Try putting self.update() at the d of your setDataethod?
On Fri, Aug 17, 2018, 01:51 Lior Weintraub <[email protected]> wrote:
> Hi Luke,
>
> I love pyqtgraph and use it whenever I need to plot data.
> I tried to make a live cadlestick plot but none of the options worked.
> The plot doesn't update unless I zoom in/out (interact with the window).
> The code I use:
>
> import pyqtgraph as pg
> from pyqtgraph import QtCore, QtGui
> import collections
> import numpy as np
>
> class CandlestickItem(pg.GraphicsObject):
> data = []
> def __init__(self):
> pg.GraphicsObject.__init__(self)
> self.picture = QtGui.QPicture()
>
> def setData(self, toclh):
> # toclh is a tuple of (time, open, close, min, max)
> self.data.append(toclh)
> p = QtGui.QPainter(self.picture)
> p.setPen(pg.mkPen('w'))
> w = 1./3.
> for (t, open, close, min, max) in self.data:
> p.drawLine(QtCore.QPointF(t, min), QtCore.QPointF(t, max))
> if open > close:
> p.setBrush(pg.mkBrush('r'))
> else:
> p.setBrush(pg.mkBrush('g'))
> p.drawRect(QtCore.QRectF(t-w, open, w*2, close-open))
> p.end()
>
>
> def paint(self, p, *args):
> p.drawPicture(0, 0, self.picture)
>
> def boundingRect(self):
> ## boundingRect _must_ indicate the entire area that will be
> drawn on
> ## or else we will get artifacts and possibly crashing.
> ## (in this case, QPicture does all the work of computing the
> bouning rect for us)
> return QtCore.QRectF(self.picture.boundingRect())
>
> data = [ ## fields are (time, open, close, min, max).
> (1., 10, 13, 5, 15),
> (2., 13, 17, 9, 20),
> (3., 17, 14, 11, 23),
> (4., 14, 15, 5, 19),
> (5., 15, 9, 8, 22),
> (6., 9, 15, 8, 16),
> ]
>
>
> class DynamicPlotter():
> def __init__(self, sampleinterval, timewindow, size=(600,350)):
> # Data stuff
> self.tick_idx = 0
> self._bufsize = int(timewindow/sampleinterval)
> self.databuffer = collections.deque([0.0]*self._bufsize, self.
> _bufsize)
> self.x = np.linspace(0.0, timewindow, self._bufsize)
> self.y = np.zeros(self._bufsize, dtype=np.float)
> # Candlestick data
> self.candlestick_item = CandlestickItem()
> # PyQtGraph stuff
> self.app = QtGui.QApplication([])
> self.plt = pg.plot(title='Plot Viewer')
> self.plt.resize(*size)
> self.plt.showGrid(x=True, y=True)
> self.plt.setLabel('left', 'amplitude', 'V')
> self.plt.setLabel('bottom', 'time', 's')
> self.plt.setXRange(0.,timewindow)
> self.plt.setYRange(0.,30)
> self.curve = self.plt.plot(self.x, self.y, pen=(255,0,0))
> self.plt.addItem(self.candlestick_item)
>
>
> # QTimer
> self.timer = QtCore.QTimer()
> self.timer.timeout.connect(self.updateplot)
> self.timer.start(1000)
>
>
> def updateplot(self):
> if(self.tick_idx < len(data)):
> self.candlestick_item.setData(data[self.tick_idx])
> self.databuffer.appendleft( 1.0 )
> self.y[:] = self.databuffer
> self.curve.setData(self.x, self.y)
> self.tick_idx += 1
> self.app.processEvents()
>
>
> def run(self):
> self.app.exec_()
>
>
> if __name__ == '__main__':
> m = DynamicPlotter(sampleinterval=1., timewindow=7.)
> m.run()
>
>
>
>
>
> Thanks,
> Lior.
>
> On Tuesday, March 12, 2013 at 11:09:20 PM UTC+2, Luke Campagnola wrote:
>>
>>
>>
>> On Tue, Mar 12, 2013 at 4:33 PM, Julio Trevisan <[email protected]>
>> wrote:
>>
>>> Hi Luke
>>>
>>> Yes, it solved my original problem! Thank you so much for this!!!
>>>
>>> May I ask you a related question? I saw your comment inside
>>> CustomGraphicsItem saying that generating a QPicture makes rendering
>>> faster. I believe that this is not the case if I want to update my plot in
>>> realtime. In such case, it would be better to draw the primitives when
>>> paint is requested. What do you think?
>>>
>>
>> That's correct; if you expect each data set to be drawn only once, then
>> using QPicture will probably slow you down. Note that if you get rid of
>> QPicture, then you'll also have to do your own bounding rectangle
>> calculations. The boundingRect() methods are called quite frequently, so
>> make sure to optimize that as much as you can. If you have trouble with
>> performance, I'd be happy to discuss the tricks I've used.
>>
>> Luke
>>
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