Module: Sass::Script::Functions

Defined in:
lib/compass-svg-polyfill/sass_functions.rb

Instance Method Summary collapse

Instance Method Details

#svg_polyfill(width, height, svgName, pngName, imageConverter) ⇒ Object 



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# File 'lib/compass-svg-polyfill/sass_functions.rb', line 7

def svg_polyfill(width, height, svgName, pngName, imageConverter)
  assert_type width, :Number
  assert_type height, :Number
  assert_type svgName, :String
  assert_type pngName, :String
  assert_type imageConverter, :String

  # Normalise values
  svgFilepath = File.join Compass.configuration.images_path, svgName.value.to_s
  pngFilepath = File.join Compass.configuration.images_path, pngName.value.to_s
  imageConverter = imageConverter.value.to_sym

  # Helper objects
  logger = Compass::Logger.new
  cache_store = environment.options[:cache_store]

  # Check if file exists
  if !File.exists? svgFilepath
    raise Sass::SyntaxError, "SVG file does not exist #{svgName.value.to_s}"
  end

  # Create a temporary output file
  tmpFile = Tempfile.new(['compass-svg-polyfill', '.png'])
  tmpFile.close false

  case imageConverter
  when :imagemagick
    img = Magick::Image.read(svgFilepath).first
    img.resize!(width.value.to_i, height.value.to_i)
    img.write tmpFile.path
  when :librsvg
    system(
      "rsvg-convert",      # Process
      "-w", width.value,   # Width
      "-h", height.value,  # Height
      svgFilepath,         # Input
      "-o", tmpFile.path   # Output
    )
  else
    raise Sass::SyntaxError, "Unknown image converter #{imageConverter}"
  end

  # Setup cache values
  cacheKey = cache_store.key(File.dirname(pngFilepath), File.basename(pngFilepath))
  cacheSHA = Digest::SHA1.hexdigest(pngFilepath)
  cacheVal = "#{width} #{height} #{Digest::SHA1.file(svgFilepath).hexdigest}"

  action = nil

  if File.exists? pngFilepath
    action = :overwrite

    if (cachedSHA = cache_store.retrieve(cacheKey, cacheSHA)) then
      if cachedSHA.eql? cacheVal then
        action = :unchanged
      end
    end
  else
    action = :create
  end

  logger.record action, pngName.value

  case action
  when :overwrite, :create
    # Save the file
    FileUtils.mv(tmpFile.path, pngFilepath)
  end

  # Save the cache key
  cache_store.store(cacheKey, cacheSHA, cacheVal)

  # Remove temp file
  tmpFile.unlink

  Sass::Script::Bool.new true
end