Class: VectorSalad::StandardShapes::Path

Inherits:
BasicShape
  • Object
show all
Defined in:
lib/vector_salad/standard_shapes/path.rb,
lib/vector_salad/exporters/svg_exporter.rb

Overview

The simplest shape primitive, all shapes can be represented as a Path.

Instance Attribute Summary collapse

Attributes inherited from BasicShape

#options

Instance Method Summary collapse

Constructor Details

#initialize(*nodes, closed: true, **options) ⇒ Path

Returns a new instance of Path.



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# File 'lib/vector_salad/standard_shapes/path.rb', line 22

def initialize(*nodes, closed: true, **options)
  @nodes = []
  nodes.each_index do |i|
    node = nodes[i].class == Array ? N.new(*nodes[i]) : nodes[i]
    if i == 0 && ![:node, :g2, :g4, :left, :right].include?(node.type)
      fail "First node in a path must be :node or :spiro type."
    end
    case node.type
    when :cubic
      unless nodes[i - 1].type == :node ||
            (nodes[i - 2].type == :node && nodes[i - 1].type == :cubic)
        fail ":cubic node must follow a :node and at most 1 other :cubic."
      end
    when :quadratic
      unless nodes[i - 1].type == :node
        fail ":quadratic nodes must follow a :node."
      end
    when :mirror
      if nodes[i - 1].type == :node &&
         (nodes[i - 2].type == :quadratic || nodes[i - 2].type == :cubic)
        pivot = nodes[i - 1]
        source = nodes[i - 2]

        dx = pivot.x - source.x
        dy = pivot.y - source.y
        node[pivot.x + dx, pivot.y + dy]

        node.type = source.type
      else
        fail ":reflect nodes must be preceeded by a :node with a
          :quadratic or :cubic before that."
      end
    when :node
    end
    @nodes << node
  end

  @closed = closed
  @options = options
  self
end

Instance Attribute Details

#closed ⇒ Object (readonly)

Returns the value of attribute closed.



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# File 'lib/vector_salad/standard_shapes/path.rb', line 11

def closed
  @closed
end

#nodes ⇒ Object (readonly)

Returns the value of attribute nodes.



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# File 'lib/vector_salad/standard_shapes/path.rb', line 11

def nodes
  @nodes
end

Instance Method Details

#[](x, y) ⇒ Object 



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# File 'lib/vector_salad/standard_shapes/path.rb', line 66

def [](x, y)
  @nodes.map do |node|
    node[x, y]
  end
  self
end

#flip(axis) ⇒ Object 



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# File 'lib/vector_salad/standard_shapes/path.rb', line 104

def flip(axis)
  x = axis == :y ? -1 : 1
  y = axis == :x ? -1 : 1

  Path.new(
    *to_path.nodes.map { |n| N.new(n.x * x, n.y * y, n.type) },
    closed: @closed, **@options
  )
end

#flip_x ⇒ Object 



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# File 'lib/vector_salad/standard_shapes/path.rb', line 87

def flip_x
  flip(:x)
end

#flip_y ⇒ Object 



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# File 'lib/vector_salad/standard_shapes/path.rb', line 93

def flip_y
  flip(:y)
end

#jitter(max, min: 0, fn: nil) ⇒ Object 



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# File 'lib/vector_salad/standard_shapes/path.rb', line 162

def jitter(max, min: 0, fn: nil)
  Path.new(
    *to_simple_path(fn).nodes.map do |n|
      r = Random.rand(min..max)
      a = Random.rand(0..Math::PI * 2)
      x = r * Math.cos(a)
      y = r * Math.sin(a)
      n.move(x, y)
    end, closed: @closed, **@options
  )
end

#move(x, y) ⇒ Object 



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# File 'lib/vector_salad/standard_shapes/path.rb', line 75

def move(x, y)
  Path.new(
    *to_path.nodes.map do |node|
      node.move(x, y)
    end,
    closed: @closed,
    **@options
  )
end

#rotate(angle) ⇒ Object 



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# File 'lib/vector_salad/standard_shapes/path.rb', line 121

def rotate(angle)
  theta = angle / 180.0 * Math::PI

  # http://stackoverflow.com/a/786508
  # p'x = cos(theta) * (px-ox) - sin(theta) * (py-oy) + ox
  # p'y = sin(theta) * (px-ox) + cos(theta) * (py-oy) + oy
  Path.new(
    *to_path.nodes.map do |n|
      N.new(
        Math.cos(theta) * n.x - Math.sin(theta) * n.y,
        Math.sin(theta) * n.x + Math.cos(theta) * n.y,
        n.type
      )
    end, closed: @closed, **@options
  )
end

