Added export method to export highchart in different formats

lib/daru/view/adapters/googlecharts.rb

@@ -182,6 +182,10 @@ def export_html_file(plot, path='./plot.html')
           File.write(path, str)
         end
 
+        def export(_plot, _export_type='png', _file_name='chart')
+          raise 'Not implemented yet'
+        end
+
         def show_in_iruby(plot)
           plot.show_in_iruby
         end

lib/daru/view/adapters/highcharts.rb

@@ -70,6 +70,21 @@ def export_html_file(plot, path='./plot.html')
           File.write(path, str)
         end
 
+        # Exporting in web frameworks is completely offline. In IRuby notebook,
+        #   offline-export supports only the exporting to png, jpeg and svg format.
+        #   Export to PDF is not working (not even through the exporting button in
+        #   highchart). So, online exporting is done in IRuby notebook. There is a
+        #   problem in online exporting that if we run-all all the cells of IRuby
+        #   notebook then only the last chart will be exported. Individually,
+        #   running the cells works fine.
+        #
+        # @see #Daru::View::Plot.export
+        def export(plot, export_type='png', file_name='chart')
+          plot.export_iruby(export_type, file_name) if defined? IRuby
+        rescue NameError
+          plot.export(export_type, file_name)
+        end
+
         def show_in_iruby(plot)
           plot.show_in_iruby
         end

lib/daru/view/adapters/highcharts/display.rb

@@ -49,6 +49,10 @@ def self.init_script
   end
 
   class HighChart
+    # Holds a value only when to_html or to_html_iruby method is invoked
+    # @return [String] The ID of the DIV element that the HighChart should
+    #   be rendered in
+    attr_accessor :div_id
     # @example
     #
     # To display the html code of the chart, use `to_html`. To see the same
@@ -62,6 +66,7 @@ class HighChart
     def to_html(placeholder=random_canvas_id)
       chart_hash_must_be_present
       script = load_dependencies('web_frameworks')
+      @div_id = placeholder
       script << high_chart_css(placeholder)
       # Helps to denote either of the three classes.
       chart_class = extract_chart_class
@@ -88,6 +93,7 @@ def show_in_iruby(placeholder=random_canvas_id)
     # `high_chart_iruby` which doesn't use `onload` in chart script.
     def to_html_iruby(placeholder=random_canvas_id)
       # TODO : placeholder pass, in plot#div
+      @div_id = placeholder
       load_dependencies('iruby')
       chart_hash_must_be_present
       script = high_chart_css(placeholder)
@@ -160,6 +166,95 @@ def get_map_data_dependencies(dep_js)
       end
     end
 
+    # @see #Daru::View::Plot.export
+    def export(export_type='png', file_name='chart')
+      js = ''
+      js << to_html
+      js << extract_export_code(@div_id, export_type, file_name)
+      js
+    end
+
+    # Exports chart to different formats in IRuby notebook
+    #
+    # @param type [String] format to which chart has to be exported
+    # @param file_name [String] The name of the file after exporting the chart
+    # @return [void] loads the js code of chart along with the code to export
+    #   in IRuby notebook
+    def export_iruby(export_type='png', file_name='chart')
+      js = ''
+      js << to_html_iruby
+      js << extract_export_code_iruby(@div_id, export_type, file_name)
+      IRuby.html js
+    end
+
+    # Returns the script to export the chart in different formats for
+    #   web frameworks
+    #
+    # @param file_name [String] The name of the file after exporting the chart
+    # @param placeholder [String] The ID of the DIV element that
+    #   the HighChart should be rendered in
+    # @param type [String] format to which chart has to be exported
+    # @return [String] the script to export the chart in web frameworks
+    def extract_export_code(
+      placeholder=random_canvas_id, export_type='png', file_name='chart'
+    )
+      js = ''
+      js << "\n <script>"
+      js << "\n (function() {"
+      js << "\n \tvar onload = window.onload;"
+      js << "\n \twindow.onload = function(){"
+      js << "\n \t\tif (typeof onload == 'function') onload();"
+      js << "\n \t\tvar chartDom = document.getElementById('#{placeholder}');"
+      js << "\n \t\tvar chart = Highcharts.charts[Highcharts.attr(chartDom,"
+      js << " 'data-highcharts-chart')]"
+      js << "\n \t\tchart.exportChartLocal({"
+      js << "\n \t\t\t" + append_chart_type(export_type)
+      js << "\n \t\t\tfilename: '#{file_name}'"
+      js << "\n \t\t});\n \t};\n })();"
+      js << "\n </script>"
+      js
+    end
+
+    # Returns the script to export the chart in different formats in
+    #   IRuby notebook
+    #
+    # @param (see #extract_export_code)
+    # @return [String] the script to export the chart in IRuby notebook
+    def extract_export_code_iruby(
+      placeholder=random_canvas_id, export_type='png', file_name='chart'
+    )
+      js = ''
+      js << "\n <script>"
+      js << "\n (function() {"
+      js << "\n \tvar chartDom = document.getElementById('#{placeholder}');"
+      js << "\n \tvar chart = Highcharts.charts[Highcharts.attr(chartDom,"
+      js << " 'data-highcharts-chart')]"
+      js << "\n \tchart.exportChart({"
+      js << "\n \t\t" + append_chart_type(export_type)
+      js << "\n \t\tfilename: '#{file_name}'"
+      js << "\n \t});"
+      js << "\n })();"
+      js << "\n </script>"
+      js
+    end
+
+    # @param type [String] format to which chart has to be exported
+    # @return [String] code stating the type to which chart has to be exported
+    def append_chart_type(export_type='png')
+      case export_type
+      when 'pdf'
+        "type: 'application/pdf',"
+      when 'png'
+        "type: 'image/png',"
+      when 'jpg', 'jpeg'
+        "type: 'image/jpeg',"
+      when 'svg'
+        "type: 'image/svg+xml',"
+      else
+        raise TypeError, 'Invalid format'
+      end
+    end
+
     # @return [String] the class of the chart
     def extract_chart_class
       # Provided by user and can take two values ('stock' or 'map').

