diff --git a/.rubocop.yml b/.rubocop.yml
index 499c8c39..23155551 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -154,3 +154,7 @@ Style/YodaExpression:
 
 Performance/ChainArrayAllocation:
   Enabled: false
+
+Style/RbsInline/MissingTypeAnnotation:
+  Exclude:
+    - 'test/**/*'
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index a461b9dd..07bac888 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -6,12 +6,6 @@
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 726
-# Configuration parameters: EnforcedStyle, Visibility.
-# SupportedStyles: doc_style, doc_style_and_return_annotation, method_type_signature, method_type_signature_or_return_annotation
-Style/RbsInline/MissingTypeAnnotation:
-  Enabled: false
-
 # Offense count: 193
 Style/RbsInline/UntypedInstanceVariable:
   Enabled: false
diff --git a/lib/gruff.rb b/lib/gruff.rb
index f3a87298..3512383c 100644
--- a/lib/gruff.rb
+++ b/lib/gruff.rb
@@ -17,6 +17,8 @@
 #
 module Gruff
   # @private
+  # @rbs path: String
+  # @rbs return: String
   def self.libpath(path)
     File.join(__dir__, 'gruff', path) # steep:ignore
   end
diff --git a/lib/gruff/accumulator_bar.rb b/lib/gruff/accumulator_bar.rb
index aacc125d..5f0ffcd4 100644
--- a/lib/gruff/accumulator_bar.rb
+++ b/lib/gruff/accumulator_bar.rb
@@ -18,6 +18,7 @@
 class Gruff::AccumulatorBar < Gruff::StackedBar
 private
 
+  # @rbs return: void
   def setup_data
     raise(Gruff::IncorrectNumberOfDatasetsException) unless store.length == 1
 
diff --git a/lib/gruff/area.rb b/lib/gruff/area.rb
index 84b63cb0..986453c6 100644
--- a/lib/gruff/area.rb
+++ b/lib/gruff/area.rb
@@ -24,6 +24,7 @@ class Gruff::Area < Gruff::Base
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @sorted_drawing = true
@@ -31,6 +32,7 @@ def initialize_attributes
     @stroke_width = 2.0
   end
 
+  # @rbs return: void
   def draw_graph
     x_increment = (@graph_width / (column_count - 1)).to_f
 
diff --git a/lib/gruff/bar.rb b/lib/gruff/bar.rb
index 2559ea32..60d85c67 100644
--- a/lib/gruff/bar.rb
+++ b/lib/gruff/bar.rb
@@ -51,6 +51,7 @@ class Gruff::Bar < Gruff::Base
   # Default value is +0.9+.
   #
   # @rbs space_percent: Float | Integer
+  # @rbs return: void
   def spacing_factor=(space_percent)
     raise ArgumentError, 'spacing_factor must be between 0.00 and 1.00' if (space_percent < 0) || (space_percent > 1)
 
@@ -59,6 +60,7 @@ def spacing_factor=(space_percent)
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @spacing_factor = 0.9
@@ -68,6 +70,7 @@ def initialize_attributes
     @hide_labels = false
   end
 
+  # @rbs return: void
   def setup_drawing
     # Labels will be centered over the left of the bar if
     # there are more labels than columns. This is basically the same
@@ -92,6 +95,7 @@ def hide_bottom_label_area?
     hide_labels? && @x_axis_label.nil? && @legend_at_bottom == false
   end
 
+  # @rbs return: void
   def setup_graph_measurements
     super
     return if @hide_line_markers
@@ -106,6 +110,7 @@ def setup_graph_measurements
     end
   end
 
+  # @rbs return: void
   def draw_graph
     # Setup spacing.
     #
diff --git a/lib/gruff/base.rb b/lib/gruff/base.rb
index 4e754805..5c015bba 100644
--- a/lib/gruff/base.rb
+++ b/lib/gruff/base.rb
@@ -154,6 +154,7 @@ def initialize(target_width = DEFAULT_TARGET_WIDTH)
       self.theme = Themes::KEYNOTE
     end
 
+    # @rbs return: void
     def initialize_graph_scale
       @raw_columns = DEFAULT_TARGET_WIDTH
       @raw_rows = DEFAULT_TARGET_WIDTH * (@rows / @columns)
@@ -165,6 +166,7 @@ def initialize_graph_scale
     end
     protected :initialize_graph_scale
 
+    # @rbs return: void
     def initialize_store
       @store = Gruff::Store.new(Gruff::Store::BasicData)
     end
@@ -176,6 +178,8 @@ def initialize_store
     #
     # This makes it possible to set defaults in a subclass but still allow
     # developers to change this values in their program.
+    #
+    # @rbs return: void
     def initialize_attributes
       @marker_count = nil
       @maximum_value = @minimum_value = nil
@@ -228,6 +232,7 @@ def initialize_attributes
     #   g = Gruff::Bar.new
     #   g.labels = ['2005', nil, nil, '2006', nil, nil, '2007', nil, nil, '2008'] # same labels for columns
     #
+    # @rbs return: void
     def labels=(labels)
       if labels.is_a?(Array)
         labels = labels.each_with_index.with_object({}) do |(label, index), hash|
@@ -243,6 +248,7 @@ def labels=(labels)
     #
     # @param rotation [Numeric] the rotation.
     # @rbs rotation: Float | Integer
+    # @rbs return: void
     def label_rotation=(rotation)
       raise ArgumentError, 'rotation must be between 0.0 and 45.0 or between 0.0 and -45.0' if rotation > 45.0 || rotation < -45.0
 
@@ -251,6 +257,7 @@ def label_rotation=(rotation)
 
     # Height of staggering between labels.
     # @deprecated
+    # @rbs return: void
     def label_stagger_height=(_value)
       warn '#label_stagger_height= is deprecated. It is no longer effective.'
     end
@@ -269,6 +276,7 @@ def label_stagger_height=(_value)
     #   g = Gruff::Bar.new
     #   g.title = ['The first line of title', 'The second line of title']
     #
+    # @rbs return: void
     def title=(title)
       if title.is_a?(Array)
         title = title.join("\n")
@@ -281,6 +289,7 @@ def title=(title)
     #
     # @param margin [Numeric] The margin size.
     # @rbs margin: Float | Integer
+    # @rbs return: void
     def margins=(margin)
       @top_margin = @left_margin = @right_margin = @bottom_margin = margin
     end
@@ -289,6 +298,7 @@ def margins=(margin)
     #
     # @param font_path [String] The path to font.
     # @rbs font_path: String
+    # @rbs return: void
     def font=(font_path)
       @title_font.path = font_path unless @title_font.path
       @marker_font.path = font_path
@@ -300,6 +310,7 @@ def font=(font_path)
     #
     # @param font_path [String] The path to font.
     # @rbs font_path: String
+    # @rbs return: void
     def title_font=(font_path)
       @title_font.path = font_path
     end
@@ -308,6 +319,7 @@ def title_font=(font_path)
     #
     # @param value [Numeric] title font size
     # @rbs value: Float | Integer
+    # @rbs return: void
     def title_font_size=(value)
       @title_font.size = value
     end
@@ -316,6 +328,7 @@ def title_font_size=(value)
     #
     # @param value [Numeric] marker font size
     # @rbs value: Float | Integer
+    # @rbs return: void
     def marker_font_size=(value)
       @marker_font.size = value
     end
@@ -327,6 +340,7 @@ def marker_font_size=(value)
     #
     # @param value [Numeric] legend font size
     # @rbs value: Float | Integer
+    # @rbs return: void
     def legend_font_size=(value)
       @legend_font.size = value
     end
@@ -335,6 +349,7 @@ def legend_font_size=(value)
     #
     # @param value [Numeric] no data font size
     # @rbs value: Float | Integer
+    # @rbs return: void
     def no_data_font_size=(value)
       @no_data_font.size = value
     end
@@ -343,6 +358,7 @@ def no_data_font_size=(value)
     #
     # @param value [Boolean] specifies whether to draw the title bolded or not.
     # @rbs value: bool
+    # @rbs return: void
     def bold_title=(value)
       @title_font.bold = value
     end
@@ -351,6 +367,7 @@ def bold_title=(value)
     #
     # @param value [String] color
     # @rbs value: String
+    # @rbs return: void
     def font_color=(value)
       @title_font.color = value
       @marker_font.color = value
@@ -365,6 +382,7 @@ def font_color=(value)
     #
     # @example
     #   add_color('#c0e9d3')
+    # @rbs return: void
     def add_color(colorname)
       @colors << colorname
     end
@@ -385,6 +403,7 @@ def add_color(colorname)
     #
     # @example
     #   replace_colors ['#cc99cc', '#d9e043', '#34d8a2']
+    # @rbs return: void
     def replace_colors(color_list = [])
       @colors = color_list
     end
@@ -393,6 +412,7 @@ def replace_colors(color_list = [])
     #
     # @param value [Boolean] Specify whether to make background transparent.
     # @rbs value: bool
+    # @rbs return: void
     def transparent_background=(value)
       @renderer.transparent_background(@columns, @rows) if value
     end
@@ -428,6 +448,7 @@ def transparent_background=(value)
     #
     # @param options [Hash] The optional setting for theme
     # @rbs options: Hash[Symbol, untyped]
+    # @rbs return: void
     def theme=(options)
       reset_themes
 
@@ -451,31 +472,37 @@ def theme=(options)
     end
 
     # Apply Apple's keynote theme.
+    # @rbs return: void
     def theme_keynote
       self.theme = Themes::KEYNOTE
     end
 
     # Apply 37signals theme.
+    # @rbs return: void
     def theme_37signals
       self.theme = Themes::THIRTYSEVEN_SIGNALS
     end
 
     # Apply Rails theme.
+    # @rbs return: void
     def theme_rails_keynote
       self.theme = Themes::RAILS_KEYNOTE
     end
 
     # Apply Odeo theme.
+    # @rbs return: void
     def theme_odeo
       self.theme = Themes::ODEO
     end
 
     # Apply pastel theme.
+    # @rbs return: void
     def theme_pastel
       self.theme = Themes::PASTEL
     end
 
     # Apply greyscale theme.
+    # @rbs return: void
     def theme_greyscale
       self.theme = Themes::GREYSCALE
     end
@@ -503,6 +530,7 @@ def theme_greyscale
     #
     # @example
     #   data("Bart S.", [95, 45, 78, 89, 88, 76], '#ffcc00')
+    # @rbs return: void
     def data(name, data_points = [], color = nil)
       store.add(name, data_points, color)
     end
@@ -540,6 +568,7 @@ def maximum_value
     #
     # @example
     #   write('graphs/my_pretty_graph.png')
+    # @rbs return: void
     def write(file_name = 'graph.png')
       to_image.write(file_name)
     end
@@ -561,6 +590,7 @@ def write(file_name = 'graph.png')
     #   image = image.resize(400, 300).quantize(128, Magick::RGBColorspace)
     #   image.write('test.png')
     #
+    # @rbs return: untyped
     def to_image(format = 'PNG')
       @to_image ||= begin
         draw
@@ -587,6 +617,7 @@ def to_blob(format = 'PNG')
     end
 
     # Draw a graph.
+    # @rbs return: void
     def draw
       setup_data
 
@@ -610,6 +641,7 @@ def draw
     attr_reader :renderer #: Gruff::Renderer
 
     # Perform data manipulation before calculating chart measurements
+    # @rbs return: void
     def setup_data
       if @y_axis_increment && !@hide_line_markers
         self.maximum_value = [@y_axis_increment, maximum_value, (maximum_value / @y_axis_increment).round * @y_axis_increment].max
@@ -624,6 +656,7 @@ def setup_data
     # * line markers
     # * legend
     # * title
+    # @rbs return: void
     def setup_drawing
       calculate_spread
       calculate_increment
@@ -666,10 +699,12 @@ def marker_count
 
     # Make copy of data with values scaled between 0-100
     # @rbs return: Array[Gruff::Store::BasicData | Gruff::Store::XYData | Gruff::Store::XYPointsizeData]
+    # @rbs return: void
     def normalize
       store.normalize(minimum: minimum_value, spread: @spread)
     end
 
+    # @rbs return: Float
     def calculate_spread
       @spread = maximum_value.to_f - minimum_value.to_f
       @spread = @spread > 0 ? @spread : 1.0
@@ -698,6 +733,7 @@ def hide_bottom_label_area?
     ##
     # Calculates size of drawable area, general font dimensions, etc.
 
+    # @rbs return: void
     def setup_graph_measurements
       @graph_right = setup_right_margin
       @graph_left = setup_left_margin
@@ -709,6 +745,7 @@ def setup_graph_measurements
     end
 
     # Draw the optional labels for the x axis and y axis.
+    # @rbs return: void
     def draw_axis_labels
       if @x_axis_label
         # X Axis
@@ -728,6 +765,7 @@ def draw_axis_labels
     end
 
     # Draws horizontal background lines and labels
+    # @rbs return: void
     def draw_line_markers
       return if @hide_line_markers
 
@@ -747,11 +785,16 @@ def draw_line_markers
       end
     end
 
+    # @rbs y: Float | Integer
+    # @rbs return: void
     def draw_marker_horizontal_line(y)
       Gruff::Renderer::Line.new(renderer, color: @marker_color).render(@graph_left, y, @graph_right, y)
       Gruff::Renderer::Line.new(renderer, color: @marker_shadow_color).render(@graph_left, y + 1, @graph_right, y + 1) if @marker_shadow_color
     end
 
+    # @rbs x: Float | Integer
+    # @rbs tick_mark_mode: bool
+    # @rbs return: void
     def draw_marker_vertical_line(x, tick_mark_mode: false)
       if tick_mark_mode
         Gruff::Renderer::Line.new(renderer, color: @marker_color).render(x, @graph_bottom, x, @graph_bottom + 5)
@@ -775,6 +818,7 @@ def center(size)
 
     # Draws a legend with the names of the datasets matched
     # to the colors used to draw them.
+    # @rbs return: void
     def draw_legend
       return if @hide_legend
 
@@ -824,6 +868,7 @@ def draw_legend
     end
 
     # Draws a title on the graph.
+    # @rbs return: void
     def draw_title
       return if hide_title?
 
@@ -842,6 +887,7 @@ def draw_title
     # @rbs index: Integer
     # @rbs gravity: untyped
     # @rbs &: () -> void
+    # @rbs return: void
     def draw_label(x, index, gravity = Magick::NorthGravity, &block)
       draw_unique_label(index) do
         if x.between?(@graph_left, @graph_right)
@@ -856,6 +902,7 @@ def draw_label(x, index, gravity = Magick::NorthGravity, &block)
 
     # @rbs index: Integer
     # @rbs yields: () -> void
+    # @rbs return: void
     def draw_unique_label(index)
       return if hide_labels?
 
@@ -873,6 +920,7 @@ def draw_unique_label(index)
     # @rbs text: String | _ToS
     # @rbs gravity: untyped
     # @rbs rotation: Float | Integer
+    # @rbs return: void
     def draw_label_at(width, height, x, y, text, gravity: Magick::NorthGravity, rotation: 0)
       label_text = truncate_label_text(text)
       text_renderer = Gruff::Renderer::Text.new(renderer, label_text, font: @marker_font, rotation: rotation)
@@ -887,6 +935,7 @@ def draw_label_at(width, height, x, y, text, gravity: Magick::NorthGravity, rota
     # @rbs y_offset: Float | Integer
     # @rbs data_point: String | _ToS
     # @rbs gravity: untyped
+    # @rbs return: void
     def draw_value_label(width, height, x_offset, y_offset, data_point, gravity: Magick::CenterGravity)
       return if @hide_line_markers
 
@@ -894,17 +943,20 @@ def draw_value_label(width, height, x_offset, y_offset, data_point, gravity: Mag
     end
 
     # Shows an error message because you have no data.
+    # @rbs return: void
     def draw_no_data
       font = @no_data_font
       text_renderer = Gruff::Renderer::Text.new(renderer, @no_data_message, font: font)
       text_renderer.render(@raw_columns, @raw_rows, 0, 0, Magick::CenterGravity)
     end
 
+    # @rbs return: void
     def draw_graph
       raise 'Should implement this method at inherited class.'
     end
 
     # Resets everything to defaults (except data).
+    # @rbs return: void
     def reset_themes
       @theme_options = {}
     end
@@ -945,17 +997,20 @@ def significant(i)
     end
 
     # Sort with largest overall summed value at front of array.
+    # @rbs return: void
     def sort_data
       store.sort_data!
     end
 
     # Set the color for each data set unless it was given in the data(...) call.
+    # @rbs return: void
     def set_colors
       store.change_colors(@colors)
     end
 
     # Sort with largest overall summed value at front of array so it shows up
     # correctly in the drawn graph.
+    # @rbs return: void
     def sort_norm_data
       store.sort_norm_data!
     end
@@ -1156,7 +1211,9 @@ def y_axis_label(value, increment)
       end
     end
 
-    # TODO: RBS signature
+    # @rbs legend_labels: Array[String]
+    # @rbs legend_square_width: Float | Integer
+    # @rbs return: Array[Array[Float | Integer]]
     def calculate_legend_label_widths_for_each_line(legend_labels, legend_square_width)
       label_widths = [[]]
       label_lines = [[]]
@@ -1179,7 +1236,7 @@ def calculate_legend_label_widths_for_each_line(legend_labels, legend_square_wid
       label_widths.map(&:sum).zip(label_lines)
     end
 
-    # TODO: RBS signature
+    # @rbs return: Float
     def calculate_legend_height
       return 0.0 if @hide_legend
 
diff --git a/lib/gruff/bezier.rb b/lib/gruff/bezier.rb
index 005f1abb..74ff42e4 100644
--- a/lib/gruff/bezier.rb
+++ b/lib/gruff/bezier.rb
@@ -23,6 +23,7 @@
 class Gruff::Bezier < Gruff::Base
 private
 
