import sys


def pgm2ppm(filename, invert):

  pgm = open(filename,'r')
  outname = filename + '_out.ppm'
  ppm = open(outname,'w')

  line = pgm.readline()   # P2
  line = pgm.readline()   # comment line

  ppm.write('P3\n')
  ppm.write('# from %s\n' % filename)

  line = pgm.readline()   # 360 360
  ppm.write(line)

  line = pgm.readline()   # maxVal
  if (line[0] == '#'):
    ppm.write(line)
    line = pgm.readline()
    
  maxVal = float(line.strip())
  if (maxVal == 0):
    print 'maxVal = 0'
    pgm.close()
    ppm.close()
    sys.exit(0)

  ppm.write('255\n')

  for line in pgm.readlines():
    line = line.strip()
    val  = float(line) / maxVal
    if not invert:
      color = get_color_descending(val)
    else:
      color = get_color_ascending(val)
    ppm.write(color)

  pgm.close()
  ppm.close()



def get_color_descending(i):
  # i is an intensity between 0.0 and 1.0

  # big values are red. small values are blue. smallest 0.2% are bg. 

  # picks a colour from a spectrum wheel according to value of i
  # spectrum wheel:
  # colour = blue-> cyan->green->yellow->  red->magenta->blue
  # i      =  0  ->0.167->0.383->  0.5 ->0.667-> 0.833 -> 1

  if (i < 0.002):
    return '255 255 255\n'   # white bg

  i = i * 0.7  

  ang = i * 360.
  if (ang <= 60):
    blue  = 255
    green = int(ang / 60 * 255)
    red   = 0
  elif (ang <= 120):
    blue  = int((60-(ang-60)) / 60 * 255)
    green = 255
    red   = 0
  elif (ang <= 180):
    blue  = 0
    green = 255
    red   = int((ang-120) / 60 * 255)
  elif (ang <= 240):
    blue  = 0
    green = int((60-(ang-180)) / 60 * 255)
    red   = 255
  elif (ang <= 300):
    blue  = int((ang-240) / 60 * 255)
    green = 0
    red   = 255
  else:
    blue  = 255
    green = 0
    red   = int((60-(ang-300)) / 60 * 255)

  return '%d %d %d\n' % (red, green, blue)




def get_color_ascending(i):

  # small values are red. big values are blue. biggest 0.2% are bg. 

  if (i > (1-0.002)):
    return '0 0 0\n'   # black bg

  i = i * 0.7

  ang = i * 360.
  if (ang <= 60):
    red   = 255
    green = int(ang / 60 * 255)
    blue  = 0
  elif (ang <= 120):
    red   = int((60-(ang-60)) / 60 * 255)
    green = 255
    blue  = 0
  elif (ang <= 180):
    red   = 0
    green = 255
    blue  = int((ang-120) / 60 * 255)
  elif (ang <= 240):
    red   = 0
    green = int((60-(ang-180)) / 60 * 255)
    blue  = 255
  elif (ang <= 300):
    red   = int((ang-240) / 60 * 255)
    green = 0
    blue  = 255
  else:
    red   = 255
    green = 0
    blue  = int((60-(ang-300)) / 60 * 255)

  return '%d %d %d\n' % (red, green, blue)



if (__name__ == '__main__'):

  if ('-invert' in sys.argv):
    argNum = 3
    invert = 1
  else:
    argNum = 2
    invert = 0

  if (len(sys.argv) < argNum):
    print 'Usage: python pgm2ppm.py listfile.txt [-invert]'
    sys.exit(0)

  fopen = open(sys.argv[1],'r')
  for line in fopen.readlines():
    line = line.strip()
    print line
    pgm2ppm(line, invert)

  fopen.close()