pyqtgraph/examples/RemoteSpeedTest.py
Luke Campagnola 513e904a59 Improved performance for remote plotting:
- reduced cost of transferring arrays between processes (pickle is too slow)
  - avoid unnecessary synchronous calls

Added RemoteSpeedTest example
2013-01-10 16:10:27 -05:00

79 lines
2.9 KiB
Python

# -*- coding: utf-8 -*-
"""
This example demonstrates the use of RemoteGraphicsView to improve performance in
applications with heavy load. It works by starting a second process to handle
all graphics rendering, thus freeing up the main process to do its work.
In this example, the update() function is very expensive and is called frequently.
After update() generates a new set of data, it can either plot directly to a local
plot (bottom) or remotely via a RemoteGraphicsView (top), allowing speed comparison
between the two cases. IF you have a multi-core CPU, it should be obvious that the
remote case is much faster.
"""
import initExample ## Add path to library (just for examples; you do not need this)
from pyqtgraph.Qt import QtGui, QtCore
import pyqtgraph as pg
import pyqtgraph.widgets.RemoteGraphicsView
import numpy as np
app = pg.mkQApp()
view = pg.widgets.RemoteGraphicsView.RemoteGraphicsView()
pg.setConfigOptions(antialias=True) ## this will be expensive for the local plot
view.pg.setConfigOptions(antialias=True) ## prettier plots at no cost to the main process!
label = QtGui.QLabel()
rcheck = QtGui.QCheckBox('plot remote')
rcheck.setChecked(True)
lcheck = QtGui.QCheckBox('plot local')
lplt = pg.PlotWidget()
layout = pg.LayoutWidget()
layout.addWidget(rcheck)
layout.addWidget(lcheck)
layout.addWidget(label)
layout.addWidget(view, row=1, col=0, colspan=3)
layout.addWidget(lplt, row=2, col=0, colspan=3)
layout.resize(800,800)
layout.show()
## Create a PlotItem in the remote process that will be displayed locally
rplt = view.pg.PlotItem()
rplt._setProxyOptions(deferGetattr=True) ## speeds up access to rplt.plot
view.setCentralItem(rplt)
lastUpdate = pg.ptime.time()
avgFps = 0.0
def update():
global check, label, plt, lastUpdate, avgFps, rpltfunc
data = np.random.normal(size=(10000,50)).sum(axis=1)
data += 5 * np.sin(np.linspace(0, 10, data.shape[0]))
if rcheck.isChecked():
rplt.plot(data, clear=True, _callSync='off') ## We do not expect a return value.
## By turning off callSync, we tell
## the proxy that it does not need to
## wait for a reply from the remote
## process.
if lcheck.isChecked():
lplt.plot(data, clear=True)
now = pg.ptime.time()
fps = 1.0 / (now - lastUpdate)
lastUpdate = now
avgFps = avgFps * 0.8 + fps * 0.2
label.setText("Generating %0.2f fps" % avgFps)
timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(0)
## Start Qt event loop unless running in interactive mode or using pyside.
if __name__ == '__main__':
import sys
if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
QtGui.QApplication.instance().exec_()