#!/usr/bin/env python3

# Render image to Oscilloscope XY vector audio
#
# ----------------------------------------------------------------------------
# Copyright (c) 2024 Thomas Buck (thomas@xythobuz.de)
#
# 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.
#
# See <http://www.gnu.org/licenses/>.
# ----------------------------------------------------------------------------

import sys
import wave

import pyaudio
from PIL import Image

samplerate = 44100 #192000
default_duration = 5.0

def read_image(image):
    print("image: width={} height={} total={}".format(image.width, image.height, image.width * image.height))

    # resize coordinates for conversion to amplitude values
    max_len = max(image.width, image.height)
    fact = 32767 / max_len
    sw, sh = int(image.width * fact), int(image.height * fact)
    print("amplitude: width={} height={}".format(sw, sh))

    data = bytearray()
    for x in range(0, image.width):
        for y in range(0, image.height):
            if image.getpixel((x, y))[3] > 127:
                xc, yc = int((x - (image.width / 2)) * fact), int((y - (image.height / 2)) * fact)
                data.extend(yc.to_bytes(2, byteorder="little", signed=True))
                data.extend(xc.to_bytes(2, byteorder="little", signed=True))
    return data

def play_waveform(data):
    pa = pyaudio.PyAudio()

    # int16
    stream = pa.open(format=pa.get_format_from_width(2),
                    channels=2,
                    rate=samplerate,
                    output=True)

    stream.write(data, int(len(data) / 4), True)

    stream.stop_stream()
    stream.close()

    pa.terminate()

def write_waveform(data):
    with wave.open("out.wav", "w") as f:
        f.setnchannels(2)
        f.setsampwidth(2)
        f.setframerate(samplerate)
        f.writeframes(data)

def main():
    if len(sys.argv) <= 1:
        print("Usage:")
        print("\t" + sys.argv[0] + " image.png [seconds]")
        sys.exit(1)

    if len(sys.argv) >= 3:
        duration = float(sys.argv[2])
    else:
        duration = default_duration

    with Image.open(sys.argv[1]) as image:
        wave = read_image(image)

    samplecount = int(len(wave) / 2 / 2) # stereo, int16
    drawrate = samplerate / samplecount
    drawcount = drawrate * duration
    print("len={} samples={} drawrate={:.2f} count={:.2f}".format(len(wave), samplecount, drawrate, drawcount))

    data = bytearray()
    for n in range(0, int(drawcount)):
        data.extend(wave)
    print("len={}".format(len(data)))

    #play_waveform(bytes(data))
    write_waveform(bytes(data))

if __name__ == "__main__":
    main()