EasyImaging

If you are using the Paperclip Gem to store your files but would also like to be manipulate the images in your app, then this is the easiest Gem to get you started.

You can use any of the ImageMagick (or even Graphicsmagick) methods.

Find a list of image manipulation options here: http://www.imagemagick.org/script/command-line-options.php

Installation

Add this line to your application's Gemfile:

gem 'easy_imaging'

And then execute:

$ bundle

Or install it yourself as:

$ gem install easy_imaging

You can perform image manipulation in 2 ways with this gem

1. Image manipulation through the EasyImaging Module.
2. Image manipulation through instance methods.

Any of the following examples will be for a 'User' model with a Paperclip image attribute name of 'avatar'.

Example Model I'll be referencing:

  class User < ActiveRecord::Base
    validates :avatar, presence: true

    # Paperclip details:
    has_attached_file :avatar,
        styles: {
          large: '640x480>',
          thumb: '105x105>',
          listing: '225x225>',
          general: '640x480>'
        },
        :url  => "/avatars/:class/:style/:id",
        :path => ":rails_root/public/avatars/:class/:style/:id"
  end

1) Image manipulation through the EasyImaging Module.

Any model instance with a Paperclip image attached can now run any of ImageMagick's methods.

You have the option of applying manipulation to all the instance's style keys, or to all style keys but the original. To apply to all including the original, add a "bang" to the end of the method.

Using the ImageMagick methods are easy, the naming convention follows a simple pattern.

EasyImaging.#{method}_image(@user.avatar, *args)

Apply to all styles but the original:

  # Reflect the scanlines in the vertical direction. The image will be mirrored upside-down.
  EasyImaging.flip_image(@user.avatar)

  # Reflect the scanlines in the horizontal direction, just like the image in a vertical mirror.
  EasyImaging.flop_image(@user.avatar)

  # Rotate the picture 90 degrees counter clockwise.
  EasyImaging.rotate_image(@user.avatar, "-90")

  # Crop the image at these xy points in the picture.
  EasyImaging.crop_image(@user.avatar, "120x120+10+5")

Apply to all styles, including original:

  # Reflect the scanlines in the vertical direction. The image will be mirrored upside-down.
  EasyImaging.flip_image!(@user.avatar)

  # Reflect the scanlines in the horizontal direction, just like the image in a vertical mirror.
  EasyImaging.flop_image!(@user.avatar)

  # Rotate the picture 90 degrees counter clockwise.
  EasyImaging.rotate_image!(@user.avatar, "-90")

  # Crop the image at these xy points in the picture.
  EasyImaging.crop_image!(@user.avatar, "120x120+10+5")

2) Image manipulation through instance methods.

You can actually apply the methods onto the Paperclip image's model and use the methods as instance methods.

You'll need to add 2 things to your model which has the image instance in order to do this. 1) 'include EasyImaging' inside your model. 2) define a paperclip_image method which returns the attribute holding your image.

For an example, I'll add the instance methods to a 'User' Model which calls it's Paperclip image attribute 'avatar'

class User < ActiveRecord::Base

  include EasyImaging

  ...

  def paperclip_image
    avatar
  end
end

Once you are ready to use the instance methods:

  # Reflect the scanlines in the vertical direction. The image will be mirrored upside-down.
  @user.flip_image

  # Reflect the scanlines in the horizontal direction, just like the image in a vertical mirror.
  @user.flop_image

  # Rotate the picture 90 degrees counter clockwise.
  @user.rotate_image("-90")

  # Crop the image at these xy points in the picture.
  @user.crop_image("120x120+10+5")

Development

After checking out the repo, run bin/setup to install dependencies. Then, run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release to create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

1. Fork it ( https://github.com/[my-github-username]/easy_imaging/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request