Jekyll-iiif

Jekyll plugin to embed static IIIF images in jekyll pages

This project is maintained by pbinkley

This is a first stab at a Jekyll plugin that generates static tiles and a IIIF Image API info.json file for images that will be displayed in the Jekyll site. It uses iiif_s3 and incorporates the OpenSeadragon and Mirador viewers.

Demo: Ship of Fools

Quick Start

  1. Create a new Jekyll instance in a local directory.
  2. Download the demo package (containing some images from Internet Archive and Wikipedia and other configuration files) and unzip it into your Jekyll directory. It will overwrite your _config.yml and other files.
  3. Run bundle install to install the needed gems (jekyll-iiif and iiif_s3).
  4. Run jekyll serve to generate the site and start serving it.
  5. Visit the site at http://127.0.0.1:4000/jekyll-iiif-demo/. It will be the same as the Ship of Fools demo site above.

Use

Add images

collections:
  narrenschiff:
    output: true
    iiif: true
    paged: true
    fields:
      label: "Sebastian Brant, Aff-ghebeelde narren speel-schuyt, verciert met meer als hondert schoone figueren nae den aerdt van veelderley sotten die op aerden syn: bewesen met stichtelijcke exempelen, so uyt de H. Schrift als oock uyt de kerckelijcke oudt-vaders ende andere schrijvers meer, tot dienste van een yegelijcken"
      description: "Ghedruckt tot Leyden : By Henrick Lodewicxsz. van Haestens"
      attribution: "jekyll-iiif demo"
      logo: "http://127.0.0.1:4000/jekyll-iiif-demo/logo.jpg"
  iiif_images:
    output: true
    iiif: true

defaults:
  - scope:
      path: ""
      type: iiif_collection
    values:
      layout: iiif_image

Serve single image

To serve a single image, create a Markdown page such as iiif.md, containing a yaml header and a call to the iiif plugin, like this:

---
title: jekyll-iiif demo
---

{% iiif <imagename> %}

(Using the base name, without file extension, of one of the images you put in the _iiif directory)

Render and serve the site with jekyll s. Tiles and IIIF artefacts will be generated for images that need them.

Visit the page at http://127.0.0.1:4000/iiif.html. You should see your image displayed by OpenSeadragon in a deeply-zoomable tiled IIIF display.

Tiles are stored in a directory at tiles/images/<filename>, and will be copied to the Jekyll site as static files. Tiles are only generated if their target directory doesn't already exist. To force tiles to be regenerated, therefore, just delete the tiles directory.

Instead of specifying the image name in the iiif call, you can put it in the page yaml header as "iiif_image: imagename" (again without the filename extension), and invoke it simply with {% iiif %}.

A page can include more than one IIIF image.

The size of the IIIF viewer div is hardcoded in lib/_includes/iiif_image.html as width: 100%; height: 500px. It can be overriden by overriding iiif_image.html (i.e. by making a modified copy in the _includes directory of your Jekyll instance), or simply by applying css rules to div.iiif_image.

Collection

You can have jekyll-iiif generate pages for a Collection based one-to-one on the images you provide. The idea is to make it easy to publish a set of images with minimal overhead: you can drop all the images in a subdirectory of the _iiif directory, and the necessary skeleton pages will be created for you. You can then edit those pages as needed.

---
layout: default
---

{% capture the_collection %}{{page.collection}}{% endcapture %}
  {% if page.collection %}
    {% assign documents = site[the_collection] %}
  {% endif %}
{% for link in documents  %}
  {% if link.title == page.title %}
    {% unless forloop.first %}
      {% assign prevurl = prev.url %}
      {% assign prevtitle = prev.title %}
    {% endunless %}
    {% unless forloop.last %}
      {% assign next = documents[forloop.index] %}
      {% assign nexturl = next.url %}
      {% assign nexttitle = next.title %}
    {% endunless %}
  {% endif %}
  {% assign prev = link %}
{% endfor %}

<div class="prevnext">
{% if prevurl %}Previous: <a href="{{site.baseurl}}{{prevurl}}" class="prev">{{prevtitle}}</a>{% endif %}<br />

{% if nexturl %}Next: <a href="{{site.baseurl}}{{nexturl}}" class="next">{{nexttitle}}</a>{% endif %}
</div>

<article class="post">

  <header class="post-header">
    <h1 class="post-title">{{ page.title }}</h1>
  </header>

  <div class="post-content">
    {% iiif %}
    {{ content }}
  </div>
</article>

The important thing is that the layout must contain the {% iiif %} tag, which will trigger the display of the image that is specified in the page's iiif_image yaml tag. (The presentation of previous and next links is based on this).

When you start the server again, you can visit the collection at http://127.0.0.1:4000/iiif_collection/

A directory _<directoryname> (note the leading underscore) will be created for each collection if it doesn't already exist. This will contain the markdown files corresponding to the images in _iiif/<directoryname> (e.g. image page001.tiff triggers a file page001.md). Files will be created by jekyll-iiif for any image that doesn't already have one, so it's easy to create the necessary skeleton pages and then edit them as needed. The default skeleton pages just contain the yaml header, populated with the filename:

---
layout: iiif
title: 'page001'
iiif_image: 'iiif_collection-1'
---

(Note that the title is from the original image name, but the iiif_image uses the new name provided by iiif_s3, based on the collection name.) This markdown file can be modified to provide the proper title, add text to be displayed under the IIIF viewer, or anything else Jekyll can do. The file won't be overwritten by jekyll-iiif.

A page of thumbnails for the images in the collection can be generated using the iiif_gallery tag. One is generated automatically for each collection, providing the index.html in the collection directory. Each image is represented by a thumbnail; the formatting can be controlled by CSS applied to div.iiif_thumbnail. Clicking a thumbnail will take you to the page for that image. Each thumbnail is accompanied by a IIIF logo, which supports drag-and-drop to another IIIF viewer.

Manifests

Thanks to iiif_s3, Presentation Manifests are created for each collection or image. This allows external IIIF clients to import the item and display it. All images belong to collections, but collections can be paged or unpaged. Paged collections are like books: the images are viewable as parts of a single item. Unpaged collections treat images as independent items. The status of a collection is controlled by the paged element in the collection's metadata in _config.yml: paged: true or paged: false. Paged collections get a single manifest containing all pages, unpaged collections get a separate manifest for each image.

To serve manifests to external clients over HTTP it is necessary to add a CORS header. In the jekyll development environment, this is achieved by adding this configuration to _config.yml:

webrick:
  headers:
    "Access-Control-Allow-Origin": "*"

In a production Apache environment, add Header set Access-Control-Allow-Origin "*" to a .htaccess file in the root of the jekyll deployment.

In either case you can find the manifest at tiles/<name>/manifest.json. You can paste its url into a demo such as Mirador.

Note that the manifest must include absolute urls to all IIIF resources, since it must be usable outside of the original site. This is awkward when moving between development and production jekyll environments. jekyll-iiif will use the default development host http://127.0.0.1:4000 when building the manifest, unless the JEKYLL_ENV environment variable is set to "production". In that case it will use the url property set in _config.yml. However, iiif_s3 won't be aware of the change, and won't regenerate the manifests when the environment changes. When changing environments, therefore, it is currently necessary to delete the tiles directory to force the regeneration of all the tiles and manifests.

Next steps