ruby-vips¶ ↑

This gem is a Ruby binding for the libvips image processing library. It has been tested on Linux, macOS and Windows, and with ruby 2, ruby 3 and jruby. It uses ruby-ffi to call functions in the libvips library.

libvips is a demand-driven, horizontally threaded image processing library. Compared to similar libraries, libvips runs quickly and uses little memory. libvips is licensed under the LGPL 2.1+.

Install on linux and macOS¶ ↑

Install the libvips binary with your package manager (eg. apt install libvips42 or perhaps brew install vips, see the libvips install instructions) then install this gem with:

gem install ruby-vips

Or include gem "ruby-vips" in your gemfile.

Install on Windows¶ ↑

The gemspec will pull in the msys libvips for you, so all you need is:

gem install ruby-vips

Or include gem "ruby-vips" in your gemfile.

Tested with the ruby and msys from choco, but others may work.

Example¶ ↑

require "vips"

im = Vips::Image.new_from_file filename

# put im at position (100, 100) in a 3000 x 3000 pixel image,
# make the other pixels in the image by mirroring im up / down /
# left / right, see
# https://www.libvips.org/API/current/method.Image.embed.html
im = im.embed 100, 100, 3000, 3000, extend: :mirror

# multiply the green (middle) band by 2, leave the other two alone
im *= [1, 2, 1]

# make an image from an array constant, convolve with it
mask = Vips::Image.new_from_array [
    [-1, -1, -1],
    [-1, 16, -1],
    [-1, -1, -1]], 8
im = im.conv mask, precision: :integer

# finally, write the result back to a file on disk
im.write_to_file output_filename

Documentation¶ ↑

There are full API docs for ruby-vips on rubydoc. This sometimes has issues updating, so we have a copy on the gh-pages for this site as well, which should always work.

See the Vips section in the docs for a tutorial introduction with examples.

The libvips reference manual has a complete explanation of every method.

The {example/} directory has some simple example programs.

Benchmarks¶ ↑

The benchmark at vips-benchmarks loads a large image, crops, shrinks, sharpens and saves again, and repeats 10 times.

real time in seconds, fastest of five runs
benchmark       tiff    jpeg
ruby-vips.rb    0.85    0.78    
image-magick    2.03    2.44    
rmagick.rb      3.87    3.89    

peak memory use in kb
benchmark       peak RES
ruby-vips.rb    43864
rmagick.rb      788768

See also benchmarks at the official libvips website.