Class: VectorSalad::StandardShapes::Circle

Inherits:

BasicShape

• Object
• BasicShape
• VectorSalad::StandardShapes::Circle

show all

Includes:

Mixins::At

Defined in:

lib/vector_salad/standard_shapes/circle.rb,
lib/vector_salad/exporters/svg_exporter.rb

Overview

Instance Attribute Summary (collapse)

• - (Object) options inherited from BasicShape

  Returns the value of attribute options.

• - (Object) radius readonly

  Returns the value of attribute radius.

Instance Method Summary (collapse)

• - (Any) [](x, y) included from Mixins::At

  Set the x, y coordinates of the shape.

• - (Coords) at included from Mixins::At

  Get the x, y coordinates of the shape.

• - (Any) at=(at) included from Mixins::At

  Set the x, y coordinates of the shape directly.

• - (Circle) initialize(radius, **options) constructor

  Create a perfectly round circle.

• - (Any) move(x, y) included from Mixins::At

  Move the shape relatively.

• - (Object) to_path

  Convert the shape to a path.

• - (Path) to_simple_path(fn = nil)

  Flatten the circle into many small straight line segments.

• - (Object) to_svg

  Export the shape to an svg string.

new(100)

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# File 'lib/vector_salad/standard_shapes/circle.rb', line 17

def initialize(radius, **options)
  @options = options
  @radius = radius
  @x, @y = 0, 0
  self
end

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# File 'lib/vector_salad/standard_shapes/circle.rb', line 10

def radius
  @radius
end

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# File 'lib/vector_salad/standard_shapes/circle.rb', line 25

def to_path
  # Standard:
  # http://stackoverflow.com/a/13338311
  # c = 4 * (Math.sqrt(2) - 1) / 3
  # c = 0.5522847498307936
  #
  # Better:
  # http://spencermortensen.com/articles/bezier-circle/
  c = 0.551915024494
  d = c * @radius
  Path.new(
    N.n(@x + @radius, @y),
    N.c(@x + @radius, @y + d),
    N.c(@x + d, @y + @radius),
    N.n(@x, @y + @radius),
    N.c(@x - d, @y + @radius),
    N.c(@x - @radius, @y + d),
    N.n(@x - @radius, @y),
    N.c(@x - @radius, @y - d),
    N.c(@x - d, @y - @radius),
    N.n(@x, @y - @radius),
    N.c(@x + d, @y - @radius),
    N.c(@x + @radius, @y - d),
    N.n(@x + @radius, @y),
    **@options
  )
end

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# File 'lib/vector_salad/standard_shapes/circle.rb', line 57

def to_simple_path(fn = nil)
  fn ||= (@radius * 4).ceil

  nodes = []
  arc = (2.0 * Math::PI) / fn
  fn.times do |t|
    a = arc * t
    x = @radius * Math.cos(a) + @x
    y = @radius * Math.sin(a) + @y
    nodes << N.n(x, y)
  end
  Path.new(*nodes, **@options)
end

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# File 'lib/vector_salad/exporters/svg_exporter.rb', line 102

def to_svg
  svg = "<circle cx=\"#{at[0]}\" cy=\"#{at[1]}\" r=\"#{radius}\""
  svg << Exporters::SvgExporter.options(@options)
  svg << "/>"
end