+  # @rbs return: void
   def draw_graph
     x_increment = (@graph_width / (column_count - 1)).to_f
 
diff --git a/lib/gruff/box.rb b/lib/gruff/box.rb
index a59dddf4..701a6baa 100644
--- a/lib/gruff/box.rb
+++ b/lib/gruff/box.rb
@@ -26,6 +26,7 @@ class Gruff::Box < Gruff::Base
   # Default value is +0.8+.
   #
   # @rbs space_percent: Float | Integer
+  # @rbs return: void
   def spacing_factor=(space_percent)
     raise ArgumentError, 'spacing_factor must be between 0.00 and 1.00' if (space_percent < 0) || (space_percent > 1)
 
@@ -34,6 +35,7 @@ def spacing_factor=(space_percent)
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @fill_opacity = 0.2
@@ -41,6 +43,7 @@ def initialize_attributes
     @spacing_factor = 0.8
   end
 
+  # @rbs return: void
   def draw_graph
     # Setup the BarConversion Object
     conversion = Gruff::BarConversion.new(
@@ -93,6 +96,7 @@ def draw_graph
     end
   end
 
+  # @rbs return: Array[Gruff::Box::BoxData]
   def normalized_boxes
     @normalized_boxes ||= store.norm_data.map { |data| Gruff::Box::BoxData.new(data.label, data.points, data.color) }
   end
@@ -113,6 +117,10 @@ class BoxData
     attr_accessor :points #: Array[Float | Integer]
     attr_accessor :color #: String
 
+    # @rbs label: String
+    # @rbs points: Array[Float | Integer]
+    # @rbs color: String
+    # @rbs return: void
     def initialize(label, points, color)
       @label = label
       @points = points.compact.sort
diff --git a/lib/gruff/bubble.rb b/lib/gruff/bubble.rb
index a7a1eed4..cee1bc3a 100644
--- a/lib/gruff/bubble.rb
+++ b/lib/gruff/bubble.rb
@@ -60,6 +60,7 @@ class Gruff::Bubble < Gruff::Scatter
   # @rbs y_data_points: Array[nil | Float | Integer] | nil
   # @rbs point_sizes: Array[nil | Float | Integer] | nil
   # @rbs color: String
+  # @rbs return: void
   def data(name, x_data_points = [], y_data_points = [], point_sizes = [], color = nil)
     # make sure it's an array
     x_data_points = Array(x_data_points)
@@ -78,10 +79,12 @@ def data(name, x_data_points = [], y_data_points = [], point_sizes = [], color =
 
 private
 
+  # @rbs return: void
   def initialize_store
     @store = Gruff::Store.new(Gruff::Store::XYPointsizeData)
   end
 
+  # @rbs return: void
   def initialize_attributes
     super
 
@@ -89,6 +92,7 @@ def initialize_attributes
     @stroke_width = 1.0
   end
 
+  # @rbs return: void
   def draw_graph
     store.norm_data.each do |data_row|
       data_row.coordinate_and_pointsizes.each do |x_value, y_value, point_size|
diff --git a/lib/gruff/bullet.rb b/lib/gruff/bullet.rb
index a863d4b2..e1d780ce 100644
--- a/lib/gruff/bullet.rb
+++ b/lib/gruff/bullet.rb
@@ -31,6 +31,7 @@ def initialize(target_width = '400x40')
     self.theme = Gruff::Themes::GREYSCALE
   end
 
+  # @rbs return: void
   def initialize_attributes
     super
 
@@ -42,6 +43,7 @@ def initialize_attributes
   # @rbs value: Float | Integer
   # @rbs maximum_value: Float | Integer
   # @rbs options: Hash[Symbol, Float | Integer]
+  # @rbs return: void
   def data(value, maximum_value, options = {})
     @value = value.to_f
     self.maximum_value = maximum_value.to_f
@@ -49,6 +51,7 @@ def data(value, maximum_value, options = {})
     @options.map { |k, v| @options[k] = v.to_f if v.respond_to?(:to_f) }
   end
 
+  # @rbs return: void
   def draw
     # TODO: Left label
     # TODO Bottom labels and markers
@@ -95,6 +98,7 @@ def draw
 
 private
 
+  # @rbs return: void
   def draw_title
     return if hide_title?
 
diff --git a/lib/gruff/candlestick.rb b/lib/gruff/candlestick.rb
index 9281f46e..88ee2ff4 100644
--- a/lib/gruff/candlestick.rb
+++ b/lib/gruff/candlestick.rb
@@ -36,6 +36,7 @@ class Gruff::Candlestick < Gruff::Base
   # Default value is +0.9+.
   #
   # @rbs space_percent: Float | Integer
+  # @rbs return: void
   def spacing_factor=(space_percent)
     raise ArgumentError, 'spacing_factor must be between 0.00 and 1.00' if (space_percent < 0) || (space_percent > 1)
 
@@ -43,11 +44,13 @@ def spacing_factor=(space_percent)
   end
 
   # The sort feature is not supported in this graph.
+  # @rbs return: void
   def sort=(_value)
     raise 'Not support #sort= in Gruff::Candlestick'
   end
 
   # The sort feature is not supported in this graph.
+  # @rbs return: void
   def sorted_drawing=(_value)
     raise 'Not support #sorted_drawing= in Gruff::Candlestick'
   end
@@ -56,12 +59,14 @@ def sorted_drawing=(_value)
   # @rbs high: Float | Integer
   # @rbs open: Float | Integer
   # @rbs close: Float | Integer
+  # @rbs return: void
   def data(low:, high:, open:, close:)
     super('', [low, high, open, close])
   end
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @show_vertical_markers = false
@@ -74,6 +79,7 @@ def initialize_attributes
     @hide_legend = true
   end
 
+  # @rbs return: void
   def draw_graph
     # Setup the BarConversion Object
     conversion = Gruff::BarConversion.new(
@@ -106,6 +112,7 @@ def draw_graph
     end
   end
 
+  # @rbs return: Array[Gruff::Candlestick::CandlestickData]
   def normalized_candlesticks
     @normalized_candlesticks ||= store.norm_data.map { |data| Gruff::Candlestick::CandlestickData.new(*data.points) } # steep:ignore
   end
@@ -127,11 +134,16 @@ def show_marker_vertical_line?
 
   # @private
   class CandlestickData
-    attr_accessor :low
-    attr_accessor :high
-    attr_accessor :open
-    attr_accessor :close
-
+    attr_accessor :low #: Float | Integer
+    attr_accessor :high #: Float | Integer
+    attr_accessor :open #: Float | Integer
+    attr_accessor :close #: Float | Integer
+
+    # @rbs low: Float | Integer
+    # @rbs high: Float | Integer
+    # @rbs open: Float | Integer
+    # @rbs close: Float | Integer
+    # @rbs return: void
     def initialize(low, high, open, close)
       @low = low.to_f
       @high = high.to_f
diff --git a/lib/gruff/dot.rb b/lib/gruff/dot.rb
index 4e9aaeaa..98472a73 100644
--- a/lib/gruff/dot.rb
+++ b/lib/gruff/dot.rb
@@ -29,6 +29,7 @@ def initialize(target_width = DEFAULT_TARGET_WIDTH)
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @hide_labels = false
@@ -49,6 +50,7 @@ def hide_bottom_label_area?
     @hide_line_markers && @x_axis_label.nil? && @legend_at_bottom == false
   end
 
+  # @rbs return: void
   def draw_graph
     # Setup spacing.
     #
@@ -76,6 +78,7 @@ def draw_graph
   end
 
   # Instead of base class version, draws vertical background lines and label
+  # @rbs return: void
   def draw_line_markers
     return if @hide_line_markers
 
@@ -98,6 +101,7 @@ def draw_line_markers
 
   # @rbs y_offset: Float | Integer
   # @rbs index: Integer
+  # @rbs return: void
   def draw_label(y_offset, index)
     draw_unique_label(index) do
       draw_label_at(@graph_left - @label_margin, 1.0, 0.0, y_offset, @labels[index], gravity: Magick::EastGravity)
diff --git a/lib/gruff/font.rb b/lib/gruff/font.rb
index 200b2bb0..3ade3571 100644
--- a/lib/gruff/font.rb
+++ b/lib/gruff/font.rb
@@ -26,6 +26,7 @@ class Gruff::Font
   # @rbs size: Float | Integer
   # @rbs bold: bool
   # @rbs color: String
+  # @rbs return: void
   def initialize(path: nil, size: 20.0, bold: false, color: 'white')
     @path = path
     @bold = bold
@@ -36,6 +37,7 @@ def initialize(path: nil, size: 20.0, bold: false, color: 'white')
   # Get font weight.
   # @return [Magick::WeightType] font weight
   # TODO: type annotation of return value
+  # @rbs return: untyped
   def weight
     @bold ? Magick::BoldWeight : Magick::NormalWeight
   end
diff --git a/lib/gruff/helper/bar_value_label.rb b/lib/gruff/helper/bar_value_label.rb
index ba18dac4..6de1cb8c 100644
--- a/lib/gruff/helper/bar_value_label.rb
+++ b/lib/gruff/helper/bar_value_label.rb
@@ -45,6 +45,7 @@ class Bar < Base
     # @rbs format: nil | String | Proc
     # @rbs proc_text_metrics: Proc
     # @rbs yields: (Float | Integer, Float | Integer, String, Float, Float) -> void
+    # @rbs return: void
     def prepare_rendering(format, proc_text_metrics)
       left_x, left_y, _right_x, _right_y = @coordinate
       val, metrics = Gruff::BarValueLabel.metrics(@value, format, proc_text_metrics)
@@ -59,6 +60,7 @@ class SideBar < Base
     # @rbs format: nil | String | Proc
     # @rbs proc_text_metrics: Proc
     # @rbs yields: (Float | Integer, Float | Integer, String, Float, Float) -> void
+    # @rbs return: void
     def prepare_rendering(format, proc_text_metrics)
       left_x, left_y, right_x, _right_y = @coordinate
       val, metrics = Gruff::BarValueLabel.metrics(@value, format, proc_text_metrics)
diff --git a/lib/gruff/helper/stacked_mixin.rb b/lib/gruff/helper/stacked_mixin.rb
index baadaff6..f914af2d 100644
--- a/lib/gruff/helper/stacked_mixin.rb
+++ b/lib/gruff/helper/stacked_mixin.rb
@@ -7,6 +7,7 @@ module Gruff::Base::StackedMixin
   # Used by StackedBar and child classes.
   #
   # tsal: moved from Base 03 FEB 2007
+  # @rbs return: void
   def calculate_maximum_by_stack
     # steep:ignore:start
     # Get sum of each stack
diff --git a/lib/gruff/histogram.rb b/lib/gruff/histogram.rb
index 8036dc1c..76a3fadd 100644
--- a/lib/gruff/histogram.rb
+++ b/lib/gruff/histogram.rb
@@ -35,12 +35,14 @@ def initialize(target_width = DEFAULT_TARGET_WIDTH)
   # @rbs name: String | Symbol
   # @rbs data_points: Array[Float | Integer] | nil
   # @rbs color: String
+  # @rbs return: void
   def data(name, data_points = [], color = nil)
     @data << [name, Array(data_points), color]
   end
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @bin_width = 10
@@ -48,6 +50,7 @@ def initialize_attributes
     @maximum_bin = nil
   end
 
+  # @rbs return: void
   def setup_data
     @data.each do |(name, data_points, color)|
       if data_points.empty?
diff --git a/lib/gruff/line.rb b/lib/gruff/line.rb
index f112687e..8bf8ebed 100644
--- a/lib/gruff/line.rb
+++ b/lib/gruff/line.rb
@@ -51,6 +51,7 @@ class Gruff::Line < Gruff::Base
   #
   # The preferred way is to call {#hide_dots=} or {#hide_lines=} instead.
   #
+  # @rbs *args: untyped
   # @rbs return: void
   def initialize(*args)
     raise ArgumentError, 'Wrong number of arguments' if args.length > 2
@@ -74,6 +75,7 @@ def baseline_value
   # Set a value for a baseline reference line..
   #
   # @rbs new_value: Float | Integer
+  # @rbs return: Float | Integer
   def baseline_value=(new_value)
     @reference_lines[:baseline] ||= {}
     @reference_lines[:baseline][:value] = new_value
@@ -87,6 +89,7 @@ def baseline_color
   end
 
   # @rbs new_value: Float | Integer
+  # @rbs return: Float | Integer
   def baseline_color=(new_value)
     @reference_lines[:baseline] ||= {}
     @reference_lines[:baseline][:color] = new_value
@@ -115,6 +118,7 @@ def baseline_color=(new_value)
   #
   # @example
   #   data("Bart S.", [95, 45, 78, 89, 88, 76], '#ffcc00')
+  # @rbs return: void
   def data(name, data_points = [], color = nil)
     store.add(name, nil, data_points, color)
   end
@@ -158,6 +162,7 @@ def data(name, data_points = [], color = nil)
   # @rbs x_data_points: Array[nil | Float | Integer] | Array[[nil | Float | Integer, nil | Float | Integer]] | nil
   # @rbs y_data_points: Array[nil | Float | Integer] | nil | String
   # @rbs color: String
+  # @rbs return: void
   def dataxy(name, x_data_points = [], y_data_points = [], color = nil)
     # make sure it's an array
     x_data_points = Array(x_data_points)
@@ -179,10 +184,12 @@ def dataxy(name, x_data_points = [], y_data_points = [], color = nil)
 
 private
 
+  # @rbs return: void
   def initialize_store
     @store = Gruff::Store.new(Gruff::Store::XYData)
   end
 
+  # @rbs return: void
   def initialize_attributes
     super
     @reference_lines = {}
@@ -201,22 +208,33 @@ def initialize_attributes
     @show_vertical_markers = false
   end
 
+  # @rbs reference_line: Hash[Symbol, untyped]
+  # @rbs left: Float | Integer
+  # @rbs right: Float | Integer
+  # @rbs top: Float | Integer
+  # @rbs bottom: Float | Integer
+  # @rbs return: void
   def draw_reference_line(reference_line, left, right, top, bottom)
     color = reference_line[:color] || @reference_line_default_color
     width = reference_line[:width] || @reference_line_default_width
     Gruff::Renderer::DashLine.new(renderer, color: color, width: width).render(left, top, right, bottom)
   end
 
+  # @rbs reference_line: Hash[Symbol, untyped]
+  # @rbs return: void
   def draw_horizontal_reference_line(reference_line)
     level = @graph_top + (@graph_height - (reference_line[:norm_value] * @graph_height))
     draw_reference_line(reference_line, @graph_left, @graph_left + @graph_width, level, level)
   end
 
+  # @rbs reference_line: Hash[Symbol, untyped]
+  # @rbs return: void
   def draw_vertical_reference_line(reference_line)
     index = @graph_left + (@x_increment * reference_line[:index])
     draw_reference_line(reference_line, index, index, @graph_top, @graph_top + @graph_height)
   end
 
+  # @rbs return: void
   def draw_graph
     # Check to see if more than one datapoint was given. NaN can result otherwise.
     @x_increment = column_count > 1 ? @graph_width / (column_count - 1) : @graph_width
@@ -268,6 +286,7 @@ def draw_graph
     end
   end
 
+  # @rbs return: void
   def setup_data
     # Update the global min/max values for the x data
     @maximum_x_value = (@maximum_x_value || store.max_x).to_f
@@ -290,11 +309,13 @@ def setup_data
     super
   end
 
+  # @rbs return: void
   def setup_drawing
     @marker_x_count ||= column_count - 1
     super
   end
 
+  # @rbs return: void
   def normalize
     return unless data_given?
 
