Class: XRVG::Line

Inherits:
Curve show all
Includes:
Samplable
Defined in:
lib/shape.rb

Overview

Line class

Intro

Used to draw polylines and polygons

Attributes

attribute :points, [V2D[0.0, 0.0], V2D[1.0, 1.0]]

WARNING : getter “points” is not defined, because is defined as Curve.points( abscissa ) !!!

Example

line = Line[ :points, [V2D::O, V2D::X] ]

Instance Method Summary collapse

Methods included from Samplable

#apply_samples, build, #mean, #sample, #samples

Methods included from FloatFunctor

#addfilter, #alternate, #apply, #applyhash, #compute, #filter, #generate, #geo, #geofull, #modify, #process, #random, #shuffle, #sin, #ssort, #transform, #transforms, #trigger

Methods inherited from Curve

#acc_normal, #curvature, #default_style, #frame, #frames, #framev, #normal, #normals, #rotation, #scale, #tangent0, #tangent0_angle, #tangent0_length, #tangents

Methods inherited from Shape

#contour, #default_style, #size, #surface

Constructor Details

#initialize(*args) ⇒ Line

:nodoc:



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# File 'lib/shape.rb', line 228

def initialize (*args) #:nodoc:
  super( *args )
  self.init_tangents
end

Instance Method Details

#acc(abscissa, container = nil) ⇒ Object

acc V2D.O



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# File 'lib/shape.rb', line 286

def acc( abscissa, container=nil )
  container ||= V2D[]
  container.xy = [0.0,0.0]
  return container
end

#init_tangents ⇒ Object

:nodoc:



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# File 'lib/shape.rb', line 233

def init_tangents #:nodoc:
  index = 0
  @tangents = Array.new
  @points.pairs { |p1, p2| 
    @tangents[ index ] = (p2-p1).norm 
    index += 1
  }
end

#length ⇒ Object

return the total length of the polyline



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# File 'lib/shape.rb', line 243

def length
  if not @length
    @length = 0.0
    @points.pairs do |p1, p2|
	@length += (p1 - p2).r
    end
  end
  return @length
end

#point(abscissa, container = nil) ⇒ Object Also known as: apply_sample

compute line point at abscissa

Line[ :points, [V2D::O, V2D::X] ].point( 0.3 ) => V2D[0.0,0.3]



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# File 'lib/shape.rb', line 255

def point (abscissa, container=nil)
  container ||= V2D[]
  piece1   = abscissa.to_int
  if piece1 == @points.size - 1
    container.xy = @points[-1]
  else
    abscissa -= piece1
    cpoints = @points.slice( piece1, 2 )
    container.xy = [(cpoints[0].x..cpoints[1].x).sample( abscissa ), 
             (cpoints[0].y..cpoints[1].y).sample( abscissa )]
  end
  return container
end

#points(arg = nil) ⇒ Object

redefining to discriminate between @points and map.point



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# File 'lib/shape.rb', line 270

def points(arg=nil)
  if not arg
    return @points
  else
    super(arg)
  end
end

#reverse ⇒ Object

reverse a line

return a new line with :points reversed



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# File 'lib/shape.rb', line 309

def reverse
  return Line[ :points, @points.reverse ]
end

#svg ⇒ Object

return line svg description



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# File 'lib/shape.rb', line 314

def svg
  path = "M #{points[0].x} #{points[0].y} "
  @points[1..-1].each { |p|
    path += "L #{p.x} #{p.y}"
  }
  return "<path d=\"" + path + "\"/>"
end

#tangent(abscissa, container = nil) ⇒ Object

compute line tangent at abscissa



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# File 'lib/shape.rb', line 279

def tangent (abscissa, container=nil)
  container ||= V2D[]
  container.xy = @tangents[abscissa.to_int]
  return container
end

#translate(v) ⇒ Object

translate a line of v offset, v being a vector

return a new line with every point of :points translated



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# File 'lib/shape.rb', line 302

def translate( v )
  return Line[ :points, @points.map {|ext| ext + v } ]
end

#viewbox ⇒ Object

compute viewbox of the line

simply call V2D.viewbox on :points



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# File 'lib/shape.rb', line 295

def viewbox
  return V2D.viewbox( @points )
end