Dear Sir, I have been using pglive 0.3.3 and very much impressed with your work. Thank you very much for developing the module, it really simplifies the development effort to making pyqtgraph live. I use pglive for plotting live stock quote (just a live line plot, i have also tested candleplot too).

problem : I have recently updated the version to 0.4.4 and my previously working code is not usable now. I use livelineplot, and cb_set_data and cb_append_data_point to load initial data and append live data respectively. In the ver0.3.3, when the initial set of historical data is loaded using cb_set_data, the x,y axis view is is properly set and can see the plot (even if live data is unavailable). Whereas in the ver0.4.4, possibly because of introducing the x and y live axis controller, once initial data is set using cb_set_data , the plot view is blank. Note,I use datetime axis on X. Once cb_set_data command is issued, the x axis defaults to epoch (1970) and y axis is 0 to1. I am unable to autorange even by clicking the 'A' button of pyqtgraph which is on the bottom left.

However, once the live data arrives, the plot shows up in the view box. Please let me know the method to enable x,y auto range during normal conditions (i.e, prior to the arrival of live data). I need to view historical data sometimes, when the live tick is not available. Actually, I would like to know the autorange command just like we use for pg.PlotWidget so that i can enable it as and when the view changes. I do not want to use pg.PlotWidget commands like setXrange, setLimits etc beacuse it interferes with pglive auto range features during live tick plotting.

Hello,

I have successfully been using PGlive for awhile now and love it.

Can PGlive do Horizontal Bar chart with categories like below?

If so can you add some details to accomplish this? Categories on the Y-axis and keep the time on the X-axis.

Thanks for a great charting app!

Hi, I am a little confused with cb_set_data and cb_append_data_point. Source code says, it "replaces current data" for cb_set_data, and "appends new data point" for cb_append_data_point. My understanding is that, when using cb_append_data_point, we can retain old data. For instance, if the plot widget is set to max_points of 600, the plot will start scrolling when it reaches max_points, but we will be able to pan and look at the past data if cb_append_data_point is used. Whereas, if we use cb_set_data, points in the view box will be replaced by a new set of data points when max_point is reached. Please let me know if this is correct. Thanks.

I initialize a LiveLinePlot, which is passed to a DataConnector for later updating. On the first iteration where I try to add a datapoint through the connecter via cb_append_data_point I receive the following error:

/home/user/.local/lib/python3.10/site-packages/pyqtgraph/debug.py:128: RuntimeWarning: Ignored exception:
Traceback (most recent call last):
  File "/home/user/path/pysideGUI.py", line 1101, in <module>
    app.exec()
  File "/home/user/.local/lib/python3.10/site-packages/pglive/sources/live_plot_widget.py", line 165, in paintEvent
    return super().paintEvent(ev)
  File "/home/user/.local/lib/python3.10/site-packages/pyqtgraph/widgets/GraphicsView.py", line 137, in paintEvent
    return super().paintEvent(ev)
  File "/home/user/.local/lib/python3.10/site-packages/pyqtgraph/debug.py", line 128, in w
    printExc('Ignored exception:')
  --- exception caught here ---
  File "/home/user/.local/lib/python3.10/site-packages/pyqtgraph/debug.py", line 126, in w
    func(*args, **kwds)
  File "/home/user/.local/lib/python3.10/site-packages/pyqtgraph/graphicsItems/PlotCurveItem.py", line 905, in paint
    p.drawLines(*self._getLineSegments())
TypeError: QPainter.drawLines() takes exactly one argument (0 given)
  printExc('Ignored exception:')

I've found that checking for the presence of data in the x or y variable in the DataConnector and adding the first datapoint twice if there is none prevents the error from appearing. E.g.:

if len(connector.x) < 1:
  *add extra datapoint*
*add datapoint like normal*

It seems like there just needs to be an additional check somewhere(?)

Using: Python 3.10 pglive 0.5.5

Not sure if its a bug or simply requires proper formatting on my part. Using bottom_axis = LiveAxis("bottom", **{Axis.TICK_FORMAT: Axis.TIME}) the X crosshair is displayed in raw unformatted epoch time.

