Class: Autocad::BoundingBox

Inherits:
Object
  • Object
show all
Defined in:
lib/autocad/bounding_box.rb

Overview

A BoundingBox represents a bounding box around a picture.

A bounding box also defines a local coordinate system for a picture. The bounding box must contain the origin of the coordinate system. However the origin need not be centered within the box.

No particular guarantees are made about the tightness of the bounding box, though it can assumed to be reasonably tight.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(left, top, right, bottom) ⇒ BoundingBox

Returns a new instance of BoundingBox.



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# File 'lib/autocad/bounding_box.rb', line 40

def initialize(left, top, right, bottom)
  @left = left
  @top = top
  @right = right
  @bottom = bottom
end

Instance Attribute Details

#bottom ⇒ Object (readonly)

Returns the value of attribute bottom.



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# File 'lib/autocad/bounding_box.rb', line 38

def bottom
  @bottom
end

#left ⇒ Object (readonly)

Returns the value of attribute left.



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# File 'lib/autocad/bounding_box.rb', line 38

def left
  @left
end

#right ⇒ Object (readonly)

Returns the value of attribute right.



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# File 'lib/autocad/bounding_box.rb', line 38

def right
  @right
end

#top ⇒ Object (readonly)

Returns the value of attribute top.



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# File 'lib/autocad/bounding_box.rb', line 38

def top
  @top
end

Class Method Details

.centered(width, height) ⇒ Object

Create a BoundingBox with the given width and height and the origin centered within the box.



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# File 'lib/autocad/bounding_box.rb', line 18

def centered(width, height)
  w = width / 2.0
  h = height / 2.0
  new(-w, h, w, -h)
end

.empty ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 12

def empty
  new(0, 0, 0, 0)
end

.from_min_max(min_pt, max_pt) ⇒ Object

Create a BoundingBox from minimum and maximum points



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# File 'lib/autocad/bounding_box.rb', line 25

def from_min_max(min_pt, max_pt)
  min_pt = Point3d.new(min_pt)
  max_pt = Point3d.new(max_pt)

  new(
    min_pt.x,  # left
    max_pt.y,  # top
    max_pt.x,  # right
    min_pt.y   # bottom
  )
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 59

def ==(other)
  return false unless other.is_a?(BoundingBox)

  left.round(6) == other.left.round(6) &&
    top.round(6) == other.top.round(6) &&
    right.round(6) == other.right.round(6) &&
    bottom.round(6) == other.bottom.round(6)
end

#above(other) ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 114

def above(other)
  self.class.new(
    [left, other.left].min,
    (height + other.height) / 2.0,
    [right, other.right].max,
    -(height + other.height) / 2.0
  )
end

#at(point) ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 133

def at(point)
  x = point.x
  y = point.y

  new_left = [left + x, 0].min
  new_top = [top + y, 0].max
  new_right = [right + x, 0].max
  new_bottom = [bottom + y, 0].min

  self.class.new(new_left, new_top, new_right, new_bottom)
end

#at_landmark(landmark) ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 145

def at_landmark(landmark)
  at(eval(landmark))
end

#beside(other) ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 105

def beside(other)
  self.class.new(
    -(width + other.width) / 2.0,
    [top, other.top].max,
    (width + other.width) / 2.0,
    [bottom, other.bottom].min
  )
end

#center ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 80

def center
  Point3d.new((left + right) / 2.0, (top + bottom) / 2.0, 0)
end

#contains?(pt) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/autocad/bounding_box.rb', line 84

def contains?(pt)
  pt.x >= left && pt.x <= right && pt.y >= bottom && pt.y <= top
end

#enclose(point) ⇒ Object

Expand bounding box to enclose the given Point



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# File 'lib/autocad/bounding_box.rb', line 169

def enclose(point)
  self.class.new(
    [left, point.x].min,
    [top, point.y].max,
    [right, point.x].max,
    [bottom, point.y].min
  )
end

#eql?(other) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/autocad/bounding_box.rb', line 51

def eql?(other)
  other.class == self.class &&
    other.left == left &&
    other.top == top &&
    other.right == right &&
    other.bottom == bottom
end

#eval(landmark) ⇒ Object

Evaluate the landmark relative to the origin of this bounding box, returning the location described by the landmark.



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# File 'lib/autocad/bounding_box.rb', line 125

def eval(landmark)
  Point3d.new(
    landmark.x.eval(left, right),
    landmark.y.eval(bottom, top),
    0
  )
end

#expand(expansion) ⇒ Object

Add expansion to all sides of this bounding box



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# File 'lib/autocad/bounding_box.rb', line 185

def expand(expansion)
  self.class.new(
    left - expansion,
    top + expansion,
    right + expansion,
    bottom - expansion
  )
end

#hash ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 47

def hash
  [self.class, left, top, right, bottom].hash
end

#height ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 92

def height
  top - bottom
end

#lower_left ⇒ Object Also known as: bottom_left 



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# File 'lib/autocad/bounding_box.rb', line 74

def lower_left
  Point3d.new(left, bottom, 0)
end

#on(other) ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 96

def on(other)
  self.class.new(
    [left, other.left].min,
    [top, other.top].max,
    [right, other.right].max,
    [bottom, other.bottom].min
  )
end

#origin_at(point) ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 149

def origin_at(point)
  # Vector maths to work out where the edges of the bounding box lie in
  # relation to the new origin
  new_top_left = Point3d.new(left, top, 0) - point
  new_bottom_right = Point3d.new(right, bottom, 0) - point

  # Make sure the bounding box includes the origin
  new_left = [new_top_left.x, 0].min
  new_top = [new_top_left.y, 0].max
  new_right = [new_bottom_right.x, 0].max
  new_bottom = [new_bottom_right.y, 0].min

  self.class.new(new_left, new_top, new_right, new_bottom)
end

#origin_at_landmark(landmark) ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 164

def origin_at_landmark(landmark)
  origin_at(eval(landmark))
end

#scale_to_fit(bb) ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 178

def scale_to_fit(bb)
  return 1 if bb.width == 0 || bb.height == 0

  [width / bb.width, height / bb.height].min
end

#transform(transform) ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 194

def transform(transform)
  self.class.empty
    .enclose(transform.call(Point3d.new(left, top, 0)))
    .enclose(transform.call(Point3d.new(right, top, 0)))
    .enclose(transform.call(Point3d.new(left, bottom, 0)))
    .enclose(transform.call(Point3d.new(right, bottom, 0)))
end

#upper_right ⇒ Object Also known as: top_right 



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# File 'lib/autocad/bounding_box.rb', line 68

def upper_right
  Point3d.new(right, top, 0)
end

#width ⇒ Object 



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# File 'lib/autocad/bounding_box.rb', line 88

def width
  right - left
end