CarrierWave image processing powered by VIPS
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README.md

CarrierWave-VIPS

Build Status

Debian does not have a library for VIPS 8 yet. As soon as I can work out how to get it in a Travis build the tests should pass. In the meantime you can clone this repo yourself and run rspec in the base directory.

This adds support to CarrierWave for the ultrafast and resource efficient VIPS library.

Installation

gem install carrierwave-vips

If you need support for VIPS 7 please install a 1.0.x version of this gem. You will also need ruby-vips for VIPS 8. For instructions on how to install that see the repo: https://github.com/jcupitt/ruby-vips

If you are using bundler, add this to your Gemfile:

gem 'carrierwave-vips'

You will need to install the rmagick gem if you want to load GIF files. Writing GIFs is not supported by ruby-vips or this library.

A quick overview

See the instructions for CarrierWave to use this processor. You will need to include the Vips module in the upload class:

class AvatarUploader < CarrierWave::Uploader::Base
  include CarrierWave::Vips
end

You can use the following methods to change your images.

  • resize_to_fill(x,y) Will increase/decrease the size of the image and match the specified dimensions exactly, chopping off any extraneous bits.
  • resize_to_fit(x,y) Will increase/decrease the size of the image to fit within the specified dimensions. One dimension may be less than specified.
  • resize_to_limit(x,y) Just like resize_to_fit except will not increase size of image.
  • convert("jpeg|png") Changes the format of the image
  • quality(0-100) Sets the quality of the image being saved if JPEG
  • strip Removes any exif and ICC metadata contained in the image to reduce filesize.
  • auto_orient Rotates the image according to the Orientation EXIF tag and then removes the tag.

To see how vips stands up to other image processing libraries, see this benchmark: https://github.com/stanislaw/carrierwave-vips-benchmarks

Configuration

When reducing the size of images, a sharpening mask is used. To change or disable this behavior:

CarrierWave::Vips.configure do |c|
  c.sharpen_mask = false  # Disable sharpening mask on image reduction
  c.sharpen_mask = [      # Default mask
    [ -1, -1, -1 ], 
    [ -1, 24, -1 ], 
    [ -1, -1, -1 ] 
  ]
  c.sharpen_scale = 16     
end

See VIPS::Image.new_from_array for more information on what these two do.

Special considerations

If you use convert this library overrides the filename method used by CarrierWave to give the proper extension to the upload. If you want to override this method yourself, you can use the format_override method to get the file extension.

Libraries which rely on CarrierWave-VIPS

Contributors

  • John Cupitt (@jcupitt)
  • Stanislaw Pankevich (@stanislaw)
  • Mario Visic (@mariovisic)
  • Thom van Kalkeren (@fletcher91)