Angles Along Polyline

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• Version 1 • Released on: 2013-03-11 11:52:44
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  Description:

  initial version

  /* From:
   * http://stackoverflow.com/questions/6719563/compute-the-angle-of-a-triangle-when-3-points-are-given
   */
  
  importClass(Packages.icy.sequence.Sequence)
  importClass(Packages.icy.roi.ROI2DPolyLine)
  
  seq = getSequence()
  if (seq == null) throw "Please open a sequence first!"
  
  roi = seq.getSelectedROI2D()
  
  if (roi == null || !(roi instanceof ROI2DPolyLine)) throw "Selected ROI is null or not a polyline."
  
  list = roi.getPoints() // get the list of points
  
  // generate arrays of x and y values for simpler manipulations
  x = []
  y = []
  for (i = 0; i < list.size(); i++) {
  	x[i] = list.get(i).x
  	y[i] = list.get(i).y
  }
  
  // calculates the dot product
  for (i = 1; i < x.length - 1; i++) {
  	dotprod = (x[i + 1] - x[i]) * (x[i - 1] - x[i]) + (y[i + 1] - y[i]) * (y[i - 1] - y[i]);
  	len1 = Math.sqrt((x[i - 1] - x[i]) * (x[i - 1] - x[i]) + (y[i - 1] - y[i]) * (y[i - 1] - y[i]));
  	len2 = Math.sqrt((x[i + 1] - x[i]) * (x[i + 1] - x[i]) + (y[i + 1] - y[i]) * (y[i + 1] - y[i]));
  
  	angle = Math.acos(dotprod / (len1 * len2)) * 180 / Math.PI;
  	println(i + ":" + angle);
  }