Method: Dse::Geometry::Polygon#initialize

Defined in:
lib/dse/geometry/polygon.rb

#initialize(*args) ⇒ Polygon

Returns a new instance of Polygon.

Examples:

Construct an empty Polygon

polygon = Polygon.new

Construct a Polygon with LineString objects.

exterior_ring = LineString.new(Point.new(0, 0), Point.new(10, 0), Point.new(10, 10), Point.new(0, 0))
interior_ring = LineString.new(Point.new(1, 1), Point.new(1, 5), Point.new(5, 1), Point.new(1, 1))
polygon = Polygon.new(exterior_ring, interior_ring)

Construct a line-string with a wkt string.

polygon = Polygon.new('POLYGON ((0.0 0.0, 10.0 0.0, 10.0 10.0, 0.0 0.0), ' \
                      '(1.0 1.0, 1.0 5.0, 5.0 1.0, 1.0 1.0))')

Parameters:

  • args (Array<LineString>, Array<String>) —

    varargs-style arguments in two forms:

    • ordered collection of linear-rings that make up this polygon. Can be empty.
    • one-element string array with the wkt representation.


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# File 'lib/dse/geometry/polygon.rb', line 44

def initialize(*args)
  # The constructor has two forms:
  # 1. 0 or more LineString objects where the first is the exterior ring and the rest are interior rings.
  # 2. one String arg as the wkt representation.

  if args.size == 1 && args.first.is_a?(String)
    # subsitute eol chars in the string with a space.
    wkt = args.first.gsub(EOL_RE, ' ')
    # Consolidate whitespace before/after commas and parens.
    wkt.gsub!(/\s*([,\(\)])\s*/, '\1')
    if wkt == 'POLYGON EMPTY'
      @rings = [].freeze
    else
      match = wkt.match(WKT_RE)
      raise ArgumentError, "#{wkt.inspect} is not a valid WKT representation of a polygon" unless match
      @rings = parse_wkt_internal(match[1])
    end
  else
    @rings = args.freeze
    @rings.each do |ring|
      Cassandra::Util.assert_instance_of(LineString, ring, "#{ring.inspect} is not a LineString")
    end
  end
end