@@ -309,6 +330,7 @@ def normalize
     end
   end
 
+  # @rbs return: void
   def draw_line_markers
     # do all of the stuff for the horizontal lines on the y-axis
     super
@@ -320,6 +342,10 @@ def draw_line_markers
     end
   end
 
+  # @rbs x_data: Float | Integer | nil
+  # @rbs new_x: Float | Integer
+  # @rbs index: Integer
+  # @rbs return: void
   def draw_label_for_x_data(x_data, new_x, index)
     if x_data.nil?
       draw_label(new_x, index)
@@ -330,6 +356,8 @@ def draw_label_for_x_data(x_data, new_x, index)
     end
   end
 
+  # @rbs data_row: Gruff::Store::XYData
+  # @rbs return: bool
   def contains_one_point_only?(data_row)
     data_row.y_points.compact.count == 1
   end
diff --git a/lib/gruff/mini/bar.rb b/lib/gruff/mini/bar.rb
index a3f1a10c..ae9df11b 100644
--- a/lib/gruff/mini/bar.rb
+++ b/lib/gruff/mini/bar.rb
@@ -18,6 +18,7 @@ class Gruff::Mini::Bar < Gruff::Bar
 
   include Gruff::Mini::Legend
 
+  # @rbs return: void
   def initialize_attributes
     super
 
@@ -31,11 +32,13 @@ def initialize_attributes
     @minimum_value = 0.0
   end
 
+  # @rbs return: void
   def setup_data
     expand_canvas_for_vertical_legend # steep:ignore
     super
   end
 
+  # @rbs return: void
   def draw_graph
     super
     draw_vertical_legend # steep:ignore
diff --git a/lib/gruff/mini/legend.rb b/lib/gruff/mini/legend.rb
index b99fd6f1..c4eec1e2 100644
--- a/lib/gruff/mini/legend.rb
+++ b/lib/gruff/mini/legend.rb
@@ -4,8 +4,10 @@
 # A module to handle the small legend.
 # @private
 module Gruff::Mini::Legend
-  attr_accessor :hide_mini_legend, :legend_position
+  attr_accessor :hide_mini_legend #: bool
+  attr_accessor :legend_position  #: Symbol
 
+  # @rbs return: void
   def initialize(*)
     @hide_mini_legend = false
     @legend_position = nil
@@ -13,6 +15,7 @@ def initialize(*)
   end
 
   # The canvas needs to be bigger so we can put the legend beneath it.
+  # @rbs return: Gruff::Renderer
   def expand_canvas_for_vertical_legend
     # steep:ignore:start
 
@@ -39,10 +42,12 @@ def expand_canvas_for_vertical_legend
     # steep:ignore:end
   end
 
+  # @rbs return: Float
   def calculate_line_height
     calculate_caps_height(@legend_font) * 1.7 # steep:ignore
   end
 
+  # @rbs return: Float
   def calculate_legend_width
     # steep:ignore:start
     width = @legend_labels.map { |label| calculate_width(@legend_font, label) }.max
@@ -51,6 +56,7 @@ def calculate_legend_width
   end
 
   # Draw the legend beneath the existing graph.
+  # @rbs return: void
   def draw_vertical_legend
     # steep:ignore:start
     return if @hide_mini_legend
@@ -88,6 +94,9 @@ def draw_vertical_legend
   end
 
   # Shorten long labels so they will fit on the canvas.
+  # @rbs label: String | Symbol
+  # @rbs x_offset: Float | Integer
+  # @rbs return: String
   def truncate_legend_label(label, x_offset)
     # steep:ignore:start
     truncated_label = label.to_s
@@ -102,7 +111,9 @@ def truncate_legend_label(label, x_offset)
     # steep:ignore:end
   end
 
+  # @rbs value: Float | Integer
+  # @rbs return: Float
   def scale(value)
-    value * @scale
+    (value.to_f * @scale).to_f
   end
 end
diff --git a/lib/gruff/mini/pie.rb b/lib/gruff/mini/pie.rb
index 48d49232..9e89c08a 100644
--- a/lib/gruff/mini/pie.rb
+++ b/lib/gruff/mini/pie.rb
@@ -17,6 +17,7 @@ class Gruff::Mini::Pie < Gruff::Pie
 
   include Gruff::Mini::Legend
 
+  # @rbs return: void
   def initialize_attributes
     super
 
@@ -28,11 +29,13 @@ def initialize_attributes
     @legend_font.size = 50.0
   end
 
+  # @rbs return: void
   def setup_data
     expand_canvas_for_vertical_legend # steep:ignore
     super
   end
 
+  # @rbs return: void
   def draw_graph
     super
     draw_vertical_legend # steep:ignore
diff --git a/lib/gruff/mini/side_bar.rb b/lib/gruff/mini/side_bar.rb
index 2dd15dd9..b5a02f1d 100644
--- a/lib/gruff/mini/side_bar.rb
+++ b/lib/gruff/mini/side_bar.rb
@@ -25,6 +25,7 @@ class Gruff::Mini::SideBar < Gruff::SideBar
 
   include Gruff::Mini::Legend
 
+  # @rbs return: void
   def initialize_attributes
     super
     @hide_legend = true
@@ -35,11 +36,13 @@ def initialize_attributes
     @legend_font.size = 50.0
   end
 
+  # @rbs return: void
   def setup_data
     expand_canvas_for_vertical_legend # steep:ignore
     super
   end
 
+  # @rbs return: void
   def draw_graph
     super
     draw_vertical_legend # steep:ignore
diff --git a/lib/gruff/net.rb b/lib/gruff/net.rb
index e93b8ee4..15d03580 100644
--- a/lib/gruff/net.rb
+++ b/lib/gruff/net.rb
@@ -34,6 +34,7 @@ class Gruff::Net < Gruff::Base
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
 
@@ -45,11 +46,13 @@ def initialize_attributes
     @marker_font.bold = true
   end
 
+  # @rbs return: void
   def setup_drawing
     @center_labels_over_point = false
     super
   end
 
+  # @rbs return: void
   def setup_graph_measurements
     super
 
@@ -60,6 +63,7 @@ def setup_graph_measurements
     @center_y = @graph_top + (@graph_height / 2.0) + 10
   end
 
+  # @rbs return: void
   def draw_graph
     store.norm_data.each do |data_row|
       poly_points = []
@@ -94,6 +98,7 @@ def draw_graph
   end
 
   # the lines connecting in the center, with the first line vertical
+  # @rbs return: void
   def draw_line_markers
     return if @hide_line_markers
 
@@ -114,6 +119,7 @@ def draw_line_markers
   # @rbs angle: Float | Integer
   # @rbs radius: Float
   # @rbs amount: String | Integer
+  # @rbs return: void
   def draw_label(center_x, center_y, angle, radius, amount)
     x_offset = center_x # + 15 # The label points need to be tweaked slightly
     y_offset = center_y # + 0  # This one doesn't though
diff --git a/lib/gruff/patch/rmagick.rb b/lib/gruff/patch/rmagick.rb
index 265b29b2..6387bbc0 100644
--- a/lib/gruff/patch/rmagick.rb
+++ b/lib/gruff/patch/rmagick.rb
@@ -7,6 +7,14 @@ module Magick
   module GruffAnnotate
     refine Draw do
       # Additional method to scale annotation text since Draw.scale doesn't.
+      # @rbs img: untyped
+      # @rbs width: Integer
+      # @rbs height: Integer
+      # @rbs x: Integer
+      # @rbs y: Integer
+      # @rbs text: String
+      # @rbs scale: Float
+      # @rbs return: void
       def annotate_scaled(img, width, height, x, y, text, scale)
         scaled_width = [(width * scale), 1].max
         scaled_height = [(height * scale), 1].max
@@ -23,6 +31,8 @@ def annotate_scaled(img, width, height, x, y, text, scale)
         # FIXME(uwe):  We should NOT need to implement this method.
         #              Remove this method as soon as RMagick4J Issue #16 is fixed.
         #              https://github.com/Serabe/RMagick4J/issues/16
+        # @rbs fill: String | Symbol
+        # @rbs return: void
         def fill=(fill)
           fill = { white: '#FFFFFF' }[fill.to_sym] || fill
           @draw.fill = Magick4J.ColorDatabase.query_default(fill)
diff --git a/lib/gruff/patch/string.rb b/lib/gruff/patch/string.rb
index 0063f9bc..2ed678ce 100644
--- a/lib/gruff/patch/string.rb
+++ b/lib/gruff/patch/string.rb
@@ -8,6 +8,8 @@ module String::GruffCommify
 
   refine String do
     # Taken from http://codesnippets.joyent.com/posts/show/330
+    # @rbs delimiter: String
+    # @rbs return: String
     def commify(delimiter = THOUSAND_SEPARATOR)
       gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1#{delimiter}") # steep:ignore
     end
diff --git a/lib/gruff/pie.rb b/lib/gruff/pie.rb
index cb6df696..ffdb6036 100644
--- a/lib/gruff/pie.rb
+++ b/lib/gruff/pie.rb
@@ -41,6 +41,8 @@ class Gruff::Pie < Gruff::Base
   # Can be used to make the pie start cutting slices at the top (-90.0)
   # or at another angle. Default is +-90.0+, which starts at 3 o'clock.
   # @deprecated Please use {#start_degree=} instead.
+  # @rbs value: Float | Integer
+  # @rbs return: void
   def zero_degree=(value)
     warn '#zero_degree= is deprecated. Please use `start_degree` attribute instead'
     @start_degree = value
@@ -48,6 +50,7 @@ def zero_degree=(value)
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @start_degree = -90.0
@@ -63,11 +66,13 @@ def initialize_attributes
     @label_formatting = ->(value, percentage) { @show_values_as_labels ? value.to_s : "#{percentage}%" }
   end
 
+  # @rbs return: void
   def setup_drawing
     @center_labels_over_point = false
     super
   end
 
+  # @rbs return: void
   def draw_graph
     slices.each do |slice|
       if slice.value > 0
@@ -79,6 +84,7 @@ def draw_graph
     end
   end
 
+  # @rbs return: Array[Gruff::Pie::PieSlice]
   def slices
     @slices ||= begin
       slices = store.data.map { |data| Gruff::Pie::PieSlice.new(data.label, data.points.first, data.color) }
@@ -93,6 +99,7 @@ def slices
   # General Helper Methods
 
   # @rbs degrees: Float | Integer
+  # @rbs return: void
   def update_chart_degrees_with(degrees)
     @chart_degrees = chart_degrees + degrees
   end
@@ -150,6 +157,7 @@ def ellipse_factor
   # Label-Related Methods
 
   # @rbs slice: Gruff::Pie::PieSlice
+  # @rbs return: void
   def process_label_for(slice)
     if slice.percentage >= @hide_labels_less_than
       x, y = label_coordinates_for slice
diff --git a/lib/gruff/renderer/bezier.rb b/lib/gruff/renderer/bezier.rb
index d1e57c2d..6e2264de 100644
--- a/lib/gruff/renderer/bezier.rb
+++ b/lib/gruff/renderer/bezier.rb
@@ -16,6 +16,7 @@ def initialize(renderer, color:, width: 1.0)
     end
 
     # @rbs points: Array[Float | Integer]
+    # @rbs return: void
     def render(points)
       @renderer.draw.push
       @renderer.draw.stroke_width(@width)
diff --git a/lib/gruff/renderer/circle.rb b/lib/gruff/renderer/circle.rb
index 8598939d..57ef2e53 100644
--- a/lib/gruff/renderer/circle.rb
+++ b/lib/gruff/renderer/circle.rb
@@ -21,6 +21,7 @@ def initialize(renderer, color:, width: 1.0, opacity: 1.0)
     # @rbs origin_y: Float | Integer
     # @rbs perim_x: Float | Integer
     # @rbs perim_y: Float | Integer
+    # @rbs return: void
     def render(origin_x, origin_y, perim_x, perim_y)
       @renderer.draw.push
       @renderer.draw.stroke_width(@width)
diff --git a/lib/gruff/renderer/dash_line.rb b/lib/gruff/renderer/dash_line.rb
index 67626abb..1e71a70d 100644
--- a/lib/gruff/renderer/dash_line.rb
+++ b/lib/gruff/renderer/dash_line.rb
@@ -21,6 +21,7 @@ def initialize(renderer, color:, width:, dasharray: [10, 20])
     # @rbs start_y: Float | Integer
     # @rbs end_x: Float | Integer
     # @rbs end_y: Float | Integer
+    # @rbs return: void
     def render(start_x, start_y, end_x, end_y)
       @renderer.draw.push
       @renderer.draw.stroke_color(@color)
diff --git a/lib/gruff/renderer/dot.rb b/lib/gruff/renderer/dot.rb
index 7f89f4ba..ece86e78 100644
--- a/lib/gruff/renderer/dot.rb
+++ b/lib/gruff/renderer/dot.rb
@@ -22,6 +22,7 @@ def initialize(renderer, style, color:, width: 1.0, opacity: 1.0)
     # @rbs new_x: Float | Integer
     # @rbs new_y: Float | Integer
     # @rbs radius: Float | Integer
+    # @rbs return: void
     def render(new_x, new_y, radius)
       @renderer.draw.push
       @renderer.draw.stroke_width(@width)
@@ -41,10 +42,18 @@ def render(new_x, new_y, radius)
 
   private
 
+    # @rbs new_x: Float | Integer
+    # @rbs new_y: Float | Integer
+    # @rbs radius: Float | Integer
+    # @rbs return: void
     def circle(new_x, new_y, radius)
       @renderer.draw.circle(new_x, new_y, new_x - radius, new_y)
     end
 
+    # @rbs new_x: Float | Integer
+    # @rbs new_y: Float | Integer
+    # @rbs radius: Float | Integer
+    # @rbs return: void
     def square(new_x, new_y, radius)
       corner1 = new_x - radius
       corner2 = new_y - radius
@@ -53,6 +62,10 @@ def square(new_x, new_y, radius)
       @renderer.draw.rectangle(corner1, corner2, corner3, corner4)
     end
 
+    # @rbs new_x: Float | Integer
+    # @rbs new_y: Float | Integer
+    # @rbs radius: Float | Integer
+    # @rbs return: void
     def diamond(new_x, new_y, radius)
       polygon = []
       polygon += [new_x - radius, new_y]
diff --git a/lib/gruff/renderer/ellipse.rb b/lib/gruff/renderer/ellipse.rb
index fffb39ff..baf152ac 100644
--- a/lib/gruff/renderer/ellipse.rb
+++ b/lib/gruff/renderer/ellipse.rb
@@ -21,6 +21,7 @@ def initialize(renderer, color:, width: 1.0)
     # @rbs height: Float | Integer
     # @rbs arc_start: Float | Integer
     # @rbs arc_end: Float | Integer
+    # @rbs return: void
     def render(origin_x, origin_y, width, height, arc_start, arc_end)
       @renderer.draw.push
       @renderer.draw.stroke_width(@width)
diff --git a/lib/gruff/renderer/line.rb b/lib/gruff/renderer/line.rb
index cf9f2a63..fc3f5ec8 100644
--- a/lib/gruff/renderer/line.rb
+++ b/lib/gruff/renderer/line.rb
@@ -21,12 +21,19 @@ def initialize(renderer, color:, width: nil)
     # @rbs start_y: Float | Integer
     # @rbs end_x: Float | Integer
     # @rbs end_y: Float | Integer
+    # @rbs return: void
     def render(start_x, start_y, end_x, end_y)
       render_line(start_x, start_y, end_x, end_y, @color)
     end
 
   private
 
+    # @rbs start_x: Float | Integer
+    # @rbs start_y: Float | Integer
+    # @rbs end_x: Float | Integer
+    # @rbs end_y: Float | Integer
+    # @rbs color: String
+    # @rbs return: void
     def render_line(start_x, start_y, end_x, end_y, color)
       # FIXME(uwe): Workaround for Issue #66
       #             https://github.com/topfunky/gruff/issues/66
diff --git a/lib/gruff/renderer/polygon.rb b/lib/gruff/renderer/polygon.rb
index c557d0da..26f56566 100644
--- a/lib/gruff/renderer/polygon.rb
+++ b/lib/gruff/renderer/polygon.rb
@@ -17,6 +17,7 @@ def initialize(renderer, color:, width: 1.0, opacity: 1.0)
     end
 
     # @rbs points: Array[Float | Integer]
+    # @rbs return: void
     def render(points)
       @renderer.draw.push
       @renderer.draw.stroke_width(@width)
diff --git a/lib/gruff/renderer/polyline.rb b/lib/gruff/renderer/polyline.rb
index 53ea1fab..1f634a76 100644
--- a/lib/gruff/renderer/polyline.rb
+++ b/lib/gruff/renderer/polyline.rb
@@ -18,6 +18,7 @@ def initialize(renderer, color:, width: 1.0, linejoin: 'bevel')
     end
 
     # @rbs points: Array[Float | Integer]
+    # @rbs return: void
     def render(points)
       @renderer.draw.push
       @renderer.draw.stroke_linejoin(@linejoin)
diff --git a/lib/gruff/renderer/rectangle.rb b/lib/gruff/renderer/rectangle.rb
index c8a2a671..d60c18a2 100644
--- a/lib/gruff/renderer/rectangle.rb
+++ b/lib/gruff/renderer/rectangle.rb
@@ -21,6 +21,7 @@ def initialize(renderer, color: nil, width: 1.0, opacity: 1.0)
     # @rbs upper_left_y: Float | Integer
     # @rbs lower_right_x: Float | Integer
     # @rbs lower_right_y: Float | Integer
+    # @rbs return: void
     def render(upper_left_x, upper_left_y, lower_right_x, lower_right_y)
       @renderer.draw.push
       @renderer.draw.stroke_width(@width)
diff --git a/lib/gruff/renderer/renderer.rb b/lib/gruff/renderer/renderer.rb
index a6b348e7..f6816678 100644
--- a/lib/gruff/renderer/renderer.rb
+++ b/lib/gruff/renderer/renderer.rb
@@ -6,9 +6,9 @@ module Gruff
   # @private
   class Renderer
     attr_accessor :text_renderers #: Array[Gruff::Renderer::Text]
-    attr_reader :draw
-    attr_reader :image
-    attr_reader :scale #: real
+    attr_reader :draw #: untyped
+    attr_reader :image #: untyped
+    attr_reader :scale #: Float | Integer
 
     # @rbs columns: Integer
     # @rbs rows: Integer
@@ -24,6 +24,7 @@ def initialize(columns, rows, scale, theme_options)
       @image = background(columns, rows, scale, theme_options)
     end
 
+    # @rbs return: void
     def finish
       @draw.draw(@image)
 
@@ -34,12 +35,18 @@ def finish
 
     # @rbs columns: Integer
     # @rbs rows: Integer
+    # @rbs return: void
     def transparent_background(columns, rows)
       @image = render_transparent_background(columns, rows)
     end
 
   private
 
+    # @rbs columns: Integer
+    # @rbs rows: Integer
+    # @rbs scale: Float | Integer
+    # @rbs theme_options: ::Hash[Symbol, untyped]
+    # @rbs return: void
     def background(columns, rows, scale, theme_options)
       return image_background(scale, *theme_options[:background_image]) if theme_options[:background_image] # steep:ignore
 
