Class: Scruffy::Layers::PieSlice

Inherits:
Base
  • Object
show all
Defined in:
lib/scruffy/layers/pie_slice.rb

Overview

Scruffy::Layers::PieSlice

Author

A.J. Ostman

Date

August 14th, 2006

Basic Pie Chart Slice..

Constant Summary collapse

RADIANS =

Setup Constants

Math::PI / 180
MARKER_OFFSET_RATIO = 
1.2
MARKER_FONT_SIZE = 
6

Instance Attribute Summary collapse

Attributes inherited from Base

#color, #complexity, #height, #max_value, #min_value, #opacity, #options, #points, #preferred_color, #relevant_data, #title, #width

Instance Method Summary collapse

Methods inherited from Base

#bottom_value, #initialize, #legend_data, #relevant_data?, #render, #sum_values, #top_value

Constructor Details

This class inherits a constructor from Scruffy::Layers::Base

Instance Attribute Details

#center_x ⇒ Object

Returns the value of attribute center_x.



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# File 'lib/scruffy/layers/pie_slice.rb', line 20

def center_x
  @center_x
end

#center_y ⇒ Object

Returns the value of attribute center_y.



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# File 'lib/scruffy/layers/pie_slice.rb', line 20

def center_y
  @center_y
end

#degree_offset ⇒ Object

Returns the value of attribute degree_offset.



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# File 'lib/scruffy/layers/pie_slice.rb', line 18

def degree_offset
  @degree_offset
end

#diameter ⇒ Object

Returns the value of attribute diameter.



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# File 'lib/scruffy/layers/pie_slice.rb', line 16

def diameter
  @diameter
end

#percent_used ⇒ Object

Returns the value of attribute percent_used.



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# File 'lib/scruffy/layers/pie_slice.rb', line 17

def percent_used
  @percent_used
end

#scaler ⇒ Object

Returns the value of attribute scaler.



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# File 'lib/scruffy/layers/pie_slice.rb', line 19

def scaler
  @scaler
end

Instance Method Details

#draw(svg, coords, options = {}) ⇒ Object 



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# File 'lib/scruffy/layers/pie_slice.rb', line 22

def draw(svg, coords, options = {})
  # Scaler is the multiplier to normalize the values to a percentage across
  # the Pie Chart
  @scaler = options[:scaler] || 1
  
  # Degree Offset is degrees by which the pie chart is twisted when it
  # begins
  @degree_offset = options[:degree_offset] || @options[:degree_offset] || 0
  
  # Percent Used keeps track of where in the pie chart we are
  @percent_used = options[:percent_used] || @options[:percent_used] || 0
  
  # Diameter of the pie chart defaults to 80% of the height
  @diameter = relative(options[:diameter]) || relative(@options[:diameter]) || relative(80.0)
  
  # Stroke
  stroke = options[:stroke] || @options[:stroke] || "none"

  # Shadow
  shadow = options[:shadow] || @options[:shadow_] || false
  shadow_x = relative(options[:shadow_x]) || relative(@options[:shadow_x]) || relative(-0.5)
  shadow_y = relative(options[:shadow_y]) || relative(@options[:shadow_y]) || relative(0.5)
  shadow_color = options[:shadow_color] || @options[:shadow_color] || "white"
  shadow_opacity = options[:shadow_opacity] || @options[:shadow_opacity] || 0.06
  
  # Coordinates for the center of the pie chart.
  @center_x = relative_width(options[:center_x]) || relative_width(@options[:center_x]) || relative_width(50)
  @center_y = relative_height(options[:center_y]) || relative_height(@options[:center_y]) || relative_height(50)
  radius = @diameter / 2.0
  
  # Graphing calculated using percent of graph. We later multiply by 3.6 to
  # convert to 360 degree system.
  percent = @scaler * sum_values
  

  # Calculate the Radian Start Point
  radians_start = ((@percent_used * 3.6) + @degree_offset) * RADIANS
  # Calculate the Radian End Point
  radians_end = ((@percent_used + percent) * 3.6 + @degree_offset) * RADIANS

  radians_mid_point = radians_start + ((radians_end - radians_start) / 2)
  
  if options[:explode]
    @center_x = @center_x + (Math.sin(radians_mid_point) * relative(options[:explode]))
    @center_y = @center_y - (Math.cos(radians_mid_point) * relative(options[:explode]))
  end
  

  # Calculate the beginning coordinates
  x_start = @center_x + (Math.sin(radians_start) * radius)
  y_start = @center_y - (Math.cos(radians_start) * radius)
  
  # Calculate the End Coords
  x_end = @center_x + (Math.sin(radians_end) * radius)
  y_end = @center_y - (Math.cos(radians_end) * radius)

  

  # If percentage is really really close to 100% then draw a circle instead!
  if percent >= 99.9999
    
    if shadow
      svg.circle(:cx => "#{@center_x + shadow_x}", :cy => "#{@center_y + shadow_y}", :r=>"#{radius}",:stroke => "none", 
        :fill => shadow_color.to_s,  :style => "fill-opacity: #{shadow_opacity.to_s};")
    end
    
    svg.circle(:cx => "#{@center_x}", :cy => "#{@center_y}", :r=>"#{radius}",:stroke => stroke, :fill => color.to_s)

  else  
    if shadow
      svg.path(:d =>  "M#{@center_x + shadow_x},#{@center_y + shadow_y} L#{x_start + shadow_x},#{y_start + shadow_y} A#{radius},#{radius} 0, #{percent >= 50 ? '1' : '0'}, 1, #{x_end + shadow_x} #{y_end + shadow_y} Z", 
        :fill => shadow_color.to_s, :style => "fill-opacity: #{shadow_opacity.to_s};")
    end
    
    svg.path(:d =>  "M#{@center_x},#{@center_y} L#{x_start},#{y_start} A#{radius},#{radius} 0, #{percent >= 50 ? '1' : '0'}, 1, #{x_end} #{y_end} Z", 
      :stroke => stroke, :fill => color.to_s)
  end
  
  text_x = @center_x + (Math.sin(radians_mid_point) * radius * MARKER_OFFSET_RATIO)
  text_y = @center_y - (Math.cos(radians_mid_point) * radius * MARKER_OFFSET_RATIO)

  svg.text("#{sprintf('%d', percent)}%",
    :x => text_x,
    :y => text_y + relative(MARKER_FONT_SIZE / 2), 
    'font-size' => relative(MARKER_FONT_SIZE),
    'font-family' => options[:theme].font_family,
    :fill => (options[:theme].marker || 'black').to_s, 
    'text-anchor' => 'middle')
end