Class: VectorSalad::StandardShapes::Path

Inherits:
BasicShape
  • Object
show all
Defined in:
lib/vector_salad/standard_shapes/path.rb,
lib/vector_salad/exporters/svg_exporter.rb

Overview

The simplest shape primitive, all shapes can be represented as a Path.

Instance Attribute Summary collapse

Attributes inherited from BasicShape

#options

Instance Method Summary collapse

Constructor Details

#initialize(*nodes, closed: true, **options) ⇒ Path

Returns a new instance of Path.



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
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 22

def initialize(*nodes, closed: true, **options)
  @nodes = []
  nodes.each_index do |i|
    node = nodes[i].class == Array ? N.new(*nodes[i]) : nodes[i]
    if i == 0 && ![:node, :g2, :g4, :left, :right].include?(node.type)
      fail "First node in a path must be :node or :spiro type."
    end
    case node.type
    when :cubic
      unless nodes[i - 1].type == :node ||
            (nodes[i - 2].type == :node && nodes[i - 1].type == :cubic)
        fail ":cubic node must follow a :node and at most 1 other :cubic."
      end
    when :quadratic
      unless nodes[i - 1].type == :node
        fail ":quadratic nodes must follow a :node."
      end
    when :mirror
      if nodes[i - 1].type == :node &&
         (nodes[i - 2].type == :quadratic || nodes[i - 2].type == :cubic)
        pivot = nodes[i - 1]
        source = nodes[i - 2]

        dx = pivot.x - source.x
        dy = pivot.y - source.y
        node.at = [pivot.x + dx, pivot.y + dy]

        node.type = source.type
      else
        fail ":reflect nodes must be preceeded by a :node with a
          :quadratic or :cubic before that."
      end
    when :node
    end
    @nodes << node
  end

  @closed = closed
  @options = options
  self
end

Instance Attribute Details

#closed ⇒ Object (readonly)

Returns the value of attribute closed.



11
12
13
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 11

def closed
  @closed
end

#nodes ⇒ Object (readonly)

Returns the value of attribute nodes.



11
12
13
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 11

def nodes
  @nodes
end

Instance Method Details

#[](x, y) ⇒ Object 



66
67
68
69
70
71
72
73
74
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 66

def [](x, y)
  Path.new(
    *to_path.nodes.map do |node|
      node[x, y]
    end,
    closed: @closed,
    **@options
  )
end

#flip(axis) ⇒ Object 



107
108
109
110
111
112
113
114
115
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 107

def flip(axis)
  x = axis == :y ? -1 : 1
  y = axis == :x ? -1 : 1

  Path.new(
    *to_path.nodes.map { |n| N.new(n.x * x, n.y * y, n.type) },
    closed: @closed, **@options
  )
end

#flip_x ⇒ Object 



90
91
92
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 90

def flip_x
  flip(:x)
end

#flip_y ⇒ Object 



96
97
98
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 96

def flip_y
  flip(:y)
end

#jitter(max, min: 0, fn: nil) ⇒ Object 



165
166
167
168
169
170
171
172
173
174
175
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 165

def jitter(max, min: 0, fn: nil)
  Path.new(
    *to_simple_path(fn).nodes.map do |n|
      r = Random.rand(min..max)
      a = Random.rand(0..Math::PI * 2)
      x = r * Math.cos(a)
      y = r * Math.sin(a)
      n.move(x, y)
    end, closed: @closed, **@options
  )
end

#move(x, y) ⇒ Object 



78
79
80
81
82
83
84
85
86
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 78

def move(x, y)
  Path.new(
    *to_path.nodes.map do |node|
      node.move(x, y)
    end,
    closed: @closed,
    **@options
  )
end

#rotate(angle) ⇒ Object 



124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 124

def rotate(angle)
  theta = angle / 180.0 * Math::PI

  # http://stackoverflow.com/a/786508
  # p'x = cos(theta) * (px-ox) - sin(theta) * (py-oy) + ox
  # p'y = sin(theta) * (px-ox) + cos(theta) * (py-oy) + oy
  Path.new(
    *to_path.nodes.map do |n|
      N.new(
        Math.cos(theta) * n.x - Math.sin(theta) * n.y,
        Math.sin(theta) * n.x + Math.cos(theta) * n.y,
        n.type
      )
    end, closed: @closed, **@options
  )
end

