app/views/viewers/_mirador3.html.erb
<% exhibit_specific_manifest = document.exhibit_specific_manifest(current_exhibit.required_viewer.custom_manifest_pattern) %>
<% if exhibit_specific_manifest.present? %>
<%= content_tag :iframe, '',
src: "#{Settings.iiif_embed.url}?#{{ url: exhibit_specific_manifest, image_tools: true, canvas_id: document.canvas.iiif_id }.to_query}",
allowfullscreen: true,
class: 'mirador-embed-wrapper',
frameborder: 0,
marginwidth: 0,
marginheight: 0,
scrolling: 'no',
width: '100%'
%>
<%= iiif_drag_n_drop(exhibit_specific_manifest) %>
<% end %>