OpenLayers Zoom (plugin for Omeka)

Summary

This plugin for the Omeka platform adds a zoom widget that creates zoom-able tiles from images and presents it in a pure javascript zoom viewer (no Flash).

Tiles are automatically created when the selected image is saved.

This plugin is compatible with IIPImage realtime tiles server, which avoids creation and storage of tiles.

This plugin uses the OpenLayers widget to display images and the base of the code was built for OldsMapOnline.

Tiles that are created follow the Zoomify standard.

Visit the OpenLayers Zoom demo for more info.

Installation

ImageMagick or GD should be installed on the server and enabled in php.

Unzip OpenLayers Zoom into the plugin directory, rename the folder "OpenLayersZoom" if needed, then install it from the settings panel.

In the items/show.php of your theme, replace:

    <div id="item-images">
        <?php echo files_for_item(); ?>
    </div>

by

    <div id="item-images">
        <?php set_loop_records('files', $item->getFiles());
        foreach (loop('files') as $file):
            fire_plugin_hook('open_layers_zoom_display_file', array('file' => $file));
        endforeach; ?>
    </div>

Be careful to keep the div with id "item-images" around the call to OpenLayers, otherwise it won't work.

Edit views/shared/css/OpenLayersZoom.css to change the size/appearance of the zoom viewer.

Use

Edit an item with an image attached to it. On the left is a zoom tab. Check the box next to the image thumbnail and save changes. The image will now be presented as a zoomed image in the public item page.

Currently, tiling is made without job process, so you may have to increase the max allowed time (and the memory limit) for process in php.ini.

For huge images, it's recommanded to create tiles offline via a specialized photo software, eventually with a Zoomify plugin, or to use a script that calls the ZoomifyFileProcessor.php library, else to use IIPImage.

To use IIPImage, the element Tile Server URL should be created in the Item Type Metadata set, and this field should be filled in the item form with the query url to the image.

Warning

Use it at your own risk.

It's always recommended to backup your files and database so you can roll back if needed.

Troubleshooting

See online OpenLayers Zoom issues page on GitHub.

License

• This plugin is published under GNU/GPL.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

• This plugin contains libraries with other free and open source licences. See files inside helpers folder.

Contact

Current maintainers:

• Daniel Berthereau (see Daniel-KM)
• Peter Binkley for University of Alberta Libraries
• Matt Miller

First version of this plugin has been built by Matt Miller. Thanks to Nancy Moussa @ U of Michigan for bug fixes and individual unzoom feature. It has been improved by Peter Binkley for University of Alberta Libraries. The upgrade for Omeka 2.0 has been built for Mines ParisTech.

Copyright

• @copyright Daniel Berthereau, 2013
• @copyright Peter Binkley, 2012-2013
• @copyright Matt Miller, 2012

See copyrights for libraries in files inside helpers folder.