move backend to module level class variable

Author: v0dro

lib/rubyplot.rb

@@ -14,7 +14,13 @@
 
 module Rubyplot
   @@backend = Rubyplot::Backend::MagickWrapper.new
-  def self.backend
-    @@backend
+  class << self
+    def backend
+      @@backend
+    end
+
+    def set_backend_magick
+      @@backed = Rubyplot::Backend::MagickWrapper.new
+    end
   end
-end
+end # module Rubyplot

lib/rubyplot/artist/axes.rb

@@ -72,7 +72,6 @@ def initialize(figure)
         @legend_font_size = 20.0
         @legend_margin = LEGEND_MARGIN
         @title_font_size = 25.0
-        @backend = @figure.backend
         @plot_colors = []
         @legends = []
         @lines = []
@@ -147,10 +146,6 @@ def bubble!(*_args)
         @plots << plot
       end
 
-      def dot!(*args, &block)
-        add_plot 'Dot', *args, &block
-      end
-
       def stacked_bar!(*_args)
         plot = Rubyplot::Artist::Plot::StackedBar.new self
         yield(plot) if block_given?
@@ -252,26 +247,8 @@ def assign_y_ticks
         end
       end
 
-      def add_plot plot_type, *args, &block
-        plot = with_backend plot_type, *args
-        yield(plot) if block_given?
-        @plots << plot
-      end
-
-      def with_backend(plot_type, *args)
-        plot =
-          case Rubyplot.backend
-          when :magick
-            Kernel.const_get("Rubyplot::MagickWrapper::Plot::#{plot_type}").new self, *args
-          when :gr
-            Kernel.const_get("Rubyplot::GRWrapper::Plot::#{plot_type}").new self, *args
-          end
-        plot
-      end
-
       # Figure out the co-ordinates of the title text w.r.t Axes.
       def configure_title
-
         @texts << Rubyplot::Artist::Text.new(
           @title, self, abs_x: abs_x + width / 2, abs_y: abs_y + @title_margin,
           font: @font, color: @font_color,

lib/rubyplot/artist/axis/base.rb

@@ -16,7 +16,6 @@ def initialize axes
           @min_val = nil
           @max_val = nil
           @stroke_width = 1.0
-          @backend = @axes.backend
           @major_ticks_count = 5
           @x_ticks = nil
           @texts = []

lib/rubyplot/artist/base.rb

@@ -1,14 +1,11 @@
 module Rubyplot
   module Artist
     class Base
-      # Artist backend. ImageMagick or whatever.
-      attr_reader :backend
       # Absolute X co-ordinate of this Aritist on the canvas.
       attr_reader :abs_x
       # Absolute Y co-ordinate of this Aritist on the canvas.
       attr_reader :abs_y
-      def initialize(backend, abs_x, abs_y)
-        @backend = backend
+      def initialize(abs_x, abs_y)
         @abs_x = abs_x
         @abs_y = abs_y
       end

lib/rubyplot/artist/circle.rb

@@ -4,7 +4,7 @@ class Circle < Base
       # rubocop:disable Metrics/ParameterLists
       def initialize(owner, abs_x:, abs_y:, radius:, stroke_opacity: 0.0,
         color: :default, stroke_width:)
-        super(owner.backend, abs_x, abs_y)
+        super(abs_x, abs_y)
         @owner = owner
         @radius = radius
         @stroke_width = stroke_width
@@ -14,7 +14,7 @@ def initialize(owner, abs_x:, abs_y:, radius:, stroke_opacity: 0.0,
       # rubocop:enable Metrics/ParameterLists
 
       def draw
-        @backend.draw_circle(
+        Rubyplot.backend.draw_circle(
           x: @abs_x,
           y: @abs_y,
           radius: @radius,

lib/rubyplot/artist/figure.rb

@@ -33,7 +33,7 @@ class Figure < Artist::Base
       # @param height [Integer] nil Height in pixels of the complete Figure.
       # @param width [Integer] nil Width in pixels of the complete Figure.
       def initialize(height: nil, width: nil)
-        super(Rubyplot::Backend::MagickWrapper.new, 0, 0)
+        super(0, 0)
         @title = ''
         @nrows = 1
         @ncols = 1
@@ -62,15 +62,15 @@ def add_subplot(nrow, ncol)
       #
       # @param output [TrueClass, FalseClass] true Whether to output to file or not.
       def write(file_name, output: true)
-        @backend.set_base_image_gradient(
+        Rubyplot.backend.set_base_image_gradient(
           Rubyplot::Color::COLOR_INDEX[@theme_options[:background_colors][0]],
           Rubyplot::Color::COLOR_INDEX[@theme_options[:background_colors][1]],
           @width,
           @height,
           @theme_options[:background_direction]
         )
         @subplots.each { |i| i.each(&:draw) }
-        @backend.write(file_name) if output
+        Rubyplot.backend.write(file_name) if output
       end
 
       private

lib/rubyplot/artist/legend.rb

@@ -9,7 +9,7 @@ class Legend < Artist::Base
 
       # rubocop:disable Metrics/ParameterLists
       def initialize(legend_box, axes, text:, color:,abs_x:,abs_y:)
-        super(legend_box.backend, abs_x, abs_y)
+        super(abs_x, abs_y)
         @legend_box = legend_box
         @axes = axes
         @text = text

lib/rubyplot/artist/legend_box.rb

@@ -13,7 +13,7 @@ class LegendBox < Base
       attr_accessor :border_color
 
       def initialize(axes, abs_x:, abs_y:)
-        super(axes.backend, abs_x, abs_y)
+        super(abs_x, abs_y)
         @axes = axes
         @border_color = :black
         @legends = []

lib/rubyplot/artist/line2d.rb

@@ -12,12 +12,11 @@ def initialize(owner,abs_x1:,abs_y1:,abs_x2:,abs_y2:,color: '#000000',
         @color = color
         @stroke_opacity = stroke_opacity
         @stroke_width = stroke_width
-        @backend = @owner.backend
       end
       # rubocop:enable Metrics/ParameterLists
 
       def draw
-        @backend.draw_line(x1: @abs_x1, y1: @abs_y1, x2: @abs_x2, y2: @abs_y2,
+        Rubyplot.backend.draw_line(x1: @abs_x1, y1: @abs_y1, x2: @abs_x2, y2: @abs_y2,
                            stroke_width: @stroke_width)
       end
     end # class Line2D

lib/rubyplot/artist/plot/base.rb

@@ -6,9 +6,8 @@ class Base < Artist::Base
         attr_writer :stroke_width, :stroke_opacity
 
         def initialize axes
-          super(axes.backend, axes.abs_x, axes.abs_y)
+          super(axes.abs_x, axes.abs_y)
           @axes = axes
-          @backend = @axes.backend
           @data = {
             label: '',
             color: :default