finished stacked bar plots

Author: v0dro

CONTRIBUTING.md

@@ -12,6 +12,17 @@ The absolute co-ordinates are calculated during the draw phase. Therefore there
 should be no code except in the `draw` methods where actual co-ordinates are calcualted.
 
 Varible naming conventions:
-* All values that are absolute values will be prefixed with `abs_`.
+* All values that are absolute values will be prefixed with `abs_**.
 * Variables relating to positioning of the graph other than the absolute
 variables are always ratios.
+
+## Drawing flow
+
+When the `draw` method in `Axes` is called, the call sequence is as follows:
+* Determine X and Y ranges.
+* Normalize the data within these ranges.
+* Assign defaults (if not assigned by user):
+  - Default label colors.
+* Consolidate plots like bar plots into 'Multi-' plots.
+* Figure out location of the Axes title.
+* Figure out location of the legends.

lib/rubyplot/artist/axes.rb

@@ -112,13 +112,19 @@ def legend_box_iy
       end
 
       # Write an image to a file by communicating with the backend.
+      # FIXME: (refactor) Currently draw first assigns default colors and then
+      # performs consolidation etc of the data and then assigns the default X ticks.
+      # The reason for this is that default labels are needed by the consolidated
+      # plots when they create the required rectangles etc. However assigning
+      # default ticks should be a part of the 'assign defaults' step and should
+      # therefore should be clubbed with the assign labels step.
       def draw
+        set_axes_ranges
+        normalize_plotting_data
         assign_default_label_colors
         consolidate_plots
-        gather_plot_data
         configure_title
         configure_legends
-        configure_plotting_data
         assign_x_ticks
         actually_draw
       end
@@ -158,7 +164,9 @@ def dot! *args, &block
       end
 
       def stacked_bar! *args, &block
-        appdd_plot "StackedBar", *args, &block
+        plot = Rubyplot::Artist::Plot::StackedBar.new self
+        yield(plot) if block_given?
+        @plots << plot
       end
 
       def write file_name
@@ -274,7 +282,7 @@ def configure_legends
 
       # Make adjustments to the data that will be plotted. Maps the data
       # contained in the plot to actual pixel values.
-      def configure_plotting_data
+      def normalize_plotting_data
         @plots.each do |plot|
           plot.normalize
         end
@@ -341,7 +349,7 @@ def consolidate_plots
       end
 
       # FIXME: replace x_range and y_range with XAxis::max/min_value and YAxis::max/min_value.
-      def gather_plot_data
+      def set_axes_ranges
         set_xrange
         set_yrange
       end

lib/rubyplot/artist/plot.rb

@@ -3,5 +3,7 @@
 require_relative 'plot/line'
 require_relative 'plot/bar'
 require_relative 'plot/multi_bars'
+require_relative 'plot/stacked_bar'
+require_relative 'plot/multi_stacked_bar'
 require_relative 'plot/bubble'
 require_relative 'plot/area'

lib/rubyplot/artist/plot/multi_stacked_bar.rb

@@ -2,26 +2,41 @@ module Rubyplot
   module Artist
     module Plot
       class MultiStackedBar < Artist::Plot::Base
-        def initialize(*, stacked_bars:)
-          super
+        def initialize(*args, stacked_bars:)
+          super(args[0])
           @stacked_bars = stacked_bars
           @x_min = @stacked_bars.map(&:x_min).min
           @y_min = @stacked_bars.map(&:y_min).min
           @x_max = @stacked_bars.map(&:x_max).max
           @y_max = @stacked_bars.map(&:y_max).max
+          reset_axes_ranges
+          renormalize_data
           configure_plot_geometry_data
           configure_x_ticks
         end
 
