Class: PerfectShape::Path

Inherits:
Shape
  • Object
show all
Includes:
MultiPoint
Defined in:
lib/perfect_shape/path.rb

Constant Summary collapse

SHAPE_TYPES =

Available class types for path shapes

[Array, PerfectShape::Point, PerfectShape::Line, PerfectShape::QuadraticBezierCurve, PerfectShape::CubicBezierCurve, PerfectShape::Arc, PerfectShape::Ellipse, PerfectShape::Circle]
WINDING_RULES =

Available winding rules

[:wind_even_odd, :wind_non_zero]

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from MultiPoint

#max_x, #max_y, #min_x, #min_y, normalize_point_array

Methods inherited from Shape

#==, #bounding_box, #center_point, #center_x, #center_y, #height, #max_x, #max_y, #min_x, #min_y, #width

Constructor Details

#initialize(shapes: [], closed: false, winding_rule: :wind_even_odd, line_to_complex_shapes: false) ⇒ Path

Constructs Path with winding rule, closed status, line_to_complex_shapes option, and shapes (must always start with PerfectShape::Point or Array of [x,y] coordinates) Shape class types can be any of SHAPE_TYPES: Array (x,y coordinates), PerfectShape::Point, PerfectShape::Line, PerfectShape::QuadraticBezierCurve, PerfectShape::CubicBezierCurve PerfectShape::Arc, PerfectShape::Ellipse, or PerfectShape::Circle Complex shapes, meaning Arc, Ellipse, and Circle, are decomposed into basic path shapes, meaning Point, Line, QuadraticBezierCurve, and CubicBezierCurve. winding_rule can be any of WINDING_RULES: :wind_non_zero (default) or :wind_even_odd closed can be true or false (default) line_to_complex_shapes can be true or false (default), indicating whether to connect to complex shapes, meaning Arc, Ellipse, and Circle, with a line, or otherwise move to their start point instead.



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# File 'lib/perfect_shape/path.rb', line 53

def initialize(shapes: [], closed: false, winding_rule: :wind_even_odd, line_to_complex_shapes: false)
  self.closed = closed
  self.winding_rule = winding_rule
  self.shapes = shapes
  self.line_to_complex_shapes = line_to_complex_shapes
end

Instance Attribute Details

#closed ⇒ Object Also known as: closed?

Returns the value of attribute closed.



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# File 'lib/perfect_shape/path.rb', line 41

def closed
  @closed
end

#line_to_complex_shapes ⇒ Object Also known as: line_to_complex_shapes?

Returns the value of attribute line_to_complex_shapes.



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# File 'lib/perfect_shape/path.rb', line 41

def line_to_complex_shapes
  @line_to_complex_shapes
end

#shapes ⇒ Object

Returns the value of attribute shapes.



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# File 'lib/perfect_shape/path.rb', line 41

def shapes
  @shapes
end

#winding_rule ⇒ Object

Returns the value of attribute winding_rule.



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# File 'lib/perfect_shape/path.rb', line 40

def winding_rule
  @winding_rule
end

Instance Method Details

#basic_shapes ⇒ Object

Returns basic shapes (i.e. Point, Line, QuadraticBezierCurve, and CubicBezierCurve), decomposed from complex shapes like Arc, Ellipse, and Circle by calling their ‘#to_path_shapes` method



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# File 'lib/perfect_shape/path.rb', line 384

def basic_shapes
  the_shapes = []
  @shapes.each do |shape|
    if shape.respond_to?(:to_path_shapes)
      shape_basic_shapes = shape.to_path_shapes
      if @line_to_complex_shapes
        first_basic_shape = shape_basic_shapes.shift
        new_first_basic_shape = PerfectShape::Line.new(points: [first_basic_shape.to_a])
        shape_basic_shapes.unshift(new_first_basic_shape)
      end
      the_shapes += shape_basic_shapes
    else
      the_shapes << shape
    end
  end
  the_shapes
end

#contain?(x_or_point, y = nil, outline: false, distance_tolerance: 0) ⇒ Boolean

Checks if path contains point (two-number Array or x, y args) using the Nonzero-Rule (aka Winding Number Algorithm): en.wikipedia.org/wiki/Nonzero-rule or using the Even-Odd Rule (aka Ray Casting Algorithm): en.wikipedia.org/wiki/Even%E2%80%93odd_rule

the path or false if the point lies outside of the path’s bounds.

