Module: GeometryDocs

Included in:
Geometry
Defined in:
dragon/geometry_docs.rb

Overview

Copyright 2019 DragonRuby LLC MIT License geometry_docs.rb has been released under MIT (*only this file*).

Instance Method Summary collapse

Instance Method Details

#docs_classObject


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# File 'dragon/geometry_docs.rb', line 11

def docs_class
  <<-S
* DOCS: ~Geometry~

The Geometry module contains methods for calculations that are frequently used in game development.

S
end

#docs_method_sort_orderObject


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# File 'dragon/geometry_docs.rb', line 7

def docs_method_sort_order
  [:docs_class, :docs_scale_rect]
end

#docs_scale_rectObject


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# File 'dragon/geometry_docs.rb', line 20

def docs_scale_rect
  <<-S
* DOCS: ~GTK::Geometry#scale_rect~

Given an array with 4 elements representing a rect [x, y, w, h], this function returns a scaled rect. It accepts three arguments:

~ratio~: the ratio by which to scale the rect. A ratio of 2 will double the dimensions of the rect while a ratio of 0.5 will halve its dimensions. 

~anchor_x~ and ~anchor_y~ specify the point within the rect from which to resize it. Setting both to 0 will affect the width and height of the rect, leaving x and y unchanged. Setting both to 0.5 will scale all sides of the rect proportionally from the center.

The ~scale_rect~ method can be applied directly to a sprite or other primitives. See CHEATSHEET: How to Scale a Sprite.

#+begin_src ruby
def tick args
  #       x,   y,   w,   h
  my_rect = [100, 100, 200, 200]

  # halve the dimensions of the rect: 
  #                             ratio, anchor_x, anchor_y
  new_rect = my_rect.scale_rect(0.5,   0.5,      0.5)

  puts new_rect # => [150.0, 150.0, 100.0, 100.0]
end
#+end_src

S
end