Class: Geometry::RegularPolygon

Inherits:
Polygon show all
Defined in:
lib/geometry/regular_polygon.rb

Overview

A RegularPolygon is a lot like a Polygon, but more regular.

http://en.wikipedia.org/wiki/Regular_polygon

Usage

polygon = Geometry::RegularPolygon.new sides:4, center:[1,2], radius:3
polygon = Geometry::RegularPolygon.new sides:6, center:[1,2], diameter:6

polygon = Geometry::RegularPolygon.new sides:4, center:[1,2], inradius:3
polygon = Geometry::RegularPolygon.new sides:6, center:[1,2], indiameter:6

Accessors collapse

Instance Attribute Summary collapse

Accessors collapse

Instance Method Summary collapse

Methods inherited from Polygon

#<=>, #clockwise?, #close, #convex, #outset, #outset_bisectors, #reverse, #reverse!, #spokes, #union, #wrap

Methods inherited from Polyline

#bisectors, #close, #close!, #left_bisectors, #offset, #reverse, #reverse!, #right_bisectors, #rightset, #spokes

Constructor Details

#new(sides, center, radius) ⇒ RegularPolygon #new(sides, center, inradius) ⇒ RegularPolygon #new(sides, center, diameter) ⇒ RegularPolygon #new(sides, center, indiameter) ⇒ RegularPolygon

Returns A new Geometry::RegularPolygon object.

Overloads:

Raises:

  • (ArgumentError) 


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# File 'lib/geometry/regular_polygon.rb', line 45

def initialize(edge_count:nil, sides:nil, center:nil, radius:nil, diameter:nil, indiameter:nil, inradius:nil)
    @edge_count = edge_count || sides
    raise ArgumentError, "RegularPolygon requires an edge count" unless @edge_count

    raise ArgumentError, "RegularPolygon.new requires a radius or a diameter" unless diameter || indiameter || inradius || radius

    @center = center ? Point[center] : Point.zero
    @diameter = diameter
    @indiameter = indiameter
    @inradius = inradius
    @radius = radius
end

Instance Attribute Details

#center ⇒ Point (readonly)

Returns The Geometry::RegularPolygon‘s center point.

Returns:



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# File 'lib/geometry/regular_polygon.rb', line 19

def center
  @center
end

#diameter ⇒ Object (readonly) Also known as: circumdiameter 



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# File 'lib/geometry/regular_polygon.rb', line 77

def diameter
    @diameter || (@radius && 2*@radius) || (@indiameter && @indiameter/cosine_half_angle)
end

#edge_count ⇒ Number (readonly)

Returns The Geometry::RegularPolygon‘s number of sides.

Returns:



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# File 'lib/geometry/regular_polygon.rb', line 22

def edge_count
  @edge_count
end

#indiameter ⇒ Object 



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# File 'lib/geometry/regular_polygon.rb', line 112

def indiameter
    @indiameter || (@inradius && 2*@inradius) || (@diameter && (@diameter * cosine_half_angle)) || (@radius && (2 * @radius * cosine_half_angle))
end

#inradius ⇒ Object Also known as: apothem 



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# File 'lib/geometry/regular_polygon.rb', line 118

def inradius
    @inradius || (@indiameter && @indiameter/2) || (@radius && (@radius * cosine_half_angle))
end

#radius ⇒ Number (readonly) Also known as: circumradius

Returns The Geometry::RegularPolygon‘s radius.

Returns:



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# File 'lib/geometry/regular_polygon.rb', line 125

def radius
    @radius || (@diameter && @diameter/2) || (@inradius && (@inradius / cosine_half_angle)) || (@indiameter && @indiameter/cosine_half_angle/2)
end

#side_length ⇒ Object (readonly) 



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# File 'lib/geometry/regular_polygon.rb', line 132

def side_length
    2 * circumradius * Math.sin(Math::PI/edge_count)
end

Instance Method Details

#bounds ⇒ Rectangle

Returns The smallest axis-aligned Geometry::Rectangle that bounds the receiver.

Returns:



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# File 'lib/geometry/regular_polygon.rb', line 71

def bounds
    return Rectangle.new(self.min, self.max)
end

#closed? ⇒ True

Check to see if the Polygon is closed (always true)

Returns:

  • (True) —

    Always true because a Polygon is always closed



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# File 'lib/geometry/regular_polygon.rb', line 65

def closed?
    true
end

#edges ⇒ Object

!@attribute [r] edges



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# File 'lib/geometry/regular_polygon.rb', line 83

def edges
    points = self.vertices
    points.each_cons(2).map {|p1,p2| Edge.new(p1,p2) } + [Edge.new(points.last, points.first)]
end

#eql?(other) ⇒ Boolean Also known as: ==

Returns:

  • (Boolean) 


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# File 'lib/geometry/regular_polygon.rb', line 58

def eql?(other)
    (self.center == other.center) && (self.edge_count == other.edge_count) && (self.radius == other.radius)
end

#max ⇒ Point

Returns The upper right corner of the bounding Geometry::Rectangle.

Returns:



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# File 'lib/geometry/regular_polygon.rb', line 96

def max
    @center+Point[radius, radius]
end

#min ⇒ Point

Returns The lower left corner of the bounding Geometry::Rectangle.

Returns:



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# File 'lib/geometry/regular_polygon.rb', line 101

def min
    @center-Point[radius, radius]
end

#minmax ⇒ Array<Point>

Returns The lower left and upper right corners of the bounding Geometry::Rectangle.

Returns:



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# File 'lib/geometry/regular_polygon.rb', line 106

def minmax
    [self.min, self.max]
end

#vertices ⇒ Object Also known as: points

!@attribute [r] vertices

@return [Array]



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# File 'lib/geometry/regular_polygon.rb', line 90

def vertices
    (0...2*Math::PI).step(2*Math::PI/edge_count).map {|angle| center + Point[Math::cos(angle), Math::sin(angle)]*radius }
end