Module: Jpegtran

Extended by:
Jpegtran
Included in:
Jpegtran
Defined in:
lib/jpegtran.rb,
lib/jpegtran/version.rb,
lib/jpegtran/configuration.rb

Defined Under Namespace

Classes: Configuration, Error

Constant Summary collapse

BOOLEAN_ARGS = 
[
  :arithmetic, :grayscale, :optimize, :perfect, :progressive,
  :transpose, :transverse, :trim, :verbose
]
COPY_OPTIONS = 
[
  :none, :comments, :all
]
FLIP_OPTIONS = 
[
  :horizontal, :vertical
]
VERSION = 
"0.3.1"

Instance Method Summary collapse

Instance Method Details

#configuration ⇒ Object 



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# File 'lib/jpegtran.rb', line 30

def configuration
  @configuration ||= Configuration.new
end

#configure {|configuration| ... } ⇒ Object

Yields:



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# File 'lib/jpegtran.rb', line 34

def configure
  yield configuration
end

#configured? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jpegtran.rb', line 22

def configured?
  !executable.nil?
end

#executable ⇒ Object 



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# File 'lib/jpegtran.rb', line 26

def executable
  configuration.executable
end

#optimize(path, options = {}) ⇒ Object 



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# File 'lib/jpegtran.rb', line 38

def optimize(path, options = {})
  cmd = [executable]

  # Boolean arguments
  options.each_pair do |k, v|
    if BOOLEAN_ARGS.include?(k) && v
      cmd << "-#{k}"
    end
  end

  # Fixnum arguments
  [ :rotate, :restart ].each do |arg|
    if Fixnum === options[arg]
      cmd << "-#{arg} #{options[arg]}"
    elsif options.include?(arg)
      raise Error.new("Invalid value for :#{arg} option. Fixnum expected.")
    end
  end

  # String arguments
  [ :crop, :scans ].each do |arg|
    if String === options[arg]
      cmd << "-#{arg} #{options[arg]}"
    elsif options.include?(arg)
      raise Error.new("Invalid value for :#{arg} option. Structured string expected. See 'jpegtran' reference.")
    end
  end

  # Copy
  if options.include?(:copy)
    value = options[:copy].to_sym

    if COPY_OPTIONS.include?(value)
      cmd << "-copy #{value}"
    else
      raise Error.new("Invalid value for :copy. Expected #{COPY_OPTIONS}")
    end
  end

  # Flip
  if options.include?(:flip)
    value = options[:flip].to_sym

    if FLIP_OPTIONS.include?(value)
      cmd << "-flip #{value}"
    else
      raise Error.new("Invalid value for :flip. Expected #{FLIP_OPTIONS}")
    end
  end

  # Outfile
  if options.include?(:outfile)
    if String === options[:outfile]
      out = options[:outfile]
    else
      raise Error.new("Invalid value for :outfile option. String expected.")
    end
  else
    out = path.to_s
  end

  cmd << "-outfile #{out}"
  cmd << path.to_s
  cmd = cmd.join(" ")

  IO.popen(cmd) do |f|
    f.read.chomp
  end
end