pie.rb in gruff-0.0.4

- old
+ new
@@ -1,15 +1,92 @@
 
 require 'gruff/base'
 
-module Gruff
-  class Pie < Base
+class Gruff::Pie < Gruff::Base
 
-    # TODO Not yet implemented.
-    def draw
-      super
+  def draw
+    @show_line_markers = false
+    
+    super
 
-      @d.draw(@base_image)
+    diameter = @graph_height
+    radius = @graph_height / 2.0
+    top_x = @graph_left + (@graph_width - diameter) / 2.0
+    center_x = @graph_left + (@graph_width / 2.0)
+    center_y = @graph_top + (@graph_height / 2.0)
+    total_sum = sums_for_pie()
+    prev_degrees = 0.0
+
+    @norm_data.each do |data_row|
+      @d = @d.stroke current_color
+      @d = @d.fill 'transparent'
+      @d.stroke_width(200.0)
+
+      current_degrees = (data_row[1][0] / total_sum) * 360.0
+      #@d = @d.pie_slice(center_x, center_y, radius, 
+      #                  current_percent * 100.0)
+      
+      #@d = @d.arc(top_x, @graph_top, 
+      #            top_x + diameter, @graph_top + diameter,
+      #            prev_degrees, prev_degrees + current_degrees)
+      radius = 100.0
+      @d = @d.ellipse(center_x, center_y, 
+                  radius, radius,
+                  prev_degrees, prev_degrees + current_degrees)
+      
+      
+      prev_degrees += current_degrees
+      increment_color()
     end
 
+    @d.draw(@base_image)
   end
-end
\ No newline at end of file
+
+private
+
+  def sums_for_pie
+    total_sum = 0.0
+    @norm_data.collect {|data_row| total_sum += data_row[1][0] }
+    total_sum
+  end
+
+end
+
+class Magick::Draw
+  
+  def pie_slice(center_x=0.0, center_y=0.0, radius=100.0, percent=0.0, rot_x=0.0)
+    # Okay, this part is as confusing as hell, so pay attention:
+		# This line determines the horizontal portion of the point on the circle where the X-Axis
+		# should end.  It's caculated by taking the center of the on-image circle and adding that
+		# to the radius multiplied by the formula for determinig the point on a unit circle that a
+		# angle corresponds to.  3.6 * percent gives us that angle, but it's in degrees, so we need to
+		# convert, hence the muliplication by Pi over 180
+		arc_end_x = radius + (radius * Math.cos((3.6 * percent)*(Math::PI/180.0)))
+
+		# The same goes for here, except it's the vertical point instead of the horizontal one
+		arc_end_y = radius + (radius * Math.sin((3.6 * percent)*(Math::PI/180.0)))
+
+		# Because the SVG path format is seriously screwy, we need to set the large-arc-flag to 1
+		# if the angle of an arc is greater than 180 degrees.  I have no idea why this is, but it is.
+		percent > 50 ? large_arc_flag = 1 : large_arc_flag = 0
+
+		# This is also confusing
+		#  M tells us to move to an absolute point on the image.  
+		#   We're moving to the center of the pie
+		#  h tells us to move to a relative point.  
+		#   We're moving to the right edge of the circle.
+		#  A tells us to start an absolute elliptical arc.  
+		#   The first two values are the radii of the ellipse
+		#   The third value is the x-axis-rotation (how to rotate the ellipse)
+		#   The fourth value is our large-arc-flag
+		#   The fifth is the sweep-flag
+		#   The sixth and seventh values are the end point of the arc which we calculated previously
+		# More info on the SVG path string format at: http://www.w3.org/TR/SVG/paths.html
+		#
+		#path = "M#{radius + 2},#{radius + 2} h#{radius} A#{radius},#{radius} #{rot_x} #{large_arc_flag},1 #{arc_end_x},#{arc_end_y} z"
+		path = "M#{radius},#{radius} h#{radius} A#{radius},#{radius} #{rot_x} #{large_arc_flag},1 #{arc_end_x},#{arc_end_y} z"
+    puts "PATH: #{path}"
+
+		self.path(path)
+  end
+  
+end