Merge pull request #86 from peetucket/add-nav-place-support

add support for navPlace element

Author: jcoyne

iiif-presentation.gemspec

@@ -25,4 +25,5 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'json'
   spec.add_dependency 'activesupport', '>= 3.2.18'
   spec.add_dependency 'faraday', '~> 2.7'
+  spec.add_dependency 'geo_coord'
 end

lib/iiif/v3/presentation.rb

@@ -11,6 +11,7 @@
   choice
   collection
   manifest
+  nav_place
   resource
   image_resource
   sequence

lib/iiif/v3/presentation/nav_place.rb

@@ -0,0 +1,109 @@
+require 'geo/coord'
+
+module IIIF
+  module V3
+    module Presentation
+      class NavPlace < IIIF::V3::AbstractResource
+        Rect = Struct.new(:coord1, :coord2)
+
+        COORD_REGEX = /(?<hemisphere>[NSEW]) (?<degrees>\d+)[°⁰*] ?(?<minutes>\d+)?[ʹ']? ?(?<seconds>\d+)?[ʺ"]?/
+
+        def initialize(coordinate_texts:, base_uri:)
+          @coordinate_texts = coordinate_texts
+          @base_uri = base_uri
+        end
+
+        # @return [Boolean] indicates if coordinate_texts passed in are valid
+        def valid?
+          !(coordinates.nil? || coordinates.empty?)
+        end
+
+        def build
+          raise ArgumentError.new('invalid coordinates') unless valid?
+
+          {
+            id: "#{base_uri}/feature-collection/1",
+            type: 'FeatureCollection',
+            features: features
+          }
+        end
+
+        private
+
+        attr_reader :coordinate_texts, :base_uri
+
+        def coordinates
+          @coordinates ||= coordinate_texts.map do |coordinate_text|
+            coordinate_parts = coordinate_text.split(%r{ ?--|/})
+            case coordinate_parts.length
+            when 2
+              coord_for(coordinate_parts[0], coordinate_parts[1])
+            when 4
+              rect_for(coordinate_parts)
+            end
+          end.compact
+        end
+
+        def coord_for(long_str, lat_str)
+          long_matcher = long_str.match(COORD_REGEX)
+          lat_matcher = lat_str.match(COORD_REGEX)
+          return unless long_matcher && lat_matcher
+
+          Geo::Coord.new(latd: lat_matcher[:degrees], latm: lat_matcher[:minutes], lats: lat_matcher[:seconds], lath: lat_matcher[:hemisphere],
+                        lngd: long_matcher[:degrees], lngm: long_matcher[:minutes], lngs: long_matcher[:seconds], lngh: long_matcher[:hemisphere])
+        end
+
+        def rect_for(coordinate_parts)
+          coord1 = coord_for(coordinate_parts[0], coordinate_parts[2])
+          coord2 = coord_for(coordinate_parts[1], coordinate_parts[3])
+          return if coord1.nil? || coord2.nil?
+
+          Rect.new(coord1, coord2)
+        end
+
+        def features
+          coordinates.map.with_index(1) do |coordinate, index|
+            {
+              id: "#{base_uri}/iiif/feature/#{index}",
+              type: 'Feature',
+              properties: {},
+              geometry: coordinate.is_a?(Rect) ? polygon_geometry(coordinate) : point_geometry(coordinate)
+            }
+          end
+        end
+
+        def point_geometry(coord)
+          {
+            type: 'Point',
+            coordinates: [format(coord.lng), format(coord.lat)]
+          }
+        end
+
+        def polygon_geometry(rect)
+          {
+            type: 'Polygon',
+            coordinates: [
+              [
+                [format(rect.coord1.lng), format(rect.coord1.lat)],
+                [format(rect.coord2.lng), format(rect.coord1.lat)],
+                [format(rect.coord2.lng), format(rect.coord2.lat)],
+                [format(rect.coord1.lng), format(rect.coord2.lat)],
+                [format(rect.coord1.lng), format(rect.coord1.lat)]
+              ]
+            ]
+          }
+        end
+
+        # @param [BigDecimal] coordinate value from geocoord gem
+        # @return [String] string formatted with max 6 digits after the decimal point
+        # The to_f ensures removal of scientific notation of BigDecimal before converting to a string.
+        # examples:
+        # input value is BigDecimal("-23.9") or "0.239e2", output value is "-23.9" as string
+        # input value is BigDecimal("23.9424213434") or "0.239424213434e2", output value is "23.942421" as string
+        def format(decimal)
+          decimal.truncate(6).to_f.to_s
+        end
+      end
+    end
+  end
+end

spec/unit/iiif/v3/presentation/nav_place_spec.rb

@@ -0,0 +1,80 @@
+describe IIIF::V3::Presentation::NavPlace do
+  let(:subject) { described_class.new(coordinate_texts: coordinate_texts, base_uri: base_uri) }
+  let(:base_uri) { "https://purl.stanford.edu" }
+  let(:invalid_coordinates) { ["bogus", "stuff", "is", "here"] }
+  let(:valid_coordinates) do
+    ["W 23°54'00\"--E 53°36'00\"/N 71°19'00\"--N 33°30'00\"",
+    'E 103°48ʹ/S 3°46ʹ).',
+    'X 103°48ʹ/Y 3°46ʹ).',
+    'In decimal degrees: (E 138.0--W 074.0/N 073.0--N 041.2).']
+  end
+  let(:nav_place) do
+    { id: 'https://purl.stanford.edu/feature-collection/1',
+      type: 'FeatureCollection',
+      features: [{ id: 'https://purl.stanford.edu/iiif/feature/1',
+                  type: 'Feature',
+                  properties: {},
+                  geometry: { type: 'Polygon',
+                              coordinates: [[['-23.9', '71.316666'],
+                                              ['53.6', '71.316666'],
+                                              ['53.6', '33.5'],
+                                              ['-23.9', '33.5'],
+                                              ['-23.9', '71.316666']]] } },
+                { id: 'https://purl.stanford.edu/iiif/feature/2',
+                  type: 'Feature',
+                  properties: {},
+                  geometry: { type: 'Point', coordinates: ['103.8', '-3.766666'] } }] }
+  end
+
+  describe '#build' do
+    context 'when coordinates are valid' do
+      let(:coordinate_texts) { valid_coordinates }
+
+      it 'returns navPlace' do
+        expect(subject.build).to eq nav_place
+      end
+    end
+
+    context 'when coordinates are not present' do
+      let(:coordinate_texts) { [] }
+
+      it 'raises ArgumentError' do
+        expect { subject.build }.to raise_error(ArgumentError)
+      end
+    end
+
+    context 'when coordinates are invalid' do
+      let(:coordinate_texts) { invalid_coordinates }
+
+      it 'raises ArgumentError' do
+        expect { subject.build }.to raise_error(ArgumentError)
+      end
+    end
+  end
+
+  describe '#valid' do
+    context 'when coordinates are valid' do
+      let(:coordinate_texts) { valid_coordinates }
+
+      it 'returns true' do
+        expect(subject.valid?).to be true
+      end
+    end
+
+    context 'when coordinates are not present' do
+      let(:coordinate_texts) { [] }
+
+      it 'returns false' do
+        expect(subject.valid?).to be false
+      end
+    end
+
+    context 'when coordinates are invalid' do
+      let(:coordinate_texts) { invalid_coordinates }
+
+      it 'returns false' do
+        expect(subject.valid?).to be false
+      end
+    end
+  end
+end