generate a random colormap for itk-snap. Useful for supervoxels.

generate_random_colormap_itksnap.py

import random
import sys

def print_xml_format(color, index, value):
    if value == 0 or value == 1:
        ctype = 'Discontinuous'
    else:
        ctype = 'Continuous'
        
    print('''<folder key="ControlPoint[{}]" >
    <entry key="Index" value="{}" />
    <entry key="Type" value="{}" />
    <folder key="Left" >
      <entry key="A" value="255" />
      <entry key="B" value="{}" />
      <entry key="G" value="{}" />
      <entry key="R" value="{}" />
    </folder>
    <folder key="Right" >
      <entry key="A" value="255" />
      <entry key="B" value="{}" />
      <entry key="G" value="{}" />
      <entry key="R" value="{}" />
    </folder>
    </folder>'''.format(str(index).zfill(4), value, ctype, color[0], color[1], color[2], color[0], color[1], color[2]))


def print_header(num_points):
    print('''<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE registry [
<!ELEMENT registry (entry*,folder*)>
<!ELEMENT folder (entry*,folder*)>
<!ELEMENT entry EMPTY>
<!ATTLIST folder key CDATA #REQUIRED>
<!ATTLIST entry key CDATA #REQUIRED>
<!ATTLIST entry value CDATA #REQUIRED>
]>
<registry>
  <entry key="NumberOfControlPoints" value="{}" />
  <entry key="Preset" value="Custom" />'''.format(num_points))
    
def print_footer():
    print('</registry>')





def main():

  '''
    generate a random colormap to be used by itk-snap

    example: python generate_random_colormap_itk-snap.py 20 > random20.xml 
  '''

  if len(sys.argv) > 1:
    num_points = max(int(sys.argv[1]),2)
  else:
    num_points = 300
  # with open('randomcolormap.xml', 'w') as sys.stdout:
  print_header(num_points)
  for i in range(num_points):
      r = random.randint(1,255)
      g = random.randint(1,255)
      b = random.randint(1,255)
      color = [r,g,b]
      print_xml_format(color, i, i/(num_points-1))
  print_footer()

if __name__ == "__main__":
    main()