#!/usr/bin/env python
#
#abs2png.py: Generate a png image from a abs range image.
#The grey level is defined using the min and the max values of Z 
#
#
# Copyright (C) 2010  Clement Creusot
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


import sys
import os
import string
from PIL import Image
import binascii  


def print_help():
    print "Usage: "+sys.argv[0]+" filein.abs[.gz] [fileout.png]"
    sys.exit()

def print_error(str):
    print "ERROR: "+str
    sys.exit()


# read parameters

if (len(sys.argv) == 2):
    pngfilename = sys.argv[1]+".png";
elif (len(sys.argv) == 3):
    pngfilename = sys.argv[2];
else:
    print_help()

absfilename = sys.argv[1];
if not os.path.exists(absfilename):
    print_error("File doesnt exist")

if absfilename.rfind(".gz") != -1:
    import tempfile
    from subprocess import *
    tmpdir = tempfile.mkdtemp()
    call(["cp",absfilename, tmpdir])
    gzfilename = os.path.join(tmpdir,os.path.basename(absfilename))
    call(["gunzip", gzfilename]);
    absfilename = gzfilename.replace("abs.gz","abs") 
    

absfile = open(absfilename, "r")

try:
    tab = string.split(absfile.readline())
    rows = int(tab[0])
    tab = string.split(absfile.readline())
    columns= int(tab[0])
    tab = string.split(absfile.readline()) # comment pixel
except ValueError:
    print_error("Bad header")

     
# Read the flags and the Z coordinate
flags = map(int,string.split(absfile.readline()))
absfile.readline() #X
absfile.readline() #Y
Z = map(float,string.split(absfile.readline()))
absfile.close()

Min = 99999.0
Max = -99999.0
sum = 0.0
count = 0.0
for i,z in enumerate(Z):
    Z[i] = flags[i]*z    
    if flags[i] == 1:
        Min = min(Min,z)
        Max = max(Max,z)
        sum = sum + z
        count = count + 1
if count != 0.0 :
    mean = sum /count
else:
    mean = 0.0
delta = Max - Min
print Min, Max, delta, mean

img = ''
for i,z in enumerate(Z):
    v = 255-int((z-Min)/delta*255)*flags[i]
    if v<16:
        s = '0'+hex(v)[2:]
    else:
        s = hex(v)[2:]
    img = img + str(binascii.unhexlify(s))

pilImage = Image.frombuffer('L',(columns,rows),img,'raw','L',0,1)
pilImage.save(pngfilename)