Hires (2x DPR) image support for Gravatars (#24927).

Patch by Jan Schulz-Hofen.

git-svn-id: https://svn.redmine.org/redmine/trunk@16313 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/plugins/gravatar/lib/gravatar.rb

@@ -52,6 +52,10 @@ module GravatarHelper
       src = h(gravatar_url(email, options))
       options = DEFAULT_OPTIONS.merge(options)
       [:class, :alt, :title].each { |opt| options[opt] = h(options[opt]) }
+
+      # double the size for hires displays
+      options[:srcset] = "#{gravatar_url(email, options.merge(size: options[:size].to_i * 2))} 2x"
+
       image_tag src, options
     end