added Star element and example.

examples/star.rb

@@ -0,0 +1,7 @@
+class Star < Sketch
+
+  def draw(canvas)
+    Sketch::Star.new(:radius => self.width.to_f / 2.1, :x => self.width.to_f / 2, :y => self.width.to_f / 2, :fill => 'yellow', :stroke => 'black', :stroke_width => 1, :orientation => 45).draw(canvas)
+  end
+end
+

lib/sketch.rb

@@ -48,4 +48,5 @@ def svg_builder
 require 'sketch/rect'
 require 'sketch/rectangle'
 require 'sketch/path'
+require 'sketch/star'
 

lib/sketch/star.rb

@@ -5,17 +5,50 @@ class Sketch::Star < Sketch::Element
   has_value :radius
   has_value :orientation, :default => 0
 
+  has_value :number_of_points, :default => 5
+
+  has_value :fill
+  has_value :stroke 
+  has_value :stroke_width
+
   central_point :x, :y
 
+  def degrees_to_radians( degrees )
+    degrees * Math::PI / 180
+  end
+
+  def angle_between_points
+    360 / number_of_points
+  end
+
+  def drawing_order_indexes
+    self.number_of_points.times.map do |n|
+      (n*2) % self.number_of_points
+    end
+  end
+
+  def points_in_drawing_order
+    drawing_order_indexes.map do |index|
+      points[index]
+    end
+  end
+
+  def points
+    @points ||= list = number_of_points.times.map do |point_number|
+      current_angle = orientation + ( angle_between_points * point_number )
+      [ x + (radius * Math.sin( degrees_to_radians( current_angle ))), y - (radius * Math.cos( degrees_to_radians( current_angle ))) ]
+    end
+  end
+
   def draw(canvas)
-    top = [x, y - radius]
-    mid_right = [x + radius, y-(.3*radius)] 
-    lower_right = [x + (0.6 * radius), y + radius]
-    lower_left = [x - (0.6 * radius), y + radius]
-    mid_left = [x - radius, y-(0.3*radius)]
-    points = [ top, lower_right, mid_left, mid_right, lower_left, top ]
-    points.each{|point| point.join(',')}
-    points = points.join(' ')
-    canvas.polygon( :points => points)
+    if x && y && radius
+      atts = {}
+      atts['points'] = points_in_drawing_order.each{|point| point.join(',')}.join(' ')
+      atts['fill'] = attributes[:fill] if attributes.has_key?(:fill)
+      atts['stroke'] = attributes[:stroke] if attributes.has_key?(:stroke)
+      atts['stroke-width'] = attributes[:stroke_width] if attributes.has_key?(:stroke_width)
+
+      canvas.polygon( atts )
+    end
   end
 end