add area plot

Author: v0dro

lib/rubyplot/artist.rb

@@ -10,3 +10,4 @@
 require_relative 'artist/axes'
 require_relative 'artist/rectangle'
 require_relative 'artist/circle'
+require_relative 'artist/polygon'

lib/rubyplot/artist/axes.rb

@@ -142,7 +142,9 @@ def line! *args, &block
       end
 
       def area! *args, &block
-        add_plot "Area", *args, &block
+        plot = Rubyplot::Artist::Plot::Area.new self
+        yield(plot) if block_given?
+        @plots << plot
       end
 
       def bubble! *args, &block
@@ -209,17 +211,17 @@ def assign_default_label_colors
 
       def assign_x_ticks
         unless @x_ticks
-          val_distance = @x_range[1] / @num_x_ticks.to_f
-          @x_ticks = Array.new(@num_x_ticks) { |c| (c*val_distance).to_s }
+          val_distance = (@x_range[1] - @x_range[0]).abs / @num_x_ticks.to_f
+          @x_ticks = (@x_range[0]..@x_range[1]).step(val_distance).map { |i| i }
         end
         unless @x_ticks.all? { |t| t.is_a?(Rubyplot::Artist::XTick) }
-          inter_ticks_distance = @x_axis.length / @num_x_ticks
+          inter_ticks_distance = @x_axis.length / (@num_x_ticks - 1)
           @x_ticks.map!.with_index do |tick_label, i|
             Rubyplot::Artist::XTick.new(
               self,
               abs_x: i * inter_ticks_distance + @x_axis.abs_x1,
               abs_y: @origin[1],
-              label: tick_label,
+              label: Rubyplot::Utils.format_label(tick_label),
               length: 6,
               label_distance: 10
             )

lib/rubyplot/artist/plot.rb

@@ -4,3 +4,4 @@
 require_relative 'plot/bar'
 require_relative 'plot/multi_bars'
 require_relative 'plot/bubble'
+require_relative 'plot/area'

lib/rubyplot/artist/plot/area.rb

@@ -0,0 +1,37 @@
+module Rubyplot
+  module Artist
+    module Plot
+      class Area < Artist::Plot::Base
+        attr_reader :sorted_data
+        def initialize(*)
+          super
+          @sorted_data = true
+        end
+
+        def data x_values, y_values=[]
+          y_values = Array.new(x_values.size) { |i| i } if y_values.empty?
+          x_values.sort! if @sorted_data
+          super(x_values, y_values)
+        end
+
+        def draw
+          poly_points = []
+          @normalized_data[:y_values].each_with_index do |iy, idx_y|
+            ix = @normalized_data[:x_values][idx_y]
+            abs_x = ix * @axes.x_axis.length + @axes.abs_x + @axes.y_axis_margin
+            abs_y = (@axes.y_axis.length - iy * @axes.y_axis.length) + @axes.abs_y
+            poly_points << [abs_x, abs_y]
+          end
+          poly_points << [@axes.x_axis.abs_x2, @axes.origin[1] - @axes.x_axis.stroke_width]
+          poly_points << [@axes.origin[0], @axes.origin[1] - @axes.x_axis.stroke_width]
+          Rubyplot::Artist::Polygon.new(
+            self,
+            coords: poly_points,
+            color: @data[:color],
+            fill_opacity: 0.3
+          ).draw
+        end
+      end # class Area
+    end # module Plot
+  end # module Artist 
+end # module Rubyplot

lib/rubyplot/artist/plot/line.rb

@@ -33,13 +33,12 @@ def draw_single_point
 
         def draw_lines
           prev_x = prev_y = nil
-          y_axis_length = (@axes.y_axis.abs_y2 - @axes.y_axis.abs_y1).abs
           @normalized_data[:x_values].each_with_index do |ix, idx_ix|
             iy = @normalized_data[:y_values][idx_ix]
             next if ix.nil? || iy.nil?
             new_x = ix * (@axes.x_axis.abs_x2 - @axes.x_axis.abs_x1).abs + @axes.abs_x +
                     @axes.y_axis_margin
-            new_y = (y_axis_length - iy * y_axis_length) + @axes.abs_y
+            new_y = (@axes.y_axis.length - iy * @axes.y_axis.length) + @axes.abs_y
 
             if !(prev_x.nil? && prev_y.nil?)
               Rubyplot::Artist::Line2D.new(

lib/rubyplot/artist/polygon.rb

@@ -0,0 +1,22 @@
+module Rubyplot
+  module Artist
+    class Polygon < Base
+      def initialize(owner, coords:, fill_opacity: 0.0, color: :default, stroke: 'transparent')
+        @backend = owner.backend
+        @coords = coords
+        @fill_opacity = fill_opacity
+        @color = color
+        @stroke = stroke
+      end
+
+      def draw
+        @backend.draw_polygon(
+          coords: @coords,
+          stroke: @stroke,
+          color: Rubyplot::Color::COLOR_INDEX[@color],
+          fill_opacity: @fill_opacity
+        )
+      end
+    end # class Polygon
+  end # module Artist
+end # module Rubyplot

lib/rubyplot/backend/magick_wrapper.rb

@@ -115,6 +115,18 @@ def draw_circle(x:,y:,radius:,stroke_opacity:,stroke_width:,color:)
         @draw.circle(x,y,x-radius,y)
       end
 
+      # Draw a polygon.
+      #
+      # @param coords [Array[Array]] Array of Arrays where first element of each sub-array is
+      #   the X co-ordinate and the second element is the Y co-ordinate.
+      def draw_polygon(coords: , fill_opacity: 0.0, color: "#000000",
+                        stroke: "transparent")
+        @draw.stroke stroke
+        @draw.fill color
+        @draw.fill_opacity fill_opacity
+        @draw.polygon *coords.flatten
+      end
+
       def write file_name
         @draw.draw(@base_image)
         @base_image.write(file_name)

lib/rubyplot/utils.rb

@@ -5,6 +5,8 @@ class << self
       def format_label label
         if label.is_a? Float
           format('%0.2f', label)
+        elsif label.is_a? String
+          label
         end
       end
     end

spec/axes_spec.rb

@@ -171,7 +171,7 @@
         FileUtils.mkdir_p @temp_dir
       end
 
-      it "plots a single bubble plot", focus: true do
+      it "plots a single bubble plot" do
         fig = Rubyplot::Figure.new
         axes = fig.add_subplot 0,0
         axes.bubble! do |p|
@@ -222,13 +222,9 @@
           p.label = "Jimmy"
         end
         axes.title = "Visual simple area graph test."
-        axes.x_ticks = {
-          0 => '0',
-          2 => '2',
-          4 => '4',
-          6 => '6'
-        }
-
+        axes.num_x_ticks = 5
+        axes.x_ticks = ['0', '22', '44', '66', '88',]
+        
         file = "/#{Rubyplot.backend}_simple_area.png"
         fig.write(@temp_dir + file)