Class: Imogen::Iiif::Region

Inherits:
Transform show all
Defined in:
lib/imogen/iiif/region.rb

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Transform

#initialize, #max, #min

Constructor Details

This class inherits a constructor from Imogen::Iiif::Transform

Class Method Details

.convert(img, region) ⇒ Object 



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# File 'lib/imogen/iiif/region.rb', line 43

def self.convert(img, region)
  edges = Region.new(img).get(region)
  if edges
    img.copy(*edges) {|crop| yield crop}
  else
    yield img
  end
end

Instance Method Details

#get(region = nil) ⇒ Object

returns leftX, topY, rightX, bottomY



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# File 'lib/imogen/iiif/region.rb', line 7

def get(region=nil)
  if region.nil? || region == 'full'
    return nil
  elsif md = /^pct:(\d+(\.\d+)?),(\d+(\.\d+)?),(\d+(\.\d+)?),(\d+(\.\d+)?)$/.match(region)
    p = [Float(md[1]),Float(md[3]),Float(md[5]),Float(md[7])]
    if p[0] == p[2] or p[1] == p[3]
      raise BadRequest.new("Invalid region: #{region}")
    end
    e = [
      max(0,(@width * p[0] / 100).round),
      max(0,(@height * p[1] / 100).round),
      min(@width,(@width * (p[0] + p[2]) / 100).round),
      min(@height,(@height * (p[1] + p[3]) / 100).round)
    ]
  elsif md = /^(\d+),(\d+),(\d+),(\d+)$/.match(region)
    p = [Integer(md[1]),Integer(md[2]),Integer(md[3]),Integer(md[4])]
    if p[2] == 0 or p[3] == 0
      raise BadRequest.new("Invalid region: #{region}")
    end
    e = [
      max(0,p[0]),
      max(0,p[1]),
      min(@width,(p[0] + p[2])),
      min(@height,(p[1] + p[3]))
    ]
  else
    raise BadRequest.new("Invalid region: #{region}")
  end
  if e[0] > e[2] or e[1] > e[3]
    raise BadRequest.new("Invalid region: #{region}")
  end
  if (e[2] - e[0]) * (e[3] - e[1]) < 100
    raise BadRequest.new("Region too small: #{region}")
  end
  return e
end