parsing of subtle.svg

gradient.gemspec

@@ -20,6 +20,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
 
   spec.add_dependency "color", "~> 1.8"
+  spec.add_dependency 'nokogiri', '~> 1.6'
   spec.add_development_dependency "bundler", "~> 1.7"
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "rspec"

lib/gradient/svg.rb

@@ -1,4 +1,10 @@
+require 'scanf'
+require 'nokogiri'
+
 module Gradient
+
+  class SVGError < StandardError ; end
+
   class SVG
 
     attr_reader :maps
@@ -29,8 +35,62 @@ def initialize
       @maps = {}
     end
 
+    SVGNS = 'http://www.w3.org/2000/svg'
+
     def parse(buffer)
+      xml = Nokogiri::XML(buffer)
+      xml.xpath('//xmlns:linearGradient', 'xmlns' => SVGNS).each do |linear_gradient|
+        unless (id = linear_gradient['id']) then
+          raise SVGError, 'linearGradient has no id'
+        end
+        @maps[id] = parse_linear_gradient(linear_gradient)
+      end
+    end
+
+    private def parse_linear_gradient(linear_gradient)
+      map = Gradient::Map.new
+      linear_gradient.children.each do |stop|
+        next unless stop.name == 'stop'
+        map.points << parse_stop(stop)
+      end
+      map
+    end
+
+    private def parse_stop(stop)
+      unless (offset = stop['offset']) then
+        raise SVGError, 'stop has no offset'
+      end
+      location = parse_location(offset)
+      # FIXME, handle style
+      unless (stop_color = stop['stop-color']) then
+        raise SVGError, 'stop has no stop-color'
+      end
+      red, green, blue, opacity = parse_stop_color(stop_color)
+      if (stop_opacity = stop['stop-opacity']) then
+        opacity = parse_stop_opacity(stop_opacity)
+      end
+      color = Color::RGB.new(red, green, blue)
+      Gradient::Point.new(location, color, opacity)
+    end
+
+    private def parse_location(offset)
+      unless (location = offset.scanf('%f%%')).count == 1 then
+        raise SVGError, "failed parse of offset #{offset}"
+      end
+      location.first
     end
 
+    private def parse_stop_color(stop_color)
+      # FIXME - handle # colours
+      if (parts = stop_color.scanf('rgb(%d,%d,%d)')).count == 3 then
+        [*parts, 1.0]
+      elsif (parts = stop_color.scanf('rgba(%d,%d,%d,%f)')).count == 4 then
+        parts
+      end
+    end
+
+    private def parse_stop_opacity(stop_opacity)
+      stop_opacity.scanf('%f')
+    end
   end
 end

spec/gradient/svg_spec.rb

@@ -21,13 +21,44 @@ def fixture_buffer(base)
     end
 
     it 'should have the correct keys' do
-      skip 'implementation'
       expect(maps.keys).to match_array ['subtle']
     end
 
-    it "should have #{described_class} values" do
-      maps.values.each do |map|
-        expect(map).to be_a described_class
+    describe 'the hash value' do
+
+      let(:map) { maps['subtle'] }
+
+      it 'should be a Gradient::Map' do
+        expect(map).to be_a Gradient::Map
+      end
+
+      describe 'the points' do
+
+        let(:points) { map.points }
+
+        it 'should be an array' do
+          expect(points).to be_an Array
+        end
+
+        it 'should have 11 elements' do
+          expect(points.count).to eq 11
+        end
+
+        it 'should consist of Gradient::Point objects' do
+          points.each do |point|
+            expect(point).to be_a Gradient::Point
+          end
+        end
+
+        describe 'the locations' do
+
+          let(:locations) { points.map(&:location) }
+
+          it 'should have the expected values' do
+            expect(locations)
+              .to match_array [0, 6, 19, 25, 32, 42, 53, 65, 75, 87, 100]
+          end
+        end
       end
     end
   end