Bitmap.php

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<?php
class BitmapHandler extends ImageHandler {
    function normaliseParams( $image, &$params ) {
        if ( !parent::normaliseParams( $image, $params ) ) {
            return false;
        }

        # Obtain the source, pre-rotation dimensions
        $srcWidth = $image->getWidth( $params['page'] );
        $srcHeight = $image->getHeight( $params['page'] );

        # Don't make an image bigger than the source
        if ( $params['physicalWidth'] >= $srcWidth ) {
            $params['physicalWidth'] = $srcWidth;
            $params['physicalHeight'] = $srcHeight;

            # Skip scaling limit checks if no scaling is required
            # due to requested size being bigger than source.
            if ( !$image->mustRender() ) {
                return true;
            }
        }

        # Check if the file is smaller than the maximum image area for thumbnailing
        $checkImageAreaHookResult = null;
        wfRunHooks(
            'BitmapHandlerCheckImageArea',
            array( $image, &$params, &$checkImageAreaHookResult )
        );

        if ( is_null( $checkImageAreaHookResult ) ) {
            global $wgMaxImageArea;

            if ( $srcWidth * $srcHeight > $wgMaxImageArea
                && !( $image->getMimeType() == 'image/jpeg'
                    && self::getScalerType( false, false ) == 'im' )
            ) {
                # Only ImageMagick can efficiently downsize jpg images without loading
                # the entire file in memory
                return false;
            }
        } else {
            return $checkImageAreaHookResult;
        }

        return true;
    }

    public function extractPreRotationDimensions( $params, $rotation ) {
        if ( $rotation == 90 || $rotation == 270 ) {
            # We'll resize before rotation, so swap the dimensions again
            $width = $params['physicalHeight'];
            $height = $params['physicalWidth'];
        } else {
            $width = $params['physicalWidth'];
            $height = $params['physicalHeight'];
        }

        return array( $width, $height );
    }

    function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
        if ( !$this->normaliseParams( $image, $params ) ) {
            return new TransformParameterError( $params );
        }
        # Create a parameter array to pass to the scaler
        $scalerParams = array(
            # The size to which the image will be resized
            'physicalWidth' => $params['physicalWidth'],
            'physicalHeight' => $params['physicalHeight'],
            'physicalDimensions' => "{$params['physicalWidth']}x{$params['physicalHeight']}",
            # The size of the image on the page
            'clientWidth' => $params['width'],
            'clientHeight' => $params['height'],
            # Comment as will be added to the Exif of the thumbnail
            'comment' => isset( $params['descriptionUrl'] )
                ? "File source: {$params['descriptionUrl']}"
                : '',
            # Properties of the original image
            'srcWidth' => $image->getWidth(),
            'srcHeight' => $image->getHeight(),
            'mimeType' => $image->getMimeType(),
            'dstPath' => $dstPath,
            'dstUrl' => $dstUrl,
        );

        # Determine scaler type
        $scaler = self::getScalerType( $dstPath );

        wfDebug( __METHOD__ . ": creating {$scalerParams['physicalDimensions']} " .
            "thumbnail at $dstPath using scaler $scaler\n" );

        if ( !$image->mustRender() &&
            $scalerParams['physicalWidth'] == $scalerParams['srcWidth']
            && $scalerParams['physicalHeight'] == $scalerParams['srcHeight']
        ) {

