"""
Emulate an oscilloscope. Requires the animation API introduced in
matplotlib 0.84. See
http://www.scipy.org/wikis/topical_software/Animations for an
explanation.
This example uses gtk but does not depend on it intimately. It just
uses the idle handler to trigger events. You can plug this into a
different GUI that supports animation (GTKAgg, TkAgg, WXAgg) and use
your toolkits idle/timer functions.
"""
import gobject, gtk
import matplotlib
matplotlib.use('GTKAgg')
import numpy as np
from matplotlib.lines import Line2D
class Scope:
def __init__(self, ax, maxt=10, dt=0.01):
self.ax = ax
self.canvas = ax.figure.canvas
self.dt = dt
self.maxt = maxt
self.tdata = [0]
self.ydata = [0]
self.line = Line2D(self.tdata, self.ydata, animated=True)
self.ax.add_line(self.line)
self.background = None
self.canvas.mpl_connect('draw_event', self.update_background)
self.ax.set_ylim(-.1, 1.1)
self.ax.set_xlim(0, self.maxt)
def update_background(self, event):
self.background = self.canvas.copy_from_bbox(self.ax.bbox)
def emitter(self, p=0.01):
'return a random value with probability p, else 0'
v = np.random.rand(1)
if v>p: return 0.
else: return np.random.rand(1)
def update(self, *args):
if self.background is None: return True
y = self.emitter()
lastt = self.tdata[-1]
if lastt>self.tdata[0]+self.maxt: # reset the arrays
self.tdata = [self.tdata[-1]]
self.ydata = [self.ydata[-1]]
self.ax.set_xlim(self.tdata[0], self.tdata[0]+self.maxt)
self.ax.figure.canvas.draw()
self.canvas.restore_region(self.background)
t = self.tdata[-1] + self.dt
self.tdata.append(t)
self.ydata.append(y)
self.line.set_data(self.tdata, self.ydata)
self.ax.draw_artist(self.line)
self.canvas.blit(self.ax.bbox)
return True
from pylab import figure,show
fig = figure()
ax = fig.add_subplot(111)
scope = Scope(ax)
gobject.idle_add(scope.update)
show()
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