Class: Assembly::Image

Inherits:
Object
  • Object
show all
Includes:
ObjectFileable
Defined in:
lib/assembly-image/image.rb,
lib/assembly-image/version.rb

Overview

Main Image class

Constant Summary collapse

VERSION =

Project version number

'1.7.2'

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#tmp_path ⇒ Object

stores the path to the tmp file generated during the JP2 creation process



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# File 'lib/assembly-image/image.rb', line 14

def tmp_path
  @tmp_path
end

Instance Method Details

#add_exif_profile_description(profile_name, force = false) ⇒ Object

Add an exif color profile descriptions to the image. This is useful if your source TIFFs do not have color profile descriptions in the EXIF data, but you know what it should be. This will allow the images to pass the validaty check and have JP2s created successfully.

Note you will need full read/write access to the source path so that new EXIF data can be saved.

Example:

source_img=Assembly::Image.new('/input/path_to_file.tif')
source_img.add_exif_profile_description('Adobe RGB 1998')

Parameters:

  • profile_name (String) —

    profile name to be added, current options are ‘Adobe RBG 1998’,‘Dot Gain 20%’,‘sRGB IEC61966-2.1’

  • force (String) (defaults to: false) —

    if set to true, force overwrite a color profile description even if it already exists (default: false)



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# File 'lib/assembly-image/image.rb', line 70

def add_exif_profile_description(profile_name, force = false)
  if profile.nil? || force
    input_profile = profile_name.gsub(/[^[:alnum:]]/, '') # remove all non alpha-numeric characters, so we can get to a filename
    path_to_profiles = File.join(Assembly::PATH_TO_IMAGE_GEM, 'profiles')
    input_profile_file = File.join(path_to_profiles, "#{input_profile}.icc")
    command = "exiftool '-icc_profile<=#{input_profile_file}' #{path}"
    result = `#{command} 2>&1`
    raise "profile addition command failed: #{command} with result #{result}" unless $CHILD_STATUS.success?
  end
rescue StandardError => e
  puts "** Error for #{filename}: #{e.message}"
end

#create_jp2(params = {}) ⇒ Assembly::Image

Create a JP2 file for the current image. Important note: this will not work for multipage TIFFs.

Example:

source_img=Assembly::Image.new('/input/path_to_file.tif')
derivative_img=source_img.create_jp2(:overwrite=>true)
puts derivative_img.mimetype # 'image/jp2'
puts derivative_image.path # '/input/path_to_file.jp2'

rubocop:disable Metrics/AbcSize rubocop:disable Metrics/MethodLength

Parameters:

  • params (Hash) (defaults to: {}) —

    Optional parameters specified as a hash, using symbols for options:

    • :output => path to the output JP2 file (default: mirrors the source file name and path, but with a .jp2 extension)

    • :overwrite => if set to false, an existing JP2 file with the same name won’t be overwritten (default: false)

    • :tmp_folder => the temporary folder to use when creating the jp2 (default: ‘/tmp’); also used by imagemagick

    • :preserve_tmp_source => if set to true, preserve the temporary file generated during the creation process and store path in ‘tmp_path’ attribute (default: false)

Returns:



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# File 'lib/assembly-image/image.rb', line 121

def create_jp2(params = {})
  output = params[:output] || jp2_filename
  create_jp2_checks(output: output, overwrite: params[:overwrite])

  # Using instance variable so that can check in tests.
  source_path = if mimetype != 'image/tiff'
                  @tmp_path = make_tmp_tiff(tmp_folder: params[:tmp_folder])
                else
                  @path
                end

  jp2_command = jp2_create_command(source_path: source_path, output: output)
  result = `#{jp2_command}`
  raise "JP2 creation command failed: #{jp2_command} with result #{result}" unless $CHILD_STATUS.success?

  File.delete(source_path) unless @tmp_path.nil? || params[:preserve_tmp_source]

  # create output response object, which is an Assembly::Image type object
  Assembly::Image.new(output)
end

#dpg_jp2_filename ⇒ string

Returns the full DPG equivalent jp2 path and filename that would match with the given image

Example:

source_img=Assembly::Image.new('/input/path_to_file.tif')
puts source_img.jp2_filename # gives /input/path_to_file.jp2

Returns:

  • (string) —

    full DPG equivalent jp2 path and filename



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# File 'lib/assembly-image/image.rb', line 99

def dpg_jp2_filename
  jp2_filename.gsub('_00_', '_05_')
end

#height ⇒ integer

Get the image height from exif data

Example:

source_img=Assembly::Image.new('/input/path_to_file.tif')
puts source_img.height # gives 100

Returns:

  • (integer) —

    image height in pixels



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# File 'lib/assembly-image/image.rb', line 44

def height
  exif.imageheight
end

#jp2_filename ⇒ string

Returns the full default jp2 path and filename that will be created from the given image

Example:

source_img=Assembly::Image.new('/input/path_to_file.tif')
puts source_img.jp2_filename # gives /input/path_to_file.jp2

Returns:

  • (string) —

    full default jp2 path and filename that will be created from the given image



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# File 'lib/assembly-image/image.rb', line 89

def jp2_filename
  File.extname(@path).empty? ? "#{@path}.jp2" : @path.gsub(File.extname(@path), '.jp2')
end

#profile ⇒ string

Get the image color profile

Example:

source_img=Assembly::Image.new('/input/path_to_file.tif')
puts source_img.profile # gives 'Adobe RGB 1998'

Returns:

  • (string) —

    image color profile



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# File 'lib/assembly-image/image.rb', line 34

def profile
  exif.nil? ? nil : exif['profiledescription']
end

#valid? ⇒ boolean

Examines the input image for validity. Used to determine if image is correct and if JP2 generation is likely to succeed.

This method is automatically called before you create a jp2 but it can be called separately earlier as a sanity check.

Example:

source_img=Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_img.valid? # gives true

Returns:

  • (boolean) —

    true if image is valid, false if not.



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# File 'lib/assembly-image/image.rb', line 24

def valid?
  valid_image? # behavior is defined in assembly-objectfile gem
end

#width ⇒ integer

Get the image width from exif data Example:

source_img=Assembly::Image.new('/input/path_to_file.tif')
puts source_img.width # gives 100

Returns:

  • (integer) —

    image height in pixels



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# File 'lib/assembly-image/image.rb', line 53

def width
  exif.imagewidth
end