lib/daru/view/adapters/highcharts/iruby_notebook.rb

@@ -36,6 +36,9 @@ def self.init_iruby(
     # , 'modules/exporting.js' : for the exporting button
     # data.js for getting data as csv or html table.
     # 'highcharts-more.js' : for arearange and some other chart type
+    # 'modules/offline-exporting.js': for enabling offline exporting. Used in
+    #  #chart.extract_export_code method (to enable chart.exportChartLocal)
+    #  to export the chart using code.
     # Note: Don't reorder the dependent_js elements. It must be loaded in
     # the same sequence. Otherwise some of the JS overlap and doesn't work.
     js = generate_init_code(dependent_js)

lib/daru/view/adapters/nyaplot.rb

@@ -16,6 +16,10 @@ def export_html_file(plot, path)
           plot.export_html path
         end
 
+        def export(_plot, _export_type='png', _file_name='chart')
+          raise 'Not implemented yet'
+        end
+
         def show_in_iruby(plot)
           plot.show
         end

lib/daru/view/constants.rb

@@ -6,14 +6,15 @@
 EXPORTING = 'modules/exporting.js'.freeze
 HIGHCHARTS_3D = 'highcharts-3d.js'.freeze
 DATA = 'modules/data.js'.freeze
+OFFLINE_EXPORTING = 'modules/offline-exporting.js'.freeze
 
 # HighCharts IRuby notebook dependencies
 HIGHCHARTS_DEPENDENCIES_IRUBY = [HIGHSTOCK, MAP, EXPORTING, HIGHCHARTS_3D,
                                  DATA].freeze
 
 # HighCharts Web Frameworks dependencies
 HIGHCHARTS_DEPENDENCIES_WEB = [HIGHSTOCK_CSS, MAP_CSS, EXPORTING,
-                               HIGHCHARTS_3D, DATA].freeze
+                               HIGHCHARTS_3D, DATA, OFFLINE_EXPORTING].freeze
 
 # HighCharts CSS dependencies
 HIGHCHARTS_DEPENDENCIES_CSS = ['highcharts.css'].freeze

lib/daru/view/plot.rb

@@ -77,6 +77,18 @@ def export_html_file(path='./plot.html')
         @adapter.export_html_file(@chart, path)
       end
 
