Add examples showing MIDI file playing.

Fix uninitialized field in Synth, custom_router_callback.
This allows MIDI generation without calling Synth.start().

fluidsynth.py

@@ -91,7 +91,7 @@ def cfunc(name, result, *args):
         return None
 
 # Bump this up when changing the interface for users
-api_version = '1.3.4'
+api_version = '1.3.5'
 
 # Function prototypes for C versions of functions
 
@@ -684,6 +684,7 @@ def __init__(self, gain=0.2, samplerate=44100, channels=256, **kwargs):
         self.audio_driver = None
         self.midi_driver = None
         self.router = None
+        self.custom_router_callback = None
     def setting(self, opt, val):
         """change an arbitrary synth setting, type-smart"""
         if isinstance(val, (str, bytes)):

test/test5.py

@@ -0,0 +1,27 @@
+import time
+
+import fluidsynth
+
+
+def local_file_path(file_name: str) -> str:
+    """
+    Return a file path to a file that is in the same directory as this file.
+    """
+    from os.path import dirname, join
+
+    return join(dirname(__file__), file_name)
+
+fs = fluidsynth.Synth()
+fs.start()
+## Your installation of FluidSynth may require a different driver.
+## Use something like:
+# fs.start(driver="pulseaudio")
+
+sfid = fs.sfload(local_file_path("example.sf2"))
+fs.program_select(0, sfid, 0, 0)
+
+fs.play_midi_file(local_file_path("1080-c01.mid"))
+while fluidsynth.fluid_player_get_status(fs.player) == fluidsynth.FLUID_PLAYER_PLAYING:
+    time.sleep(1)
+
+fs.delete()

test/test6.py

@@ -0,0 +1,42 @@
+import numpy
+import pyaudio
+import time
+
+import fluidsynth
+
+
+def local_file_path(file_name: str) -> str:
+    """
+    Return a file path to a file that is in the same directory as this file.
+    """
+    from os.path import dirname, join
+
+    return join(dirname(__file__), file_name)
+
+pa = pyaudio.PyAudio()
+strm = pa.open(
+    format = pyaudio.paInt16,
+    channels = 2,
+    rate = 44100,
+    output = True)
+
+fs = fluidsynth.Synth()
+fs.custom_router_callback = None
+
+sfid = fs.sfload(local_file_path("example.sf2"))
+fs.program_select(0, sfid, 0, 0)
+
+fs.play_midi_file(local_file_path("1080-c01.mid"))
+
+# Generate 10 seconds of audio into s
+s = []
+for _ in range(10):
+    s = numpy.append(s, fs.get_samples(44100))
+    if fluidsynth.fluid_player_get_status(fs.player) != fluidsynth.FLUID_PLAYER_PLAYING:
+        break
+
+fs.delete()
+
+samps = fluidsynth.raw_audio_string(s)
+print('Starting playback')
+strm.write(samps)