You could start with something like this, just use collectData function to
calculate your data and put it to self.collected_data variable:
import pyqtgraph
import numpy
import threading
import time
class FuncThread(threading.Thread):
def __init__(self,target,*args):
self._target=target
self._args=args
threading.Thread.__init__(self)
def run(self):
self._target(*self._args)
class MainApp(object):
def __init__(self):
plot_loop_time = 0.1
self.sleep_time = 0.001
self.number_of_points = 100
self.collected_data = numpy.zeros([self.number_of_points])
app = pyqtgraph.mkQApp()
self.graphics_layout_widget = pyqtgraph.GraphicsLayoutWidget()
self.graphics_layout_widget.show()
plot = self.graphics_layout_widget.addPlot()
plot.setRange(yRange=(-200,200),disableAutoRange=True)
cd = FuncThread(self.collectData)
cd.start()
current_time = time.time()
while self.graphics_layout_widget.isVisible():
time.sleep(self.sleep_time)
plot.plot(self.collected_data)
app.processEvents()
while time.time() - current_time < plot_loop_time:
time.sleep(self.sleep_time)
plot.clear()
current_time = time.time()
def collectData(self):
while self.graphics_layout_widget.isVisible():
self.collected_data += numpy.random.uniform(-1, 1,
size=self.number_of_points)
time.sleep(self.sleep_time)
MainApp()
On Mon, Jul 25, 2016 at 8:18 PM, <[email protected]> wrote:
> .replace('one or calculation', 'other one for a calculation')
>
> On Mon, Jul 25, 2016 at 8:14 PM, <[email protected]> wrote:
>
>> Hi.
>>
>> I think that you need to put all pyqtgraph and other graphic stuff
>> (including window initialization, processEvents etc.) in a separate thread
>> and to plot a shared data you have every 0.1s. Look at FuncThread class at
>> bottom of page
>> http://softwareramblings.com/2008/06/running-functions-as-threads-in-python.html,
>> could save you a time. So, one thread for graphic stuff, one or calculation.
>>
>> Good luck,
>> Vasilije
>>
>> On Mon, Jul 25, 2016 at 4:52 PM, Igor Muniz <[email protected]>
>> wrote:
>>
>>> Hi guys,
>>>
>>> I'm trying to plot a real time signal with python and PyQtGraph has
>>> improved the speed a lot, but still with some delay. The data comes from a
>>> DLL and it's store in a NumPy Vector.
>>> I wan't to plot this buffer every 0.1s with 100 points(the signal has
>>> 1kHz sampling rate). At the beginning this seems to work but after few
>>> seconds starts to get behind the plot.
>>>
>>> This is part of my code:
>>>
>>> def coleta():
>>> global cnt
>>> global t
>>>
>>> nsample = c_ulong(int(0.1 * sampleRate.value))
>>>
>>> status = emgSampleNSeconds(handle.value, 50)
>>>
>>> if status == 0:
>>> print("Inicia a amostragem")
>>> else:
>>> print("Não foi possível iniciar a amostragem")
>>> emgIsSampling(handle.value, byref(isSampling))
>>>
>>>
>>> canal = c_ulong(0)
>>> emgbuffer = (c_double * nsample.value)()
>>>
>>>
>>>
>>>
>>> emgDataPlot = np.zeros(10000, dtype=float)
>>>
>>> curve1 = p1.plot(emgDataPlot, pen='r')
>>> sleepVar = 0.1
>>> pltStart = pg.ptime.time()
>>> while isSampling:
>>> time.sleep(sleepVar)
>>> emgGetRealUnitDataBlock(handle.value, canal.value, emgbuffer,
>>> byref(nsample))
>>> now = time.time()
>>> for value in emgbuffer:
>>> emgDataPlot = np.append(emgDataPlot, value)
>>> if len(emgDataPlot) > sampleRate.value * 10:
>>> emgDataPlot = np.delete(emgDataPlot, 0)
>>>
>>> if t == 0:
>>> p1.enableAutoRange('xy', False) ## stop auto-scaling after the
>>> first data set is plotted
>>>
>>> t += 1
>>>
>>> curve1.setData(emgDataPlot)
>>> app.processEvents()
>>>
>>> #print(t)
>>> emgIsSampling(handle.value, byref(isSampling))
>>>
>>> #p1.enableAutoRange(True, True)
>>> print(pltStart - pg.ptime.time())
>>>
>>>
>>> What I need to do?
>>> Thanks.
>>>
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>>
>>
>
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