         def draw
-          
+          @stacked_bars.each(&:draw)
         end
 
         private
 
+        def reset_axes_ranges
+          @axes.y_range[0] = 0
+          @axes.x_range[0] = 0
+        end
+
+        # Normalize data in the stacked bar plot w.r.t each other and new X & Y ranges.
+        def renormalize_data
+          @stacked_bars.each do |p|
+            p.normalize
+            p.renormalize @stacked_bars.size
+          end
+        end
+
         def configure_plot_geometry_data
           @num_max_slots = @stacked_bars.map { |bar| bar.num_bars }.max
-          @max_slot_width = (@axes.x_axis.abs_x2 - @axes.x_axis.abs_x1).abs / @num_max_slots
+          @max_slot_width = @axes.x_axis.length / @num_max_slots
           @spacing_ratio = @stacked_bars[0].spacing_ratio
           @padding = @spacing_ratio * @max_slot_width
           @max_bars_width = @max_slot_width - @padding
@@ -32,15 +47,31 @@ def configure_plot_geometry_data
         end
 
         def configure_x_ticks
-          
+          @axes.num_x_ticks = @num_max_slots
+          labels = @axes.x_ticks || Array.new(@num_max_slots) { |i| i.to_s }
+          if labels.size != @axes.num_x_ticks
+            labels = labels[0...@axes.num_x_ticks]
+          end
+          @axes.x_ticks = labels.map.with_index do |label, i|
+            Rubyplot::Artist::XTick.new(
+              @axes,
+              abs_x: @axes.abs_x + @axes.y_axis_margin + i * @max_slot_width + @max_slot_width / 2,
+              abs_y: @axes.origin[1],
+              label: label,
+              length: 6,
+              label_distance: 10
+            )
+          end
         end
 
         def set_bar_dims bar, plot_index
           bar.bar_width = @max_bars_width
+          plots_below = @stacked_bars[0...plot_index]
           bar.num_bars.times do |i|
+            pedestal_height = plots_below.map { |p| p.member_height(i) }.inject(:+) || 0
             bar.abs_x_left[i] = @axes.abs_x + @axes.y_axis_margin +
-                                i * @max_bars_width  + @padding / 2
-            bar.abs_y_left[i] = 
+                                i * @max_slot_width  + @padding / 2
+            bar.abs_y_left[i] = (@axes.abs_y + @axes.y_axis.length) - pedestal_height
           end
         end
       end # class StackedBar

lib/rubyplot/artist/plot/stacked_bar.rb

@@ -16,6 +16,8 @@ def initialize(*)
           @spacing_ratio = 0.1
           @abs_x_left = []
           @abs_y_left = []
+          @rectangles = []
+          @renormalized_y_values = []
         end
 
         def data y_values
@@ -26,6 +28,20 @@ def num_bars
           @data[:y_values].size
         end
 
+        # Normalize this data w.r.t other plots in this graph.
+        #
+        # @param max_plots [Integer] Max number of stacked bars in this plot.
+        def renormalize max_plots
+          @renormalized_y_values = @normalized_data[:y_values].map do |iy|
+            iy / max_plots
+          end
+        end
+
+        # Return the height in pixels of the bar at 'index'.
+        def member_height index
+          @renormalized_y_values[index] * @axes.y_axis.length
+        end
+
         def draw
           setup_bar_rectangles
           @rectangles.each(&:draw)
@@ -34,6 +50,18 @@ def draw
         private
 
         def setup_bar_rectangles
+          @renormalized_y_values.each_with_index do |iy, i|
+            height = iy * @axes.y_axis.length
+            @rectangles << Rubyplot::Artist::Rectangle.new(
+              self,
+              abs_x: @abs_x_left[i],
+              abs_y: @abs_y_left[i] - height,
+              width: @bar_width,
+              height: height,
+              border_color: @data[:color],
+              fill_color: @data[:color]
+            )
+          end
         end
       end # class StackedBar
     end # module Plot

lib/rubyplot/artist/rectangle.rb

@@ -9,6 +9,10 @@ class Rectangle < Base
       # @param abs_y [Float] Absolute Y co-ordinate of the upper left corner.
       # @param width [Float] Width in pixels of the rectangle.
       # @param height [Float] Height in pixels of the rectangle.
+      # @param border_color [Symbol] Symbol from Rubyplot::Color::COLOR_INDEX
+      #   denoting border color.
+      # @param fill_color [Symbol] nil Symbol from Rubyplot::Color::COLOR_INDEX
+      #   denoting the fill color.
       def initialize(owner,abs_x:,abs_y:,width:,height:,border_color:,fill_color: nil)
         super(owner.backend, abs_x, abs_y)
         @height = height