Parameters:

  • x —

    The X coordinate of the point to test.

  • y (defaults to: nil) —

    The Y coordinate of the point to test.

Returns:

  • (Boolean) —

    true if the point lies within the bound of



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# File 'lib/perfect_shape/path.rb', line 122

def contain?(x_or_point, y = nil, outline: false, distance_tolerance: 0)
  x, y = Point.normalize_point(x_or_point, y)
  return unless x && y
  
  if outline
    disconnected_shapes.any? {|shape| shape.contain?(x, y, outline: true, distance_tolerance: distance_tolerance) }
  else
    if (x * 0.0 + y * 0.0) == 0.0
      # N * 0.0 is 0.0 only if N is finite.
      # Here we know that both x and y are finite.
      return false if shapes.count < 2
      mask = winding_rule == :wind_non_zero ? -1 : 1
      (point_crossings(x, y) & mask) != 0
    else
      # Either x or y was infinite or NaN.
      # A NaN always produces a negative response to any test
      # and Infinity values cannot be "inside" any path so
      # they should return false as well.
      false
    end
  end
end

#disconnected_shapes ⇒ Object

Disconnected shapes have their start point filled in so that each shape does not depend on the previous shape to determine its start point.

Also, if a point is followed by a non-point shape, it is removed since it is augmented to the following shape as its start point.

Lastly, if the path is closed, an extra shape is added to represent the line connecting the last point to the first



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# File 'lib/perfect_shape/path.rb', line 241

def disconnected_shapes
  initial_point = start_point = basic_shapes.first.to_a.map {|n| BigDecimal(n.to_s)}
  final_point = nil
  the_disconnected_shapes = basic_shapes.drop(1).map do |shape|
    case shape
    when Point
      disconnected_shape = Point.new(*shape.to_a)
      start_point = shape.to_a
      final_point = disconnected_shape.to_a
      nil
    when Array
      disconnected_shape = Point.new(*shape.map {|n| BigDecimal(n.to_s)})
      start_point = shape.map {|n| BigDecimal(n.to_s)}
      final_point = disconnected_shape.to_a
      nil
    when Line
      disconnected_shape = Line.new(points: [start_point.to_a, shape.points.last])
      start_point = shape.points.last.to_a
      final_point = disconnected_shape.points.last.to_a
      disconnected_shape
    when QuadraticBezierCurve
      disconnected_shape = QuadraticBezierCurve.new(points: [start_point.to_a] + shape.points)
      start_point = shape.points.last.to_a
      final_point = disconnected_shape.points.last.to_a
      disconnected_shape
    when CubicBezierCurve
      disconnected_shape = CubicBezierCurve.new(points: [start_point.to_a] + shape.points)
      start_point = shape.points.last.to_a
      final_point = disconnected_shape.points.last.to_a
      disconnected_shape
    end
  end
  the_disconnected_shapes << Line.new(points: [final_point, initial_point]) if closed?
  the_disconnected_shapes.compact
end

#drawing_types ⇒ Object 



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# File 'lib/perfect_shape/path.rb', line 88

def drawing_types
  the_drawing_shapes = basic_shapes.map do |shape|
    case shape
    when Point
      :move_to
    when Array
      :move_to
    when Line
      :line_to
    when QuadraticBezierCurve
      :quad_to
    when CubicBezierCurve
      :cubic_to
    end
  end
  the_drawing_shapes << :close if closed?
  the_drawing_shapes
end

