OpenSeadragon 

OpenSeadragon is a javascript library for displaying tiling images. This gem packages those assets and some Rails helpers for using them.

http://openseadragon.github.io/

Installation

Add the gem to your Gemfile:

``ruby
gem 'openseadragon'
`

Run bundle install:

`
$ bundle install
`

And run the openseadragon-rails install generator:

`
$ bundle exec rails g openseadragon:install
`

The generator will install the Rails helpers and openseadragon assets.

Usage

You must provide the openseadragon npm package as an external dependency.

See https://openseadragon.github.io for further details




$3


This gem provides two helpers, #picture_tag and #openseadragon_picture_tag.

#### picture_tag

The #picture_tag helper creates HTML5 tags.

In the simple case, a view like:

`ruby
picture_tag 'page1.jpg', 'page2.jpg', 'page3.jpg'
`

Creates the HTML like:

`html





`

You can control the attributes on and elements:

`ruby
picture_tag ['page1.jpg' => { id: 'first-picture'}], 'page2.jpg', 'page3.jpg', { class: "picture-image" }, { id: 'my-picture'}
`

`html





`

#### openseadragon_picture_tag

If you have an OpenSeaDragon tilesource, you can use this helper to construct a HTML5 that will render as an OpenSeaDragon tile viewer.

`ruby
openseadragon_picture_tag 'page1.jpg'
`

`html



`

This gem includes some javascript that translates that markup to the OSD viewer.

As with #picture_tag, you can provide additional options.

`ruby
openseadragon_picture_tag 'page1.jpg', 'path/to/info.json', ['some-custom-tilesource' => { Image: { xmlns: "...", Url: '...', Format: 'jpg', Overlap: 2}}], { class: 'osd-image'}, { data: { openseadragon: { preserveViewport: true, visibilityRatio: 1}}}
`

`html





`

The src attribute (or the JSON-encoded options given in the data-openseadragon) are translated into an OpenSeaDragon tilesource` configuration.