carrierwave

https://github.com/jnicklas/carrierwave

Ruby

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

CarrierWave::MiniMagick#resize_and_pad

Resize the image to fit within the specified dimensions while retaining
the original aspect ratio. If necessary, will pad the remaining area
with the given color, which defaults to transparent (for gif and png,
white for jpeg).

See http://www.imagemagick.org/script/command-line-options.php#gravity
for gravity options.

=== Parameters

[width (Integer)] the width to scale the image to
[height (Integer)] the height to scale the image to
[background (String, :transparent)] the color of the background as a hexcode, like "#ff45de"
[gravity (String)] how to position the image

=== Yields

[MiniMagick::Image] additional manipulations to perform

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-resize_and_pad-for-pr

# Commit to git

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

# 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-resize_and_pad-for-pr

hub pull-request

# Celebrate!