#
# Visualisation of Random Data as 2D Greyscale Image made by Karl-Uwe Frank
# 
# This is free and unencumbered software released into the public domain.
# 
# Anyone is free to copy, modify, publish, use, compile, sell, or
# distribute this software, either in source code form or as a compiled
# binary, for any purpose, commercial or non-commercial, and by any
# means.
# 
# In jurisdictions that recognize copyright laws, the author or authors
# of this software dedicate any and all copyright interest in the
# software to the public domain. We make this dedication for the benefit
# of the public at large and to the detriment of our heirs and
# successors. We intend this dedication to be an overt act of
# relinquishment in perpetuity of all present and future rights to this
# software under copyright law.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
# OTHER DEALINGS IN THE SOFTWARE.
# 
# For more information, please refer to <http://unlicense.org/>
# 

import sys, os, math
import matplotlib.pyplot as plt
import numpy as np


#-----------------------------------------
# Simulate missing ANSI-C "printf"
#
def printf(*args):
  sys.stdout.write(*args)
  sys.stdout.flush()

def print_stderr(*args):
  sys.stderr.write(*args)
  sys.stderr.flush()


#-----------------------------------------
#
def ShowUsage(ThisName):
  print_stderr ( "\nUsage   : python %s <binary file> [optional: <byte count>]\n" % ThisName);
  print_stderr ( "\nExample : python %s rng_out.bin\n" % ThisName);
  print_stderr ( "        : python %s rng_out.bin 1048576\n" % ThisName);
  print_stderr ( "        : python %s rng_out.bin.zx8 $((256*256))\n" % ThisName);
  print_stderr ( "        : python %s rng_out.bin.zx8 $((512*512))\n" % ThisName);
  print_stderr ( "        : python %s rng_out.bin.zx8 $((1024*1024))\n\n" % ThisName);

# -----------------------------------------
# Main 
#
def main():
  #
  # Check if a Prarmeter is passed through
  PrgName = sys.argv[0]

  if (len(sys.argv) < 2):
    ShowUsage(PrgName)
    sys.exit()

  InFile = sys.argv[1]

  try:
    fileHandle = open(InFile, "rb")
  except IOError:
    print("\nError opening file: %s\n" % InFile)
    sys.exit()

  fileHandle.seek(0,2) # EOF
  fileSize = int(fileHandle.tell())
  fileHandle.seek(0,0) # rewind
  
  fileName = os.path.basename(InFile)
  
  if (len(sys.argv) == 3):
    ByteCount = int(sys.argv[2])

    if (ByteCount > fileSize):
      ByteCount = fileSize
      
    ImageTitle = '-'+ str(ByteCount)
  else:
    ByteCount = fileSize
    ImageTitle =  ""
  
  if (ByteCount < 65536):
    print_stderr ("\nByte Count Value or File Size not >= 65536 Byte\n\n")
    sys.exit()
  
  #
  # Check for proper File Length or Byte Count
  #
  ShapeSize = int(math.sqrt(ByteCount))

  if ( (ShapeSize % 256) != 0 ):
    print_stderr ("\nByte Count Value or File Size not applicable.\n")
    print print_stderr ("ShapeSize = %d, ByteCount = %d\n\n" % (ShapeSize, ByteCount) )# Debug
    sys.exit()

  #
  # Read the binary Data into a Numpy Array
  #
  randomData = np.fromfile(fileHandle, np.uint8, count=ByteCount)
  fileHandle.close()

  ### print(randomData.shape) # Debug
  
  #
  # Re-Shape the Data into a 2D Array
  #
  randomData = randomData.reshape(ShapeSize, ShapeSize)

  #
  # Plot the 2D-Image
  #
  fig = plt.figure(figsize=(7,7), facecolor='white', edgecolor='black')

  plt.axis('off')
  plt.title('Greyscale of:  '+ os.path.basename(InFile) + ImageTitle, color='black')
  plt.imshow(randomData, cmap='gray', interpolation='nearest');
  plt.savefig(InFile + ImageTitle +'.png', format="png")
  plt.show()
  plt.close()


if __name__ == "__main__":
  main()
  sys.exit()