Render Part D Assignment

In this studio we will evolve our code from Render_Part_C_Assignment to leverage mixins.

Continue editing files in the render/assignment directory.

Background

Mixins are achieved in Ruby by including with modules.

module Nameable
  def introduce
    "Hello.  My name is #{@name}."
  end
end

class Person
  include Nameable

  def initialize(name)
    @name = name
  end
end

class Car
  include Nameable
  def initialize(name)
    @name = name
  end
end

prof_grossman = Person.new("Dan")
love_bug = Car.new("Herbie")

puts prof_grossman.introduce
puts love_bug.introduce

Warning

Do NOT use the include keyword in Ruby as you would typically in C or C++.
Be sure to include within the intended class or module definition.
If you include at the top-level, it will mixin to Object!
This may or may not rip a hole in the universe.

Code to Implement

Composite

file:	src/main/ruby/drawings/composite.rb
module:	Composite
methods:	initialize_components() push_component(component) each_component() untransformed_bounds()

module Composite should define methods initialize_components, push_component, each_component, and untransformed_bounds as well as mixin the Enumerable module.

initialize_components

add an instance variable with a suitable name to store an array of components

NOTE: initialize_components() must be private.

push_component

push a component onto your array instance variable.

each_component

if a block is given, yield for each component in your array instance variable.

otherwise use to_enum to return a new Enumerator of the components.

Note: be sure to invoke to_enum with the symbol of the method :each_component and not invoke the method by mistake.

untransformed_bounds

Similar to the untransformed bounds calculations on CompositeTransform and Scene from Part C.

Mixin Enumerable

to add a number of useful methods, include the Enumerable module and

Alias each

use alias_method to alias an :each method to the :each_component method.

CompositeTransform

Be sure to add:

require_relative 'composite'

Mixin your Composite module to the CompositeTransform class.

include Composite

Be sure to invoke initialize_components from the constructor and clean up existing code. For example bounds calculation can now use map.

Scene

Be sure to add:

require_relative 'composite'

Mixin your Composite module to the Scene class.

include Composite

Be sure to invoke initialize_components from the constructor and clean up existing code. For example bounds calculation can now use map.

Testing Your Solution

Unit Test

Part D

file:

src/test/ruby/drawings/preliminary/part_d/*.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_c/*.rb

UnitTest

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

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.