pyqtgraph/examples/PlotSpeedTest.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
"""
Update a simple plot as rapidly as possible to measure speed.
"""

## Add path to library (just for examples; you do not need this)
import initExample

from collections import deque
from pyqtgraph.Qt import QtCore, QtGui, QtWidgets, QT_LIB
import numpy as np
import pyqtgraph as pg
from time import perf_counter
import pyqtgraph.parametertree as ptree
import pyqtgraph.functions as fn
import itertools
import argparse

if QT_LIB.startswith('PyQt'):
    wrapinstance = pg.Qt.sip.wrapinstance
else:
    wrapinstance = pg.Qt.shiboken.wrapInstance

# defaults here result in the same configuration as the original PlotSpeedTest
parser = argparse.ArgumentParser()
parser.add_argument('--noise', dest='noise', action='store_true')
parser.add_argument('--no-noise', dest='noise', action='store_false')
parser.set_defaults(noise=True)
parser.add_argument('--nsamples', default=5000, type=int)
parser.add_argument('--frames', default=50, type=int)
parser.add_argument('--fsample', default=1000, type=float)
parser.add_argument('--frequency', default=0, type=float)
parser.add_argument('--amplitude', default=5, type=float)
parser.add_argument('--opengl', dest='use_opengl', action='store_true')
parser.add_argument('--no-opengl', dest='use_opengl', action='store_false')
parser.set_defaults(use_opengl=None)
parser.add_argument('--allow-opengl-toggle', action='store_true',
    help="""Allow on-the-fly change of OpenGL setting. This may cause unwanted side effects.
    """)
args = parser.parse_args()

if args.use_opengl is not None:
    pg.setConfigOption('useOpenGL', args.use_opengl)
    pg.setConfigOption('enableExperimental', args.use_opengl)

# don't limit frame rate to vsync
sfmt = QtGui.QSurfaceFormat()
sfmt.setSwapInterval(0)
QtGui.QSurfaceFormat.setDefaultFormat(sfmt)

class LineInstances:
    def __init__(self):
        self.alloc(0)

    def alloc(self, size):
        self.arr = np.empty((size, 4), dtype=np.float64)
        self.ptrs = list(map(wrapinstance,
            itertools.count(self.arr.ctypes.data, self.arr.strides[0]),
            itertools.repeat(QtCore.QLineF, self.arr.shape[0])))

    def array(self, size):
        if size > self.arr.shape[0]:
            self.alloc(size + 16)
        return self.arr[:size]

    def instances(self, size):
        return self.ptrs[:size]

class MonkeyCurveItem(pg.PlotCurveItem):
    def __init__(self, *args, **kwds):
        super().__init__(*args, **kwds)
        self.monkey_mode = ''
        self._lineInstances = LineInstances()

    def setMethod(self, param, value):
        self.monkey_mode = value

    def paint(self, painter, opt, widget):
        if self.monkey_mode not in ['drawPolyline', 'drawLines']:
            return super().paint(painter, opt, widget)

        painter.setRenderHint(painter.RenderHint.Antialiasing, self.opts['antialias'])
        painter.setPen(pg.mkPen(self.opts['pen']))

        if self.monkey_mode == 'drawPolyline':
            painter.drawPolyline(fn.arrayToQPolygonF(self.xData, self.yData))
        elif self.monkey_mode == 'drawLines':
            lines = self._lineInstances
            npts = len(self.xData)
            even_slice = slice(0, 0+(npts-0)//2*2)
            odd_slice = slice(1, 1+(npts-1)//2*2)
            for sl in [even_slice, odd_slice]:
                npairs = (sl.stop - sl.start) // 2
                memory = lines.array(npairs).reshape((-1, 2))
                memory[:, 0] = self.xData[sl]
                memory[:, 1] = self.yData[sl]
                painter.drawLines(lines.instances(npairs))

app = pg.mkQApp("Plot Speed Test")

default_pen = pg.mkPen()

