Erweiterung:PagedTiffHandler

This page is a translated version of the page Extension:PagedTiffHandler and the translation is 93% complete.
MediaWiki-Erweiterungen
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PagedTiffHandler
Freigabestatus: stabil
Einbindung Medien
Beschreibung Allows to display tiff-files
Autor(en) Hallo Welt! Medienwerkstatt GmbH for Wikimedia Deutschland e. V.
Letzte Version continuous updates
Kompatibilitätspolitik Snapshots werden zusammen mit MediaWiki veröffentlicht. Der Master ist nicht abwärtskompatibel.
MediaWiki >= 1.31.0
PHP 7.0+
Datenbankänderungen Nein
Lizenz GNU General Public License 2.0 oder neuer
Herunterladen
  • $wgImageMagickIdentifyCommand
  • $wgTiffUseExiv
  • $wgTiffUseTiffinfo
  • $wgTiffTiffinfoCommand
  • $wgTiffIntermediaryScaleStep
  • $wgTiffIdentifyRejectMessages
  • $wgTiffIdentifyBypassMessages
  • $wgTiffIdentifyRejectMessages
  • $wgTiffTiffinfoRejectMessages
  • $wgTiffMaxEmbedFiles
  • $wgTiffMaxMetaSize
  • $wgTiffErrorCacheTTL
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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.

Verwendung

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

Parameter Beispiel Funktion
page [[Image:Test.tiff|page=2]] Renders a thumbnail of the second page of test.tiff. Page numbers start with 1. Default value is 1.
lossy [[Image:Test.tiff|lossy=false]] If set to false, thumbnails are being rendered as png, otherwise as jpg. If no value is set, PagedTiffHandler determines the value based on the presence of an alpha channel. If alpha is there, thumbnail is rendered as png. Possible values for jpg: '1', 'true' and 'lossy'. Possible values for png: '0', 'false' and 'lossless'.

Voraussetzungen

Erforderlich

Paket Beschreibung Link
"imagemagick" for identify Does dynamic resizing and thumbnailing of images www.imagemagick.org

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

which identify

Erforderlich (optional)

Package Description Link
"exiv2" for exiv2 Exiv2 is a Cross-platform C++ library and a command line utility to manage image metadata. Provides support to retrieve EXIF from TIFF files. www.exiv2.org
"libtiff-tools" for tiffinfo Identify and retrieve basic TIFF metadata (more efficient than ImageMagick) www.simplesystems.org/libtiff/

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

which exiv2 tiffinfo
For additional performance on very large TIFF files, you might want to install and configure the VipsScaler extension .

Installation

  • Die Erweiterung herunterladen und die Datei(en) in ein Verzeichnis namens PagedTiffHandler im Ordner extensions/ ablegen.
  • Folgenden Code am Ende der LocalSettings.php einfügen:
    wfLoadExtension( 'PagedTiffHandler' );
    
  • Configure as required
  •   Erledigt – Zu Special:Version in dem Wiki (bei Einstellung auf deutsch nach Spezial:Version) navigieren, um die erfolgreiche Installierung der Erweiterung zu überprüfen.

Für Benutzer, die MediaWiki in der Version 1.27 und früher betreiben:

Die oben stehenden Anweisungen beschreiben die neue Installationsanweisung für diese Erweiterung unter der Verwendung von wfLoadExtension(). Wird diese Erweiterung in einer dieser früheren Versionen (MediaWiki 1.27 und früher)  – an Stelle von wfLoadExtension( 'PagedTiffHandler' ); – installiert, benutze:

require_once "$IP/extensions/PagedTiffHandler/PagedTiffHandler.php";

Konfiguration

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

  • ImageMagick is used to reject/accept the image and render thumbail images. This is mandatory, PagedTiffHandler will not work 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).
  • Extension VipsScaler 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 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.

See also