@@ -54,6 +61,9 @@ def background(columns, rows, scale, theme_options)
     end
 
     # Use with a theme to use an image (800x600 original) background.
+    # @rbs scale: Float | Integer
+    # @rbs image_path: String
+    # @rbs return: untyped
     def image_background(scale, image_path)
       image = Magick::Image.read(image_path)
       if scale != 1.0
@@ -63,6 +73,10 @@ def image_background(scale, image_path)
     end
 
     # Make a new image at the current size with a solid +color+.
+    # @rbs columns: Integer
+    # @rbs rows: Integer
+    # @rbs color: String
+    # @rbs return: void
     def solid_background(columns, rows, color)
       Magick::Image.new(columns, rows) do |img|
         img.background_color = color
@@ -70,6 +84,12 @@ def solid_background(columns, rows, color)
     end
 
     # Use with a theme definition method to draw a gradated background.
+    # @rbs columns: Integer
+    # @rbs rows: Integer
+    # @rbs top_color: String
+    # @rbs bottom_color: String
+    # @rbs direct: Symbol
+    # @rbs return: void
     def gradated_background(columns, rows, top_color, bottom_color, direct = :top_bottom)
       gradient_fill = begin
         case direct
@@ -105,6 +125,9 @@ def gradated_background(columns, rows, top_color, bottom_color, direct = :top_bo
     end
 
     # Use with a theme to make a transparent background
+    # @rbs columns: Integer
+    # @rbs rows: Integer
+    # @rbs return: void
     def render_transparent_background(columns, rows)
       Magick::Image.new(columns, rows) do |img|
         img.background_color = 'transparent'
diff --git a/lib/gruff/renderer/text.rb b/lib/gruff/renderer/text.rb
index 4371515f..b5191aba 100644
--- a/lib/gruff/renderer/text.rb
+++ b/lib/gruff/renderer/text.rb
@@ -11,6 +11,7 @@ class Renderer::Text
     # @rbs text: String
     # @rbs font: Gruff::Font
     # @rbs rotation: Float | Integer
+    # @rbs return: void
     def initialize(renderer, text, font:, rotation: nil)
       @renderer = renderer
       @text = text.to_s
@@ -19,13 +20,14 @@ def initialize(renderer, text, font:, rotation: nil)
     end
 
     attr_reader :width, :height, :x, :y #: Float | Integer
-    attr_reader :gravity
+    attr_reader :gravity #: untyped
 
     # @rbs width: Float | Integer
     # @rbs height: Float | Integer
     # @rbs x: Float | Integer
     # @rbs y: Float | Integer
     # @rbs gravity: untyped
+    # @rbs return: void
     def add_to_render_queue(width, height, x, y, gravity = Magick::NorthGravity)
       @width = width
       @height = height
@@ -41,6 +43,7 @@ def add_to_render_queue(width, height, x, y, gravity = Magick::NorthGravity)
     # @rbs x: Float | Integer
     # @rbs y: Float | Integer
     # @rbs gravity: untyped
+    # @rbs return: void
     def render(width, height, x, y, gravity = Magick::NorthGravity)
       @renderer.draw.push
       @renderer.draw.rotation = @rotation if @rotation
@@ -58,6 +61,7 @@ def render(width, height, x, y, gravity = Magick::NorthGravity)
       @renderer.draw.pop
     end
 
+    # @rbs return: untyped
     def metrics
       @renderer.draw.push
       @renderer.draw.font = @font.file_path
diff --git a/lib/gruff/scatter.rb b/lib/gruff/scatter.rb
index 53a82399..afd7b73d 100644
--- a/lib/gruff/scatter.rb
+++ b/lib/gruff/scatter.rb
@@ -31,6 +31,8 @@ class Gruff::Scatter < Gruff::Base
 
   # Allow enabling vertical lines. When you have a lot of data, they can work great.
   # @deprecated Please use {#show_vertical_markers=} instead.
+  # @rbs value: bool
+  # @rbs return: void
   def enable_vertical_line_markers=(value)
     warn '#enable_vertical_line_markers= is deprecated. Please use `show_vertical_markers` attribute instead'
     @show_vertical_markers = value
@@ -38,12 +40,16 @@ def enable_vertical_line_markers=(value)
 
   # Allow using vertical labels in the X axis.
   # @deprecated Please use {Gruff::Base#label_rotation=} instead.
+  # @rbs _value: untyped
+  # @rbs return: void
   def use_vertical_x_labels=(_value)
     warn '#use_vertical_x_labels= is deprecated. It is no longer effective. Please use `#label_rotation=` instead'
   end
 
   # Allow using vertical labels in the X axis (and setting the label margin).
   # @deprecated
+  # @rbs _value: untyped
+  # @rbs return: void
   def x_label_margin=(_value)
     warn '#x_label_margin= is deprecated. It is no longer effective.'
   end
@@ -51,6 +57,8 @@ def x_label_margin=(_value)
   # Allow disabling the significant rounding when labeling the X axis.
   # This is useful when working with a small range of high values (for example, a date range of months, while seconds as units).
   # @deprecated
+  # @rbs _value: untyped
+  # @rbs return: void
   def disable_significant_rounding_x_axis=(_value)
     warn '#disable_significant_rounding_x_axis= is deprecated. It is no longer effective.'
   end
@@ -93,6 +101,7 @@ def disable_significant_rounding_x_axis=(_value)
   # @rbs x_data_points: Array[nil | Float | Integer] | nil
   # @rbs y_data_points: Array[nil | Float | Integer] | nil
   # @rbs color: String
+  # @rbs return: void
   def data(name, x_data_points = [], y_data_points = [], color = nil)
     # make sure it's an array
     x_data_points = Array(x_data_points)
@@ -111,10 +120,12 @@ def data(name, x_data_points = [], y_data_points = [], color = nil)
 
 private
 
+  # @rbs return: void
   def initialize_store
     @store = Gruff::Store.new(Gruff::Store::XYData)
   end
 
+  # @rbs return: void
   def initialize_attributes
     super
 
@@ -125,11 +136,13 @@ def initialize_attributes
     @stroke_width = nil
   end
 
+  # @rbs return: void
   def setup_drawing
     @center_labels_over_point = false
     super
   end
 
+  # @rbs return: void
   def setup_data
     # TODO: Need to get x-axis labels working. Current behavior will be to not allow.
     @labels = {}
@@ -147,6 +160,7 @@ def setup_data
     super
   end
 
+  # @rbs return: void
   def draw_graph
     stroke_width  = @stroke_width  || clip_value_if_greater_than(@columns / (store.norm_data.first.x_points.size * 4.0), 5.0)
     circle_radius = @circle_radius || clip_value_if_greater_than(@columns / (store.norm_data.first.x_points.size * 2.5), 5.0)
@@ -163,18 +177,21 @@ def draw_graph
     end
   end
 
+  # @rbs return: void
   def calculate_spread
     super
     @x_spread = @maximum_x_value.to_f - @minimum_x_value.to_f
     @x_spread = @x_spread > 0 ? @x_spread : 1.0
   end
 
+  # @rbs return: void
   def normalize
     return unless data_given?
 
     store.normalize(minimum_x: @minimum_x_value, spread_x: @x_spread, minimum_y: minimum_value, spread_y: @spread)
   end
 
+  # @rbs return: void
   def draw_line_markers
     # do all of the stuff for the horizontal lines on the y-axis
     super
diff --git a/lib/gruff/side_bar.rb b/lib/gruff/side_bar.rb
index 2fa3774f..7566fa41 100644
--- a/lib/gruff/side_bar.rb
+++ b/lib/gruff/side_bar.rb
@@ -55,12 +55,15 @@ def initialize(target_width = DEFAULT_TARGET_WIDTH)
 
   # With Side Bars use the data label for the marker value to the left of the bar.
   # @deprecated
+  # @rbs _value: untyped
+  # @rbs return: void
   def use_data_label=(_value)
     warn '#use_data_label is deprecated. It is no longer effective.'
   end
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @bar_spacing = 0.9
@@ -85,6 +88,7 @@ def hide_bottom_label_area?
     @hide_line_markers && @x_axis_label.nil? && @legend_at_bottom == false
   end
 
+  # @rbs return: void
   def setup_graph_measurements
     super
     return if @hide_line_markers
@@ -105,6 +109,7 @@ def setup_graph_measurements
     end
   end
 
+  # @rbs return: void
   def draw_graph
     # Setup spacing.
     #
@@ -148,6 +153,7 @@ def draw_graph
   end
 
   # Instead of base class version, draws vertical background lines and label
+  # @rbs return: void
   def draw_line_markers
     return if @hide_line_markers
 
@@ -176,6 +182,9 @@ def draw_line_markers
   ##
   # Draw on the Y axis instead of the X
 
+  # @rbs y_offset: Float | Integer
+  # @rbs index: Integer
+  # @rbs return: void
   def draw_label(y_offset, index)
     draw_unique_label(index) do
       draw_label_at(@graph_left - @label_margin, 1.0, 0.0, y_offset, @labels[index], gravity: Magick::EastGravity)
diff --git a/lib/gruff/side_stacked_bar.rb b/lib/gruff/side_stacked_bar.rb
index f40bc2dd..f836b8cb 100644
--- a/lib/gruff/side_stacked_bar.rb
+++ b/lib/gruff/side_stacked_bar.rb
@@ -52,6 +52,7 @@ def initialize(target_width = DEFAULT_TARGET_WIDTH)
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @bar_spacing = 0.9
@@ -62,11 +63,13 @@ def initialize_attributes
     @minimum_value = 0.0
   end
 
+  # @rbs return: void
   def setup_data
     calculate_maximum_by_stack
     super
   end
 
+  # @rbs return: void
   def draw_graph
     # Setup spacing.
     #
diff --git a/lib/gruff/spider.rb b/lib/gruff/spider.rb
index b08bb540..5fe34ccb 100644
--- a/lib/gruff/spider.rb
+++ b/lib/gruff/spider.rb
@@ -30,12 +30,14 @@ def initialize(max_value, target_width = 800)
   end
 
   # @rbs value: bool
+  # @rbs return: void
   def hide_text=(value)
     @hide_title = @hide_text = value
   end
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @hide_legend = true
@@ -48,11 +50,13 @@ def initialize_attributes
     @hide_line_markers.freeze
   end
 
+  # @rbs return: void
   def setup_drawing
     @center_labels_over_point = false
     super
   end
 
+  # @rbs return: void
   def setup_graph_measurements
     super
 
@@ -65,12 +69,14 @@ def setup_graph_measurements
     @graph_height = @graph_bottom - @graph_top
   end
 
+  # @rbs return: void
   def setup_data
     raise(Gruff::IncorrectNumberOfDatasetsException, 'Requires 3 or more data sets') if store.length < 3
 
     super
   end
 
+  # @rbs return: void
   def draw_graph
     # Setup basic positioning
     radius = @graph_height / 2.0
@@ -88,11 +94,18 @@ def draw_graph
     draw_polygon(center_x, center_y, additive_angle)
   end
 
-  # @rbs value: nil | Float | Integer
+  # @rbs value: Float | Integer
+  # @rbs return: Float
   def normalize_points(value)
-    value.to_f * @unit_length
+    (value.to_f * @unit_length).to_f
   end
 
+  # @rbs center_x: Float | Integer
+  # @rbs center_y: Float | Integer
+  # @rbs angle: Float | Integer
+  # @rbs radius: Float | Integer
+  # @rbs amount: Float | Integer
+  # @rbs return: void
   def draw_label(center_x, center_y, angle, radius, amount)
     degree = rad2deg(angle)
     metrics = text_metrics(@marker_font, amount)
@@ -118,6 +131,12 @@ def draw_label(center_x, center_y, angle, radius, amount)
     draw_label_at(metrics.width, metrics.height, x, y, amount, gravity: Magick::CenterGravity)
   end
 
+  # @rbs center_x: Float | Integer
+  # @rbs center_y: Float | Integer
+  # @rbs radius: Float | Integer
+  # @rbs additive_angle: Float | Integer
+  # @rbs line_color: String | nil
+  # @rbs return: void
   def draw_axes(center_x, center_y, radius, additive_angle, line_color = nil)
     return if @hide_axes
 
@@ -136,6 +155,11 @@ def draw_axes(center_x, center_y, radius, additive_angle, line_color = nil)
     end
   end
 
+  # @rbs center_x: Float | Integer
+  # @rbs center_y: Float | Integer
+  # @rbs additive_angle: Float | Integer
+  # @rbs color: String | nil
+  # @rbs return: void
   def draw_polygon(center_x, center_y, additive_angle, color = nil)
     points = []
     current_angle = deg2rad(@rotation)
diff --git a/lib/gruff/stacked_area.rb b/lib/gruff/stacked_area.rb
index 3702a091..f4e1624c 100644
--- a/lib/gruff/stacked_area.rb
+++ b/lib/gruff/stacked_area.rb
@@ -18,22 +18,27 @@ class Gruff::StackedArea < Gruff::Base
   include Gruff::Base::StackedMixin
 
   # @deprecated
+  # @rbs _value: untyped
+  # @rbs return: void
   def last_series_goes_on_bottom=(_value)
     warn '#last_series_goes_on_bottom is deprecated. It is no longer effective.'
   end
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @minimum_value = 0.0
   end
 
+  # @rbs return: void
   def setup_data
     calculate_maximum_by_stack
     super
   end
 
+  # @rbs return: void
   def draw_graph
     x_increment = (@graph_width / (column_count - 1)).to_f
 
diff --git a/lib/gruff/stacked_bar.rb b/lib/gruff/stacked_bar.rb
index ba4827da..c08971cc 100644
--- a/lib/gruff/stacked_bar.rb
+++ b/lib/gruff/stacked_bar.rb
@@ -36,6 +36,7 @@ class Gruff::StackedBar < Gruff::Base
 
 private
 
+  # @rbs return: void
   def initialize_attributes
     super
     @bar_spacing = 0.9
@@ -46,6 +47,7 @@ def initialize_attributes
     @minimum_value = 0.0
   end
 
+  # @rbs return: void
   def setup_drawing
     # Labels will be centered over the left of the bar if
     # there are more labels than columns. This is basically the same
@@ -55,11 +57,13 @@ def setup_drawing
     super
   end
 
+  # @rbs return: void
   def setup_data
     calculate_maximum_by_stack
     super
   end
 
+  # @rbs return: void
   def setup_graph_measurements
     super
     return if @hide_line_markers
@@ -75,6 +79,7 @@ def setup_graph_measurements
   end
 
   # Draws a bar graph, but multiple sets are stacked on top of each other.
+  # @rbs return: void
   def draw_graph
     # Setup spacing.
     #
diff --git a/lib/gruff/store/basic_data.rb b/lib/gruff/store/basic_data.rb
index 691b66ec..5b15772b 100644
--- a/lib/gruff/store/basic_data.rb
+++ b/lib/gruff/store/basic_data.rb
@@ -13,6 +13,7 @@ class BasicData
       # @rbs label: String | Symbol
       # @rbs points: Array[nil | Float | Integer] | nil
       # @rbs color: String
+      # @rbs return: void
       def initialize(label, points, color)
         @label = label.to_s
         @points = Array(points)
@@ -21,14 +22,17 @@ def initialize(label, points, color)
 
       alias x_points points
 
+      # @rbs return: void
       def y_points
         raise NotImplementedError, 'x_points is not implemented for BasicData'
       end
 
+      # @rbs return: void
       def coordinates
         raise NotImplementedError, 'This method is not implemented for BasicData'
       end
 
+      # @rbs return: void
       def coordinate_and_pointsizes
         raise NotImplementedError, 'This method is not implemented for BasicData'
       end
diff --git a/lib/gruff/store/store.rb b/lib/gruff/store/store.rb
index d140b137..f9abdb3a 100644
--- a/lib/gruff/store/store.rb
+++ b/lib/gruff/store/store.rb
@@ -7,12 +7,15 @@ module Gruff
   class Store
     attr_reader :data #: Array[Gruff::Store::BasicData | Gruff::Store::XYData | Gruff::Store::XYPointsizeData]
 
+    # @rbs data_class: untyped
     # @rbs return: void
     def initialize(data_class)
       @data_class = data_class
       @data = []
     end
 
+    # @rbs *args: untyped
+    # @rbs return: void
     def add(*args)
       @data << @data_class.new(*args)
     end
@@ -22,6 +25,8 @@ def norm_data
       @norm_data || []
     end
 
+    # @rbs **keywords: untyped
+    # @rbs return: untyped
     def normalize(**keywords)
       @norm_data = @data.map { |data_row| data_row.normalize(**keywords) } # steep:ignore
     end
@@ -63,10 +68,12 @@ def max_x
       @max_x ||= @data.filter_map(&:max_x).max
     end
 
+    # @rbs return: void
     def sort_data!
       @data = @data.sort_by { |a| -a.points.sum(&:to_f) }
     end
 
+    # @rbs return: void
     def sort_norm_data!
       @norm_data = @norm_data.sort_by { |a| -a.points.sum(&:to_f) }
     end
@@ -77,6 +84,7 @@ def reverse!
     end
 
     # @rbs colors: Array[String]
+    # @rbs return: void
     def change_colors(colors)
       index = 0
       @data.each do |data_row|
diff --git a/lib/gruff/store/xy_data.rb b/lib/gruff/store/xy_data.rb
index d3352d06..cbee8090 100644
--- a/lib/gruff/store/xy_data.rb
+++ b/lib/gruff/store/xy_data.rb
@@ -15,6 +15,7 @@ class XYData
       # @rbs x_points: Array[nil | Float | Integer] | nil
       # @rbs y_points: Array[nil | Float | Integer] | nil
       # @rbs color: String
+      # @rbs return: void
       def initialize(label, x_points, y_points, color)
         y_points = Array(y_points)
         x_points = x_points ? Array(x_points) : Array.new(y_points.length)
@@ -33,6 +34,7 @@ def coordinates
         x_points.zip(y_points)
       end
 