#scale(x_multiplier, y_multiplier = x_multiplier) ⇒ Object 



147
148
149
150
151
152
153
154
155
156
157
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 147

def scale(x_multiplier, y_multiplier = x_multiplier)
  Path.new(
    *to_path.nodes.map do |n|
      N.new(
        n.x * x_multiplier,
        n.y * y_multiplier,
        n.type
      )
    end, closed: @closed, **@options
  )
end

#to_a ⇒ Object

Return the nodes as an array of coordinates.



270
271
272
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 270

def to_a
  nodes.map(&:at)
end

#to_bezier_path ⇒ Object

Convert the complex path to a bezier path. This will convert any Spiro curve nodes into beziers.



184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 184

def to_bezier_path
  path = to_path
  spiro = false
  flat_path = path.nodes.map do |n|
    spiro = true if spiro || [:g2, :g4, :left, :right].include?(n.type)
    [n.x, n.y, n.type]
  end
  if spiro
    flat_spline_path = Spiro.spiros_to_splines(flat_path, @closed)
    if flat_spline_path.nil?
      fail "Spiro failed, try different coordinates or using G2 nodes."
    else
      path = Path.new(*flat_spline_path.map do |n|
        N.new(n[0], n[1], n[2])
      end, closed: @closed, **@options)
    end
  end
  path
end

#to_cubic_path ⇒ Object

Convert the path into a cubic bezier path (no quadratics). This will convert any Spiro curve nodes into beziers and any quadratic beziers into cubics.



207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 207

def to_cubic_path
  path = to_bezier_path.nodes
  cubic_path = []
  quadratic_last = false
  path.each_index do |i|
    n = path[i]
    if quadratic_last
      n0 = path[i - 2]
      q  = path[i - 1]

      # CP1 = QP0 + 2/3 * (QP1-QP0)
      # CP2 = QP2 + 2/3 * (QP1-QP2)
      third = 2 / 3.0
      cubic_path << N.c(
        n0.x + third * (q.x - n0.x),
        n0.y + third * (q.y - n0.y)
      )
      cubic_path << N.c(
        n.x + third * (q.x - n.x),
        n.y + third * (q.y - n.y)
      )
      cubic_path << n

      quadratic_last = false
    elsif n.type == :quadratic
      quadratic_last = true
    else
      cubic_path << n
    end
  end
  Path.new(*cubic_path, closed: @closed, **@options)
end

#to_multi_path ⇒ Object

Wrap the path in a multi_path.



265
266
267
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 265

def to_multi_path
  MultiPath.new(self)
end

#to_path ⇒ Object

Convert the path to a path (it returns self)



178
179
180
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 178

def to_path
  self
end

#to_simple_path(*_) ⇒ Object

Flatten any curves in the path into many small straight line segments.



241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
 
# File 'lib/vector_salad/standard_shapes/path.rb', line 241

def to_simple_path(*_)
  # convert bezier curves and spiro splines
  path = to_cubic_path.nodes

  nodes = []
  path.each_index do |i|
    case path[i].type
    when :node
      if path[i - 1].type == :cubic
        curve = path[i - 3..i].map(&:at)
        nodes += VectorSalad::Interpolate.new.casteljau(curve)
      else
        nodes << path[i]
      end
    when :cubic
    else
      fail "Only :node and :cubic nodes in a path can be converted
        to a simple path, was #{path[i].type}."
    end
  end
  Path.new(*nodes, closed: @closed, **@options)
end

#to_svg ⇒ Object

Export the shape to an svg string



38
39
40
41
42
43
44
 
# File 'lib/vector_salad/exporters/svg_exporter.rb', line 38

def to_svg
  svg = '<path d="'
  svg << to_svg_d_attribute
  svg << '"'
  svg << VectorSalad::Exporters::SvgExporter.options(@options)
  svg << "/>"
end