GeezerVison

MediaWiki extensions manual

PagedTiffHandler Release status: stable
Implementation	Media
Description	Allows to display tiff-files
Author(s)	Hallo Welt! Medienwerkstatt GmbH for Wikimedia Deutschland e. V.
Latest version	continuous updates
Compatibility policy	Snapshots releases along with MediaWiki. Master is not backward compatible.
PHP	7.0+
Database changes	No
Parameters $wgImageMagickIdentifyCommand $wgTiffUseExiv $wgTiffUseTiffinfo $wgTiffTiffinfoCommand $wgTiffIntermediaryScaleStep $wgTiffIdentifyRejectMessages $wgTiffIdentifyBypassMessages $wgTiffIdentifyRejectMessages $wgTiffTiffinfoRejectMessages $wgTiffMaxEmbedFiles $wgTiffMaxMetaSize $wgTiffErrorCacheTTL
Hooks provided PagedTiffHandlerTiffData PagedTiffHandlerExifData PagedTiffHandlerRenderCommand
Licence	GNU General Public License 2.0 or later
Download	Download extension Git [?]: Browse repository (Phabricator · GitHub) Gerrit code review Git commit log Download source tarball
Translate the PagedTiffHandler extension if it is available at translatewiki.net
Issues	Open tasks · Report a bug

The PagedTiffHandler extension allows to upload and display tiff-files into your wiki. It can handle multi-paged images and render them into thumbnails on per page basis.

You can embed images using standard image syntax. Additionally, there are two new parameters:

Type the following in your shell to see if you have the above installed first:

which identify

Type the following in your shell to see if you have the above installed first:

which exiv2 tiffinfo

• Download and move the extracted PagedTiffHandler folder to your extensions/ directory.
  Developers and code contributors should install the extension from Git instead, using:

  cd extensions/
  git clone https://gerrit.wikimedia.org/r/mediawiki/extensions/PagedTiffHandler
  

• Add the following code at the bottom of your LocalSettings.php file:

  wfLoadExtension( 'PagedTiffHandler' );
  

• Configure as required.
• Done – Navigate to Special:Version on your wiki to verify that the extension is successfully installed.

PagedTiffHandler depends on various external programs in order to process Tiff images.

• ImageMagick is used to reject/accept the image and render thumbail images. PagedTiffHandler will not work on any locally uploaded image without ImageMagick.
• tiffinfo can be used to reject/accept the image instead of ImageMagick, but it does not provide rendering (optional).
• Exiv2 is used to extract image metadata (optional).
• VipsScaler extension can be used for fast processing of large image files (optional).

Example configuration:

// Path to identify
$wgImageMagickIdentifyCommand = '/usr/bin/identify';
// Use exiv2? if false, MediaWiki's internal EXIF parser will be used
$wgTiffUseExiv = false;
// Path to exiv2 (MediaWiki core configuration option)
$wgExiv2Command = '/usr/bin/exiv2';
// Use tiffinfo? if false, ImageMagick's identify command will be used
$wgTiffUseTiffinfo = false;
// Path to tiffinfo
$wgTiffTiffinfoCommand = '/usr/bin/tiffinfo';

When thumbnailing very large images to very small sizes, it can be better to downscale to an intermediary size first, instead of resizing in one go. By default PagedTiffHandler will downsize images larger than $wgTiffIntermediaryScaleStep (2048 pixels wide by default) first to $wgTiffIntermediaryScaleStep before downsizing to even smaller dimensions.

Example configuration:

// For thumbnails smaller than this, first scale to this amount
// Set to 0 to disable
$wgTiffIntermediaryScaleStep = 2048;

PagedTiffHandler rejects images based on error messages of ImageMagick or tiffinfo. There are three options:

• Images are rejected if the error message matches $wgTiffIdentifyRejectMessages or $wgTiffTiffinfoRejectMessages
• Images are accepted without moaning if the error message matches $wgTiffIdentifyBypassMessages or $wgTiffTiffinfoBypassMessages
• In other cases, images are accepted but the error message is recorded in the image metadata.

Example configuration (all of the parameters show the default configuration):

$wgTiffIdentifyRejectMessages = [
	'/^identify: Compression algorithm does not support random access/',
	'/^identify: Old-style LZW codes, convert file/',
	'/^identify: Sorry, requested compression method is not configured/',
	'/^identify: ThunderDecode: Not enough data at scanline/',
	'/^identify: .+?: Read error on strip/',
	'/^identify: .+?: Can not read TIFF directory/',
	'/^identify: Not a TIFF/',
];

$wgTiffIdentifyBypassMessages = [
	'/^identify: .*TIFFReadDirectory/',
	'/^identify: .+?: unknown field with tag .+? encountered/'
];

PagedTiffHandler also checks a few parameters of the image in order to be able to control the necessary processing time.

Example configuration:

// Maximum number of embedded files in tiff image
$wgTiffMaxEmbedFiles = 10000;
// Maximum size of meta data
$wgTiffMaxMetaSize = 64*1024; // 64kB

When thumbnailing fails for an image, PagedTiffHandler will not try again to render this image for some time. The setting below controls after how many seconds thumbnailing may be tried again.

Example configuration:

// TTL of Cacheentries for Errors
$wgTiffErrorCacheTTL = 84600;

Defaults

All of the above shown parameters are set as default in the configuration of the extension.

• Extension:PdfHandler

This extension is being used on one or more Wikimedia projects. This probably means that the extension is stable and works well enough to be used by such high-traffic websites. Look for this extension's name in Wikimedia's CommonSettings.php and InitialiseSettings.php configuration files to see where it's installed. A full list of the extensions installed on a particular wiki can be seen on the wiki's Special:Version page.

This extension is included in the following wiki farms/hosts and/or packages: Miraheze

• Stable extensions
• Media handling extensions
• GPL licensed extensions
• Extensions in Wikimedia version control
• All extensions
• Extensions used on Wikimedia
• Extensions included in Miraheze
• Image extensions
• Extensions by HalloWelt

• Extensions without an image
• Extensions with release branches compatibility policy