+      # @rbs return: void
       def coordinate_and_pointsizes
         raise NotImplementedError, 'This method is not implemented for XYData'
       end
diff --git a/lib/gruff/store/xy_pointsizes_data.rb b/lib/gruff/store/xy_pointsizes_data.rb
index a4ae647c..4e3bc3c7 100644
--- a/lib/gruff/store/xy_pointsizes_data.rb
+++ b/lib/gruff/store/xy_pointsizes_data.rb
@@ -17,6 +17,7 @@ class XYPointsizeData
       # @rbs y_points: Array[nil | Float | Integer] | nil
       # @rbs point_sizes: Array[nil | Float | Integer]
       # @rbs color: String
+      # @rbs return: void
       def initialize(label, x_points, y_points, point_sizes, color)
         y_points = Array(y_points)
         x_points = x_points ? Array(x_points) : Array.new(y_points.length)
@@ -32,6 +33,7 @@ def initialize(label, x_points, y_points, point_sizes, color)
 
       alias points y_points
 
+      # @rbs return: void
       def coordinates
         raise NotImplementedError, 'This method is not implemented for XYPointsizeData'
       end
diff --git a/sig/generated/gruff.rbs b/sig/generated/gruff.rbs
index 0af65bca..f3244461 100644
--- a/sig/generated/gruff.rbs
+++ b/sig/generated/gruff.rbs
@@ -4,7 +4,9 @@
 #  = Gruff. Graphs.
 module Gruff
   # @private
-  def self.libpath: (untyped path) -> untyped
+  # @rbs path: String
+  # @rbs return: String
+  def self.libpath: (String path) -> String
 
   # @private
   class Renderer
diff --git a/sig/generated/gruff/accumulator_bar.rbs b/sig/generated/gruff/accumulator_bar.rbs
index dd4e0e25..08ae5a4d 100644
--- a/sig/generated/gruff/accumulator_bar.rbs
+++ b/sig/generated/gruff/accumulator_bar.rbs
@@ -15,5 +15,6 @@
 class Gruff::AccumulatorBar < Gruff::StackedBar
   private
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 end
diff --git a/sig/generated/gruff/area.rbs b/sig/generated/gruff/area.rbs
index a45d1796..1a59a352 100644
--- a/sig/generated/gruff/area.rbs
+++ b/sig/generated/gruff/area.rbs
@@ -21,7 +21,9 @@ class Gruff::Area < Gruff::Base
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 end
diff --git a/sig/generated/gruff/bar.rbs b/sig/generated/gruff/bar.rbs
index b04cbb48..005c16d3 100644
--- a/sig/generated/gruff/bar.rbs
+++ b/sig/generated/gruff/bar.rbs
@@ -45,13 +45,16 @@ class Gruff::Bar < Gruff::Base
   # Default value is +0.9+.
   #
   # @rbs space_percent: Float | Integer
-  def spacing_factor=: (Float | Integer space_percent) -> untyped
+  # @rbs return: void
+  def spacing_factor=: (Float | Integer space_percent) -> void
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_drawing: () -> untyped
+  # @rbs return: void
+  def setup_drawing: () -> void
 
   # @rbs return: bool
   def hide_labels?: () -> bool
@@ -62,9 +65,11 @@ class Gruff::Bar < Gruff::Base
   # @rbs return: bool
   def hide_bottom_label_area?: () -> bool
 
-  def setup_graph_measurements: () -> untyped
+  # @rbs return: void
+  def setup_graph_measurements: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
   # @rbs return: Float | Integer
   def calculate_spacing: () -> (Float | Integer)
diff --git a/sig/generated/gruff/base.rbs b/sig/generated/gruff/base.rbs
index 39fbae76..bddbf565 100644
--- a/sig/generated/gruff/base.rbs
+++ b/sig/generated/gruff/base.rbs
@@ -133,9 +133,11 @@ module Gruff
     # @rbs return: void
     def initialize: (?String | Float | Integer target_width) -> void
 
-    def initialize_graph_scale: () -> untyped
+    # @rbs return: void
+    def initialize_graph_scale: () -> void
 
-    def initialize_store: () -> untyped
+    # @rbs return: void
+    def initialize_store: () -> void
 
     # Initialize instance variable of attributes
     #
@@ -143,7 +145,9 @@ module Gruff
     #
     # This makes it possible to set defaults in a subclass but still allow
     # developers to change this values in their program.
-    def initialize_attributes: () -> untyped
+    #
+    # @rbs return: void
+    def initialize_attributes: () -> void
 
     # A hash of names for the individual columns, where the key is the array
     # index for the column this label represents.
@@ -160,18 +164,22 @@ module Gruff
     #
     #   g = Gruff::Bar.new
     #   g.labels = ['2005', nil, nil, '2006', nil, nil, '2007', nil, nil, '2008'] # same labels for columns
-    def labels=: (Hash[Integer, String] | [ String | nil ] labels) -> untyped
+    #
+    # @rbs return: void
+    def labels=: (Hash[Integer, String] | [ String | nil ] labels) -> void
 
     # Set a rotation for labels. You can use  Default is +0+.
     # You can use a rotation between +0.0+ and +45.0+, or between +0.0+ and +-45.0+.
     #
     # @param rotation [Numeric] the rotation.
     # @rbs rotation: Float | Integer
-    def label_rotation=: (Float | Integer rotation) -> untyped
+    # @rbs return: void
+    def label_rotation=: (Float | Integer rotation) -> void
 
     # Height of staggering between labels.
     # @deprecated
-    def label_stagger_height=: (untyped _value) -> untyped
+    # @rbs return: void
+    def label_stagger_height=: (untyped _value) -> void
 
     # Set the large title of the graph displayed at the top.
     # You can draw a multi-line title by putting a line break in the string
@@ -186,37 +194,44 @@ module Gruff
     #
     #   g = Gruff::Bar.new
     #   g.title = ['The first line of title', 'The second line of title']
-    def title=: (String | Array[String] title) -> untyped
+    #
+    # @rbs return: void
+    def title=: (String | Array[String] title) -> void
 
     # Sets the top, bottom, left and right margins to +margin+.
     #
     # @param margin [Numeric] The margin size.
     # @rbs margin: Float | Integer
-    def margins=: (Float | Integer margin) -> untyped
+    # @rbs return: void
+    def margins=: (Float | Integer margin) -> void
 
     # Sets the font for graph text to the font at +font_path+.
     #
     # @param font_path [String] The path to font.
     # @rbs font_path: String
-    def font=: (String font_path) -> untyped
+    # @rbs return: void
+    def font=: (String font_path) -> void
 
     # Same as {#font=} but for the title.
     #
     # @param font_path [String] The path to font.
     # @rbs font_path: String
-    def title_font=: (String font_path) -> untyped
+    # @rbs return: void
+    def title_font=: (String font_path) -> void
 
     # Set the font size of the large title at the top of the graph. Default is +36+.
     #
     # @param value [Numeric] title font size
     # @rbs value: Float | Integer
-    def title_font_size=: (Float | Integer value) -> untyped
+    # @rbs return: void
+    def title_font_size=: (Float | Integer value) -> void
 
     # The font size of the labels around the graph. Default is +21+.
     #
     # @param value [Numeric] marker font size
     # @rbs value: Float | Integer
-    def marker_font_size=: (Float | Integer value) -> untyped
+    # @rbs return: void
+    def marker_font_size=: (Float | Integer value) -> void
 
     # Optionally set the size of the font. Based on an 800x600px graph.
     # Default is +20+.
@@ -225,25 +240,29 @@ module Gruff
     #
     # @param value [Numeric] legend font size
     # @rbs value: Float | Integer
-    def legend_font_size=: (Float | Integer value) -> untyped
+    # @rbs return: void
+    def legend_font_size=: (Float | Integer value) -> void
 
     # Set the font size of the no data message. Default is +80+.
     #
     # @param value [Numeric] no data font size
     # @rbs value: Float | Integer
-    def no_data_font_size=: (Float | Integer value) -> untyped
+    # @rbs return: void
+    def no_data_font_size=: (Float | Integer value) -> void
 
     # Specifies whether to draw the title bolded or not. Default is +true+.
     #
     # @param value [Boolean] specifies whether to draw the title bolded or not.
     # @rbs value: bool
-    def bold_title=: (bool value) -> untyped
+    # @rbs return: void
+    def bold_title=: (bool value) -> void
 
     # Specifies the text color.
     #
     # @param value [String] color
     # @rbs value: String
-    def font_color=: (String value) -> untyped
+    # @rbs return: void
+    def font_color=: (String value) -> void
 
     # Add a color to the list of available colors for lines.
     #
@@ -252,7 +271,8 @@ module Gruff
     #
     # @example
     #   add_color('#c0e9d3')
-    def add_color: (String colorname) -> untyped
+    # @rbs return: void
+    def add_color: (String colorname) -> void
 
     # Replace the entire color list with a new array of colors. Also
     # aliased as the {#colors=} setter method.
@@ -270,13 +290,15 @@ module Gruff
     #
     # @example
     #   replace_colors ['#cc99cc', '#d9e043', '#34d8a2']
-    def replace_colors: (?Array[String] color_list) -> untyped
+    # @rbs return: void
+    def replace_colors: (?Array[String] color_list) -> void
 
     # Set whether to make background transparent.
     #
     # @param value [Boolean] Specify whether to make background transparent.
     # @rbs value: bool
-    def transparent_background=: (bool value) -> untyped
+    # @rbs return: void
+    def transparent_background=: (bool value) -> void
 
     # You can set a theme manually. Assign a hash to this method before you
     # send your data.
@@ -309,25 +331,32 @@ module Gruff
     #
     # @param options [Hash] The optional setting for theme
     # @rbs options: Hash[Symbol, untyped]
-    def theme=: (Hash[Symbol, untyped] options) -> untyped
+    # @rbs return: void
+    def theme=: (Hash[Symbol, untyped] options) -> void
 
     # Apply Apple's keynote theme.
-    def theme_keynote: () -> untyped
+    # @rbs return: void
+    def theme_keynote: () -> void
 
     # Apply 37signals theme.
-    def theme_37signals: () -> untyped
+    # @rbs return: void
+    def theme_37signals: () -> void
 
     # Apply Rails theme.
-    def theme_rails_keynote: () -> untyped
+    # @rbs return: void
+    def theme_rails_keynote: () -> void
 
     # Apply Odeo theme.
-    def theme_odeo: () -> untyped
+    # @rbs return: void
+    def theme_odeo: () -> void
 
     # Apply pastel theme.
-    def theme_pastel: () -> untyped
+    # @rbs return: void
+    def theme_pastel: () -> void
 
     # Apply greyscale theme.
-    def theme_greyscale: () -> untyped
+    # @rbs return: void
+    def theme_greyscale: () -> void
 
     # Input the data in the graph.
     #
@@ -352,7 +381,8 @@ module Gruff
     #
     # @example
     #   data("Bart S.", [95, 45, 78, 89, 88, 76], '#ffcc00')
-    def data: (String | Symbol name, ?Array[Float | Integer] | nil data_points, ?String color) -> untyped
+    # @rbs return: void
+    def data: (String | Symbol name, ?Array[Float | Integer] | nil data_points, ?String color) -> void
 
     # You can manually set a minimum value instead of having the values
     # guessed for you.
@@ -384,7 +414,8 @@ module Gruff
     #
     # @example
     #   write('graphs/my_pretty_graph.png')
-    def write: (?String file_name) -> untyped
+    # @rbs return: void
+    def write: (?String file_name) -> void
 
     # Return a rendered graph image.
     # This can use RMagick's methods to adjust the image before saving.
@@ -402,6 +433,8 @@ module Gruff
     #   image = g.to_image
     #   image = image.resize(400, 300).quantize(128, Magick::RGBColorspace)
     #   image.write('test.png')
+    #
+    # @rbs return: untyped
     def to_image: (?String format) -> untyped
 
     # Return the graph as a rendered binary blob.
@@ -416,19 +449,22 @@ module Gruff
     def to_blob: (?String format) -> String
 
     # Draw a graph.
-    def draw: () -> untyped
+    # @rbs return: void
+    def draw: () -> void
 
     attr_reader renderer: Gruff::Renderer
 
     # Perform data manipulation before calculating chart measurements
-    def setup_data: () -> untyped
+    # @rbs return: void
+    def setup_data: () -> void
 
     # Calculates size of drawable area and generates normalized data.
     #
     # * line markers
     # * legend
     # * title
-    def setup_drawing: () -> untyped
+    # @rbs return: void
+    def setup_drawing: () -> void
 
     attr_reader store: Gruff::Store
 
@@ -443,9 +479,11 @@ module Gruff
 
     # Make copy of data with values scaled between 0-100
     # @rbs return: Array[Gruff::Store::BasicData | Gruff::Store::XYData | Gruff::Store::XYPointsizeData]
+    # @rbs return: void
     def normalize: () -> Array[Gruff::Store::BasicData | Gruff::Store::XYData | Gruff::Store::XYPointsizeData]
 
-    def calculate_spread: () -> untyped
+    # @rbs return: Float
+    def calculate_spread: () -> Float
 
     # @rbs return: bool
     def hide_title?: () -> bool
@@ -459,17 +497,25 @@ module Gruff
     # @rbs return: bool
     def hide_bottom_label_area?: () -> bool
 
-    def setup_graph_measurements: () -> untyped
+    # @rbs return: void
+    def setup_graph_measurements: () -> void
 
     # Draw the optional labels for the x axis and y axis.
-    def draw_axis_labels: () -> untyped
+    # @rbs return: void
+    def draw_axis_labels: () -> void
 
     # Draws horizontal background lines and labels
-    def draw_line_markers: () -> untyped
+    # @rbs return: void
+    def draw_line_markers: () -> void
 
-    def draw_marker_horizontal_line: (untyped y) -> untyped
+    # @rbs y: Float | Integer
+    # @rbs return: void
+    def draw_marker_horizontal_line: (Float | Integer y) -> void
 
-    def draw_marker_vertical_line: (untyped x, ?tick_mark_mode: untyped) -> untyped
+    # @rbs x: Float | Integer
+    # @rbs tick_mark_mode: bool
+    # @rbs return: void
+    def draw_marker_vertical_line: (Float | Integer x, ?tick_mark_mode: bool) -> void
 
     # Return a calculation of center
     # @rbs size: Float | Integer
@@ -478,10 +524,12 @@ module Gruff
 
     # Draws a legend with the names of the datasets matched
     # to the colors used to draw them.
-    def draw_legend: () -> untyped
+    # @rbs return: void
+    def draw_legend: () -> void
 
     # Draws a title on the graph.
-    def draw_title: () -> untyped
+    # @rbs return: void
+    def draw_title: () -> void
 
     # Draws column labels below graph, centered over x
     #
@@ -489,11 +537,13 @@ module Gruff
     # @rbs index: Integer
     # @rbs gravity: untyped
     # @rbs &: () -> void
-    def draw_label: (Float | Integer x, Integer index, ?untyped gravity) { () -> void } -> untyped
+    # @rbs return: void
+    def draw_label: (Float | Integer x, Integer index, ?untyped gravity) { () -> void } -> void
 
     # @rbs index: Integer
     # @rbs yields: () -> void
-    def draw_unique_label: (Integer index) -> untyped
+    # @rbs return: void
+    def draw_unique_label: (Integer index) -> void
 
     # @rbs width: Float | Integer
     # @rbs height: Float | Integer
@@ -502,7 +552,8 @@ module Gruff
     # @rbs text: String | _ToS
     # @rbs gravity: untyped
     # @rbs rotation: Float | Integer
-    def draw_label_at: (Float | Integer width, Float | Integer height, Float | Integer x, Float | Integer y, String | _ToS text, ?gravity: untyped, ?rotation: Float | Integer) -> untyped
+    # @rbs return: void
+    def draw_label_at: (Float | Integer width, Float | Integer height, Float | Integer x, Float | Integer y, String | _ToS text, ?gravity: untyped, ?rotation: Float | Integer) -> void
 
     # Draws the data value over the data point in bar graphs
     #
@@ -512,15 +563,19 @@ module Gruff
     # @rbs y_offset: Float | Integer
     # @rbs data_point: String | _ToS
     # @rbs gravity: untyped
-    def draw_value_label: (Float | Integer width, Float | Integer height, Float | Integer x_offset, Float | Integer y_offset, String | _ToS data_point, ?gravity: untyped) -> untyped
+    # @rbs return: void
+    def draw_value_label: (Float | Integer width, Float | Integer height, Float | Integer x_offset, Float | Integer y_offset, String | _ToS data_point, ?gravity: untyped) -> void
 
     # Shows an error message because you have no data.
-    def draw_no_data: () -> untyped
+    # @rbs return: void
+    def draw_no_data: () -> void
 
-    def draw_graph: () -> untyped
+    # @rbs return: void
+    def draw_graph: () -> void
 
     # Resets everything to defaults (except data).
-    def reset_themes: () -> untyped
+    # @rbs return: void
+    def reset_themes: () -> void
 
     # @rbs value: Float | Integer
     # @rbs max_value: Float | Integer
@@ -533,14 +588,17 @@ module Gruff
     def significant: (Integer i) -> (Integer | Float | BigDecimal)
 
     # Sort with largest overall summed value at front of array.
-    def sort_data: () -> untyped
+    # @rbs return: void
+    def sort_data: () -> void
 
     # Set the color for each data set unless it was given in the data(...) call.
-    def set_colors: () -> untyped
+    # @rbs return: void
+    def set_colors: () -> void
 
