1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
|
module Rubyvis
# Returns a {@link pv.Vector} for the specified <i>x</i> and <i>y</i>
# coordinate. This is a convenience factory method, equivalent to <tt>new
# pv.Vector(x, y)</tt>.
#
# @see pv.Vector
# @param {number} x the <i>x</i> coordinate.
# @param {number} y the <i>y</i> coordinate.
# @returns {pv.Vector} a vector for the specified coordinates.
def self.vector(x,y)
Rubyvis::Vector.new(x,y)
end
class Vector
attr_accessor :x,:y
# Constructs a {@link pv.Vector} for the specified <i>x</i> and <i>y</i>
# coordinate. This constructor should not be invoked directly; use
# {@link pv.vector} instead.
#
# @class Represents a two-dimensional vector; a 2-tuple <i>⟨x,
# y⟩</i>. The intent of this class is to simplify vector math. Note that
# in performance-sensitive cases it may be more efficient to represent 2D
# vectors as simple objects with <tt>x</tt> and <tt>y</tt> attributes, rather
# than using instances of this class.
#
# @param {number} x the <i>x</i> coordinate.
# @param {number} y the <i>y</i> coordinate.
def initialize(x,y)
@x=x
@y=y
end
def ==(v)
@x==v.x and @y==v.y
end
# Returns a vector perpendicular to this vector: <i>⟨-y, x⟩</i>.
#
# @returns {pv.Vector} a perpendicular vector.
#/
def perp
Rubyvis::Vector.new(-@y,@x)
end
# Returns a normalized copy of this vector: a vector with the same direction,
# but unit length. If this vector has zero length this method returns a copy of
# this vector.
#
# @returns {pv.Vector} a unit vector.
def norm
l=length()
times(l!=0 ? (1.0 / l) : 1.0)
end
# Returns the magnitude of this vector, defined as <i>sqrt(x * x + y * y)</i>.
#
# @returns {number} a length.
def length
Math.sqrt(@x**2 + @y**2)
end
# Returns a scaled copy of this vector: <i>⟨x * k, y * k⟩</i>.
# To perform the equivalent divide operation, use <i>1 / k</i>.
#
# @param {number} k the scale factor.
# @returns {pv.Vector} a scaled vector.
def times(k)
Rubyvis::Vector.new(@x * k, @y * k)
end
# Returns this vector plus the vector <i>v</i>: <i>⟨x + v.x, y +
# v.y⟩</i>. If only one argument is specified, it is interpreted as the
# vector <i>v</i>.
#
# @param {number} x the <i>x</i> coordinate to add.
# @param {number} y the <i>y</i> coordinate to add.
# @returns {pv.Vector} a new vector.
def plus(x,y=nil)
return (y.nil?) ? Rubyvis::Vector.new(@x + x.x, @y + x.y) : Rubyvis::Vector.new(@x + x, @y + y)
end
# Returns this vector minus the vector <i>v</i>: <i>⟨x - v.x, y -
# v.y⟩</i>. If only one argument is specified, it is interpreted as the
# vector <i>v</i>.
#
# @param {number} x the <i>x</i> coordinate to subtract.
# @param {number} y the <i>y</i> coordinate to subtract.
# @returns {pv.Vector} a new vector.
def minus(x,y=nil)
return (y.nil?) ? Rubyvis::Vector.new(@x - x.x, @y - x.y) : Rubyvis::Vector.new(@x - x, @y - y)
end
# Returns the dot product of this vector and the vector <i>v</i>: <i>x * v.x +
# y * v.y</i>. If only one argument is specified, it is interpreted as the
# vector <i>v</i>.
#
# @param {number} x the <i>x</i> coordinate to dot.
# @param {number} y the <i>y</i> coordinate to dot.
# @returns {number} a dot product.
def dot(x, y=nil)
(y.nil?) ? @x * x.x + @y * x.y : @x * x + @y * y
end
end
end
|