#scale(x_multiplier, y_multiplier = x_multiplier) ⇒ Object 



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# File 'lib/vector_salad/standard_shapes/path.rb', line 144

def scale(x_multiplier, y_multiplier = x_multiplier)
  Path.new(
    *to_path.nodes.map do |n|
      N.new(
        n.x * x_multiplier,
        n.y * y_multiplier,
        n.type
      )
    end, closed: @closed, **@options
  )
end

#to_a ⇒ Object

Return the nodes as an array of coordinates.



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# File 'lib/vector_salad/standard_shapes/path.rb', line 267

def to_a
  nodes.map(&:at)
end

#to_bezier_path ⇒ Object

Convert the complex path to a bezier path. This will convert any Spiro curve nodes into beziers.



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# File 'lib/vector_salad/standard_shapes/path.rb', line 181

def to_bezier_path
  path = to_path
  spiro = false
  flat_path = path.nodes.map do |n|
    spiro = true if spiro || [:g2, :g4, :left, :right].include?(n.type)
    [n.x, n.y, n.type]
  end
  if spiro
    flat_spline_path = Spiro.spiros_to_splines(flat_path, @closed)
    if flat_spline_path.nil?
      fail "Spiro failed, try different coordinates or using G2 nodes."
    else
      path = Path.new(*flat_spline_path.map do |n|
        N.new(n[0], n[1], n[2])
      end, closed: @closed, **@options)
    end
  end
  path
end

#to_cubic_path ⇒ Object

Convert the path into a cubic bezier path (no quadratics). This will convert any Spiro curve nodes into beziers and any quadratic beziers into cubics.



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# File 'lib/vector_salad/standard_shapes/path.rb', line 204

def to_cubic_path
  path = to_bezier_path.nodes
  cubic_path = []
  quadratic_last = false
  path.each_index do |i|
    n = path[i]
    if quadratic_last
      n0 = path[i - 2]
      q  = path[i - 1]

      # CP1 = QP0 + 2/3 * (QP1-QP0)
      # CP2 = QP2 + 2/3 * (QP1-QP2)
      third = 2 / 3.0
      cubic_path << N.c(
        n0.x + third * (q.x - n0.x),
        n0.y + third * (q.y - n0.y)
      )
      cubic_path << N.c(
        n.x + third * (q.x - n.x),
        n.y + third * (q.y - n.y)
      )
      cubic_path << n

      quadratic_last = false
    elsif n.type == :quadratic
      quadratic_last = true
    else
      cubic_path << n
    end
  end
  Path.new(*cubic_path, closed: @closed, **@options)
end

#to_multi_path ⇒ Object

Wrap the path in a multi_path.



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# File 'lib/vector_salad/standard_shapes/path.rb', line 262

def to_multi_path
  MultiPath.new(self)
end

#to_path ⇒ Object

Convert the path to a path (it returns self)



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# File 'lib/vector_salad/standard_shapes/path.rb', line 175

def to_path
  self
end

#to_simple_path(*_) ⇒ Object

Flatten any curves in the path into many small straight line segments.



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# File 'lib/vector_salad/standard_shapes/path.rb', line 238

def to_simple_path(*_)
  # convert bezier curves and spiro splines
  path = to_cubic_path.nodes

  nodes = []
  path.each_index do |i|
    case path[i].type
    when :node
      if path[i - 1].type == :cubic
        curve = path[i - 3..i].map(&:at)
        nodes += VectorSalad::Interpolate.new.casteljau(curve)
      else
        nodes << path[i]
      end
    when :cubic
    else
      fail "Only :node and :cubic nodes in a path can be converted
        to a simple path, was #{path[i].type}."
    end
  end
  Path.new(*nodes, closed: @closed, **@options)
end

#to_svg ⇒ Object

Export the shape to an svg string



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# File 'lib/vector_salad/exporters/svg_exporter.rb', line 38

def to_svg
  svg = '<path d="'
  svg << to_svg_d_attribute
  svg << '"'
  svg << VectorSalad::Exporters::SvgExporter.options(@options)
  svg << "/>"
end