[PATCH] mouseover/out for image_tag

This is definitely a helpful patch. I'm not sure if it should be applied to trunk, but if it is going to be it needs documentation.

A better implementation is probably to make a helper to make the JS tags and then use: (if the helper is named 'toggle_image')

image_tag("mouse.png", {}, toggle_image(image_path("mouseover.png")))

That should have been:

image_tag("mouse.png", toggle_image(image_path("mouseover.png")))

I sometimes use something like this:

  def image_rollover_tag(source, source_rollover, options = {})
      normal_image     = image_path(source) 
      rollover_image   = image_path(source_rollover)      
      image_tag(source, options.merge(:onmouseover => swap_image_to(rollover_image), :onmouseout => swap_image_to(normal_image)))
  end
  
  def swap_image_to(path)
    "this.src='#{path}'"
  end

A JS helper that generates the options for image_tag (like dcmanges suggests) might be cool too. Something like :

 def toggle_image(image1, image2)
   { :onmouseover => "this.src='#{image_path(image2)}'", 
     :onmouseout => "this.src='#{image_path(image1)}'" }
 end

Im attaching an updated patch that includes docs with some examples, and an additional test case.

revised patch with examples/docs/tests

To all people attached to this ticket, is is possible to get a +1? The revised patch has docs, tests and works great, so this can become Verified real quick. Thanks.

The mouseover img path should be passed through image_path as well.

Did just that. I have reapplied the patch to current trunk. Tests all pass.

Up to date patch including David's suggestion

This seems like a clear fit for a plugin. What's the case for inclusion in core?

In my opinion it's too tiny for a plugin, and it is a helpful helper for a common use of images. I see it as on par with the :size attribute. Nessesary? No. Helpful? Yes.

It decreases the amount of code if one wants to show onmouseover images. It does this in a way that is usable by 100% of the audience: the onmouseover and onmouseout attributes are standard. It decreases the amount of per-application helper methods, too, and does it in a properly tested and well-documented fashion.

(In [8110]) Added :mouseover short-cut to AssetTagHelper#image_tag for doing easy image swaps (closes #6893) [joost]