Enabled to show graph in preview.

init.rb

@@ -4,7 +4,7 @@ Redmine::Plugin.register :redmine_mermaid_macro do
   name 'Redmine Mermaid Macro plugin'
   author 'Taiki IKEGAME'
   description 'Add mermaid graphs to your wiki.'
-  version '0.0.1'
+  version '1.0.0'
   url 'https://github.com/taikii/redmine_mermaid_macro'
   author_url 'https://taikii.github.io'
 
@@ -21,8 +21,10 @@ Redmine::Plugin.register :redmine_mermaid_macro do
          "    C-->D;\n" +
          "}}"
     macro :mermaid do |obj, args, text|
+      divid = "mermaid_" + SecureRandom.urlsafe_base64(8)
       out = ''.html_safe
-      out << content_tag('div', text, :class => 'mermaid')
+      out << content_tag(:div, text, id: divid, class: 'mermaid')
+      out << javascript_tag("if (typeof mermaidInitialized != 'undefined') {mermaid.init(undefined, $('#" + divid + "'));};")
       out
     end
   end

lib/mermaid_macro_hook.rb

@@ -5,7 +5,7 @@ class MermaidMacroHookListener < Redmine::Hook::ViewListener
   def view_layouts_base_body_bottom(context={})
     html = ""
     html << javascript_include_tag(Setting.plugin_redmine_mermaid_macro['mermaid_url'])
-    html << javascript_tag("mermaid.initialize({startOnLoad:true});")
+    html << javascript_tag("mermaid.initialize({startOnLoad:true});var mermaidInitialized = 1;")
     return html
   end