aligned animations with start time, added one-shot animation support

anim/__init__.py

-from .core import animation, Pixels, run
+from .core import animation, Pixels, run, AnimationCompleted

anim/core.py

@@ -115,6 +115,9 @@ def _(host: str, port: int):
 	mqttProxy = (host, port)
 
 
+class AnimationCompleted(Exception):
+	pass
+
 
 def run():
 	cli.process()
@@ -146,16 +149,21 @@ def run():
 	pixels.pixmap = pixmaps.dode_matrix
 	t0 = time.time()
 
+	tstart = t0
+
 	while True:
 
 		t1 = time.time()
 		dt = t1 - t0
 		t0 = t1
-		anim(dt,t1, pixels)
-		if not fDisplay.value or fTerminal.value:
-			pixels.render_terminal()
-		if fDisplay.value:
-			pixels.render_mqtt(mqtt_client)
-
+		try:
+			anim(dt, t1 - tstart, pixels)
+			if not fDisplay.value or fTerminal.value:
+				pixels.render_terminal()
+			if fDisplay.value:
+				pixels.render_mqtt(mqtt_client)
+
+		except AnimationCompleted:
+			break
 		delay = 1 / 60 - dt
 		if delay > 0: time.sleep(delay)