            # normaliseParams (or the user) wants us to return the unscaled image
            wfDebug( __METHOD__ . ": returning unscaled image\n" );

            return $this->getClientScalingThumbnailImage( $image, $scalerParams );
        }

        if ( $scaler == 'client' ) {
            # Client-side image scaling, use the source URL
            # Using the destination URL in a TRANSFORM_LATER request would be incorrect
            return $this->getClientScalingThumbnailImage( $image, $scalerParams );
        }

        if ( $flags & self::TRANSFORM_LATER ) {
            wfDebug( __METHOD__ . ": Transforming later per flags.\n" );
            $params = array(
                'width' => $scalerParams['clientWidth'],
                'height' => $scalerParams['clientHeight']
            );

            return new ThumbnailImage( $image, $dstUrl, false, $params );
        }

        # Try to make a target path for the thumbnail
        if ( !wfMkdirParents( dirname( $dstPath ), null, __METHOD__ ) ) {
            wfDebug( __METHOD__ . ": Unable to create thumbnail destination " .
                "directory, falling back to client scaling\n" );

            return $this->getClientScalingThumbnailImage( $image, $scalerParams );
        }

        # Transform functions and binaries need a FS source file
        $scalerParams['srcPath'] = $image->getLocalRefPath();
        if ( $scalerParams['srcPath'] === false ) { // Failed to get local copy
            wfDebugLog( 'thumbnail',
                sprintf( 'Thumbnail failed on %s: could not get local copy of "%s"',
                    wfHostname(), $image->getName() ) );

            return new MediaTransformError( 'thumbnail_error',
                $scalerParams['clientWidth'], $scalerParams['clientHeight'],
                wfMessage( 'filemissing' )->text()
            );
        }

        # Try a hook
        $mto = null;
        wfRunHooks( 'BitmapHandlerTransform', array( $this, $image, &$scalerParams, &$mto ) );
        if ( !is_null( $mto ) ) {
            wfDebug( __METHOD__ . ": Hook to BitmapHandlerTransform created an mto\n" );
            $scaler = 'hookaborted';
        }

        switch ( $scaler ) {
            case 'hookaborted':
                # Handled by the hook above

                $err = $mto->isError() ? $mto : false;
                break;
            case 'im':
                $err = $this->transformImageMagick( $image, $scalerParams );
                break;
            case 'custom':
                $err = $this->transformCustom( $image, $scalerParams );
                break;
            case 'imext':
                $err = $this->transformImageMagickExt( $image, $scalerParams );
                break;
            case 'gd':
            default:
                $err = $this->transformGd( $image, $scalerParams );
                break;
        }

        # Remove the file if a zero-byte thumbnail was created, or if there was an error
        $removed = $this->removeBadFile( $dstPath, (bool)$err );
        if ( $err ) {
            # transform returned MediaTransforError
            return $err;
        } elseif ( $removed ) {
            # Thumbnail was zero-byte and had to be removed
            return new MediaTransformError( 'thumbnail_error',
                $scalerParams['clientWidth'], $scalerParams['clientHeight'],
                wfMessage( 'unknown-error' )->text()
            );
        } elseif ( $mto ) {
            return $mto;
        } else {
            $params = array(
                'width' => $scalerParams['clientWidth'],
                'height' => $scalerParams['clientHeight']
            );

            return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
        }
    }

    protected static 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;
    }

    protected function getClientScalingThumbnailImage( $image, $scalerParams ) {
        $params = array(
            'width' => $scalerParams['clientWidth'],
            'height' => $scalerParams['clientHeight']
        );

        return new ThumbnailImage( $image, $image->getURL(), null, $params );
    }

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

        $quality = array();
        $sharpen = array();
        $scene = false;
        $animation_pre = array();
        $animation_post = array();
        $decoderHint = array();
        if ( $params['mimeType'] == 'image/jpeg' ) {
            $quality = array( '-quality', '80' ); // 80%
            # Sharpening, see bug 6193
            if ( ( $params['physicalWidth'] + $params['physicalHeight'] )
                / ( $params['srcWidth'] + $params['srcHeight'] )
                < $wgSharpenReductionThreshold
            ) {
                $sharpen = array( '-sharpen', $wgSharpenParameter );
            }
            if ( version_compare( $this->getMagickVersion(), "6.5.6" ) >= 0 ) {
                // JPEG decoder hint to reduce memory, available since IM 6.5.6-2
                $decoderHint = array( '-define', "jpeg:size={$params['physicalDimensions']}" );
            }
        } elseif ( $params['mimeType'] == 'image/png' ) {
            $quality = array( '-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 (bug 1017).
                $animation_pre = array( '-coalesce' );
                // We optimize the output, but -optimize is broken,
                // use optimizeTransparency instead (bug 11822)
                if ( version_compare( $this->getMagickVersion(), "6.3.5" ) >= 0 ) {
                    $animation_post = array( '-fuzz', '5%', '-layers', 'optimizeTransparency' );
                }
            }
        } elseif ( $params['mimeType'] == 'image/x-xcf' ) {
            $animation_post = array( '-layers', 'merge' );
        }

