add argparse to render script, add makefile.

Makefile

@@ -0,0 +1,28 @@
+inputs = $(wildcard *.svg)
+
+outputs = $(inputs:%.svg=output/%_44100.wav)
+outputs += $(inputs:%.svg=output/%_48000.wav)
+outputs += $(inputs:%.svg=output/%_96000.wav)
+outputs += $(inputs:%.svg=output/%_192000.wav)
+
+.PHONY: all
+all: output ${outputs}
+
+output:
+	mkdir output
+
+output/%_44100.wav: %.svg
+	./render.py -s 44100 -o $(@:%.svg=%_44100.wav) $<
+
+output/%_48000.wav: %.svg
+	./render.py -s 48000 -o $(@:%.svg=%_48000.wav) $<
+
+output/%_96000.wav: %.svg
+	./render.py -s 96000 -o $(@:%.svg=%_96000.wav) $<
+
+output/%_192000.wav: %.svg
+	./render.py -s 192000 -o $(@:%.svg=%_192000.wav) $<
+
+.PHONY: clean
+clean:
+	rm -rf output

README.md

@@ -5,3 +5,6 @@ Please see [my blog post for more details](https://www.xythobuz.de/osci_music_pl
 Quick start instructions can be found in the top comment of the Python script in this repo.
 
     ssh osci-music "sudo systemctl disable --now osci.service" && scp osci-pi.py osci-music:~ && ssh osci-music "sudo systemctl enable --now osci.service"
+
+Also include a simple script to convert single SVG paths to audio.
+Run the included makefile to convert the SVG files in this directory.

render.py

@@ -23,15 +23,10 @@
 
 import sys
 import wave
+import argparse
 from svgpathtools import svg2paths
 
-samplerate = 44100 #192000
-volume_percent = 70
-path_steps = 10
-default_duration = 5.0
-default_outfile = "out.wav"
-
-def read_image(filename):
+def read_image(filename, path_steps, volume_percent):
     paths, attributes = svg2paths(filename)
     path = paths[0]
     if len(paths) > 1:
@@ -72,16 +67,25 @@ def read_image(filename):
             p.append(v)
         return p
 
+    def add_segment(p1, p2, f):
+        p = interpolate(p1, p2, f)
+        add_point(p)
+
     for n in range(0, len(points) - 1):
-        p1 = points[n]
-        p2 = points[n + 1]
         for step in range(0, path_steps):
-            p = interpolate(p1, p2, step / path_steps)
-            add_point(p)
-    add_point(points[len(points) - 1])
+            add_segment(points[n], points[n + 1], step / path_steps)
+
+    #add_point(points[len(points) - 1])
+
+    for n in range(len(points) - 2, -1, -1):
+        for step in range(0, path_steps):
+            add_segment(points[n + 1], points[n], step / path_steps)
+
+    add_point(points[0])
+
     return data
 
-def write_waveform(data, filename):
+def write_waveform(data, filename, samplerate):
     with wave.open(filename, "w") as f:
         f.setnchannels(2)
         f.setsampwidth(2)
@@ -89,26 +93,31 @@ def write_waveform(data, filename):
         f.writeframes(data)
 
 def main():
-    if len(sys.argv) <= 1:
-        print("Usage:")
-        print("\t" + sys.argv[0] + " image.png [out.wav] [seconds]")
-        sys.exit(1)
-
-    if len(sys.argv) == 3:
-        duration = float(sys.argv[2])
-        outfile = default_outfile
-    if len(sys.argv) >= 4:
-        duration = float(sys.argv[2])
-        outfile = sys.argv[3]
-    else:
-        duration = default_duration
-        outfile = default_outfile
-
-    wave = read_image(sys.argv[1])
+    parser = argparse.ArgumentParser(
+        prog=sys.argv[0],
+        description='Render SVG path to vector XY audio file',
+        epilog='Made by Thomas Buck <thomas@xythobuz.de>. Licensed as GPLv3.')
+
+    parser.add_argument("input", help="Input SVG image file path.")
+    parser.add_argument("-o", "--output", dest="output", default="out.wav",
+                        help="Output wav sound file path. Defaults to 'out.wav'.")
+    parser.add_argument("-t", "--time", dest="time", default=5.0, type=float,
+                        help="Length of sound file in seconds. Defaults to 5s.")
+    parser.add_argument("-s", "--samplerate", dest="samplerate", default=44100, type=int,
+                        help="Samplerate of output file in Hz. Defaults to 44.1kHz.")
+    parser.add_argument("-v", "--volume", dest="volume", default=100.0, type=float,
+                        help="Volume of output file in percent. Defaults to 100%%.")
+    parser.add_argument("-i", "--interpolate", dest="interpolate", default=10, type=int,
+                        help="Steps on interpolated paths. Defaults to 10.")
+
+    args = parser.parse_args()
+    print(args)
+
+    wave = read_image(args.input, args.interpolate, args.volume)
 
     samplecount = int(len(wave) / 2 / 2) # stereo, int16
-    drawrate = samplerate / samplecount
-    drawcount = drawrate * duration
+    drawrate = args.samplerate / samplecount
+    drawcount = drawrate * args.time
     print("len={} samples={} drawrate={:.2f} count={:.2f}".format(len(wave), samplecount, drawrate, drawcount))
 
     data = bytearray()
@@ -116,7 +125,7 @@ def main():
         data.extend(wave)
     print("len={}".format(len(data)))
 
-    write_waveform(bytes(data), outfile)
+    write_waveform(bytes(data), args.output, args.samplerate)
 
 if __name__ == "__main__":
     main()