#intersect?(rectangle) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/perfect_shape/path.rb', line 277

def intersect?(rectangle)
  x = rectangle.x
  y = rectangle.y
  w = rectangle.width
  h = rectangle.height
  # [xy]+[wh] is NaN if any of those values are NaN,
  # or if adding the two together would produce NaN
  # by virtue of adding opposing Infinte values.
  # Since we need to add them below, their sum must
  # not be NaN.
  # We return false because NaN always produces a
  # negative response to tests
  return false if (x+w).nan? || (y+h).nan?
  return false if w <= 0 || h <= 0
  mask = winding_rule == :wind_non_zero ? -1 : 2
  crossings = rect_crossings(x, y, x+w, y+h)
  crossings == PerfectShape::Rectangle::RECT_INTERSECTS ||
    (crossings & mask) != 0
end

#point_crossings(x_or_point, y = nil) ⇒ Object

Calculates the number of times the given path crosses the ray extending to the right from (x,y). If the point lies on a part of the path, then no crossings are counted for that intersection. +1 is added for each crossing where the Y coordinate is increasing -1 is added for each crossing where the Y coordinate is decreasing The return value is the sum of all crossings for every segment in the path. The path must start with a PerfectShape::Point (initial location) The caller must check for NaN values. The caller may also reject infinite values as well.



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# File 'lib/perfect_shape/path.rb', line 156

def point_crossings(x_or_point, y = nil)
  x, y = Point.normalize_point(x_or_point, y)
  return unless x && y
  return 0 if shapes.count == 0
  movx = movy = curx = cury = endx = endy = 0
  coords = points.flatten
  curx = movx = coords[0]
  cury = movy = coords[1]
  crossings = 0
  ci = 2
  1.upto(shapes.count - 1).each do |i|
    case drawing_types[i]
    when :move_to
      if cury != movy
        line = PerfectShape::Line.new(points: [[curx, cury], [movx, movy]])
        crossings += line.point_crossings(x, y)
      end
      movx = curx = coords[ci]
      ci += 1
      movy = cury = coords[ci]
      ci += 1
    when :line_to
      endx = coords[ci]
      ci += 1
      endy = coords[ci]
      ci += 1
      line = PerfectShape::Line.new(points: [[curx, cury], [endx, endy]])
      crossings += line.point_crossings(x, y)
      curx = endx
      cury = endy
    when :quad_to
      quad_ctrlx = coords[ci]
      ci += 1
      quad_ctrly = coords[ci]
      ci += 1
      endx = coords[ci]
      ci += 1
      endy = coords[ci]
      ci += 1
      quad = PerfectShape::QuadraticBezierCurve.new(points: [[curx, cury], [quad_ctrlx, quad_ctrly], [endx, endy]])
      crossings += quad.point_crossings(x, y)
      curx = endx
      cury = endy
    when :cubic_to
      cubic_ctrl1x = coords[ci]
      ci += 1
      cubic_ctrl1y = coords[ci]
      ci += 1
      cubic_ctrl2x = coords[ci]
      ci += 1
      cubic_ctrl2y = coords[ci]
      ci += 1
      endx = coords[ci]
      ci += 1
      endy = coords[ci]
      ci += 1
      cubic = PerfectShape::CubicBezierCurve.new(points: [[curx, cury], [cubic_ctrl1x, cubic_ctrl1y], [cubic_ctrl2x, cubic_ctrl2y], [endx, endy]])
      crossings += cubic.point_crossings(x, y)
      curx = endx
      cury = endy
    when :close
      if cury != movy
        line = PerfectShape::Line.new(points: [[curx, cury], [movx, movy]])
        crossings += line.point_crossings(x, y)
      end
      curx = movx
      cury = movy
    end
  end
  if cury != movy
    line = PerfectShape::Line.new(points: [[curx, cury], [movx, movy]])
    crossings += line.point_crossings(x, y)
  end
  crossings
end

