WIP rethinking ratios and proportions

Author: v0dro

CONTRIBUTING.md

@@ -0,0 +1,15 @@
+# Developer notes
+
+## Co-ordinate system
+Each Artist contains a `(abs_x, abs_y)` pair that denotes the absolute position of the 
+Artist on the canvas. For `Figure` and `Axes` this pair denotes the top left corner.
+
+During the data collection phase (anything before calling `draw`), all the co-ordinates
+exist in the form of ratios. The absolute co-ordinates are calculated during the draw
+phase. Therefore there should be no code except in the `draw` methods where actual
+co-ordinates are calcualted.
+
+Varible naming conventions:
+* All values that are absolute values will be prefixed with `abs_`.
+* Variables relating to positioning of the graph other than the absolute
+variables are always ratios.

lib/rubyplot/artist.rb

@@ -1,4 +1,5 @@
 require_relative 'artist/base'
+require_relative 'artist/figure'
 require_relative 'artist/legend'
 require_relative 'artist/line2d'
 require_relative 'artist/tick'

lib/rubyplot/artist/axes.rb

@@ -38,12 +38,6 @@ class Axes < Base
       attr_reader :figure
       # Array of plots contained in this Axes.
       attr_reader :plots
-      # Position of this Axes object in the subplots.
-      attr_reader :position
-      # Width in pixels of the graph
-      attr_reader :width
-      # Height in pixels of the graph
-      attr_reader :height
       # data variables for something
       attr_reader :raw_rows
       attr_reader :backend
@@ -54,19 +48,12 @@ class Axes < Base
 
       attr_reader :label_stagger_height
       # FIXME: possibly disposable attrs
-      attr_reader :graph_height, :title_caps_height, :graph_bottom
-      # left margin of the actual plot
-      attr_reader :graph_left
-      # top margin of the actual plot to leave space for the title
-      attr_reader :graph_top
-      # total width of the actual graph
-      attr_reader :graph_width
+      attr_reader :title_caps_height
+      attr_reader :top_spacing
 
       # @param figure [Rubyplot::Figure] Figure object to which this Axes belongs.
-      # @param position [Integer] Position among the rest of the Axes in the Figure.
-      def initialize figure, width, height, position
+      def initialize figure
         @figure = figure
-        @position = position
 
         @x_title = ''
         @y_title = ''
@@ -86,8 +73,6 @@ def initialize figure, width, height, position
         @y_axis_padding = :default
         @x_ticks = {}
         @plots = []
-        @width = width
-        @height = height
 
         @raw_rows = @width * (@height/@width)
 
@@ -162,6 +147,25 @@ def stacked_bar! *args, &block
       def write file_name
         @plots[0].write file_name
       end
+      
+      # Absolute X co-ordinate of the Axes. Top left corner.
+      def abs_x
+        @figure.top_spacing * @figure.abs_height + @figure.abs_x
+      end
+      
+      # Absolute Y co-ordinate of the Axes. Top left corner.
+      def abs_y
+        @figure.top_spacing * @figure.abs_height + @figure.abs_y
+      end
+      # Absolute width of the Axes in pixels.
+      def abs_width
+        (@figure.left_spacing + @figure.right_spacing) * @figure.abs_width
+      end
+
+      # Absolute height of the Axes in pixels.
+      def abs_height
+        (@figure.top_spacing + @figure.bottom_spacing) * @figure.abs_height
+      end
 
       private
 
@@ -241,7 +245,7 @@ def setup_default_theme
       # * X/Y offsets
       def setup_drawing
         calculate_spread
-        normalize
+        normalize # FIXME: maybe doesnt need to go here.
         setup_graph_measurements
       end
 
@@ -267,6 +271,11 @@ def normalize
       # It calcuates the measurments in pixels to figure out the positioning
       # gap pixels of Legends, Labels and Titles from the picture edge. 
       def setup_graph_measurements
+        calculate_font_spaces
+        calculate_top_spacing
+        calculate_left_spacing
+        calculate_bottom_spacing
+        calculate_right_spacing
         @marker_caps_height = @backend.caps_height @font, @marker_font_size
         @title_caps_height = @geometry.hide_title || @title.nil? ? 0 :
                                @backend.caps_height(@font, @title_font_size) * @title.lines.to_a.size
@@ -328,6 +337,12 @@ def setup_graph_measurements
         @graph_height = @graph_bottom - @graph_top
       end
 
