drawStar.coffee

  # http://svg-whiz.com/svg/starPrimative.svg
  # Smoothing: http://www.codeproject.com/Articles/128705/WPF-rounded-corners-polygon
  drawStar: (cx, cy, r1, r2, rCorner, arms, shift = 0) ->
    polyPoints = null
    segments = []    

    if arms in [1,3,5,7,9]
      orient = 'point'
    else
      orient = 'edge'

    for s in [0..arms]

      # Segment A

      angle = 2.0 * pi * (s / arms)

      if orient == 'point'
        angle -= pi/2
      else
        angle = (angle + (pi/arms)) - (pi/2)

      x = (r1 * cos(angle)) + cx
      y = (r1 * sin(angle)) + cy

      if s == 0
        polyPoints = "M #{x} #{y}"
      else
        polyPoints += " L #{x} #{y}"

      # Segment B

      angle = (2.0 * pi * (s / arms)) + (pi/arms)
      
      if orient == 'point'
        angle -= pi/2
      else
        angle = (angle + (pi/arms)) - (pi/2)

      angle += shift

      x = (r2 * cos(angle)) + cx
      y = (r2 * sin(angle)) + cy

      polyPoints += " L #{x} #{y}"

    $star = svg 'path', canvas.$drawing
    $star.setAttribute 'boxy:shape', 'star'
    $star.setAttribute 'boxy:cx', cx
    $star.setAttribute 'boxy:cy', cy
    $star.setAttribute 'boxy:r1', r1
    $star.setAttribute 'boxy:r2', r2

    $star.setAttributeNS null, 'd', polyPoints
    $star.setAttributeNS null, 'fill', 'blue'
    $star.setAttributeNS(null, 'stroke', 'red')
    $star.setAttributeNS(null, 'stroke-width', '2')