Can you suggest a way to format the X crosshair label when using tick format Time?

thank you

Is LiveAxisRange supposed to work with multiple plots? if you turn one of the plots off with the legend the "A" autorange breaks and plots disappear.

    PV1watts_plot = LiveLinePlot(pen='orange',name='PV-1',fillLevel=0, brush=(213,129,44,100))
    PV2watts_plot = LiveLinePlot(pen='cyan',name='PV-2', fillLevel=0, brush=(102,102,255,100))

    # Data connectors for each plot with dequeue of max_points
    self.PV1watts_connector = DataConnector(PV1watts_plot, max_points=48000) 
    self.PV2watts_connector = DataConnector(PV2watts_plot, max_points=48000) 


    # Setup bottom axis with TIME tick format
    # use Axis.DATETIME to show date
    pv1_watts_bottom_axis = LiveAxis("bottom", **{Axis.TICK_FORMAT: Axis.TIME})

    # Create plot
    self.PV1_graph_Widget = LivePlotWidget(title="Charger 1 & 2 Watts 1 Hour of 24",
    axisItems={'bottom': pv1_watts_bottom_axis},
    x_range_controller=LiveAxisRange(roll_on_tick=1800, offset_left=1), **kwargs)

    self.PV1_graph_Widget.x_range_controller.crop_left_offset_to_data = True
    
  
    # Show grid
    self.PV1_graph_Widget.showGrid(x=True, y=True, alpha=0.3)

    # Set labels
    self.PV1_graph_Widget.setLabel('bottom')
    self.PV1_graph_Widget.setLabel('left', 'Watts')

    self.PV1_graph_Widget.addLegend() # If plot is named, auto add name to legend

    # Add Line
    self.PV1_graph_Widget.addItem(PV1watts_plot)
    self.PV1_graph_Widget.addItem(PV2watts_plot)

    # Add chart to Layout in Qt Designer
    self.PV1_Watts_Layout.addWidget(self.PV1_graph_Widget)

Thanks for making this. Using your examples I can make a stand alone window with my live data and it looks and works great.

I am having difficulty placing the widget into an existing window made with PYQT designer. I have promoted a Qwidget to a PlotWidget class but cannot figure out how to embed it into the promoted widget.

Can you include an example how this might be achieved?

Thank you.

Per the pyqtgraph documentation it's possible to specify the connectivity of data points on a line plot via the PlotDataItem:

connect supports the following arguments:

- ‘all’ connects all points.- 
- ‘pairs’ generates lines between every other point.- 
- ‘finite’ creates a break when a nonfinite points is encountered.- 
- If an ndarray is passed, it should contain N int32 values of 0 or 1. Values of 1 indicate that the respective point will be connected to the next.- 
- In the default ‘auto’ mode, PlotDataItem will normally use ‘all’, but if any nonfinite data points are detected, it will automatically switch to ‘finite’.

The connect arg is also found in the PlotCurveItem.setData() function.

Is this supported in pglive? I haven't found anything for it so far.

I don't normally use a promoted widget but thought I would try it out in QT Designer. Normally I create the widget manually. If it's promoted and created in the QT Designer how do I add, LivePlotWidget(title="Chart Title", axisItems={'bottom': bottom_axis}, **kwargs)

I can add title with .setLabels I can add axisItems with .setAxisItems

Those are done with pyqtgraph options. How do I add ** kwargs that recognize the pglive crosshairs?

Can it all be done with a one liner like I normally do with a widget created manually?

I know you're busy. Thanks for looking.

I cant determine if this is a pyqtgraph function or PGlive.

A graph with multiple plots and a legend. If you click an item in the legend box its plot is turned off in the graph. (its still collecting data)

What I have is three plots with what can be large variations in Y axis values. I was hoping to autorange the remaining plots when a plot is turned off from the legend. For example below. Turn off Watts and have Volts and Amps auto scale for best viewable resolution.

Are Crosshairs expected to work with the Categorized Bar Chart?

I think I would only need it for the Date Time Axis to see preciously when the state changed happened.