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

        $rotation = $this->getRotation( $image );
        list( $width, $height ) = $this->extractPreRotationDimensions( $params, $rotation );

        $cmd = call_user_func_array( 'wfEscapeShellArg', array_merge(
            array( $wgImageMagickConvertCommand ),
            $quality,
            // Specify white background color, will be used for transparent images
            // in Internet Explorer/Windows instead of default black.
            array( '-background', 'white' ),
            $decoderHint,
            array( $this->escapeMagickInput( $params['srcPath'], $scene ) ),
            $animation_pre,
            // For the -thumbnail option a "!" is needed to force exact size,
            // or ImageMagick may decide your ratio is wrong and slice off
            // a pixel.
            array( '-thumbnail', "{$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'] !== ''
                ? array( '-set', 'comment', $this->escapeMagickProperty( $params['comment'] ) )
                : array() ),
            array( '-depth', 8 ),
            $sharpen,
            array( '-rotate', "-$rotation" ),
            $animation_post,
            array( $this->escapeMagickOutput( $params['dstPath'] ) ) ) );

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

        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;

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

            if ( $params['mimeType'] == 'image/jpeg' ) {
                // Sharpening, see bug 6193
                if ( ( $params['physicalWidth'] + $params['physicalHeight'] )
                    / ( $params['srcWidth'] + $params['srcHeight'] )
                    < $wgSharpenReductionThreshold
                ) {
                    // Hack, since $wgSharpenParamater is written specifically for the command line convert
                    list( $radius, $sigma ) = explode( 'x', $wgSharpenParameter );
                    $im->sharpenImage( $radius, $sigma );
                }
                $im->setCompressionQuality( 80 );
            } elseif ( $params['mimeType'] == 'image/png' ) {
                $im->setCompressionQuality( 95 );
            } 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 (bug 1017).
                    $im = $im->coalesceImages();
                }
            }

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

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

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

        return false; # No error
    }

    public function getMediaTransformError( $params, $errMsg ) {
        return new MediaTransformError( 'thumbnail_error', $params['clientWidth'],
            $params['clientHeight'], $errMsg );
    }

    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 = array(
            'image/gif' => array( 'imagecreatefromgif', 'palette', 'imagegif' ),
            'image/jpeg' => array( 'imagecreatefromjpeg', 'truecolor',
                array( __CLASS__, 'imageJpegWrapper' ) ),
            'image/png' => array( 'imagecreatefrompng', 'bits', 'imagepng' ),
            'image/vnd.wap.wbmp' => array( 'imagecreatefromwbmp', 'palette', 'imagewbmp' ),
            'image/xbm' => array( 'imagecreatefromxbm', 'palette', '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, $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 );
        }

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

        $rotation = function_exists( 'imagerotate' ) ? $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 );

        call_user_func( $saveType, $dst_image, $params['dstPath'] );
        imagedestroy( $dst_image );
        imagedestroy( $src_image );

        return false; # No error
    }

    function escapeMagickProperty( $s ) {
        // Double the backslashes
        $s = str_replace( '\\', '\\\\', $s );
        // Double the percents
        $s = str_replace( '%', '%%', $s );
        // Escape initial - or @
        if ( strlen( $s ) > 0 && ( $s[0] === '-' || $s[0] === '@' ) ) {
            $s = '\\' . $s;
        }

        return $s;
    }

    function escapeMagickInput( $path, $scene = false ) {
        # Die on initial metacharacters (caller should prepend path)
        $firstChar = substr( $path, 0, 1 );
        if ( $firstChar === '~' || $firstChar === '@' ) {
            throw new MWException( __METHOD__ . ': cannot escape this path name' );
        }

