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Contents
require 'just_checkers/direction'
module JustCheckers
# = Vector
#
# An element of Vector space
class Vector
# New objects can be instantiated by passing in a two points with x and y co-ordinates
#
# @param [Point] a
# the start point.
#
# @param [Point] b
# the end point.
#
# ==== Example:
# # Instantiates a new Vector
# JustCheckers::Vector.new({
# a: JustCheckers::Point.new(x: 1, y: 1),
# b: JustCheckers::Point.new(x: 3, y: 3)
# })
def initialize(a, b)
@a, @b = a, b
end
# @return [Point] the start point.
attr_reader :a
# @return [Point] the end point.
attr_reader :b
# How big the vector is if it's diagonal, otherwise, nil.
#
# @return [Fixnum,NilClass]
def magnitude
if diagonal
dx.abs
else
nil
end
end
# The direction of the vector as a object
#
# @return [Direction]
def direction
Direction.new(direction_x, direction_y)
end
# The x component of the direction, 1 if moving down, -1 if moving up, 0 otherwise
#
# @return [Fixnum]
def direction_x
if dx > 0
1
elsif dx == 0
0
else
-1
end
end
# The y component of the direction, 1 if moving right, -1 if moving left, 0 otherwise
#
# @return [Fixnum]
def direction_y
if dy > 0
1
elsif dy == 0
0
else
-1
end
end
# Is the vector diagonal?
#
# @return [Boolean]
def diagonal
dx.abs == dy.abs
end
private
def dx
b.x - a.x
end
def dy
b.y - a.y
end
end
end
Version data entries
7 entries across 7 versions & 1 rubygems