115 lines
2.8 KiB
Python
115 lines
2.8 KiB
Python
# -*- coding: utf-8 -*-
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"""
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Various methods of drawing scrolling plots.
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"""
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import initExample ## Add path to library (just for examples; you do not need this)
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import pyqtgraph as pg
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from pyqtgraph.Qt import QtCore, QtGui
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import numpy as np
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from time import perf_counter
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win = pg.GraphicsLayoutWidget(show=True)
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win.setWindowTitle('pyqtgraph example: Scrolling Plots')
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# 1) Simplest approach -- update data in the array such that plot appears to scroll
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# In these examples, the array size is fixed.
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p1 = win.addPlot()
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p2 = win.addPlot()
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data1 = np.random.normal(size=300)
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curve1 = p1.plot(data1)
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curve2 = p2.plot(data1)
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ptr1 = 0
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def update1():
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global data1, ptr1
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data1[:-1] = data1[1:] # shift data in the array one sample left
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# (see also: np.roll)
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data1[-1] = np.random.normal()
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curve1.setData(data1)
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ptr1 += 1
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curve2.setData(data1)
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curve2.setPos(ptr1, 0)
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# 2) Allow data to accumulate. In these examples, the array doubles in length
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# whenever it is full.
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win.nextRow()
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p3 = win.addPlot()
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p4 = win.addPlot()
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# Use automatic downsampling and clipping to reduce the drawing load
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p3.setDownsampling(mode='peak')
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p4.setDownsampling(mode='peak')
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p3.setClipToView(True)
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p4.setClipToView(True)
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p3.setRange(xRange=[-100, 0])
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p3.setLimits(xMax=0)
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curve3 = p3.plot()
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curve4 = p4.plot()
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data3 = np.empty(100)
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ptr3 = 0
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def update2():
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global data3, ptr3
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data3[ptr3] = np.random.normal()
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ptr3 += 1
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if ptr3 >= data3.shape[0]:
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tmp = data3
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data3 = np.empty(data3.shape[0] * 2)
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data3[:tmp.shape[0]] = tmp
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curve3.setData(data3[:ptr3])
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curve3.setPos(-ptr3, 0)
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curve4.setData(data3[:ptr3])
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# 3) Plot in chunks, adding one new plot curve for every 100 samples
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chunkSize = 100
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# Remove chunks after we have 10
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maxChunks = 10
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startTime = perf_counter()
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win.nextRow()
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p5 = win.addPlot(colspan=2)
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p5.setLabel('bottom', 'Time', 's')
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p5.setXRange(-10, 0)
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curves = []
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data5 = np.empty((chunkSize+1,2))
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ptr5 = 0
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def update3():
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global p5, data5, ptr5, curves
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now = perf_counter()
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for c in curves:
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c.setPos(-(now-startTime), 0)
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i = ptr5 % chunkSize
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if i == 0:
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curve = p5.plot()
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curves.append(curve)
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last = data5[-1]
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data5 = np.empty((chunkSize+1,2))
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data5[0] = last
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while len(curves) > maxChunks:
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c = curves.pop(0)
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p5.removeItem(c)
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else:
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curve = curves[-1]
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data5[i+1,0] = now - startTime
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data5[i+1,1] = np.random.normal()
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curve.setData(x=data5[:i+2, 0], y=data5[:i+2, 1])
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ptr5 += 1
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# update all plots
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def update():
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update1()
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update2()
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update3()
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timer = pg.QtCore.QTimer()
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timer.timeout.connect(update)
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timer.start(50)
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if __name__ == '__main__':
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pg.exec()
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