#!/usr/bin/python

"""Computes an inverse fourier transform, i.e. converts a bitmap into frequency/time.
(C) 2002 by Sami Kyöstilä, Joonas Kerttula."""

xres = 64
yres = 64		# must be 64
picture = "in.raw"
output = "out.wav"
base = 2048		# base frequency, i.e. the bottom of the image on the spectrogram
scale = 700		# the size of the image
volume = 0.07
invert = 0		# should the picture be inverted?

import wave
import sys
import math
import time

def sample(amp):
    return chr(int((amp+1.0)*127))
    

i = open(picture, "rb")

image = []
for y in range(0,yres):
    row = []
    str = ""
    for x in range(0,xres):
        p = i.read(1)
        if not p: raise UserWarning("Kuva on rikki! (%d, %d)" % (x,y))
        if invert:
            row.append(1.0-float(ord(p)/256.0))
        else:
            row.append(float(ord(p)/256.0))
#        str+=(chr(ord('A') + (ord(p)/8)))
    image.append(row)
#    print str[:70]
        
i.close()

f = wave.open(output, "wb")
f.setnchannels(1)
f.setsampwidth(1)
f.setframerate(11025)

t = 0
r = range(0,yres)
start = time.time()

while t<xres/64.0:
    amp=0
    row = int((t/(xres/64.0))*(xres-1))
    for i in r:
        amp += math.sin((i+t) * (base+i*scale)) * volume * image[yres-i-1][row]

    if amp<-1.0: amp=-1.0
    if amp>1.0: amp=1.0
    amp *= 0.3

    f.writeframes(sample(amp))
    
    t+=1.0/(11025.0*4)
    if time.time()>start+1:
        start=time.time()
        p = t / (xres/64.0)
        print "[" + "=" * int(p*40) + ">" + "." * int((1-p)*40) + "] ",
        print "%.1f%%" % (p*100)

f.close()

print "Valamis!"