Class: WaxIiif::ImageVariant

Inherits:
Object
  • Object
show all
Includes:
MiniMagick, Utilities::Helpers
Defined in:
lib/wax_iiif/image_variant.rb

Overview

Class ImageVariant represents a single image file within a manifest.

Direct Known Subclasses

FullImage, ImageTile, Thumbnail

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Utilities::Helpers

#escape_yaml, #generate_build_location, #generate_id, #generate_image_location, #get_data_path, #save_to_disk

Constructor Details

#initialize(data, config, size = nil) ⇒ ImageVariant

Initializing an ImageVariant will create the actual image file on the file system.

To initialize an image, you will need the data hash to have an “id”, a “image_path”, and a “page_number”.

Parameters:

  • data (Hash) —

    A Image Data object.

  • config (WaxIiif::Config) —

    The configuration object

  • width (Number) —

    the desired width of this object in pixels

  • height (Number) —

    the desired height of this object in pixels

Raises:

  • WaxIiif::Error::InvalidImageData



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# File 'lib/wax_iiif/image_variant.rb', line 27

def initialize(data, config, size = nil)
  @config = config

  raise WaxIiif::Error::InvalidImageData, 'Each image needs an ID' if data.id.nil? || data.id.to_s.empty?
  raise WaxIiif::Error::InvalidImageData, 'Each image needs an path.' if data.image_path.nil? || data.image_path.to_s.empty?

  # open image
  begin
    @image = Image.open(data.image_path)
  rescue MiniMagick::Invalid => e
    raise WaxIiif::Error::InvalidImageData, "Cannot read this image file: #{data.image_path}. #{e}"
  end

  width = size.nil? ? width : size
  resize(width)

  @image.format 'jpg'
  @id   = generate_image_id(data.id)
  @uri  = "#{id}#{filestring}/default.jpg"

  # Create the on-disk version of the file
  path = "#{@id}#{filestring}".gsub(@config.base_url, @config.output_dir)
  FileUtils.mkdir_p path
  filename = "#{path}/default.jpg"
  @image.write filename unless File.exist? filename
end

Instance Attribute Details

#id ⇒ Object (readonly)

Returns the value of attribute id.



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# File 'lib/wax_iiif/image_variant.rb', line 60

def id
  @id
end

#uri ⇒ String (readonly)

Returns The URI for the jpeg image.

Returns:

  • (String) —

    The URI for the jpeg image



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# File 'lib/wax_iiif/image_variant.rb', line 56

def uri
  @uri
end

Instance Method Details

#generate_image_id(id) ⇒ <type>

Generate a URI for an image

Parameters:

  • id (String) —

    The specific ID for the image

  • page_number (String, Number) —

    The page number for this particular image.

Returns:

  • (<type>) —

    <description>



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# File 'lib/wax_iiif/image_variant.rb', line 91

def generate_image_id(id)
  "#{@config.base_url}#{@config.prefix}/#{@config.image_directory_name}/#{id}"
end

#height ⇒ Number

Get the image height

Returns:

  • (Number) —

    The height of the image in pixels



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# File 'lib/wax_iiif/image_variant.rb', line 72

def height
  @image.height
end

#mime_type ⇒ String

Get the MIME Content-Type of the image.

Returns:

  • (String) —

    the MIME Content-Type (typically ‘image/jpeg’)



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# File 'lib/wax_iiif/image_variant.rb', line 80

def mime_type
  @image.mime_type
end

#width ⇒ Number

Get the image width

Returns:

  • (Number) —

    The width of the image in pixels



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# File 'lib/wax_iiif/image_variant.rb', line 65

def width
  @image.width
end