#points ⇒ Object 



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# File 'lib/perfect_shape/path.rb', line 60

def points
  the_points = []
  basic_shapes.each do |shape|
    case shape
    when Point
      the_points << shape.to_a
    when Array
      the_points << shape.map {|n| BigDecimal(n.to_s)}
    when Line
      the_points << shape.points.last.to_a
    when QuadraticBezierCurve
      shape.points.each do |point|
        the_points << point.to_a
      end
    when CubicBezierCurve
      shape.points.each do |point|
        the_points << point.to_a
      end
    end
  end
  the_points << basic_shapes.first.to_a if closed?
  the_points
end

#points=(some_points) ⇒ Object 



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# File 'lib/perfect_shape/path.rb', line 84

def points=(some_points)
  raise "Cannot assign points directly! Must set shapes instead and points are calculated from them automatically."
end

#rect_crossings(rxmin, rymin, rxmax, rymax) ⇒ Object 



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# File 'lib/perfect_shape/path.rb', line 297

def rect_crossings(rxmin, rymin, rxmax, rymax)
  numTypes = drawing_types.count
  return 0 if numTypes == 0
  coords = points.flatten
  curx = cury = movx = movy = endx = endy = nil
  curx = movx = coords[0]
  cury = movy = coords[1]
  crossings = 0
  ci = 2
  i = 1
  
  while crossings != PerfectShape::Rectangle::RECT_INTERSECTS && i < numTypes
    case drawing_types[i]
    when :move_to
      if curx != movx || cury != movy
        line = PerfectShape::Line.new(points: [curx, cury, movx, movy])
        crossings = line.rect_crossings(rxmin, rymin, rxmax, rymax, crossings)
      end
      # Count should always be a multiple of 2 here.
      # assert((crossings & 1) != 0)
      movx = curx = coords[ci]
      ci += 1
      movy = cury = coords[ci]
      ci += 1
    when :line_to
      endx = coords[ci]
      ci += 1
      endy = coords[ci]
      ci += 1
      line = PerfectShape::Line.new(points: [curx, cury, endx, endy])
      crossings = line.rect_crossings(rxmin, rymin, rxmax, rymax, crossings)
      curx = endx
      cury = endy
    when :quad_to
      cx = coords[ci]
      ci += 1
      cy = coords[ci]
      ci += 1
      endx = coords[ci]
      ci += 1
      endy = coords[ci]
      ci += 1
      quadratic_bezier_curve = PerfectShape::QuadraticBezierCurve.new(points: [curx, cury, cx, cy, endx, endy])
      crossings = quadratic_bezier_curve.rect_crossings(rxmin, rymin, rxmax, rymax, 0, crossings)
      curx = endx
      cury = endy
    when :cubic_to
      c1x = coords[ci]
      ci += 1
      c1y = coords[ci]
      ci += 1
      c2x = coords[ci]
      ci += 1
      c2y = coords[ci]
      ci += 1
      endx = coords[ci]
      ci += 1
      endy = coords[ci]
      ci += 1
      cubic_bezier_curve = PerfectShape::CubicBezierCurve.new(points: [curx, cury, c1x, c1y, c2x, c2y, endx, endy])
      crossings = cubic_bezier_curve.rect_crossings(rxmin, rymin, rxmax, rymax, 0, crossings)
      curx = endx
      cury = endy
    when :close
      if curx != movx || cury != movy
        line = PerfectShape::Line.new(points: [curx, cury, movx, movy])
        crossings = line.rect_crossings(rxmin, rymin, rxmax, rymax, crossings)
      end
      curx = movx
      cury = movy
      # Count should always be a multiple of 2 here.
      # assert((crossings & 1) != 0)
    end
    i += 1
  end
  if crossings != PerfectShape::Rectangle::RECT_INTERSECTS &&
    (curx != movx || cury != movy)
    line = PerfectShape::Line.new(points: [curx, cury, movx, movy])
    crossings = line.rect_crossings(rxmin, rymin, rxmax, rymax, crossings)
  end
  # Count should always be a multiple of 2 here.
  # assert((crossings & 1) != 0)
  crossings
end