Add support for @2x, @3x, etc. hires images (#24922).

Patch by Jan Schulz-Hofen.

git-svn-id: http://svn.redmine.org/redmine/trunk@16311 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/helpers/application_helper.rb

@@ -636,7 +636,7 @@ module ApplicationHelper
 
     parse_sections(text, project, obj, attr, only_path, options)
     text = parse_non_pre_blocks(text, obj, macros) do |text|
-      [:parse_inline_attachments, :parse_wiki_links, :parse_redmine_links].each do |method_name|
+      [:parse_inline_attachments, :parse_hires_images, :parse_wiki_links, :parse_redmine_links].each do |method_name|
         send method_name, text, project, obj, attr, only_path, options
       end
     end
@@ -681,6 +681,15 @@ module ApplicationHelper
     parsed
   end
 
+  # add srcset attribute to img tags if filename includes @2x, @3x, etc.
+  # to support hires displays
+  def parse_hires_images(text, project, obj, attr, only_path, options)
+    text.gsub!(/src="([^"]+@(\dx)\.(bmp|gif|jpg|jpe|jpeg|png))"/i) do |m|
+      filename, dpr = $1, $2
+      m + " srcset=\"#{filename} #{dpr}\""
+    end
+  end
+
   def parse_inline_attachments(text, project, obj, attr, only_path, options)
     return if options[:inline_attachments] == false