     # Sort with largest overall summed value at front of array so it shows up
     # correctly in the drawn graph.
-    def sort_norm_data: () -> untyped
+    # @rbs return: void
+    def sort_norm_data: () -> void
 
     private
 
@@ -599,11 +657,13 @@ module Gruff
     # @rbs return: String
     def y_axis_label: (Float | Integer | BigDecimal value, Float | Integer increment) -> String
 
-    # TODO: RBS signature
-    def calculate_legend_label_widths_for_each_line: (untyped legend_labels, untyped legend_square_width) -> untyped
+    # @rbs legend_labels: Array[String]
+    # @rbs legend_square_width: Float | Integer
+    # @rbs return: Array[Array[Float | Integer]]
+    def calculate_legend_label_widths_for_each_line: (Array[String] legend_labels, Float | Integer legend_square_width) -> Array[Array[Float | Integer]]
 
-    # TODO: RBS signature
-    def calculate_legend_height: () -> untyped
+    # @rbs return: Float
+    def calculate_legend_height: () -> Float
 
     # Returns the height of the capital letter 'X' for the current font and
     # size.
diff --git a/sig/generated/gruff/bezier.rbs b/sig/generated/gruff/bezier.rbs
index f482c666..5753eb69 100644
--- a/sig/generated/gruff/bezier.rbs
+++ b/sig/generated/gruff/bezier.rbs
@@ -20,5 +20,6 @@
 class Gruff::Bezier < Gruff::Base
   private
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 end
diff --git a/sig/generated/gruff/box.rbs b/sig/generated/gruff/box.rbs
index c40325e6..7596e42f 100644
--- a/sig/generated/gruff/box.rbs
+++ b/sig/generated/gruff/box.rbs
@@ -23,15 +23,19 @@ class Gruff::Box < Gruff::Base
   # Default value is +0.8+.
   #
   # @rbs space_percent: Float | Integer
-  def spacing_factor=: (Float | Integer space_percent) -> untyped
+  # @rbs return: void
+  def spacing_factor=: (Float | Integer space_percent) -> void
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
-  def normalized_boxes: () -> untyped
+  # @rbs return: Array[Gruff::Box::BoxData]
+  def normalized_boxes: () -> Array[Gruff::Box::BoxData]
 
   # @rbs return: Integer
   def column_count: () -> Integer
@@ -47,7 +51,11 @@ class Gruff::Box < Gruff::Base
 
     attr_accessor color: String
 
-    def initialize: (untyped label, untyped points, untyped color) -> untyped
+    # @rbs label: String
+    # @rbs points: Array[Float | Integer]
+    # @rbs color: String
+    # @rbs return: void
+    def initialize: (String label, Array[Float | Integer] points, String color) -> void
 
     # @rbs return: Float | Integer
     def min: () -> (Float | Integer)
diff --git a/sig/generated/gruff/bubble.rbs b/sig/generated/gruff/bubble.rbs
index ae119e2c..29749b27 100644
--- a/sig/generated/gruff/bubble.rbs
+++ b/sig/generated/gruff/bubble.rbs
@@ -57,13 +57,17 @@ class Gruff::Bubble < Gruff::Scatter
   # @rbs y_data_points: Array[nil | Float | Integer] | nil
   # @rbs point_sizes: Array[nil | Float | Integer] | nil
   # @rbs color: String
-  def data: (String | Symbol name, ?Array[nil | Float | Integer] | nil x_data_points, ?Array[nil | Float | Integer] | nil y_data_points, ?Array[nil | Float | Integer] | nil point_sizes, ?String color) -> untyped
+  # @rbs return: void
+  def data: (String | Symbol name, ?Array[nil | Float | Integer] | nil x_data_points, ?Array[nil | Float | Integer] | nil y_data_points, ?Array[nil | Float | Integer] | nil point_sizes, ?String color) -> void
 
   private
 
-  def initialize_store: () -> untyped
+  # @rbs return: void
+  def initialize_store: () -> void
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 end
diff --git a/sig/generated/gruff/bullet.rbs b/sig/generated/gruff/bullet.rbs
index 4983be36..32368944 100644
--- a/sig/generated/gruff/bullet.rbs
+++ b/sig/generated/gruff/bullet.rbs
@@ -15,16 +15,20 @@ class Gruff::Bullet < Gruff::Base
   # @rbs return: void
   def initialize: (?String | Float | Integer target_width) -> void
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
   # @rbs value: Float | Integer
   # @rbs maximum_value: Float | Integer
   # @rbs options: Hash[Symbol, Float | Integer]
-  def data: (Float | Integer value, Float | Integer maximum_value, ?Hash[Symbol, Float | Integer] options) -> untyped
+  # @rbs return: void
+  def data: (Float | Integer value, Float | Integer maximum_value, ?Hash[Symbol, Float | Integer] options) -> void
 
-  def draw: () -> untyped
+  # @rbs return: void
+  def draw: () -> void
 
   private
 
-  def draw_title: () -> untyped
+  # @rbs return: void
+  def draw_title: () -> void
 end
diff --git a/sig/generated/gruff/candlestick.rbs b/sig/generated/gruff/candlestick.rbs
index d87aa635..193eaaf7 100644
--- a/sig/generated/gruff/candlestick.rbs
+++ b/sig/generated/gruff/candlestick.rbs
@@ -33,27 +33,34 @@ class Gruff::Candlestick < Gruff::Base
   # Default value is +0.9+.
   #
   # @rbs space_percent: Float | Integer
-  def spacing_factor=: (Float | Integer space_percent) -> untyped
+  # @rbs return: void
+  def spacing_factor=: (Float | Integer space_percent) -> void
 
   # The sort feature is not supported in this graph.
-  def sort=: (untyped _value) -> untyped
+  # @rbs return: void
+  def sort=: (untyped _value) -> void
 
   # The sort feature is not supported in this graph.
-  def sorted_drawing=: (untyped _value) -> untyped
+  # @rbs return: void
+  def sorted_drawing=: (untyped _value) -> void
 
   # @rbs low: Float | Integer
   # @rbs high: Float | Integer
   # @rbs open: Float | Integer
   # @rbs close: Float | Integer
-  def data: (low: Float | Integer, high: Float | Integer, open: Float | Integer, close: Float | Integer) -> untyped
+  # @rbs return: void
+  def data: (low: Float | Integer, high: Float | Integer, open: Float | Integer, close: Float | Integer) -> void
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
-  def normalized_candlesticks: () -> untyped
+  # @rbs return: Array[Gruff::Candlestick::CandlestickData]
+  def normalized_candlesticks: () -> Array[Gruff::Candlestick::CandlestickData]
 
   # @rbs return: Integer
   def column_count: () -> Integer
@@ -66,14 +73,19 @@ class Gruff::Candlestick < Gruff::Base
 
   # @private
   class CandlestickData
-    attr_accessor low: untyped
+    attr_accessor low: Float | Integer
 
-    attr_accessor high: untyped
+    attr_accessor high: Float | Integer
 
-    attr_accessor open: untyped
+    attr_accessor open: Float | Integer
 
-    attr_accessor close: untyped
+    attr_accessor close: Float | Integer
 
-    def initialize: (untyped low, untyped high, untyped open, untyped close) -> untyped
+    # @rbs low: Float | Integer
+    # @rbs high: Float | Integer
+    # @rbs open: Float | Integer
+    # @rbs close: Float | Integer
+    # @rbs return: void
+    def initialize: (Float | Integer low, Float | Integer high, Float | Integer open, Float | Integer close) -> void
   end
 end
diff --git a/sig/generated/gruff/dot.rbs b/sig/generated/gruff/dot.rbs
index 5fb9f091..b48c67e3 100644
--- a/sig/generated/gruff/dot.rbs
+++ b/sig/generated/gruff/dot.rbs
@@ -22,7 +22,8 @@ class Gruff::Dot < Gruff::Base
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
   # @rbs return: bool
   def hide_labels?: () -> bool
@@ -33,12 +34,15 @@ class Gruff::Dot < Gruff::Base
   # @rbs return: bool
   def hide_bottom_label_area?: () -> bool
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
   # Instead of base class version, draws vertical background lines and label
-  def draw_line_markers: () -> untyped
+  # @rbs return: void
+  def draw_line_markers: () -> void
 
   # @rbs y_offset: Float | Integer
   # @rbs index: Integer
-  def draw_label: (Float | Integer y_offset, Integer index) -> untyped
+  # @rbs return: void
+  def draw_label: (Float | Integer y_offset, Integer index) -> void
 end
diff --git a/sig/generated/gruff/font.rbs b/sig/generated/gruff/font.rbs
index 5c3c2f4d..3ebe2787 100644
--- a/sig/generated/gruff/font.rbs
+++ b/sig/generated/gruff/font.rbs
@@ -22,11 +22,13 @@ class Gruff::Font
   # @rbs size: Float | Integer
   # @rbs bold: bool
   # @rbs color: String
-  def initialize: (?path: String | nil, ?size: Float | Integer, ?bold: bool, ?color: String) -> untyped
+  # @rbs return: void
+  def initialize: (?path: String | nil, ?size: Float | Integer, ?bold: bool, ?color: String) -> void
 
   # Get font weight.
   # @return [Magick::WeightType] font weight
   # TODO: type annotation of return value
+  # @rbs return: untyped
   def weight: () -> untyped
 
   # @private
diff --git a/sig/generated/gruff/helper/bar_value_label.rbs b/sig/generated/gruff/helper/bar_value_label.rbs
index 22c5935a..3dcd9c39 100644
--- a/sig/generated/gruff/helper/bar_value_label.rbs
+++ b/sig/generated/gruff/helper/bar_value_label.rbs
@@ -28,7 +28,8 @@ module Gruff::BarValueLabel
     # @rbs format: nil | String | Proc
     # @rbs proc_text_metrics: Proc
     # @rbs yields: (Float | Integer, Float | Integer, String, Float, Float) -> void
-    def prepare_rendering: (nil | String | Proc format, Proc proc_text_metrics) -> untyped
+    # @rbs return: void
+    def prepare_rendering: (nil | String | Proc format, Proc proc_text_metrics) -> void
   end
 
   # @private
@@ -36,6 +37,7 @@ module Gruff::BarValueLabel
     # @rbs format: nil | String | Proc
     # @rbs proc_text_metrics: Proc
     # @rbs yields: (Float | Integer, Float | Integer, String, Float, Float) -> void
-    def prepare_rendering: (nil | String | Proc format, Proc proc_text_metrics) -> untyped
+    # @rbs return: void
+    def prepare_rendering: (nil | String | Proc format, Proc proc_text_metrics) -> void
   end
 end
diff --git a/sig/generated/gruff/helper/stacked_mixin.rbs b/sig/generated/gruff/helper/stacked_mixin.rbs
index b54680c7..cce1eb7d 100644
--- a/sig/generated/gruff/helper/stacked_mixin.rbs
+++ b/sig/generated/gruff/helper/stacked_mixin.rbs
@@ -5,7 +5,8 @@ module Gruff::Base::StackedMixin
   # Used by StackedBar and child classes.
   #
   # tsal: moved from Base 03 FEB 2007
-  def calculate_maximum_by_stack: () -> untyped
+  # @rbs return: void
+  def calculate_maximum_by_stack: () -> void
 
   # @rbs return: Array[Array[Gruff::Base::StackedMixin::BarData]]
   def normalized_stacked_bars: () -> Array[Array[Gruff::Base::StackedMixin::BarData]]
diff --git a/sig/generated/gruff/histogram.rbs b/sig/generated/gruff/histogram.rbs
index d3b4f7ac..9015da28 100644
--- a/sig/generated/gruff/histogram.rbs
+++ b/sig/generated/gruff/histogram.rbs
@@ -27,13 +27,16 @@ class Gruff::Histogram < Gruff::Bar
   # @rbs name: String | Symbol
   # @rbs data_points: Array[Float | Integer] | nil
   # @rbs color: String
-  def data: (String | Symbol name, ?Array[Float | Integer] | nil data_points, ?String color) -> untyped
+  # @rbs return: void
+  def data: (String | Symbol name, ?Array[Float | Integer] | nil data_points, ?String color) -> void
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 
   # @private
   # @rbs inherits Array[Float | Integer | nil]
diff --git a/sig/generated/gruff/line.rbs b/sig/generated/gruff/line.rbs
index 9d97f0ac..c3f1ea22 100644
--- a/sig/generated/gruff/line.rbs
+++ b/sig/generated/gruff/line.rbs
@@ -52,6 +52,7 @@ class Gruff::Line < Gruff::Base
   #
   # The preferred way is to call {#hide_dots=} or {#hide_lines=} instead.
   #
+  # @rbs *args: untyped
   # @rbs return: void
   def initialize: (*untyped args) -> void
 
@@ -63,13 +64,15 @@ class Gruff::Line < Gruff::Base
   # Set a value for a baseline reference line..
   #
   # @rbs new_value: Float | Integer
-  def baseline_value=: (Float | Integer new_value) -> untyped
+  # @rbs return: Float | Integer
+  def baseline_value=: (Float | Integer new_value) -> (Float | Integer)
 
   # @rbs return: Float | Integer | nil
   def baseline_color: () -> (Float | Integer | nil)
 
   # @rbs new_value: Float | Integer
-  def baseline_color=: (Float | Integer new_value) -> untyped
+  # @rbs return: Float | Integer
+  def baseline_color=: (Float | Integer new_value) -> (Float | Integer)
 
   # Input the data in the graph.
   #
@@ -94,7 +97,8 @@ class Gruff::Line < Gruff::Base
   #
   # @example
   #   data("Bart S.", [95, 45, 78, 89, 88, 76], '#ffcc00')
-  def data: (String | Symbol name, ?Array[nil | Float | Integer] | nil data_points, ?String color) -> untyped
+  # @rbs return: void
+  def data: (String | Symbol name, ?Array[nil | Float | Integer] | nil data_points, ?String color) -> void
 
   # This method allows one to plot a dataset with both X and Y data.
   #
@@ -135,31 +139,55 @@ class Gruff::Line < Gruff::Base
   # @rbs x_data_points: Array[nil | Float | Integer] | Array[[nil | Float | Integer, nil | Float | Integer]] | nil
   # @rbs y_data_points: Array[nil | Float | Integer] | nil | String
   # @rbs color: String
-  def dataxy: (String | Symbol name, ?Array[nil | Float | Integer] | Array[[ nil | Float | Integer, nil | Float | Integer ]] | nil x_data_points, ?Array[nil | Float | Integer] | nil | String y_data_points, ?String color) -> untyped
+  # @rbs return: void
+  def dataxy: (String | Symbol name, ?Array[nil | Float | Integer] | Array[[ nil | Float | Integer, nil | Float | Integer ]] | nil x_data_points, ?Array[nil | Float | Integer] | nil | String y_data_points, ?String color) -> void
 
   private
 
-  def initialize_store: () -> untyped
+  # @rbs return: void
+  def initialize_store: () -> void
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def draw_reference_line: (untyped reference_line, untyped left, untyped right, untyped top, untyped bottom) -> untyped
+  # @rbs reference_line: Hash[Symbol, untyped]
+  # @rbs left: Float | Integer
+  # @rbs right: Float | Integer
+  # @rbs top: Float | Integer
+  # @rbs bottom: Float | Integer
+  # @rbs return: void
+  def draw_reference_line: (Hash[Symbol, untyped] reference_line, Float | Integer left, Float | Integer right, Float | Integer top, Float | Integer bottom) -> void
 
-  def draw_horizontal_reference_line: (untyped reference_line) -> untyped
+  # @rbs reference_line: Hash[Symbol, untyped]
+  # @rbs return: void
+  def draw_horizontal_reference_line: (Hash[Symbol, untyped] reference_line) -> void
 
-  def draw_vertical_reference_line: (untyped reference_line) -> untyped
+  # @rbs reference_line: Hash[Symbol, untyped]
+  # @rbs return: void
+  def draw_vertical_reference_line: (Hash[Symbol, untyped] reference_line) -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 
-  def setup_drawing: () -> untyped
+  # @rbs return: void
+  def setup_drawing: () -> void
 
-  def normalize: () -> untyped
+  # @rbs return: void
+  def normalize: () -> void
 
-  def draw_line_markers: () -> untyped
+  # @rbs return: void
+  def draw_line_markers: () -> void
 
-  def draw_label_for_x_data: (untyped x_data, untyped new_x, untyped index) -> untyped
+  # @rbs x_data: Float | Integer | nil
+  # @rbs new_x: Float | Integer
+  # @rbs index: Integer
+  # @rbs return: void
+  def draw_label_for_x_data: (Float | Integer | nil x_data, Float | Integer new_x, Integer index) -> void
 
-  def contains_one_point_only?: (untyped data_row) -> untyped
+  # @rbs data_row: Gruff::Store::XYData
+  # @rbs return: bool
+  def contains_one_point_only?: (Gruff::Store::XYData data_row) -> bool
 end
diff --git a/sig/generated/gruff/mini/bar.rbs b/sig/generated/gruff/mini/bar.rbs
index c4b0b709..fed5f5c3 100644
--- a/sig/generated/gruff/mini/bar.rbs
+++ b/sig/generated/gruff/mini/bar.rbs
@@ -16,9 +16,12 @@ class Gruff::Mini::Bar < Gruff::Bar
 
   include Gruff::Mini::Legend
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 end
diff --git a/sig/generated/gruff/mini/legend.rbs b/sig/generated/gruff/mini/legend.rbs
index 2238af30..85f515ec 100644
--- a/sig/generated/gruff/mini/legend.rbs
+++ b/sig/generated/gruff/mini/legend.rbs
@@ -3,24 +3,34 @@
 # A module to handle the small legend.
 # @private
 module Gruff::Mini::Legend
-  attr_accessor hide_mini_legend: untyped
+  attr_accessor hide_mini_legend: bool
 
