Module: PDFThumbnail

Included in:
Filters
Defined in:
lib/jekyll-pdf-thumbnail.rb

Defined Under Namespace

Modules: Filters

Constant Summary collapse

CACHE_DIR = 
"/assets/pdf_thumbnails/"
HASH_LENGTH = 
32
@@cache_dir_present = 
false

Instance Method Summary collapse

Instance Method Details

#_dest_filename(src_path, resize, quality) ⇒ Object 



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# File 'lib/jekyll-pdf-thumbnail.rb', line 22

def _dest_filename(src_path, resize, quality)
  # Generates a thumbnail name using the SHA256 digest of the PDF file
  #
  # Example:
  #   >> _dest_filename("sample_1.pdf")
  #   => a35383ccca791ba6aa67ab3acde65287.png
  #
  # Arguments:
  #   src_path: (String)
  #   resize: (String) as used in the -resize parameter of convert
  #   quality: (String) as used in the -quality parameter of convert
  hash = Digest::SHA256.file(src_path)
  short_hash = hash.hexdigest()[0, HASH_LENGTH]
  basename = short_hash
  if resize
    cleaned = resize.gsub(/[^\da-z]+/i, "")
    basename << "_r#{cleaned}"
  end
  if quality
    cleaned = quality.gsub(/[^\da-z]+/i, "")
    basename << "_q#{cleaned}"
  end
  basename << ".png"
end

#_get_cache_dir(site) ⇒ Object 



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# File 'lib/jekyll-pdf-thumbnail.rb', line 13

def _get_cache_dir(site)
  full_cache_dir = File.join(site.source, CACHE_DIR)
  if not @@cache_dir_present
    FileUtils.mkdir_p(full_cache_dir)
    @@cache_dir_present = true
  end
  full_cache_dir
end

#_must_create?(src_path, dest_path) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jekyll-pdf-thumbnail.rb', line 47

def _must_create?(src_path, dest_path)
  # Returns true if dest_path doesn't exists or src_path is newer than dest_path
  !File.exist?(dest_path) || File.mtime(dest_path) <= File.mtime(src_path)
end

#generate_thumbnail(pdf, thumbnail, resize = '50%', quality = "80%") ⇒ Object 



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# File 'lib/jekyll-pdf-thumbnail.rb', line 52

def generate_thumbnail(pdf, thumbnail, resize='50%', quality="80%")
  first = PDFToImage.open(pdf).first
  first.args << "-thumbnail #{resize}"
  first.save(thumbnail)
end