Class: Ebookie::Rendering::Pdf

Inherits:
Base
  • Object
show all
Defined in:
lib/ebookie/rendering/pdf.rb

Constant Summary

Constants inherited from Base

Base::IMAGE_SRC_REGEX

Instance Attribute Summary

Attributes inherited from Base

#document

Instance Method Summary collapse

Methods inherited from Base

#clean_images, #format, format, inherited, #initialize, #output_path, #render, #render_erb_to_file, #sanitize_html, set, #template_dir, #template_file, #tmp_dir

Constructor Details

This class inherits a constructor from Ebookie::Rendering::Base

Instance Method Details

#after_initialize ⇒ Object 



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# File 'lib/ebookie/rendering/pdf.rb', line 12

def after_initialize
  @wkhtmltopdf_path = Gem.bin_path("wkhtmltopdf-binary-edge")

  @ghostscript_path = `which gs`.chomp
  raise "GhostScript not installed" unless @ghostscript_path

  @tmp_path = tmp_dir.join("document.pdf")
  @pages = []

  settings[:files] << 'cover.html.erb' if convert_cover?
end

#convert_cover ⇒ Object 



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# File 'lib/ebookie/rendering/pdf.rb', line 73

def convert_cover
  borrow document.cover.to_s, to: tmp_dir.join('images', File.basename(document.cover))
  cover_path = tmp_dir.join("cover.pdf")

  margins = ['--margin-top 0', '--margin-bottom 0', '--margin-left 0', '--margin-right 0']
  convert_page(tmp_dir.join('cover.html'), cover_path, margins)

  return cover_path
end

#convert_cover? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ebookie/rendering/pdf.rb', line 69

def convert_cover?
  document.cover && File.extname(document.cover) != '.pdf'
end

#convert_page(input_path, output_path, args = []) ⇒ Object 



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# File 'lib/ebookie/rendering/pdf.rb', line 59

def convert_page(input_path, output_path, args=[])
  args << "--quiet"
  args << "--page-size Letter"
  args << "--title '#{document.title}'"
  command = [@wkhtmltopdf_path] + args
  command << input_path
  command << output_path
  system command.join(' ')
end

#process! ⇒ Object 



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# File 'lib/ebookie/rendering/pdf.rb', line 24

def process!
  convert_page(tmp_dir.join('document.html'), @tmp_path)

  ::PDF::Reader.new(@tmp_path).pages.each_with_index do |page, idx|
    prune_blank_page(idx)
  end

  if document.cover
    if File.extname(document.cover) != '.pdf'
      cover_path = convert_cover
      @pages.unshift cover_path
    else
      borrow document.cover.to_s, to: tmp_dir.join('cover.pdf')
      @pages.unshift tmp_dir.join('cover.pdf')
    end
  end

  pdf = CombinePDF.new
  @pages.compact.each do |page|
    pdf << CombinePDF.new(page)
  end
  pdf.save output_path
end

#prune_blank_page(index) ⇒ Object 



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# File 'lib/ebookie/rendering/pdf.rb', line 83

def prune_blank_page(index)
  output_file = tmp_dir.join("page-#{index}.pdf")
  options = ["-q",
             "-dBATCH",
             "-dNOPAUSE",
             "-sDEVICE=pdfwrite",
             "-dFirstPage=#{index+1}",
             "-dLastPage=#{index+1}",
             "-sOutputFile=#{output_file}"]

  system [@ghostscript_path, options.join(' '), @tmp_path].join(' ')

  colors = `#{@ghostscript_path} -q -o - -sDEVICE=inkcov #{output_file}`
  colors = colors.split(" ").uniq[0..-3]
  unless colors.length == 1 && colors.first == "0.00000"
    @pages << tmp_dir.join("page-#{index}.pdf")
  end
end

#sanitize(html) ⇒ Object 



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# File 'lib/ebookie/rendering/pdf.rb', line 48

def sanitize(html)
  html = html.dup
  {
    "—" => "&mdash;"
  }.each do |k,v|
    html.gsub! k, v
  end

  sanitize_html clean_images(html, tmp_dir.join("images"))
end