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Badger is a simple Rails plugin that creates photo badges. A site often allows its users to upload a profile image. A profile image is just that, an image resized to fit in a predefined space to show up in the user’s profile.

With Badger, you can have something prettier – a badge that shows the user- uploaded image on top of another image that identifies the user as a part of the community. We have company badges, security badges, so why not web badges to have your users show off his/her affection for your site?

Badger works by accepting cropping parameters of the overlay image in a hash (x1, y1, width, height), which is used to crop the overlay image. It then resizes the cropped image to the size specified by composite_width and composite_height in badger.yml. Finally, it places the resized image on top of the background image at location specified by composite_x and composite_y in badger.yml. The resulting image is saved back to either the filesystem or Amazon S3, using attachment_fu.

Badger requires the attachment_fu plugin, ImageMagick, and MiniMagick. Also, the JavaScript Image Cropper UI can be used to obtain the cropping parameters from the users.

Configuration

When this plugin is installed , the badger.yml will be copied to the config directory. You need to specify the following:

1. background : filename of the background image, searching from public/images
2. composite_x : top left corner of the overlay image location in x
3. composite_y : top left corner of the overlay image location in y
4. composite_width : width of the overlay image in pixels
5. composite_height : height of the overlay image in pixels

For example, I want to overlay an image on top of a background image (badge.jpg). The box for the overlay image should be 30 pixels in width and 20 pixels in height, and it should appear at (x, y) = (60, 80) of the background image. My badger.yml then looks like:

  development:
    background: badge.jpg
    composite_x: 60
    composite_y: 80
    composite_width: 30
    composite_height: 20

Example

In the model that you use to store attachments:

  class Photo < ActiveRecord::Base
    has_attachment :content_type => :image,
                   :storage => :s3,
                   :max_size => 1.megabytes,
                   :resize_to => '320x200>',
                   :thumbnails => { :thumb => '100x100>' },
                   :processor => :MiniMagick
    validates_as_attachment
    has_badge :storage => :s3
  end

In the controller:

  def create_my_awesome_badge
    @photo = Photo.find(params[:id])
    # params[:crop_coord] is a hash with indexes x1, y1, width, height
    @photo.create_badge(params[:crop_coord])
  end

Improvements Needed

Please feel free to submit patches for bug fixes and improvements. Specifically, I would like to:

1. Use something nicer than system(“convert blah…”), but couldn’t get it to work. I don’t think Minimagick supports compositing images, so RMagick may have to be used, but is it worth the heavy memory consumption?

2. Make it more flexible (i.e. accept background image and composite params dynamically instead of in badger.yml). Maybe pass them in the call to create_badge?