Initial revision

Lib/stdwin/VUMeter.py

@@ -0,0 +1,46 @@
+# Module VUMeter
+
+import audio
+from StripChart import StripChart
+
+K = 1024
+Rates = [0, 32*K, 16*K, 8*K]
+
+class VUMeter() = StripChart():
+	#
+	# Override define() and timer() methods
+	#
+	def define(self, (win, bounds)):
+		self = StripChart.define(self, (win, bounds, 128))
+		self.sampling = 0
+		self.rate = 3
+		self.enable(0)
+		return self
+	#
+	def timer(self):
+		if self.sampling:
+			chunk = audio.wait_recording()
+			self.sampling = 0
+			nums = audio.chr2num(chunk)
+			ampl = max(abs(min(nums)), abs(max(nums)))
+			self.append(ampl)
+		if self.enabled and not self.sampling:
+			audio.setrate(self.rate)
+			size = Rates[self.rate]/10
+			size = size/48*48
+			audio.start_recording(size)
+			self.sampling = 1
+		if self.sampling:
+			self.win.settimer(1)
+	#
+	# New methods: start() and stop()
+	#
+	def stop(self):
+		if self.sampling:
+			chunk = audio.stop_recording()
+			self.sampling = 0
+		self.enable(0)
+	#
+	def start(self):
+		self.enable(1)
+		self.timer()