        # Escape glob chars
        $path = preg_replace( '/[*?\[\]{}]/', '\\\\\0', $path );

        return $this->escapeMagickPath( $path, $scene );
    }

    function escapeMagickOutput( $path, $scene = false ) {
        $path = str_replace( '%', '%%', $path );

        return $this->escapeMagickPath( $path, $scene );
    }

    protected function escapeMagickPath( $path, $scene = false ) {
        # Die on format specifiers (other than drive letters). The regex is
        # meant to match all the formats you get from "convert -list format"
        if ( preg_match( '/^([a-zA-Z0-9-]+):/', $path, $m ) ) {
            if ( wfIsWindows() && is_dir( $m[0] ) ) {
                // OK, it's a drive letter
                // ImageMagick has a similar exception, see IsMagickConflict()
            } else {
                throw new MWException( __METHOD__ . ': unexpected colon character in path name' );
            }
        }

        # If there are square brackets, add a do-nothing scene specification
        # to force a literal interpretation
        if ( $scene === false ) {
            if ( strpos( $path, '[' ) !== false ) {
                $path .= '[0--1]';
            }
        } else {
            $path .= "[$scene]";
        }

        return $path;
    }

    protected function getMagickVersion() {
        global $wgMemc;

        $cache = $wgMemc->get( "imagemagick-version" );
        if ( !$cache ) {
            global $wgImageMagickConvertCommand;
            $cmd = wfEscapeShellArg( $wgImageMagickConvertCommand ) . ' -version';
            wfDebug( __METHOD__ . ": Running convert -version\n" );
            $retval = '';
            $return = wfShellExec( $cmd, $retval );
            $x = preg_match( '/Version: ImageMagick ([0-9]*\.[0-9]*\.[0-9]*)/', $return, $matches );
            if ( $x != 1 ) {
                wfDebug( __METHOD__ . ": ImageMagick version check failed\n" );

                return null;
            }
            $wgMemc->set( "imagemagick-version", $matches[1], 3600 );

            return $matches[1];
        }

        return $cache;
    }

    static function imageJpegWrapper( $dst_image, $thumbPath ) {
        imageinterlace( $dst_image );
        imagejpeg( $dst_image, $thumbPath, 95 );
    }

    public static function canRotate() {
        $scaler = self::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 static function autoRotateEnabled() {
        global $wgEnableAutoRotation;

        if ( $wgEnableAutoRotation === null ) {
            // Only enable auto-rotation when the bitmap handler can rotate
            $wgEnableAutoRotation = BitmapHandler::canRotate();
        }

        return $wgEnableAutoRotation;
    }

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

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

        $scaler = self::getScalerType( null, false );
        switch ( $scaler ) {
            case 'im':
                $cmd = wfEscapeShellArg( $wgImageMagickConvertCommand ) . " " .
                    wfEscapeShellArg( $this->escapeMagickInput( $params['srcPath'], $scene ) ) .
                    " -rotate " . wfEscapeShellArg( "-$rotation" ) . " " .
                    wfEscapeShellArg( $this->escapeMagickOutput( $params['dstPath'] ) );
                wfDebug( __METHOD__ . ": running ImageMagick: $cmd\n" );
                wfProfileIn( 'convert' );
                $retval = 0;
                $err = wfShellExecWithStderr( $cmd, $retval );
                wfProfileOut( 'convert' );
                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" );
        }
    }

    public function mustRender( $file ) {
        return self::canRotate() && $this->getRotation( $file ) != 0;
    }
}