Improve img alt attribute for screen readers

Currently, the img_alt method in ActionView keeps underscores
in the alt attribute. Because underscores are pronounced in
Apple's VoiceOver Utility, this has serious implications for
accessibility. This patch makes underscored or hyphenated file
names (both common in projects) read more naturally in screen
readers by replacing them with spaces. See method documentation
for details.

Added documentation to image_alt method

1 files changed, 17 insertions, 3 deletions

diff --git a/actionpack/lib/action_view/helpers/asset_tag_helper.rb b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
index 5b3a2cae7c..6387b89a81 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
@@ -214,10 +214,24 @@ module ActionView
       end
 
       # Returns a string suitable for an html image tag alt attribute.
-      # +src+ is meant to be an image file path.
-      # It removes the basename of the file path and the digest, if any.
+      # The +src+ argument is meant to be an image file path.
+      # The method removes the basename of the file path and the digest, 
+      # if any. It also removes hyphens and underscores from file names and
+      # replaces them with spaces, returning a space-separated, titleized
+      # string.
+      # 
+      # ==== Examples
+      #
+      #   image_tag('rails.png')
+      #   # => <img alt="Rails" src="/assets/rails.png" />
+      #
+      #   image_tag('hyphenated-file-name.png')
+      #   # => <img alt="Hyphenated file name" src="/assets/hyphenated-file-name.png" />
+      #   
+      #   image_tag('underscored_file_name.png')
+      #   # => <img alt="Underscored file name" src="/assets/underscored_file_name.png" />
       def image_alt(src)
-        File.basename(src, '.*').sub(/-[[:xdigit:]]{32}\z/, '').capitalize
+        File.basename(src, '.*').sub(/-[[:xdigit:]]{32}\z/, '').tr('-_', ' ').capitalize
       end
 
       # Returns an html video tag for the +sources+. If +sources+ is a string,