How Thumbnails Get rendered - samvera/hyrax GitHub Wiki
Thumbnails get rendered on the UI by displaying an image with the path defined in a field in Solr. By default that field is 'thumbnail_path_ss' defined here. Once the path is indexed into solr and object would need to be re-indexed for the thumbnail to change.
The path gets indexed into solr by the Indexer. The default indexers can be found here. Each indexer uses a ThumbnailPathServer to generate the string used in solr Sound here.
You can change the default behavior by creating your own ThumbnailPathService and Indexer that includes a line to point to you new ThumnbnailPathService
module MyNamespace
class MyIndexer < Hyrax::WorkIndexer
self.thumbnail_path_service = MyNamespace::MyThumbnailPathService
end
end
You will then need your work to point at your new indexer
class MyWork
self.indexer = MyNamespace::MyIndexer
end