Render Part C Assignment

In this studio we will evolve our code from Render_Part_B_Assignment to add new methods and a new class.

Continue editing files in the drawings directory.

Background

Bounds Calculation

We will add support for calculating a bounding box for each of our drawable objects.

We will implement a BoundingBox class (via Struct, if desired) to store the min and max points of a box which bounds the object.

Transformable objects will split the responsibility into two methods, untransformed_bounds and bounds. On the subclasses the untransformed_bounds method will return its object's bounds in the same untransformed space that untransformed_render acts: that is, about its origin. On the Transform superclass, the bounds method will transform the untransformed_bounds by the x and y location (akin to how render transforms the affine matrix via glTranslate to transform the space untransformed_render operates in). The bounds method will not be able to rely on glTranslate. It will need to create a new transformed BoundingBox.

For example, an Ellipse created with an x_radius of 0.3, a y_radius of 0.4, an x location of 0.1, and a y location of 0.2 would produce an untransformed_bounds with a min of (-0.3, -0.4) and a max of (0.3, 0.4). The bounds calculation inherited from Transform would transform the untransformed bounds with the x and y locations, producing a bounding box with a min of (-0.2, -0.2) and a max of (0.4, 0.6).

Code to Implement

BoundingBox

file:	src/main/ruby/drawings/bounding_box.rb
class:	BoundingBox
superclass:	Object
methods:	initialize(min,max) min() min=(min) max() max=(max)

Note: be sure to require_relative 'point2'.

Note: min and max should be instances of Point2.

Note: You may wish to use Ruby's convenient Struct construct.

Transform

file:	src/main/ruby/drawings/transform.rb
class:	Transform
superclass:	Object
methods to evolve:	Ø
methods to add:	move(direction,amount) bounds()
methods to remove:	Ø

move

the move method will accept two parameters: direction and amount.

direction can be one of four symbols

:left
:right
:up
:down

left corresponds to translating along the negative x axis

right corresponds to translating along the positive x axis

down corresponds to translating along the negative y axis

up corresponds to translating along the positive y axis

any other value for direction should raise an ArgumentError.

bounds

invoke untransformed_bounds and transform the returned bounds by x and y.

NOTE: untransformed_bounds is abstract. it must be defined by the subclasses.

Rectangle

file:	src/main/ruby/drawings/rectangle.rb
class:	Rectangle
superclass:	ColorTransform
methods to evolve:	Ø
methods to add:	untransformed_bounds
methods to remove:	Ø

untransformed_bounds

Returns an instance of Bounds specified by min and max instances of Point2.

NOTE: this method must be private.

decorated rendering

Note: the bounding box and minimum and maximum points are only for demonstration here. The should not be drawn in your solution.

Ellipse

file:	src/main/ruby/drawings/ellipse.rb
class:	Ellipse
superclass:	ColorTransform
methods to evolve:	Ø
methods to add:	untransformed_bounds
methods to remove:	Ø

untransformed_bounds

Returns an instance of Bounds specified by min and max instances of Point2.

NOTE: this method must be private.

EquilateralTriangle

file:	src/main/ruby/drawings/equilateral_triangle.rb
class:	EquilateralTriangle
superclass:	ColorTransform
methods to evolve:	Ø
methods to add:	untransformed_bounds
methods to remove:	Ø

untransformed_bounds

Returns an instance of Bounds specified by min and max instances of Point2.

NOTE: this method must be private.

BezierCurve

file:	src/main/ruby/drawings/bezier_curve.rb
class:	BezierCurve
superclass:	ColorTransform
methods to evolve:	Ø
methods to add:	untransformed_bounds
methods to remove:	Ø

untransformed_bounds

Contemplate for a moment how you would build this method and then raise an error and move on.

