Require Text Labels instead of only numbers on Pyqtgraph plot axis - how???

[Manfred Sever]

Hello,

I am very new to Python and to Pyqtgraph.

Below I have a simple plotting function.  I supply x and y data vectors (numbers) and a title and I get a plot.

However, my data'x values are actually text and not numbers.  In one case the text labels are date with time.  In another case the text contains descriptive text to label categories of a histogram.

I've scanned the documentation, which doesn't seem very complete and cannot find an obvious way to plot either the x or the y data if it contains text (string values) instead of numbers.

Only idea I have come up with, shown, below, is to add (for example) the xLabel argument.  Then make a text item for each text label on the axis.

Below, I only plot every 100th text label (of possible tens of thousands).  The problem is that if the plot window size is changed, or the zoom level of the plot in the window is changed, then every 100th text label is no longer appropriate.

I think I need to be able to detect when the plot window size or plot zoom level is changed, and based on those parameters, calculate how many of the text labels can nicely be shown on the plot axis.  (If I zoom in far enough I want to see all text labels corresponding to data shown in the plot window, etc.

Apparently, from the documentation, I need to define a: signal, event or a slot (what's the difference anyway) to detect a change in zoom level or size, then read the new parameters (zoom level, size, etc), make the calculation and redraw the text.

Can anyone tell me how to correctly accomplish this?  I don't even know where to start reading to understand what to do; and honestly I don't think I have that much time left for this.

Or, is there a better way to accomplish how I need to make the plot axes_

Thanks,

Manfred.

import pyqtgraph as pg

def simple_plot(x, y, plotTitle, xLabel = None):

    """  Make a basic plot with title.

    """

    plotWidget = pg.plot(title = plotTitle)

    plotWidget.plot(x, y)

    plotWidget.showGrid(x=True, y=True, alpha=100.0)

    #

    if len(xLabel):

        for i in np.arange(0, len(xLabel), 100):

            text = pg.TextItem(str(xLabel[i]), anchor=(0.3,-0.5), angle=90)

            plotWidget.addItem(text)

            text.setPos(i, 0)