README.MD

A Ruby wrapper for Node SVGO

Removes metadata and editor data elements and attributes that are redundant from SVG files. Can strip files so they are optimised for web use. Go to SVGO for more documentation on features.

Note to users of 1.x versions

execjs is no longer used as a wrapper around JavaScript run times, instead mini_racer is used directly. That means one dependency is removed. mini_racer was already a dependency so it should not make a difference during installation.

How to use?

As a library

As intended: a Ruby library. Add it to your Gemfile or *.gemspec file and install it.

Method 1 (Recommended)

By supplying a block that modifies the default options in SvgoOptions.

require('svgo')
svg_file = "path/to/a.svg"
svgo = SvgOptimizer.new() do | options |
    options.plugins << :removeRasterImages # (disabled by default)
    options.plugins.delete(:cleanupIDs) # (enabled by default)
    options.js2svg.pretty = true
end
svgo.optimize(File.read(svg_file))
# => <svg xmlns="http://www.w3.org/2000/svg" ...

Method 2

You can manually pass options to the class that correspond to SVGO's documentation.

require('svgo')
svg_file = "path/to/a.svg"
options = {
    floatPrecision: 7,
    js2svg: {
        pretty: true
    },
    multipass: false
}
svgo = SvgOptimizer.new(options)
svgo.optimize(File.read(svg_file))
# => <svg xmlns="http://www.w3.org/2000/svg" ...

# OR..

svgo.optimize_file(svg_file)
# => <svg xmlns="http://www.w3.org/2000/svg" ...

You can also choose the plugins to use, you can either pass the exact plugins you want with their configuration, or you can modify the default plugin list.

require('svgo')
svg_file = "path/to/a.svg"
options = {
    plugins: {
        addAttributesToSVGElement: true,
        addClassesToSVGElement: true,
        cleanupAttrs: false,
        cleanupEnableBackground: true,
        cleanupIDs: false,
        cleanupListOfValues: true,
        collapseGroups: true,
        cleanupNumericValues: true,
        #etc..
    }
}
svgo = SvgOptimizer.new(options)

As a CLI tool

Strictly speaking this mode is for testing only. But if you can't install NodeJS, and you do have a Ruby environment and you really need a CLI tool, you might be able to squeeze out some optimised files from this utility.

gem install svgo-ruby
svgo-ruby --pretty < test/fixtures/ruby.svg > test/fixtures/ruby.optim.svg
ls -hl test/fixtures
total 72
-rw-r--r--  1 user  staff   9.5K Nov  5 22:16 ruby.optim.svg
-rw-r--r--  1 user  staff    23K Nov  5 22:12 ruby.svg

As a CLI tool from docker

Because this uses a Node utility from a monolithic JavaScript environment which is highly dependent on whatever version is available on your system, etc. There is a Dockerfile which should always build correctly and run the CLI tool.

This is also only intended for testing purposes.

docker build -t svgo ./
docker run -i svgo < test/fixtures/ruby.svg > test/fixtures/ruby.optim.svg
-rw-r--r--  1 user  staff   9.5K Nov  5 22:16 ruby.optim.svg
-rw-r--r--  1 user  staff    23K Nov  5 22:12 ruby.svg

How this works

mini_racer is used to run the Node SVGO as a library. The SVGO library returns a JavaScript Promise, which is currently not supported by mini_racer and perhaps never will be. setTimeout and sleep-like functions are also disabled in mini_racer so we can't wait for the Promise to get fulfilled. Therefore there is a small wrapper JavaScript in this repository that calls all the components that SVGO is made up of, but without the Promise. It also wraps up the configuration of plugins the way it is expected by SVGO's components. Lastly require is not supported by mini_racer so all of this is transpiled to one monolithic JavaScript file - that is completely self-contained, using browserify.

Transpiling Node SVGO

TL;DR: A transpiled version of SVGO is included in the repository, so you don't need to transpile anything.

Because mini_racer supports only self-contained modules, and does not allow require(), Promise etc.. The SGVO library is wrapped in a JavaScript that requires all the main parts of SVGO and makes an SVGO function without JavaScript Promises. The wrapper is then transpiled to a self-contained module using browserify.

The transpile command can be found in the Rakefile. Assuming you have Node and yarn installed on your system, you can then run:

yarn install
rake

Note: if you do not have yarn you can run npm install instead, but if you install Node modules often, you probably should do yourself a favour check out yarn.