children = [
    dict(name='sigopts', title='Signal Options', type='group', children=[
        dict(name='noise', type='bool', value=args.noise),
        dict(name='nsamples', type='int', limits=[0, None], value=args.nsamples),
        dict(name='frames', type='int', limits=[1, None], value=args.frames),
        dict(name='fsample', title='sample rate', type='float', value=args.fsample, units='Hz'),
        dict(name='frequency', type='float', value=args.frequency, units='Hz'),
        dict(name='amplitude', type='float', value=args.amplitude),
    ]),
    dict(name='useOpenGL', type='bool', value=pg.getConfigOption('useOpenGL'),
        readonly=not args.allow_opengl_toggle),
    dict(name='enableExperimental', type='bool', value=pg.getConfigOption('enableExperimental')),
    dict(name='pen', type='pen', value=default_pen),
    dict(name='antialias', type='bool', value=pg.getConfigOption('antialias')),
    dict(name='connect', type='list', values=['all', 'pairs', 'finite', 'array'], value='all'),
    dict(name='skipFiniteCheck', type='bool', value=False),
    dict(name='plotMethod', title='Plot Method', type='list', values=['pyqtgraph', 'drawPolyline', 'drawLines'])
]

params = ptree.Parameter.create(name='Parameters', type='group', children=children)
pt = ptree.ParameterTree(showHeader=False)
pt.setParameters(params)
pw = pg.PlotWidget()
splitter = QtWidgets.QSplitter()
splitter.addWidget(pt)
splitter.addWidget(pw)
splitter.show()

pw.setWindowTitle('pyqtgraph example: PlotSpeedTest')
pw.setLabel('bottom', 'Index', units='B')
curve = MonkeyCurveItem(pen=default_pen)
pw.addItem(curve)

rollingAverageSize = 1000
elapsed = deque(maxlen=rollingAverageSize)

def resetTimings(*args):
    elapsed.clear()

def makeData(*args):
    global data, connect_array, ptr
    sigopts = params.child('sigopts')
    nsamples = sigopts['nsamples']
    frames = sigopts['frames']
    Fs = sigopts['fsample']
    A = sigopts['amplitude']
    F = sigopts['frequency']
    ttt = np.arange(frames * nsamples, dtype=np.float64) / Fs
    data = A*np.sin(2*np.pi*F*ttt).reshape((frames, nsamples))
    if sigopts['noise']:
        data += np.random.normal(size=data.shape)
    connect_array = np.ones(data.shape[-1], dtype=bool)
    ptr = 0
    pw.setRange(QtCore.QRectF(0, -10, nsamples, 20))

def onUseOpenGLChanged(param, enable):
    pw.useOpenGL(enable)

def onEnableExperimentalChanged(param, enable):
    pg.setConfigOption('enableExperimental', enable)

def onPenChanged(param, pen):
    curve.setPen(pen)

params.child('sigopts').sigTreeStateChanged.connect(makeData)
params.child('useOpenGL').sigValueChanged.connect(onUseOpenGLChanged)
params.child('enableExperimental').sigValueChanged.connect(onEnableExperimentalChanged)
params.child('pen').sigValueChanged.connect(onPenChanged)
params.child('plotMethod').sigValueChanged.connect(curve.setMethod)
params.sigTreeStateChanged.connect(resetTimings)

makeData()

fpsLastUpdate = perf_counter()
def update():
    global curve, data, ptr, elapsed, fpsLastUpdate

    options = ['antialias', 'connect', 'skipFiniteCheck']
    kwds = { k : params[k] for k in options }
    if kwds['connect'] == 'array':
        kwds['connect'] = connect_array

    # Measure
    t_start = perf_counter()
    curve.setData(data[ptr], **kwds)
    app.processEvents(QtCore.QEventLoop.ProcessEventsFlag.AllEvents)
    t_end = perf_counter()
    elapsed.append(t_end - t_start)
    ptr = (ptr + 1) % data.shape[0]

    # update fps at most once every 0.2 secs
    if t_end - fpsLastUpdate > 0.2:
        fpsLastUpdate = t_end
        average = np.mean(elapsed)
        fps = 1 / average
        pw.setTitle('%0.2f fps - %0.1f ms avg' % (fps, average * 1_000))

timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(0)

if __name__ == '__main__':
    pg.exec()