+      # @param type [String] format to which chart has to be exported
+      # @param file_name [String] The name of the file after exporting the chart
+      # @return [String, void] js code of chart along with the code to export it
+      #   and loads the js code to export it in IRuby.
+      # @example Export a HighChart
+      #   data = Daru::Vector.new([5 ,3, 4])
+      #   hchart = Daru::View::Plot.new(data)
+      #   hchart.export('png', 'daru')
+      def export(export_type='png', file_name='chart')
+        @adapter.export(@chart, export_type, file_name)
+      end
+
       # load the corresponding JS files in IRuby notebook.
       # This is done automatically when plotting library is set using
       # Daru::View.plotting_library = :new_library

spec/adapters/highcharts/display_spec.rb

@@ -328,6 +328,83 @@
     end
   end
 
+  describe "#export" do
+    it "should generate the valid script to export the chart in different"\
+       " formats" do
+      js = @hc.chart.export('jpg','daru')
+      expect(js).to match(/\s+new\s+Highcharts.Chart/)
+      expect(js).to match(/var\s+options\s+=/)
+      expect(js).to match(/window.chart_/)
+      expect(js).to match(/\"chart\": \{ \"type\": \"bar\"/)
+      expect(js).to match(/\"data\": \[ \[ 5,2,3 \],\[ 3,2,4 \],\[ 4,3,4 \]/)
+      expect(js).to match(/script/)
+      expect(js).to match(/image\/jpeg/)
+      expect(js).to match(/daru/)
+      expect(js).to match(/chart.exportChartLocal/)
+    end
+  end
+
+  describe "#extract_export_code" do
+    it "should generate the valid script to export the chart in different"\
+       " formats in web frameworks" do
+      js = @hc.chart.extract_export_code(@placeholder)
+      expect(js).to match(/script/)
+      expect(js).to match(/var onload = window.onload/)
+      expect(js).to match(/window.onload = function()/)
+      expect(js).to match(/typeof onload == 'function'/)
+      expect(js).to match(
+        /var chartDom = document.getElementById\('placeholder'\)/
+      )
+      expect(js).to match(
+        /Highcharts.charts\[Highcharts.attr\(chartDom, 'data-highcharts-chart'\)/
+      )
+      expect(js).to match(/image\/png/)
+      expect(js).to match(/chart.exportChartLocal/)
+    end
+  end
+
+  describe "#extract_export_code_iruby" do
+    it "should generate the valid script to export the chart in different"\
+       " formats in IRuby notebook" do
+      js = @hc.chart.extract_export_code_iruby(@placeholder, 'png', 'daru')
+      expect(js).to match(/script/)
+      expect(js).to match(
+        /var chartDom = document.getElementById\('placeholder'\)/
+      )
+      expect(js).to match(
+        /Highcharts.charts\[Highcharts.attr\(chartDom, 'data-highcharts-chart'\)/
+      )
+      expect(js).to match(/image\/png/)
+      expect(js).to match(/filename: 'daru'/)
+      expect(js).to match(/chart.exportChart/)
+    end
+  end
+
+  describe "#append_chart_type" do
+    it "should return correct code stating the type to which chart has"\
+        " to be exported" do
+      expect(@hc.chart.append_chart_type).to eq("type: 'image/png',")
+      expect(@hc.chart.append_chart_type(
+        'pdf')
+      ).to eq("type: 'application/pdf',")
+      expect(@hc.chart.append_chart_type(
+        'png')
+      ).to eq("type: 'image/png',")
+      expect(@hc.chart.append_chart_type(
+        'jpg')
+      ).to eq("type: 'image/jpeg',")
+      expect(@hc.chart.append_chart_type(
+        'jpeg')
+      ).to eq("type: 'image/jpeg',")
+      expect(@hc.chart.append_chart_type(
+        'svg')
+      ).to eq("type: 'image/svg+xml',")
+      expect{@hc.chart.append_chart_type(
+        'daru')
+      }.to raise_error(TypeError, 'Invalid format')
+    end
+  end
+
   describe "#extract_chart_class" do
     it "should return Map class when chart_class is set to map" do
       @hc.options[:chart_class] = "map";

spec/adapters/highcharts_spec.rb

@@ -447,4 +447,17 @@
       expect(html).to match(/series": \[\[ 1,15 \],\[ 2,30 \],\[ 4,40 \]\]/)
     end
   end
+
+  describe "#export" do
+    it "should generate the valid script to export the chart" do
+      js = @chart_bar.adapter.export(@chart_bar.chart, 'png')
+      expect(js).to match(/\s+new\s+Highcharts.Chart/)
+      expect(js).to match(/var\s+options\s+=/)
+      expect(js).to match(/window.chart_/)
+      expect(js).to match(/\"chart\": \{ \"type\": \"bar\"/)
+      expect(js).to match(/script/)
+      expect(js).to match(/image\/png/)
+      expect(js).to match(/chart.exportChartLocal/)
+    end
+  end
 end