file this is, and select the correct
        # input routine for this.

        $typemap = [
            'image/gif' => [ 'imagecreatefromgif', 'palette', false, 'imagegif' ],
            'image/jpeg' => [ 'imagecreatefromjpeg', 'truecolor', true,
                [ __CLASS__, 'imageJpegWrapper' ] ],
            'image/png' => [ 'imagecreatefrompng', 'bits', false, 'imagepng' ],
            'image/vnd.wap.wbmp' => [ 'imagecreatefromwbmp', 'palette', false, 'imagewbmp' ],
            'image/xbm' => [ 'imagecreatefromxbm', 'palette', false, 'imagexbm' ],
        ];

        if ( !isset( $typemap[$params['mimeType']] ) ) {
            $err = 'Image type not supported';
            wfDebug( "$err\n" );
            $errMsg = wfMessage( 'thumbnail_image-type' )->text();

            return $this->getMediaTransformError( $params, $errMsg );
        }
        list( $loader, $colorStyle, $useQuality, $saveType ) = $typemap[$params['mimeType']];

        if ( !function_exists( $loader ) ) {
            $err = "Incomplete GD library configuration: missing function $loader";
            wfDebug( "$err\n" );
            $errMsg = wfMessage( 'thumbnail_gd-library', $loader )->text();

            return $this->getMediaTransformError( $params, $errMsg );
        }

        if ( !file_exists( $params['srcPath'] ) ) {
            $err = "File seems to be missing: {$params['srcPath']}";
            wfDebug( "$err\n" );
            $errMsg = wfMessage( 'thumbnail_image-missing', $params['srcPath'] )->text();

            return $this->getMediaTransformError( $params, $errMsg );
        }

        if ( filesize( $params['srcPath'] ) === 0 ) {
            $err = "Image file size seems to be zero.";
            wfDebug( "$err\n" );
            $errMsg = wfMessage( 'thumbnail_image-size-zero', $params['srcPath'] )->text();

            return $this->getMediaTransformError( $params, $errMsg );
        }

        $src_image = $loader( $params['srcPath'] );

        $rotation = function_exists( 'imagerotate' ) && !isset( $params['disableRotation'] ) ?
            $this->getRotation( $image ) :
            0;
        list( $width, $height ) = $this->extractPreRotationDimensions( $params, $rotation );
        $dst_image = imagecreatetruecolor( $width, $height );

        // Initialise the destination image to transparent instead of
        // the default solid black, to support PNG and GIF transparency nicely
        $background = imagecolorallocate( $dst_image, 0, 0, 0 );
        imagecolortransparent( $dst_image, $background );
        imagealphablending( $dst_image, false );

        if ( $colorStyle == 'palette' ) {
            // Don't resample for paletted GIF images.
            // It may just uglify them, and completely breaks transparency.
            imagecopyresized( $dst_image, $src_image,
                0, 0, 0, 0,
                $width, $height,
                imagesx( $src_image ), imagesy( $src_image ) );
        } else {
            imagecopyresampled( $dst_image, $src_image,
                0, 0, 0, 0,
                $width, $height,
                imagesx( $src_image ), imagesy( $src_image ) );
        }

        if ( $rotation % 360 != 0 && $rotation % 90 == 0 ) {
            $rot_image = imagerotate( $dst_image, $rotation, 0 );
            imagedestroy( $dst_image );
            $dst_image = $rot_image;
        }

        imagesavealpha( $dst_image, true );

        $funcParams = [ $dst_image, $params['dstPath'] ];
        if ( $useQuality && isset( $params['quality'] ) ) {
            $funcParams[] = $params['quality'];
        }
        $saveType( ...$funcParams );

        imagedestroy( $dst_image );
        imagedestroy( $src_image );

        return false; # No error
    }

    static function imageJpegWrapper( $dst_image, $thumbPath, $quality = null ) {
        global $wgJpegQuality;

        if ( $quality === null ) {
            $quality = $wgJpegQuality;
        }

        imageinterlace( $dst_image );
        imagejpeg( $dst_image, $thumbPath, $quality );
    }

    public function canRotate() {
        $scaler = $this->getScalerType( null, false );
        switch ( $scaler ) {
            case 'im':
                # ImageMagick supports autorotation
                return true;
            case 'imext':
                # Imagick::rotateImage
                return true;
            case 'gd':
                # GD's imagerotate function is used to rotate images, but not
                # all precompiled PHP versions have that function
                return function_exists( 'imagerotate' );
            default:
                # Other scalers don't support rotation
                return false;
        }
    }

    public function autoRotateEnabled() {
        global $wgEnableAutoRotation;

        if ( $wgEnableAutoRotation === null ) {
            // Only enable auto-rotation when we actually can
            return $this->canRotate();
        }

        return $wgEnableAutoRotation;
    }

    public function rotate( $file, $params ) {
        global $wgImageMagickConvertCommand;

        $rotation = ( $params['rotation'] + $this->getRotation( $file ) ) % 360;
        $scene = false;

        $scaler = $this->getScalerType( null, false );
        switch ( $scaler ) {
            case 'im':
                $cmd = Shell::escape( $wgImageMagickConvertCommand ) . " " .
                    Shell::escape( $this->escapeMagickInput( $params['srcPath'], $scene ) ) .
                    " -rotate " . Shell::escape( "-$rotation" ) . " " .
                    Shell::escape( $this->escapeMagickOutput( $params['dstPath'] ) );
                wfDebug( __METHOD__ . ": running ImageMagick: $cmd\n" );
                $retval = 0;
                $err = wfShellExecWithStderr( $cmd, $retval );
                if ( $retval !== 0 ) {
                    $this->logErrorForExternalProcess( $retval, $err, $cmd );

                    return new MediaTransformError( 'thumbnail_error', 0, 0, $err );
                }

                return false;
            case 'imext':
                $im = new Imagick();
                $im->readImage( $params['srcPath'] );
                if ( !$im->rotateImage( new ImagickPixel( 'white' ), 360 - $rotation ) ) {
                    return new MediaTransformError( 'thumbnail_error', 0, 0,
                        "Error rotating $rotation degrees" );
                }
                $result = $im->writeImage( $params['dstPath'] );
                if ( !$result ) {
                    return new MediaTransformError( 'thumbnail_error', 0, 0,
                        "Unable to write image to {$params['dstPath']}" );
                }

                return false;
            default:
                return new MediaTransformError( 'thumbnail_error', 0, 0,
                    "$scaler rotation not implemented" );
        }
    }
}