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 Use

BoundingBox

max

min

Code to Implement

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 and change the x,y position as appropriate.

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.

Note: do NOT call glTranslate here. simply update your instance fields so that later when you are rendering, you will glTranslate the updated amounts.

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 BoundingBox specified by min and max instances of Point2.

NOTE: this method must be private.

bounding box decoration 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 BoundingBox specified by min and max instances of Point2.

NOTE: this method must be private.

bounding box decoration rendering

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

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 BoundingBox specified by min and max instances of Point2.

NOTE: this method must be private.

bounding box decoration rendering

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

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.

NOTE: when computing the bounds of multiple objects, recall that the identity element of minimum and the maximum is not 0.

bounding box decoration rendering

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

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.

NOTE: when computing the bounds of multiple objects, recall that the identity element of minimum and the maximum is not 0.

bounding box decoration rendering

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

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()

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.

NOTE: when computing the bounds of multiple objects, recall that the identity element of minimum and the maximum is not 0.

bounding box decoration rendering

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

file to run:

src/main/ruby/drawings/convex_polygon.rb

Testing Your Solution

Unit Test

file:

src/test/ruby/drawings/core/relatively_fast/part_c/*.rb

UnitTest

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

file:

src/test/ruby/drawings/core/relatively_slow/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/core/relatively_fast/part_a/*.rb

UnitTest

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

file:

src/test/ruby/drawings/core/relatively_fast/part_b/*.rb

UnitTest

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

Visual Comparison

file to run:

src/test/ruby/drawings/core/snapshots/part_c_snapshots_web_page_generator.rb