Module: Ocr4pdf::CreateOcrPdf

Defined in:
lib/ocr4pdf/create_ocr_pdf.rb

Class Method Summary collapse

Class Method Details

.run(src) ⇒ Object 



7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
 
# File 'lib/ocr4pdf/create_ocr_pdf.rb', line 7

def self.run(src)
  # Make src an absolute path:
  src = File.expand_path(src)

  # Only allow PDF files as input:
  file_type = Open3.capture2("file -b --mime-type #{src}")[0].strip
  raise "Input file must be a PDF" unless file_type == "application/pdf"

  pdf_info_raw = Open3.capture2("pdfinfo", src)[0].split("\n")

  pdf_info = {}
  pdf_info_raw.each { |v| pdf_info[v.split(":")[0]] = v.split(":")[1] }

  page_count = pdf_info["Pages"].to_i
  # TODO: Eventually, should add an exception for 0 pages

  format_helper = page_count.to_s.length

  Dir.mktmpdir do |tmp_dir|
    # TODO: Eventually, should add unpaper usage right around here. That way they not only parse better but look better too.

    Dir.chdir("#{tmp_dir}/") do
      1.upto(page_count) do |page|
        base_name = page.to_s.rjust(format_helper, "0")
        # Create a TIFF file for the page:
        Open3.capture2("pdftocairo -singlefile -f #{page} -l #{page} -tiff #{src} #{base_name}")
        # Run Tesseract on the TIFF, exporting as a PDF:
        Open3.capture2("tesseract #{base_name}.tif #{base_name} pdf quiet")
      end
      # Unite the pages into a single PDF:
      Open3.capture2("pdfunite #{tmp_dir}/*.pdf #{File.basename(src, ".*")}.ocr.pdf")
      File.binread("#{File.basename(src, ".*")}.ocr.pdf").dup
    end
  end
end