Contents

# retina_image_tag

retina_image_tag is a ViewHelper for Rails 3.1. in contrast to the normal Rails image_tag knows the retina_image_tag if the user invokes an image on a Apple Retina Display.

### Retina Display
The Retina Display on the iPhone4 and iPad3 doubles the pixel resolution of the display.
You can think about a full screen display with dimensions of 320x480 for iPhone4 and 1024x768 for iPad3. The big difference is that these dimensions are now expressed in points not in pixels. What has changed is the scaling factor of the screen which determines how a point relates to a pixel. The iPhone4 retina display has a scale of 2 so that 1 point = 2 pixels.

### @2x
The '@2x' naming convention will be instantly familiar to any iOS developer. It's simply a way of naming an alternate, high-resolution version of an image so that it will be recognized and used by high-resolution Retina Displays.

### Example
herokuapp: <http://retinaimagetag-demoapp.herokuapp.com/>

sourcecode: <https://github.com/ffaerber/retina_image_tag_demoapp/>



## Installation

Add this line to your application's Gemfile:

    gem 'retina_image_tag'

add this line to application.js:
	
	//= require retina_image_tag

And then execute:

    $ bundle




## Usage

```erb
<%= retina_image_tag 'foo.jpg', :size => "400x400" %>
```


## Workflow

start working with the @2x version.

To scale down the @2x images run `rake retina_image_tag:convert`, the rake task will look for @2x image in `app/assets/images/`, creates a copy and renames those files and reduces the image dimensions.

before:

* `[e-mail] (800x800px)`
* `subdir/[e-mail] (1000×556px)` 

after:

* `[e-mail] (800x800px)`
* `foo.jpg (400x400px)`
* `subdir/[e-mail] (1000×556px)`
* `subdir/bar.png (500×278px)`


## Contributing

1. Fork it
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Added some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create new Pull Request

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
retina_image_tag-0.0.13	README.md
retina_image_tag-0.0.11	README.md