My suggestion would have been to look at the scrolling plot examples, but you have already done that. Have you tried using any of those? If so, why didn't they work for you?
On Wed, May 16, 2018, 23:39 Kaisar Khatak <[email protected]> wrote: > I have a real time application that uses a camera to measure eye aspect > ratio. The ratio will be an integer value and will fluctuate between 1-10 > (example). > > What is the easiest way to capture that value and display a scrolling plot > (best approach?) real time? Do I need threading? Just looking for simplest > solution to start off with... > > I have read the scrollingPlots.py examples... > > I have installled pyqtgraph and am running python 2/3 on ubuntu 16. > > > Thanks. > > > ---------------------------------------------------------------------------- > # -*- coding: utf-8 -*- > """ > Various methods of drawing scrolling plots. > """ > import initExample ## Add path to library (just for examples; you do not > need this) > > import pyqtgraph as pg > from pyqtgraph.Qt import QtCore, QtGui > import numpy as np > > win = pg.GraphicsLayoutWidget(show=True) > win.setWindowTitle('pyqtgraph example: Scrolling Plots') > > > # 1) Simplest approach -- update data in the array such that plot appears > to scroll > # In these examples, the array size is fixed. > p1 = win.addPlot() > p2 = win.addPlot() > data1 = np.random.normal(size=300) > curve1 = p1.plot(data1) > curve2 = p2.plot(data1) > ptr1 = 0 > def update1(): > global data1, ptr1 > data1[:-1] = data1[1:] # shift data in the array one sample left > # (see also: np.roll) > data1[-1] = np.random.normal() > curve1.setData(data1) > > ptr1 += 1 > curve2.setData(data1) > curve2.setPos(ptr1, 0) > > > # 2) Allow data to accumulate. In these examples, the array doubles in > length > # whenever it is full. > win.nextRow() > p3 = win.addPlot() > p4 = win.addPlot() > # Use automatic downsampling and clipping to reduce the drawing load > p3.setDownsampling(mode='peak') > p4.setDownsampling(mode='peak') > p3.setClipToView(True) > p4.setClipToView(True) > p3.setRange(xRange=[-100, 0]) > p3.setLimits(xMax=0) > curve3 = p3.plot() > curve4 = p4.plot() > > data3 = np.empty(100) > ptr3 = 0 > > def update2(): > global data3, ptr3 > data3[ptr3] = np.random.normal() > ptr3 += 1 > if ptr3 >= data3.shape[0]: > tmp = data3 > data3 = np.empty(data3.shape[0] * 2) > data3[:tmp.shape[0]] = tmp > curve3.setData(data3[:ptr3]) > curve3.setPos(-ptr3, 0) > curve4.setData(data3[:ptr3]) > > > # 3) Plot in chunks, adding one new plot curve for every 100 samples > chunkSize = 100 > # Remove chunks after we have 10 > maxChunks = 10 > startTime = pg.ptime.time() > win.nextRow() > p5 = win.addPlot(colspan=2) > p5.setLabel('bottom', 'Time', 's') > p5.setXRange(-10, 0) > curves = [] > data5 = np.empty((chunkSize+1,2)) > ptr5 = 0 > > def update3(): > global p5, data5, ptr5, curves > now = pg.ptime.time() > for c in curves: > c.setPos(-(now-startTime), 0) > > i = ptr5 % chunkSize > if i == 0: > curve = p5.plot() > curves.append(curve) > last = data5[-1] > data5 = np.empty((chunkSize+1,2)) > data5[0] = last > while len(curves) > maxChunks: > c = curves.pop(0) > p5.removeItem(c) > else: > curve = curves[-1] > data5[i+1,0] = now - startTime > data5[i+1,1] = np.random.normal() > curve.setData(x=data5[:i+2, 0], y=data5[:i+2, 1]) > ptr5 += 1 > > > # update all plots > def update(): > update1() > update2() > update3() > timer = pg.QtCore.QTimer() > timer.timeout.connect(update) > timer.start(50) > > > > ## 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_() > > -- > You received this message because you are subscribed to the Google Groups > "pyqtgraph" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/pyqtgraph/2ca21aaa-92a5-48eb-a3c9-7c5490032a24%40googlegroups.com > <https://groups.google.com/d/msgid/pyqtgraph/2ca21aaa-92a5-48eb-a3c9-7c5490032a24%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "pyqtgraph" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/pyqtgraph/CACZXET9sFCu51n45Hx8i9hU27h-ETnP4t2M1ycorV8Kd5Ptz2w%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