-  attr_accessor legend_position: untyped
+  attr_accessor legend_position: Symbol
 
-  def initialize: (*untyped) -> untyped
+  # @rbs return: void
+  def initialize: (*untyped) -> void
 
   # The canvas needs to be bigger so we can put the legend beneath it.
-  def expand_canvas_for_vertical_legend: () -> untyped
+  # @rbs return: Gruff::Renderer
+  def expand_canvas_for_vertical_legend: () -> Gruff::Renderer
 
-  def calculate_line_height: () -> untyped
+  # @rbs return: Float
+  def calculate_line_height: () -> Float
 
-  def calculate_legend_width: () -> untyped
+  # @rbs return: Float
+  def calculate_legend_width: () -> Float
 
   # Draw the legend beneath the existing graph.
-  def draw_vertical_legend: () -> untyped
+  # @rbs return: void
+  def draw_vertical_legend: () -> void
 
   # Shorten long labels so they will fit on the canvas.
-  def truncate_legend_label: (untyped label, untyped x_offset) -> untyped
-
-  def scale: (untyped value) -> untyped
+  # @rbs label: String | Symbol
+  # @rbs x_offset: Float | Integer
+  # @rbs return: String
+  def truncate_legend_label: (String | Symbol label, Float | Integer x_offset) -> String
+
+  # @rbs value: Float | Integer
+  # @rbs return: Float
+  def scale: (Float | Integer value) -> Float
 end
diff --git a/sig/generated/gruff/mini/pie.rbs b/sig/generated/gruff/mini/pie.rbs
index 00841c2b..df04caa3 100644
--- a/sig/generated/gruff/mini/pie.rbs
+++ b/sig/generated/gruff/mini/pie.rbs
@@ -15,9 +15,12 @@ class Gruff::Mini::Pie < Gruff::Pie
 
   include Gruff::Mini::Legend
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 end
diff --git a/sig/generated/gruff/mini/side_bar.rbs b/sig/generated/gruff/mini/side_bar.rbs
index 233b4524..428bcd30 100644
--- a/sig/generated/gruff/mini/side_bar.rbs
+++ b/sig/generated/gruff/mini/side_bar.rbs
@@ -23,9 +23,12 @@ class Gruff::Mini::SideBar < Gruff::SideBar
 
   include Gruff::Mini::Legend
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 end
diff --git a/sig/generated/gruff/net.rbs b/sig/generated/gruff/net.rbs
index 360af15c..71806c31 100644
--- a/sig/generated/gruff/net.rbs
+++ b/sig/generated/gruff/net.rbs
@@ -32,21 +32,27 @@ class Gruff::Net < Gruff::Base
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_drawing: () -> untyped
+  # @rbs return: void
+  def setup_drawing: () -> void
 
-  def setup_graph_measurements: () -> untyped
+  # @rbs return: void
+  def setup_graph_measurements: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
   # the lines connecting in the center, with the first line vertical
-  def draw_line_markers: () -> untyped
+  # @rbs return: void
+  def draw_line_markers: () -> void
 
   # @rbs center_x: Float | Integer
   # @rbs center_y: Float | Integer
   # @rbs angle: Float | Integer
   # @rbs radius: Float
   # @rbs amount: String | Integer
-  def draw_label: (Float | Integer center_x, Float | Integer center_y, Float | Integer angle, Float radius, String | Integer amount) -> untyped
+  # @rbs return: void
+  def draw_label: (Float | Integer center_x, Float | Integer center_y, Float | Integer angle, Float radius, String | Integer amount) -> void
 end
diff --git a/sig/generated/gruff/patch/rmagick.rbs b/sig/generated/gruff/patch/rmagick.rbs
index 3075afc4..3a91bfa6 100644
--- a/sig/generated/gruff/patch/rmagick.rbs
+++ b/sig/generated/gruff/patch/rmagick.rbs
@@ -5,11 +5,21 @@ module Magick
   # @private
   module GruffAnnotate
     # Additional method to scale annotation text since Draw.scale doesn't.
-    def annotate_scaled: (untyped img, untyped width, untyped height, untyped x, untyped y, untyped text, untyped scale) -> untyped
+    # @rbs img: untyped
+    # @rbs width: Integer
+    # @rbs height: Integer
+    # @rbs x: Integer
+    # @rbs y: Integer
+    # @rbs text: String
+    # @rbs scale: Float
+    # @rbs return: void
+    def annotate_scaled: (untyped img, Integer width, Integer height, Integer x, Integer y, String text, Float scale) -> void
 
     # FIXME(uwe):  We should NOT need to implement this method.
     #              Remove this method as soon as RMagick4J Issue #16 is fixed.
     #              https://github.com/Serabe/RMagick4J/issues/16
-    def fill=: (untyped fill) -> untyped
+    # @rbs fill: String | Symbol
+    # @rbs return: void
+    def fill=: (String | Symbol fill) -> void
   end
 end
diff --git a/sig/generated/gruff/patch/string.rbs b/sig/generated/gruff/patch/string.rbs
index 823fd858..1a48dbae 100644
--- a/sig/generated/gruff/patch/string.rbs
+++ b/sig/generated/gruff/patch/string.rbs
@@ -5,5 +5,7 @@ module String::GruffCommify
   THOUSAND_SEPARATOR: ::String
 
   # Taken from http://codesnippets.joyent.com/posts/show/330
-  def commify: (?untyped delimiter) -> untyped
+  # @rbs delimiter: String
+  # @rbs return: String
+  def commify: (?String delimiter) -> String
 end
diff --git a/sig/generated/gruff/pie.rbs b/sig/generated/gruff/pie.rbs
index a1525ce1..342db7f4 100644
--- a/sig/generated/gruff/pie.rbs
+++ b/sig/generated/gruff/pie.rbs
@@ -38,20 +38,27 @@ class Gruff::Pie < Gruff::Base
   # Can be used to make the pie start cutting slices at the top (-90.0)
   # or at another angle. Default is +-90.0+, which starts at 3 o'clock.
   # @deprecated Please use {#start_degree=} instead.
-  def zero_degree=: (untyped value) -> untyped
+  # @rbs value: Float | Integer
+  # @rbs return: void
+  def zero_degree=: (Float | Integer value) -> void
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_drawing: () -> untyped
+  # @rbs return: void
+  def setup_drawing: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
-  def slices: () -> untyped
+  # @rbs return: Array[Gruff::Pie::PieSlice]
+  def slices: () -> Array[Gruff::Pie::PieSlice]
 
   # @rbs degrees: Float | Integer
-  def update_chart_degrees_with: (Float | Integer degrees) -> untyped
+  # @rbs return: void
+  def update_chart_degrees_with: (Float | Integer degrees) -> void
 
   # @rbs return: Float | Integer
   def chart_degrees: () -> (Float | Integer)
@@ -85,7 +92,8 @@ class Gruff::Pie < Gruff::Base
   def ellipse_factor: () -> (Float | Integer)
 
   # @rbs slice: Gruff::Pie::PieSlice
-  def process_label_for: (Gruff::Pie::PieSlice slice) -> untyped
+  # @rbs return: void
+  def process_label_for: (Gruff::Pie::PieSlice slice) -> void
 
   # @rbs slice: Gruff::Pie::PieSlice
   # @rbs return: [Float | Integer, Float | Integer]
diff --git a/sig/generated/gruff/renderer/bezier.rbs b/sig/generated/gruff/renderer/bezier.rbs
index 31a8b24a..b77b4ccd 100644
--- a/sig/generated/gruff/renderer/bezier.rbs
+++ b/sig/generated/gruff/renderer/bezier.rbs
@@ -10,6 +10,7 @@ module Gruff
     def initialize: (Gruff::Renderer renderer, color: String, ?width: Float | Integer) -> void
 
     # @rbs points: Array[Float | Integer]
-    def render: (Array[Float | Integer] points) -> untyped
+    # @rbs return: void
+    def render: (Array[Float | Integer] points) -> void
   end
 end
diff --git a/sig/generated/gruff/renderer/circle.rbs b/sig/generated/gruff/renderer/circle.rbs
index 28bb2ee0..ea7f01ad 100644
--- a/sig/generated/gruff/renderer/circle.rbs
+++ b/sig/generated/gruff/renderer/circle.rbs
@@ -14,6 +14,7 @@ module Gruff
     # @rbs origin_y: Float | Integer
     # @rbs perim_x: Float | Integer
     # @rbs perim_y: Float | Integer
-    def render: (Float | Integer origin_x, Float | Integer origin_y, Float | Integer perim_x, Float | Integer perim_y) -> untyped
+    # @rbs return: void
+    def render: (Float | Integer origin_x, Float | Integer origin_y, Float | Integer perim_x, Float | Integer perim_y) -> void
   end
 end
diff --git a/sig/generated/gruff/renderer/dash_line.rbs b/sig/generated/gruff/renderer/dash_line.rbs
index ef46ea99..6b7c56e8 100644
--- a/sig/generated/gruff/renderer/dash_line.rbs
+++ b/sig/generated/gruff/renderer/dash_line.rbs
@@ -14,6 +14,7 @@ module Gruff
     # @rbs start_y: Float | Integer
     # @rbs end_x: Float | Integer
     # @rbs end_y: Float | Integer
-    def render: (Float | Integer start_x, Float | Integer start_y, Float | Integer end_x, Float | Integer end_y) -> untyped
+    # @rbs return: void
+    def render: (Float | Integer start_x, Float | Integer start_y, Float | Integer end_x, Float | Integer end_y) -> void
   end
 end
diff --git a/sig/generated/gruff/renderer/dot.rbs b/sig/generated/gruff/renderer/dot.rbs
index 4ba3f400..e6e8eac5 100644
--- a/sig/generated/gruff/renderer/dot.rbs
+++ b/sig/generated/gruff/renderer/dot.rbs
@@ -14,14 +14,27 @@ module Gruff
     # @rbs new_x: Float | Integer
     # @rbs new_y: Float | Integer
     # @rbs radius: Float | Integer
-    def render: (Float | Integer new_x, Float | Integer new_y, Float | Integer radius) -> untyped
+    # @rbs return: void
+    def render: (Float | Integer new_x, Float | Integer new_y, Float | Integer radius) -> void
 
     private
 
-    def circle: (untyped new_x, untyped new_y, untyped radius) -> untyped
+    # @rbs new_x: Float | Integer
+    # @rbs new_y: Float | Integer
+    # @rbs radius: Float | Integer
+    # @rbs return: void
+    def circle: (Float | Integer new_x, Float | Integer new_y, Float | Integer radius) -> void
 
-    def square: (untyped new_x, untyped new_y, untyped radius) -> untyped
+    # @rbs new_x: Float | Integer
+    # @rbs new_y: Float | Integer
+    # @rbs radius: Float | Integer
+    # @rbs return: void
+    def square: (Float | Integer new_x, Float | Integer new_y, Float | Integer radius) -> void
 
-    def diamond: (untyped new_x, untyped new_y, untyped radius) -> untyped
+    # @rbs new_x: Float | Integer
+    # @rbs new_y: Float | Integer
+    # @rbs radius: Float | Integer
+    # @rbs return: void
+    def diamond: (Float | Integer new_x, Float | Integer new_y, Float | Integer radius) -> void
   end
 end
diff --git a/sig/generated/gruff/renderer/ellipse.rbs b/sig/generated/gruff/renderer/ellipse.rbs
index 749c71d0..f07f10c3 100644
--- a/sig/generated/gruff/renderer/ellipse.rbs
+++ b/sig/generated/gruff/renderer/ellipse.rbs
@@ -15,6 +15,7 @@ module Gruff
     # @rbs height: Float | Integer
     # @rbs arc_start: Float | Integer
     # @rbs arc_end: Float | Integer
-    def render: (Float | Integer origin_x, Float | Integer origin_y, Float | Integer width, Float | Integer height, Float | Integer arc_start, Float | Integer arc_end) -> untyped
+    # @rbs return: void
+    def render: (Float | Integer origin_x, Float | Integer origin_y, Float | Integer width, Float | Integer height, Float | Integer arc_start, Float | Integer arc_end) -> void
   end
 end
diff --git a/sig/generated/gruff/renderer/line.rbs b/sig/generated/gruff/renderer/line.rbs
index d9334b01..1997d839 100644
--- a/sig/generated/gruff/renderer/line.rbs
+++ b/sig/generated/gruff/renderer/line.rbs
@@ -15,10 +15,17 @@ module Gruff
     # @rbs start_y: Float | Integer
     # @rbs end_x: Float | Integer
     # @rbs end_y: Float | Integer
-    def render: (Float | Integer start_x, Float | Integer start_y, Float | Integer end_x, Float | Integer end_y) -> untyped
+    # @rbs return: void
+    def render: (Float | Integer start_x, Float | Integer start_y, Float | Integer end_x, Float | Integer end_y) -> void
 
     private
 
-    def render_line: (untyped start_x, untyped start_y, untyped end_x, untyped end_y, untyped color) -> untyped
+    # @rbs start_x: Float | Integer
+    # @rbs start_y: Float | Integer
+    # @rbs end_x: Float | Integer
+    # @rbs end_y: Float | Integer
+    # @rbs color: String
+    # @rbs return: void
+    def render_line: (Float | Integer start_x, Float | Integer start_y, Float | Integer end_x, Float | Integer end_y, String color) -> void
   end
 end
diff --git a/sig/generated/gruff/renderer/polygon.rbs b/sig/generated/gruff/renderer/polygon.rbs
index 588d65a9..9db19b6a 100644
--- a/sig/generated/gruff/renderer/polygon.rbs
+++ b/sig/generated/gruff/renderer/polygon.rbs
@@ -11,6 +11,7 @@ module Gruff
     def initialize: (Gruff::Renderer renderer, color: String, ?width: Float | Integer, ?opacity: Float | Integer) -> void
 
     # @rbs points: Array[Float | Integer]
-    def render: (Array[Float | Integer] points) -> untyped
+    # @rbs return: void
+    def render: (Array[Float | Integer] points) -> void
   end
 end
diff --git a/sig/generated/gruff/renderer/polyline.rbs b/sig/generated/gruff/renderer/polyline.rbs
index c1f1f1c2..b80012b0 100644
--- a/sig/generated/gruff/renderer/polyline.rbs
+++ b/sig/generated/gruff/renderer/polyline.rbs
@@ -11,6 +11,7 @@ module Gruff
     def initialize: (Gruff::Renderer renderer, color: String, ?width: Float | Integer, ?linejoin: String) -> void
 
     # @rbs points: Array[Float | Integer]
-    def render: (Array[Float | Integer] points) -> untyped
+    # @rbs return: void
+    def render: (Array[Float | Integer] points) -> void
   end
 end
diff --git a/sig/generated/gruff/renderer/rectangle.rbs b/sig/generated/gruff/renderer/rectangle.rbs
index fb5b1808..b77a9df2 100644
--- a/sig/generated/gruff/renderer/rectangle.rbs
+++ b/sig/generated/gruff/renderer/rectangle.rbs
@@ -14,6 +14,7 @@ module Gruff
     # @rbs upper_left_y: Float | Integer
     # @rbs lower_right_x: Float | Integer
     # @rbs lower_right_y: Float | Integer
-    def render: (Float | Integer upper_left_x, Float | Integer upper_left_y, Float | Integer lower_right_x, Float | Integer lower_right_y) -> untyped
+    # @rbs return: void
+    def render: (Float | Integer upper_left_x, Float | Integer upper_left_y, Float | Integer lower_right_x, Float | Integer lower_right_y) -> void
   end
 end
diff --git a/sig/generated/gruff/renderer/renderer.rbs b/sig/generated/gruff/renderer/renderer.rbs
index 357eb3b9..0e8eb1ca 100644
--- a/sig/generated/gruff/renderer/renderer.rbs
+++ b/sig/generated/gruff/renderer/renderer.rbs
@@ -9,7 +9,7 @@ module Gruff
 
     attr_reader image: untyped
 
-    attr_reader scale: real
+    attr_reader scale: Float | Integer
 
     # @rbs columns: Integer
     # @rbs rows: Integer
@@ -18,26 +18,49 @@ module Gruff
     # @rbs return: void
     def initialize: (Integer columns, Integer rows, Float | Integer scale, ::Hash[Symbol, untyped] theme_options) -> void
 
-    def finish: () -> untyped
+    # @rbs return: void
+    def finish: () -> void
 
     # @rbs columns: Integer
     # @rbs rows: Integer
-    def transparent_background: (Integer columns, Integer rows) -> untyped
+    # @rbs return: void
+    def transparent_background: (Integer columns, Integer rows) -> void
 
     private
 
-    def background: (untyped columns, untyped rows, untyped scale, untyped theme_options) -> untyped
+    # @rbs columns: Integer
+    # @rbs rows: Integer
+    # @rbs scale: Float | Integer
+    # @rbs theme_options: ::Hash[Symbol, untyped]
+    # @rbs return: void
+    def background: (Integer columns, Integer rows, Float | Integer scale, ::Hash[Symbol, untyped] theme_options) -> void
 
     # Use with a theme to use an image (800x600 original) background.
-    def image_background: (untyped scale, untyped image_path) -> untyped
+    # @rbs scale: Float | Integer
+    # @rbs image_path: String
+    # @rbs return: untyped
+    def image_background: (Float | Integer scale, String image_path) -> untyped
 
