carrierwave

https://github.com/jnicklas/carrierwave

Ruby

Classier solution for file uploads for Rails, Sinatra and other Ruby web frameworks

CarrierWave::MiniMagick#manipulate!

Manipulate the image with MiniMagick. This method will load up an image
and then pass each of its frames to the supplied block. It will then
save the image to disk.

=== Gotcha

This method assumes that the object responds to +current_path+.
Any class that this module is mixed into must have a +current_path+ method.
CarrierWave::Uploader does, so you won't need to worry about this in
most cases.

=== Yields

[MiniMagick::Image] manipulations to perform

=== Raises

[CarrierWave::ProcessingError] if manipulation failed.

Source | Google | Stack overflow

Edit

git clone [email protected]:jnicklas/carrierwave.git

cd carrierwave

open lib/carrierwave/processing/mini_magick.rb

Contribute

# Make a new branch

git checkout -b -your-name--update-docs-CarrierWave--MiniMagick-manipulate--for-pr

# Commit to git

git add lib/carrierwave/processing/mini_magick.rbgit commit -m "better docs for CarrierWave::MiniMagick#manipulate!"

# Open pull request

gem install hub # on a mac you can `brew install hub`

hub fork

git push <your name> -your-name--update-docs-CarrierWave--MiniMagick-manipulate--for-pr

hub pull-request

# Celebrate!