Class: Abrizer::Canvas

Inherits:
Object
  • Object
show all
Includes:
FilepathHelpers
Defined in:
lib/abrizer/canvas.rb

Overview

Creates a IIIF Canvas JSON-LD document.

Instance Method Summary collapse

Methods included from FilepathHelpers

#audio_filepath, #audio_filepath_fragmented, #basename, #canvas_filepath, #canvas_partial_filepath, #filename_directory, #first_image_filepath, #hlsts_filepath, #hlsts_partial_filepath, #mp4_filepath, #mp4_partial_filepath, #mpd_filepath, #mpd_partial_filepath, #output_directory, #output_directory_basename, #poster_image_filepath, #poster_partial_filepath, #sprites_filepath, #sprites_partial_filepath, #vp9_filepath, #vp9_partial_filepath, #webvtt_input_filepath

Constructor Details

#initialize(filepath, output_directory, base_url) ⇒ Canvas

TODO: allow control of items/versions listed on canvas



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# File 'lib/abrizer/canvas.rb', line 8

def initialize(filepath, output_directory, base_url)
  @filename = filepath
  @output_directory = output_directory
  @base_url = base_url
  finder = AdaptationFinder.new(@filename)
  @adaptations = finder.adaptations
end

Instance Method Details

#canvas_id ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 149

def canvas_id
  File.join media_base_url, canvas_partial_filepath
end

#captions_seealso(json) ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 120

def captions_seealso(json)
  # TODO: update captions seeAlso for multiple captions
  captions_file = File.join output_directory, 'vtt/captions.vtt'
  if File.exist? captions_file
    json.child! do
      json.id vtt_id
      json.format 'application/webvtt'
      json.label 'English captions'
      json.language 'en'
      json._comments "How make explicit how whether to use these as captions or subtitles?"
    end
  end
end

#create ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 16

def create
  File.open(canvas_filepath, 'w') do |fh|
    fh.puts create_json
  end
end

#create_json ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 22

def create_json
  Jbuilder.encode do |json|
    json.set! '@context', 'http://iiif.io/api/presentation/3/context.json'
    json.id canvas_id
    json.type "Canvas"
    json.width max_width
    json.height max_height
    json.duration duration
    thumbnail_json(json)
    media_json(json)
  end
end

#duration ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 181

def duration
  informer = Abrizer::FfprobeInformer.new(mp4_filename)
  informer.duration.to_f
end

#hlsts_id ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 161

def hlsts_id
  File.join media_base_url, hlsts_partial_filepath
end

#hlsts_item(json) ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 81

def hlsts_item(json)
  if File.exist? hlsts_filepath
    json.child! do
      json.id hlsts_id
      json.type "Video"
      # TODO: or "vnd.apple.mpegURL"
      json.format "application/x-mpegURL"
      json.width max_width
      json.height max_height
    end
  end
end

#max_height ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 194

def max_height
  @adaptations.last.height
end

#max_width ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 186

def max_width
  @adaptations.last.width
end

#media_base_url ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 145

def media_base_url
  File.join @base_url, output_directory_basename
end

#media_json(json) ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 45

def media_json(json)
  json.media do
    json.child! do
      json.type "Annotation"
      json.motivation 'painting'
      json.target canvas_id
      json.body do
        json.type "Choice"
        json.items do
          mpd_item(json)
          hlsts_item(json)
          vp9_item(json)
          mp4_item(json)
        end
        json.seeAlso do
          # TODO: Allow for adding more than one captions/subtitle file
          captions_seealso(json)
          sprites_seealso(json)
        end
      end
    end
  end
end

#min_height ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 198

def min_height
  @adaptations.first.height
end

#min_width ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 190

def min_width
  @adaptations.first.width
end

#mp4_filename ⇒ Object

TODO: DRY up with progressive_mp4.rb



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# File 'lib/abrizer/canvas.rb', line 211

def mp4_filename
  File.join output_directory, "progressive.mp4"
end

#mp4_height ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 206

def mp4_height
  @adaptations[-2].height
end

#mp4_id ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 165

def mp4_id
  File.join media_base_url, mp4_partial_filepath
end

#mp4_item(json) ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 107

def mp4_item(json)
  if File.exist? mp4_filepath
    json.child! do
      json.id mp4_id
      json.type "Video"
      #TODO: add mp4 codecs
      json.format "video/mp4"
      json.width mp4_width
      json.height mp4_height
    end
  end
end

#mp4_width ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 202

def mp4_width
  @adaptations[-2].width
end

#mpd_id ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 157

def mpd_id
  File.join media_base_url, mpd_partial_filepath
end

#mpd_item(json) ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 69

def mpd_item(json)
  if File.exist? mpd_filepath
    json.child! do
      json.id mpd_id
      json.type "Video"
      json.format "application/dash+xml"
      json.width max_width
      json.height max_height
    end
  end
end

#poster_id ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 153

def poster_id
  File.join media_base_url, poster_partial_filepath
end

#sprites_id ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 177

def sprites_id
  File.join media_base_url, sprites_partial_filepath
end

#sprites_seealso(json) ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 134

def sprites_seealso(json)
  if File.exist? sprites_filepath
    json.child! do
      json.id sprites_id
      json.format 'application/webvtt'
      json.label 'image sprite metadata'
      json._comments "How to include resources like video image sprites like those created by https://github.com/jronallo/video_sprites and used by various players?"
    end
  end
end

#thumbnail_json(json) ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 35

def thumbnail_json(json)
  if File.exist? poster_image_filepath
    json.thumbnail do
      json.id poster_id
      json.type 'Image'
      json.format 'image/jpeg'
    end
  end
end

#vp9_id ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 169

def vp9_id
  File.join media_base_url, vp9_partial_filepath
end

#vp9_item(json) ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 94

def vp9_item(json)
  if File.exist? vp9_filepath
    json.child! do
      json.id vp9_id
      json.type "Video"
      #TODO: add webm codecs
      json.format "video/webm"
      json.width max_width
      json.height max_height
    end
  end
end

#vtt_id ⇒ Object 



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# File 'lib/abrizer/canvas.rb', line 173

def vtt_id
  File.join media_base_url, 'vtt/captions.vtt'
end