     # Make a new image at the current size with a solid +color+.
-    def solid_background: (untyped columns, untyped rows, untyped color) -> untyped
+    # @rbs columns: Integer
+    # @rbs rows: Integer
+    # @rbs color: String
+    # @rbs return: void
+    def solid_background: (Integer columns, Integer rows, String color) -> void
 
     # Use with a theme definition method to draw a gradated background.
-    def gradated_background: (untyped columns, untyped rows, untyped top_color, untyped bottom_color, ?untyped direct) -> untyped
+    # @rbs columns: Integer
+    # @rbs rows: Integer
+    # @rbs top_color: String
+    # @rbs bottom_color: String
+    # @rbs direct: Symbol
+    # @rbs return: void
+    def gradated_background: (Integer columns, Integer rows, String top_color, String bottom_color, ?Symbol direct) -> void
 
     # Use with a theme to make a transparent background
-    def render_transparent_background: (untyped columns, untyped rows) -> untyped
+    # @rbs columns: Integer
+    # @rbs rows: Integer
+    # @rbs return: void
+    def render_transparent_background: (Integer columns, Integer rows) -> void
   end
 end
diff --git a/sig/generated/gruff/renderer/text.rbs b/sig/generated/gruff/renderer/text.rbs
index e0b469af..b4596629 100644
--- a/sig/generated/gruff/renderer/text.rbs
+++ b/sig/generated/gruff/renderer/text.rbs
@@ -7,7 +7,8 @@ module Gruff
     # @rbs text: String
     # @rbs font: Gruff::Font
     # @rbs rotation: Float | Integer
-    def initialize: (Gruff::Renderer renderer, String text, font: Gruff::Font, ?rotation: Float | Integer) -> untyped
+    # @rbs return: void
+    def initialize: (Gruff::Renderer renderer, String text, font: Gruff::Font, ?rotation: Float | Integer) -> void
 
     attr_reader width: Float | Integer
 
@@ -24,15 +25,18 @@ module Gruff
     # @rbs x: Float | Integer
     # @rbs y: Float | Integer
     # @rbs gravity: untyped
-    def add_to_render_queue: (Float | Integer width, Float | Integer height, Float | Integer x, Float | Integer y, ?untyped gravity) -> untyped
+    # @rbs return: void
+    def add_to_render_queue: (Float | Integer width, Float | Integer height, Float | Integer x, Float | Integer y, ?untyped gravity) -> void
 
     # @rbs width: Float | Integer
     # @rbs height: Float | Integer
     # @rbs x: Float | Integer
     # @rbs y: Float | Integer
     # @rbs gravity: untyped
-    def render: (Float | Integer width, Float | Integer height, Float | Integer x, Float | Integer y, ?untyped gravity) -> untyped
+    # @rbs return: void
+    def render: (Float | Integer width, Float | Integer height, Float | Integer x, Float | Integer y, ?untyped gravity) -> void
 
+    # @rbs return: untyped
     def metrics: () -> untyped
   end
 end
diff --git a/sig/generated/gruff/scatter.rbs b/sig/generated/gruff/scatter.rbs
index 2d46d32a..f56330cc 100644
--- a/sig/generated/gruff/scatter.rbs
+++ b/sig/generated/gruff/scatter.rbs
@@ -29,20 +29,28 @@ class Gruff::Scatter < Gruff::Base
 
   # Allow enabling vertical lines. When you have a lot of data, they can work great.
   # @deprecated Please use {#show_vertical_markers=} instead.
-  def enable_vertical_line_markers=: (untyped value) -> untyped
+  # @rbs value: bool
+  # @rbs return: void
+  def enable_vertical_line_markers=: (bool value) -> void
 
   # Allow using vertical labels in the X axis.
   # @deprecated Please use {Gruff::Base#label_rotation=} instead.
-  def use_vertical_x_labels=: (untyped _value) -> untyped
+  # @rbs _value: untyped
+  # @rbs return: void
+  def use_vertical_x_labels=: (untyped _value) -> void
 
   # Allow using vertical labels in the X axis (and setting the label margin).
   # @deprecated
-  def x_label_margin=: (untyped _value) -> untyped
+  # @rbs _value: untyped
+  # @rbs return: void
+  def x_label_margin=: (untyped _value) -> void
 
   # Allow disabling the significant rounding when labeling the X axis.
   # This is useful when working with a small range of high values (for example, a date range of months, while seconds as units).
   # @deprecated
-  def disable_significant_rounding_x_axis=: (untyped _value) -> untyped
+  # @rbs _value: untyped
+  # @rbs return: void
+  def disable_significant_rounding_x_axis=: (untyped _value) -> void
 
   # The first parameter is the name of the dataset.  The next two are the
   # x and y axis data points contain in their own array in that respective
@@ -82,27 +90,36 @@ class Gruff::Scatter < Gruff::Base
   # @rbs x_data_points: Array[nil | Float | Integer] | nil
   # @rbs y_data_points: Array[nil | Float | Integer] | nil
   # @rbs color: String
-  def data: (String | Symbol name, ?Array[nil | Float | Integer] | nil x_data_points, ?Array[nil | Float | Integer] | nil y_data_points, ?String color) -> untyped
+  # @rbs return: void
+  def data: (String | Symbol name, ?Array[nil | Float | Integer] | nil x_data_points, ?Array[nil | Float | Integer] | nil y_data_points, ?String color) -> void
 
   alias dataxy data
 
   private
 
-  def initialize_store: () -> untyped
+  # @rbs return: void
+  def initialize_store: () -> void
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_drawing: () -> untyped
+  # @rbs return: void
+  def setup_drawing: () -> void
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
-  def calculate_spread: () -> untyped
+  # @rbs return: void
+  def calculate_spread: () -> void
 
-  def normalize: () -> untyped
+  # @rbs return: void
+  def normalize: () -> void
 
-  def draw_line_markers: () -> untyped
+  # @rbs return: void
+  def draw_line_markers: () -> void
 
   # @rbs return: Integer
   def marker_x_count: () -> Integer
diff --git a/sig/generated/gruff/side_bar.rbs b/sig/generated/gruff/side_bar.rbs
index 35af9ce4..92375a35 100644
--- a/sig/generated/gruff/side_bar.rbs
+++ b/sig/generated/gruff/side_bar.rbs
@@ -46,11 +46,14 @@ class Gruff::SideBar < Gruff::Base
 
   # With Side Bars use the data label for the marker value to the left of the bar.
   # @deprecated
-  def use_data_label=: (untyped _value) -> untyped
+  # @rbs _value: untyped
+  # @rbs return: void
+  def use_data_label=: (untyped _value) -> void
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
   # @rbs return: bool
   def hide_labels?: () -> bool
@@ -61,14 +64,20 @@ class Gruff::SideBar < Gruff::Base
   # @rbs return: bool
   def hide_bottom_label_area?: () -> bool
 
-  def setup_graph_measurements: () -> untyped
+  # @rbs return: void
+  def setup_graph_measurements: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
   # Instead of base class version, draws vertical background lines and label
-  def draw_line_markers: () -> untyped
+  # @rbs return: void
+  def draw_line_markers: () -> void
 
-  def draw_label: (untyped y_offset, untyped index) -> untyped
+  # @rbs y_offset: Float | Integer
+  # @rbs index: Integer
+  # @rbs return: void
+  def draw_label: (Float | Integer y_offset, Integer index) -> void
 
   # @rbs return: Float | Integer
   def calculate_spacing: () -> (Float | Integer)
diff --git a/sig/generated/gruff/side_stacked_bar.rbs b/sig/generated/gruff/side_stacked_bar.rbs
index 3e46af9c..19d511a3 100644
--- a/sig/generated/gruff/side_stacked_bar.rbs
+++ b/sig/generated/gruff/side_stacked_bar.rbs
@@ -44,9 +44,12 @@ class Gruff::SideStackedBar < Gruff::SideBar
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 end
diff --git a/sig/generated/gruff/spider.rbs b/sig/generated/gruff/spider.rbs
index 869197b2..4c222f11 100644
--- a/sig/generated/gruff/spider.rbs
+++ b/sig/generated/gruff/spider.rbs
@@ -25,26 +25,50 @@ class Gruff::Spider < Gruff::Base
   def initialize: (Float | Integer max_value, ?String | Float | Integer target_width) -> void
 
   # @rbs value: bool
-  def hide_text=: (bool value) -> untyped
+  # @rbs return: void
+  def hide_text=: (bool value) -> void
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_drawing: () -> untyped
+  # @rbs return: void
+  def setup_drawing: () -> void
 
-  def setup_graph_measurements: () -> untyped
+  # @rbs return: void
+  def setup_graph_measurements: () -> void
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
-  # @rbs value: nil | Float | Integer
-  def normalize_points: (nil | Float | Integer value) -> untyped
+  # @rbs value: Float | Integer
+  # @rbs return: Float
+  def normalize_points: (Float | Integer value) -> Float
 
-  def draw_label: (untyped center_x, untyped center_y, untyped angle, untyped radius, untyped amount) -> untyped
+  # @rbs center_x: Float | Integer
+  # @rbs center_y: Float | Integer
+  # @rbs angle: Float | Integer
+  # @rbs radius: Float | Integer
+  # @rbs amount: Float | Integer
+  # @rbs return: void
+  def draw_label: (Float | Integer center_x, Float | Integer center_y, Float | Integer angle, Float | Integer radius, Float | Integer amount) -> void
 
-  def draw_axes: (untyped center_x, untyped center_y, untyped radius, untyped additive_angle, ?untyped line_color) -> untyped
+  # @rbs center_x: Float | Integer
+  # @rbs center_y: Float | Integer
+  # @rbs radius: Float | Integer
+  # @rbs additive_angle: Float | Integer
+  # @rbs line_color: String | nil
+  # @rbs return: void
+  def draw_axes: (Float | Integer center_x, Float | Integer center_y, Float | Integer radius, Float | Integer additive_angle, ?String | nil line_color) -> void
 
-  def draw_polygon: (untyped center_x, untyped center_y, untyped additive_angle, ?untyped color) -> untyped
+  # @rbs center_x: Float | Integer
+  # @rbs center_y: Float | Integer
+  # @rbs additive_angle: Float | Integer
+  # @rbs color: String | nil
+  # @rbs return: void
+  def draw_polygon: (Float | Integer center_x, Float | Integer center_y, Float | Integer additive_angle, ?String | nil color) -> void
 end
diff --git a/sig/generated/gruff/stacked_area.rbs b/sig/generated/gruff/stacked_area.rbs
index 7b35f4e7..f340331e 100644
--- a/sig/generated/gruff/stacked_area.rbs
+++ b/sig/generated/gruff/stacked_area.rbs
@@ -13,13 +13,18 @@ class Gruff::StackedArea < Gruff::Base
   include Gruff::Base::StackedMixin
 
   # @deprecated
-  def last_series_goes_on_bottom=: (untyped _value) -> untyped
+  # @rbs _value: untyped
+  # @rbs return: void
+  def last_series_goes_on_bottom=: (untyped _value) -> void
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 end
diff --git a/sig/generated/gruff/stacked_bar.rbs b/sig/generated/gruff/stacked_bar.rbs
index 06fd7f84..91858a4e 100644
--- a/sig/generated/gruff/stacked_bar.rbs
+++ b/sig/generated/gruff/stacked_bar.rbs
@@ -31,16 +31,21 @@ class Gruff::StackedBar < Gruff::Base
 
   private
 
-  def initialize_attributes: () -> untyped
+  # @rbs return: void
+  def initialize_attributes: () -> void
 
-  def setup_drawing: () -> untyped
+  # @rbs return: void
+  def setup_drawing: () -> void
 
-  def setup_data: () -> untyped
+  # @rbs return: void
+  def setup_data: () -> void
 
-  def setup_graph_measurements: () -> untyped
+  # @rbs return: void
+  def setup_graph_measurements: () -> void
 
   # Draws a bar graph, but multiple sets are stacked on top of each other.
-  def draw_graph: () -> untyped
+  # @rbs return: void
+  def draw_graph: () -> void
 
   # @rbs return: bool
   def hide_labels?: () -> bool
diff --git a/sig/generated/gruff/store/basic_data.rbs b/sig/generated/gruff/store/basic_data.rbs
index 89c51a90..caa25532 100644
--- a/sig/generated/gruff/store/basic_data.rbs
+++ b/sig/generated/gruff/store/basic_data.rbs
@@ -13,15 +13,19 @@ module Gruff
       # @rbs label: String | Symbol
       # @rbs points: Array[nil | Float | Integer] | nil
       # @rbs color: String
-      def initialize: (String | Symbol label, Array[nil | Float | Integer] | nil points, String color) -> untyped
+      # @rbs return: void
+      def initialize: (String | Symbol label, Array[nil | Float | Integer] | nil points, String color) -> void
 
       alias x_points points
 
-      def y_points: () -> untyped
+      # @rbs return: void
+      def y_points: () -> void
 
-      def coordinates: () -> untyped
+      # @rbs return: void
+      def coordinates: () -> void
 
-      def coordinate_and_pointsizes: () -> untyped
+      # @rbs return: void
+      def coordinate_and_pointsizes: () -> void
 
       # @rbs return: bool
       def empty?: () -> bool
diff --git a/sig/generated/gruff/store/store.rbs b/sig/generated/gruff/store/store.rbs
index 061cc21d..d2b6efbf 100644
--- a/sig/generated/gruff/store/store.rbs
+++ b/sig/generated/gruff/store/store.rbs
@@ -5,14 +5,19 @@ module Gruff
   class Store
     attr_reader data: Array[Gruff::Store::BasicData | Gruff::Store::XYData | Gruff::Store::XYPointsizeData]
 
+    # @rbs data_class: untyped
     # @rbs return: void
     def initialize: (untyped data_class) -> void
 
-    def add: (*untyped args) -> untyped
+    # @rbs *args: untyped
+    # @rbs return: void
+    def add: (*untyped args) -> void
 
     # @rbs return: Array[Gruff::Store::BasicData | Gruff::Store::XYData | Gruff::Store::XYPointsizeData]
     def norm_data: () -> Array[Gruff::Store::BasicData | Gruff::Store::XYData | Gruff::Store::XYPointsizeData]
 
+    # @rbs **keywords: untyped
+    # @rbs return: untyped
     def normalize: (**untyped keywords) -> untyped
 
     # @rbs return: bool
@@ -40,14 +45,17 @@ module Gruff
     # @rbs return: Float | Integer
     def max_x: () -> (Float | Integer)
 
-    def sort_data!: () -> untyped
+    # @rbs return: void
+    def sort_data!: () -> void
 
-    def sort_norm_data!: () -> untyped
+    # @rbs return: void
+    def sort_norm_data!: () -> void
 
     # @rbs return: Array[Gruff::Store::BasicData | Gruff::Store::XYData | Gruff::Store::XYPointsizeData]
     def reverse!: () -> Array[Gruff::Store::BasicData | Gruff::Store::XYData | Gruff::Store::XYPointsizeData]
 
     # @rbs colors: Array[String]
-    def change_colors: (Array[String] colors) -> untyped
+    # @rbs return: void
+    def change_colors: (Array[String] colors) -> void
   end
 end
diff --git a/sig/generated/gruff/store/xy_data.rbs b/sig/generated/gruff/store/xy_data.rbs
index 671d9790..da4bcc6c 100644
--- a/sig/generated/gruff/store/xy_data.rbs
+++ b/sig/generated/gruff/store/xy_data.rbs
@@ -16,14 +16,16 @@ module Gruff
       # @rbs x_points: Array[nil | Float | Integer] | nil
       # @rbs y_points: Array[nil | Float | Integer] | nil
       # @rbs color: String
-      def initialize: (String | Symbol label, Array[nil | Float | Integer] | nil x_points, Array[nil | Float | Integer] | nil y_points, String color) -> untyped
+      # @rbs return: void
+      def initialize: (String | Symbol label, Array[nil | Float | Integer] | nil x_points, Array[nil | Float | Integer] | nil y_points, String color) -> void
 
       alias points y_points
 
       # @rbs return: Array[[Float | Integer | nil, Float | Integer | nil]]
       def coordinates: () -> Array[[ Float | Integer | nil, Float | Integer | nil ]]
 
-      def coordinate_and_pointsizes: () -> untyped
+      # @rbs return: void
+      def coordinate_and_pointsizes: () -> void
 
       # @rbs return: bool
       def empty?: () -> bool
diff --git a/sig/generated/gruff/store/xy_pointsizes_data.rbs b/sig/generated/gruff/store/xy_pointsizes_data.rbs
index 20b07516..34bde61f 100644
--- a/sig/generated/gruff/store/xy_pointsizes_data.rbs
+++ b/sig/generated/gruff/store/xy_pointsizes_data.rbs
@@ -19,11 +19,13 @@ module Gruff
       # @rbs y_points: Array[nil | Float | Integer] | nil
       # @rbs point_sizes: Array[nil | Float | Integer]
       # @rbs color: String
-      def initialize: (String | Symbol label, Array[nil | Float | Integer] | nil x_points, Array[nil | Float | Integer] | nil y_points, Array[nil | Float | Integer] point_sizes, String color) -> untyped
+      # @rbs return: void
+      def initialize: (String | Symbol label, Array[nil | Float | Integer] | nil x_points, Array[nil | Float | Integer] | nil y_points, Array[nil | Float | Integer] point_sizes, String color) -> void
 
       alias points y_points
 
-      def coordinates: () -> untyped
+      # @rbs return: void
+      def coordinates: () -> void
 
       # @rbs return: Array[[Float | Integer | nil, Float | Integer | nil, Float | Integer]]
       def coordinate_and_pointsizes: () -> Array[[ Float | Integer | nil, Float | Integer | nil, Float | Integer ]]