+      # Consider the various fonts that in use in this graph and calculate the
+      # ratio of the space that they will occupy w.r.t the Axes.
+      def calculate_font_spaces
+        
+      end
+
       # Return a formatted string representing a number value that should be
       # printed as a label.
       def label_string(value, increment)

lib/rubyplot/artist/base.rb

@@ -2,6 +2,10 @@ module Rubyplot
   module Artist
     class Base
       attr_reader :backend
+      # Absolute X co-ordinate of this Aritist on the canvas.
+      attr_reader :abs_x
+      # Absolute Y co-ordinate of this Aritist on the canvas.
+      attr_reader :abs_y
     end
   end
 end

lib/rubyplot/artist/figure.rb

@@ -0,0 +1,58 @@
+module Rubyplot
+  module Artist
+    class Figure < Artist::Base
+      DEFAULT_TARGET_WIDTH = 800  
+
+      # Title on the figure.
+      attr_reader :title
+      # Number of Axes objects in the rows.
+      attr_reader :nrows
+      # Number of Axes objects in the cols.
+      attr_reader :ncols
+      # Total width of the Figure in pixels.
+      attr_reader :abs_width
+      # Total height of the Figure in pixels.
+      attr_reader :abs_height
+      # Ratio of the total height that is the spacing between the top of the
+      #   Figure and the top of the Axes.
+      attr_reader :top_spacing
+      # Ratio of the total width that is the spacing between the left of the
+      #   Figure and the left of the Axes.
+      attr_reader :left_spacing
+      # Ratio of the total width that is the spacing between the right of the
+      #   Figure and the right of the Axes.
+      attr_reader :right_spacing
+      # Ratio of the total width that is the spacing between the bottom of the
+      #   Figure and the bottom of the Axes.
+      attr_reader :bottom_spacing
+      def initialize
+        @title = ''
+        @nrows = 1
+        @ncols = 1
+        @backend = Rubyplot::Backend::MagickWrapper.new
+        @abs_width = DEFAULT_TARGET_WIDTH
+        @abs_height = @width * 0.75
+        @abs_x = 0
+        @abs_y = 0
+        @top_spacing = 0.05
+        @bottom_spacing = 0.05
+        @left_spacing = 0.05
+        @right_spacing = 0.05
+        add_subplots @nrows, @ncols
+      end
+
+      def add_subplots nrows, ncols
+        @subplots = Array.new(nrows) { Array.new(ncols) { nil } }
+      end
+
+      def add_subplot nrow, ncol
+        @subplots[nrow][ncol] = Rubyplot::Artist::Axes.new(self)
+      end
+
+      def write file_name
+        @subplots.each { |i| i.each { |j| j.draw } }
+        @backend.write(file_name)
+      end
+    end # class Figure
+  end # module Artist
+end # module Rubyplot

lib/rubyplot/figure.rb

@@ -1,44 +1,2 @@
-module Rubyplot
-  class Figure
-    DEFAULT_TARGET_WIDTH = 800  
-
-    # Title on the figure.
-    attr_reader :title
-    # Number of Axes objects in the rows.
-    attr_reader :nrows
-    # Number of Axes objects in the cols.
-    attr_reader :ncols
-    # Drawing backend.
-    attr_reader :backend
-    # Total width of the Figure in pixels.
-    attr_reader :width
-    # Total height of the Figure in pixels.
-    attr_reader :height
-    
-    def initialize
-      @title = ''
-      @nrows = 1
-      @ncols = 1
-      @backend = Rubyplot::Backend::MagickWrapper.new
-      @width = DEFAULT_TARGET_WIDTH
-      @height = @width * 0.75
-      @x = 0
-      @y = 0
-      add_subplots @nrows, @ncols
-    end
-
-    def add_subplots nrows, ncols
-      @subplots = Array.new(nrows) { Array.new(ncols) { nil } }
-    end
-
-    def add_subplot nrow, ncol
-      @subplots[nrow][ncol] = Rubyplot::Artist::Axes.new(
-        self, @width, @height, nrow*@ncols + ncol)
-    end
-
-    def write file_name
-      @subplots.each { |i| i.each { |j| j.draw } }
-      @backend.write(file_name)
-    end
-  end # class Figure
-end # module Rubyplot
+# Alias meant for easy class initialization without knowing Artist details.
+Rubyplot::Figure = Rubyplot::Artist::Figure