Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Uses wkhtmltoimage to create JPGs and PNGs from HTML

README.md

IMGKit

Create JPGs using plain old HTML+CSS. Uses wkhtmltoimage on the backend which renders HTML using Webkit.

Heavily based on PDFKit.

Install

IMGKit

gem install imgkit

wkhtmltoimage

  1. Use installer: sudo imgkit --install-wkhtmltoimage install latest version into /usr/local/bin (overwrite defaults with e.g. ARCHITECTURE=amd64 TO=/home/foo/bin)
  2. Install by hand: http://wkhtmltopdf.org/downloads.html
  3. Try using the wkhtmltoimage-binary gem (mac + linux)
gem install wkhtmltoimage-binary

Usage

# IMGKit.new takes the HTML and any options for wkhtmltoimage
# run `wkhtmltoimage --extended-help` for a full list of options
kit = IMGKit.new(html, :quality => 50)
kit.stylesheets << '/path/to/css/file'
kit.javascripts << '/path/to/js/file'

# Get the image BLOB
img = kit.to_img

# New in 1.3!
img = kit.to_img(:jpg)      #default
img = kit.to_img(:jpeg)
img = kit.to_img(:png)

# Save the image to a file
file = kit.to_file('/path/to/save/file.jpg')
file = kit.to_file('/path/to/save/file.png')

# IMGKit.new can optionally accept a URL or a File.
# Stylesheets nor Javascripts can not be added when source is provided as a URL of File.
kit = IMGKit.new('http://google.com')
kit = IMGKit.new(File.new('/path/to/html'))

# Add any kind of option through meta tags
IMGKit.new('<html><head><meta name="imgkit-quality" content="75"...

# Format shortcuts - New in 1.3!
IMGKit.new("hello").to_jpg
IMGKit.new("hello").to_jpeg
IMGKit.new("hello").to_png

Note: Ruby's buffered I/O means that if you want to write the string data to a file or tempfile make sure to call `#flush` to ensure the contents don't get stuck in the buffer.

Configuration

wkhtmltoimage binary location

If you're on Windows or you installed wkhtmltoimage by hand to a location other than /usr/local/bin you will need to tell IMGKit where the binary is. You can configure IMGKit like so:

# config/initializers/imgkit.rb
IMGKit.configure do |config|
  config.wkhtmltoimage = '/path/to/wkhtmltoimage'
end

Default image format

May be set to one of IMGKit::KNOWN_FORMATS = [:jpg, :jpeg, :png]

  config.default_format = :png

Prefix for <meta> tag options (see Usage) :

May be changed from its default (imgkit-):

  config.meta_tag_prefix = 'imgkit-option'

Additional default options

Any flag accepted by wkhtmltoimage may be set thus:

  config.default_options = {
    :quality => 60
  }

For a flag which takes no parameters, use true for the value:

    'no-images' => true

For flags with multiple parameters, use an array:

    :cookie => ['my_session', '123BADBEEF456']

Overriding options

When initializing an IMGKit options may be may be set for the life time of the IMGKit object:

IMGKit.new('http://example.com/form', :post => ['my_field', 'my_unique_value'])

Heroku

get a version of wkhtmltoimage as an amd64 binary and commit it to your git repo. I like to put mine in "./bin/wkhtmltoimage-amd64"

version 0.10.0 has worked best for me

assuming its in that location you can just do:

IMGKit.configure do |config|
  config.wkhtmltoimage = Rails.root.join('bin', 'wkhtmltoimage-amd64').to_s if ENV['RACK_ENV'] == 'production'
end

If you're not using Rails just replace Rails.root with the root dir of your app.

Rails

Mime Types

register a .jpg mime type in:

#config/initializers/mime_type.rb
Mime::Type.register       "image/jpeg", :jpg

register a .png mime type in:

#config/initializers/mime_type.rb
Mime::Type.register       "image/png", :png

Controller Actions

You can respond in a controller with:

@kit = IMGKit.new(render_to_string)

format.jpg do
  send_data(@kit.to_jpg, :type => "image/jpeg", :disposition => 'inline')
end

- or -

format.png do
  send_data(@kit.to_png, :type => "image/png", :disposition => 'inline')
end

- or -

respond_to do |format|
  send_data(@kit.to_img(format.to_sym),
            :type => "image/png", :disposition => 'inline')
end

This allows you to take advantage of rails page caching so you only generate the image when you need to.

--user-style-sheet workaround

To overcome the lack of support for --user-style-sheet option by wkhtmltoimage 0.10.0 rc2 as reported here http://code.google.com/p/wkhtmltopdf/issues/detail?id=387

  require 'imgkit'
  require 'restclient'
  require 'stringio'

  url = 'http://domain/path/to/stylesheet.css'
  css = StringIO.new( RestClient.get(url) )

  kit = IMGKit.new(<<EOD)
  <!DOCTYPE HTML>
  <html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>coolest converter</title>
  </head>
  <body>
    <div class="cool">image kit</div>
  </body>
  </html>
  EOD

  kit.stylesheets << css

Paperclip Example

Model:

class Model < ActiveRecord::Base
  # attr_accessible :title, :body
   has_attached_file :snapshot, :storage => :s3,
        :s3_credentials => "#{Rails.root}/config/s3.yml"
end

Controller:

def upload_image
   model = Model.find(params[:id])
   html  = render_to_string
   kit   = IMGKit.new(html)
   img   = kit.to_img(:png)
   file  = Tempfile.new(["template_#{model.id}", 'png'], 'tmp',
                         :encoding => 'ascii-8bit')
   file.write(img)
   file.flush
   model.snapshot = file
   model.save
   file.unlink
end

CarrierWave Workaround

Contributed by @ticktricktrack

  class MyClass < ActiveRecord::Base
    mount_uploader :snapshot, SnapshotUploader

    after_create :take_snapshot

    # private

    def take_snapshot
      file = Tempfile.new(["template_#{self.id.to_s}", 'jpg'], 'tmp', :encoding => 'ascii-8bit')
      file.write(IMGKit.new(self.html_body, quality: 50, width: 600).to_jpg)
      file.flush
      self.snapshot = file
      self.save
      file.unlink
    end
  end

Note on Patches/Pull Requests

  • Fork the project.
  • Setup your development environment with: gem install bundler; bundle install
  • Make your feature addition or bug fix.
  • Add tests for it. This is important so I don't break it in a future version unintentionally.
  • Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
  • Send me a pull request. Bonus points for topic branches.

Testing

Travis.yml is configured for multiple rubies, so I would just test a 2.1.x version and let travis handle the rest.

Copyright

Copyright (c) 2010 Chris Continanza Based on work by Jared Pace See LICENSE for details.

Something went wrong with that request. Please try again.