scinote-web/app/views/canvas/_canvas_view_navigator.html.erb

<% if @experiment.my_modules.any?(&:active?) %>
  <% if @experiment.workflowimg.attached? %>
    <canvas class="canvas-preview-img" data-image-url="<%= url_for(@experiment.workflowimg) %>"></canvas>
    <canvas class="canvas-preview-rect"></canvas>
  <% else %>
    <canvas class="canvas-preview-img processing"
            data-workflowimg-present="false"
            data-workflowimg-url="<%= fetch_workflow_img_experiment_url(@experiment) %>"></canvas>
    <canvas class="canvas-preview-rect"></canvas>
  <% end %>
<% else %>
  <canvas class="canvas-preview-img empty"></canvas>
  <canvas class="canvas-preview-rect"></canvas>
<% end %>