NOTE: this method must be private.

  def untransformed_bounds
    raise StandardError.new("not yet implemented")
  end

Text

file:	src/main/ruby/drawings/text.rb
class:	Text
superclass:	ColorTransform
methods to evolve:	Ø
methods to add:	untransformed_bounds
methods to remove:	Ø

untransformed_bounds

Contemplate for a moment how you would build this method and then raise an error and move on.

NOTE: this method must be private.

  def untransformed_bounds
    raise StandardError.new("not yet implemented")
  end

CircularSegment

file:	src/main/ruby/drawings/circular_segment.rb
class:	CircularSegment
superclass:	ColorTransform
methods to evolve:	Ø
methods to add:	untransformed_bounds
methods to remove:	Ø

untransformed_bounds

Contemplate for a moment how you would build this method and then raise an error and move on.

NOTE: this method must be private.

  def untransformed_bounds
    raise StandardError.new("not yet implemented")
  end

Image

file:	src/main/ruby/drawings/image.rb
class:	Image
superclass:	Transform
methods to evolve:	Ø
methods to add:	untransformed_bounds
methods to remove:	Ø

untransformed_bounds

Contemplate for a moment how you would build this method and then raise an error and move on.

NOTE: this method must be private.

  def untransformed_bounds
    raise StandardError.new("not yet implemented")
  end

CompositeTransform

file:	src/main/ruby/drawings/composite_transform.rb
class:	CompositeTransform
superclass:	Transform
methods to evolve:	Ø
methods to add:	untransformed_bounds
methods to remove:	Ø

untransformed_bounds

Returns an instance of Bounds specified by min and max instances of Point2.

NOTE: this method must be private.

Scene

file:	src/main/ruby/drawings/scene.rb
class:	Scene
superclass:	Object
methods to evolve:	bounds()
methods to add:	Ø
methods to remove:	Ø

bounds

NOTE: this method must be public.

ConvexPolygon

file:	src/main/ruby/drawings/convex_polygon.rb
class:	ConvexPolygon
superclass:	ColorTransform
methods:	initialize(points, x: 0, y: 0, color: nil) untransformed_render() untransformed_bounds()

Note: You will need to add this file. Starter code:

require_relative 'color_transform'
require_relative 'point2'

class ConvexPolygon < ColorTransform

end

if __FILE__ == $0
  require_relative '../core/render_app'
  points = [
      Point2.new(0.85, 0.0),
      Point2.new(0.1, 0.25),
      Point2.new(0.0, 0.45),
      Point2.new(0.15, 0.7),
      Point2.new(0.65, 1.0),
      Point2.new(0.95, 0.95),
      Point2.new(1.1, 0.75)
  ]
  
  app = RenderApp.new(ConvexPolygon.new(points, x: -0.5, y: -0.5, color: Color.new(1, 0, 0)))
  app.main_loop
end

initialize

Accept a required parameter points which is an array of Point2s.

Accept keyword parameters for x: 0, y: 0, and color: nil to the constructor and pass them to the superclass.

NOTE: Be sure to not override render. Implement the render_transformed method instead.

untransformed_render

NOTE: this method must be private.

untransformed_bounds

NOTE: this method must be private.

file to run:

src/main/ruby/drawings/convex_polygon.rb

Testing Your Solution

Unit Test

Part C

file:

src/test/ruby/drawings/preliminary/part_c/*.rb

UnitTest

note: ensure that you have removed all printing to receive credit for any assignment.

file:

src/test/ruby/drawings/more_comprehensive/part_c/*.rb

UnitTest

note: ensure that you have removed all printing to receive credit for any assignment.

Backwards Compatibility

file:

src/test/ruby/drawings/preliminary/part_b/*.rb

UnitTest

note: ensure that you have removed all printing to receive credit for any assignment.

file:

src/test/ruby/drawings/preliminary/part_a/*.rb

UnitTest

note: ensure that you have removed all printing to receive credit for any assignment.

Visual Comparison

file to run:

src/main/ruby/drawings_snapshots/part_c_snapshots_web_page_generator.rb