Class: Seadragon::Slicer

Inherits:
Object
  • Object
show all
Defined in:
lib/seadragon.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(attributes = {}) ⇒ Slicer

Returns a new instance of Slicer.

Raises:

  • (ArgumentError) 


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# File 'lib/seadragon.rb', line 12

def initialize(attributes = {})
  raise ArgumentError.new('source and destination paths are required') unless attributes[:source_path] && attributes[:tiles_path]
  raise ArgumentError.new('a handle is required') unless attributes[:handle]

  @source_path  = attributes[:source_path]
  @tiles_path   = attributes[:tiles_path]
  @handle       = attributes[:handle]
  @tile_size    = attributes[:tile_size] || 512 
  @overlap      = attributes[:overlap] || 1
  @quality      = attributes[:quality] || 100
  @format       = attributes[:format] || 'jpg' 

  raise ArgumentError.new("source file doesn't exist") unless File.exist? @source_path
  @source_image = Magick::Image.read(@source_path)[0] # an Image object.
  @width, @height = @source_image.columns, @source_image.rows # image dims

end

Instance Attribute Details

#dzi_name ⇒ Object

Returns the value of attribute dzi_name.



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# File 'lib/seadragon.rb', line 9

def dzi_name
  @dzi_name
end

#format ⇒ Object

Returns the value of attribute format.



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# File 'lib/seadragon.rb', line 9

def format
  @format
end

#handle ⇒ Object

Returns the value of attribute handle.



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# File 'lib/seadragon.rb', line 9

def handle
  @handle
end

#height ⇒ Object

Returns the value of attribute height.



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# File 'lib/seadragon.rb', line 9

def height
  @height
end

#overlap ⇒ Object

Returns the value of attribute overlap.



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# File 'lib/seadragon.rb', line 9

def overlap
  @overlap
end

#quality ⇒ Object

Returns the value of attribute quality.



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# File 'lib/seadragon.rb', line 9

def quality
  @quality
end

#source_image ⇒ Object

Returns the value of attribute source_image.



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# File 'lib/seadragon.rb', line 9

def source_image
  @source_image
end

#source_path ⇒ Object

Returns the value of attribute source_path.



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# File 'lib/seadragon.rb', line 9

def source_path
  @source_path
end

#tile_size ⇒ Object

Returns the value of attribute tile_size.



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# File 'lib/seadragon.rb', line 9

def tile_size
  @tile_size
end

#tiles_path ⇒ Object

Returns the value of attribute tiles_path.



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# File 'lib/seadragon.rb', line 9

def tiles_path
  @tiles_path
end

#width ⇒ Object

Returns the value of attribute width.



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# File 'lib/seadragon.rb', line 9

def width
  @width
end

Instance Method Details

#slice! ⇒ Object

Generates the tiles.



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# File 'lib/seadragon.rb', line 33

def slice!
  # duplicate the source image, we'll be resizing it for each zoom layer.
  image = @source_image.dup 

  # create a parent folder for all of the tiles
  FileUtils.mkdir_p( File.join(tiles_path, handle+"_files") )

  max_level(width, height).downto(0) do |level|

    # get dimensions of the image (image is resized on each iteration)
    current_level_width, current_level_height = image.columns, image.rows 
    current_level_dir = File.join(tiles_path, handle+"_files", level.to_s)
    FileUtils.mkdir_p(current_level_dir) # create dir for current level
    
    # iterate over columns
    x, col_count = 0, 0
    while x < current_level_width
      # iterate over rows
      y, row_count = 0, 0
      while y < current_level_height
        tile_file_path = File.join(current_level_dir, 
          "#{col_count}_#{row_count}.#{format}")
        tile_width, tile_height = tile_dimensions(x, y, tile_size, overlap)
        save_tile(image, tile_file_path, x, y, tile_width, tile_height, quality) unless File.exist? tile_file_path
        y += (tile_height - (2 * overlap))
        row_count += 1
      end
      x += (tile_width - (2 * overlap))
      col_count += 1
    end
    image.resize!(0.5)
  end
  image.destroy!
end

#write_dzi_specification ⇒ Object

Generates the DZI (Deep Zoom Image format) descriptor file in JSON.



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# File 'lib/seadragon.rb', line 71

def write_dzi_specification
  properties = {
    'Image': {
      'xmlns':  "http://schemas.microsoft.com/deepzoom/2008",
      'Format':  format,
      'Overlap':  overlap.to_s,
      'TileSize':  tile_size.to_s,
      'Size': {
        'Height': height.to_s,
        'Width': width.to_s
      }
    }
  }
  
  FileUtils.mkdir(tiles_path) unless File.exists?(tiles_path)
  dzi_path = File.join(tiles_path, handle + ".dzi")
  
  File.open(dzi_path, 'w') do |f|
    f.write(JSON.pretty_generate(properties))
  end
end