tebs / pdf_cover

Generate PDF cover images with Paperclip and Carrierwave

PdfCover

With this gem you can easily have attachments for PDF files that have associated images generated for their first page.

Support is provided both for Paperclip and CarrierWave.

In both cases the JPEG quality and resolution are optional and will be set to 85% and 300dpi respectively when not provided.

Paperclip Support

To add a PDF cover style to your attachments you can do something like this:

class WithPaperclip < ActiveRecord::Base
  include PdfCover

  pdf_cover_attachment :pdf, styles: { pdf_cover: ['', :jpeg]},
    convert_options: { all: '-quality 95 -density 300' },

  validates_attachment_content_type :pdf, content_type: %w(application/pdf)
end

This will define an attachment called pdf which has a pdf_cover style attached to it that is a JPEG of the first page in the PDF. You can pass any option that you would normally pass to has_attached_file in the options hash and it will be passed through to the underlying has_attached_file call.

CarrierWave

When using CarrierWave you can implement this gem's functionality you can do something like this:

class WithCarrierwaveUploader < CarrierWave::Uploader::Base
  include PdfCover

  storage :file

  version :image do
    pdf_cover_attachment quality: 95, resolution: 300
  end
end

In this case, when we mix the PdfCover module in, it adds the pdf_cover_attachment method to our uploader. We only need to call it inside one of our versions to get the pdf to image feature.

Developing this gem

After cloning this gem locally just run the bin/setup script to set everything up. This will:

• Run bundle to install the development dependencies.
• Initialize the database used by the spec/dummy rails application that we use to test the ActiveRecord+(Paperclip|CarrierWave) integration.
• Generate JPEG files used in the specs.

Running the specs

Once you have setup the gem locally you can just run rake from the root folder of the gem to run the specs.