Oil¶ ↑

github.com/ender672/oil

Oil is a Ruby extension for resizing JPEG and PNG images. It aims for fast performance and low memory use.

$ gem install oil

# when using homebrew w/ jpeg-turbo
$ gem install oil --with-ldflags=-L/usr/local/opt/jpeg-turbo/lib --with-cflags=-I/usr/local/opt/jpeg-turbo/include

require 'oil'

# Oil uses IO objects for input & output.
io_in = File.open('image.jpg', 'rb')
io_out = File.open('image_resized.jpg', 'w')

# Read the source image header and prepare to fit it into a 200x300 box.
img = Oil.new(io_in, 200, 300)

# Write the resized image to disk
img.each { |data| io_out << data }

* libjpeg-turbo
* libpng

Installing libjpeg and libpng headers (Debian/Ubuntu):

$ sudo apt-get install libjpeg-dev libpng-dev

Compile & run unit tests. Should show no warnings and no failing tests:

$ rake compile
$ rake test

Valgrind should not complain (ruby-1.9.3p125, compiled with -O3):

$ valgrind /path/to/ruby -Iext:test test/test_jpeg.rb
$ valgrind /path/to/ruby -Iext:test test/test_png.rb

Changes to the interpolator should be analyzed using ResampleScope:

https://github.com/jsummers/resamplescope