import wx
import matplotlib
import matplotlib.pyplot as plt
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigureCanvas
import time
from random import random
from threading import Thread
from setproctitle import setproctitle


print ( 'Matplotlib version: ' + matplotlib.__version__ )


class measurement_instrument():
# measurement instrument

	def __init__(self):
		self.t = []
		self.val = []
		self.max_values = 1000
		
	def read(self):
		# get new data from the instrument:
		self.t.append( time.time() )
		self.val.append( random() )
		
		# truncate data length to max_values:
		self.t = self.t[-self.max_values:]
		self.val = self.val[-self.max_values:]


class measurement_thread(Thread):
# background thread that takes measurements at fixed time intervals

	def __init__(self, instrument):
		Thread.__init__(self)
		self._instrument = instrument
		self.start()
		
	def run(self):
		while True:
			self._instrument.read()
			time.sleep(0.01)


class plots_frame(wx.Frame):

	def __init__(self,instrument):

		# Access to measurement instrument (to get data for plotting):
		self._instrument = instrument
		
		# Create the window:		
		wx.Frame.__init__(self, parent=None, title='Instrument Data', style=wx.DEFAULT_FRAME_STYLE)
		
		# Create a wx panel to hold the plots
		p  = wx.Panel(self)
		p.SetBackgroundColour(wx.NullColour)
		
		# Set up figure:
		self.figure = plt.figure()
		self.axes = self.figure.add_subplot(1,1,1)
		self.axes.grid()	
		self.canvas = FigureCanvas(p, -1, self.figure)

		# wx sizer / widget arrangement within the window:
		sizer = wx.BoxSizer(wx.VERTICAL)
		sizer.Add(self.canvas, 1, wx.EXPAND)
		p.SetSizer(sizer) # apply the sizer to the panel
		sizer.SetSizeHints(self) # inform frame about size hints for the panel (min. plot canvas size and stuff)

		# install wx.Timer to update the data plot:
		self.Bind(wx.EVT_TIMER, self.on_plot_data) # bind to TIMER event
		self.plot_timer = wx.Timer(self) # timer to trigger plots
		wx.CallAfter(self.plot_timer.Start,100)
		
		# Show the wx.Frame
		self.Show()

	def on_plot_data(self,event):

		# Remove all the lines that are currently in the plot:
		while len(self.axes.lines) > 0: self.axes.lines[0].remove()
		
		# Plot the instrument data:
		self.axes.plot(self._instrument.t, self._instrument.val, label='data', color='r' )

		# x-axis limits:
		self.axes.set_xlim( [ self._instrument.t[0], self._instrument.t[-1] ] )

		# Legend (commenting out this line will avoid the memory issue!):
		self.axes.legend(loc='best')

		# Refresh the plot window:
		self.canvas.draw()
		self.Refresh()


# main:
setproctitle('memory_looser')
app = wx.App()
instrument   = measurement_instrument()
dataplots    = plots_frame(instrument)
measurements = measurement_thread(instrument)

app.MainLoop()