ViewBox and mouse coordinates

[Bertram Gilfoyle]

Is there a way to find out which viewbox or widget the current mouse coordinates are on?

I'm plotting multiple viewboxes, each with one widget inside, then using SignalProxy to capture sigMouseMoved signals.

With one viewbox, it's simple but I'm pulling hairs on how to do it with multiple. Goal is to display a simple tooltip (TextItem).

[Edmondo Giovannozzi]

I have solved it this way:

class MousePosition(QtCore.QObject):
    def __init__(self, status_bar, pl, labels):
        super().__init__()
        self.pl = pl
        self.status_bar = status_bar
        self.labels = labels
        self.proxy = pg.SignalProxy(pl.scene().sigMouseMoved, rateLimit=10, slot=self.mousemoved)


    def mousemoved(self, evt):
        pos = evt[0]
        if self.pl.sceneBoundingRect().contains(pos):
            mousePoint = self.pl.vb.mapSceneToView(pos)
            self.status_bar.set_x(mousePoint.x(),self.labels[0])
            self.status_bar.set_y(mousePoint.y(),self.labels[1])
           
class StatusBarKK3:
    def __init__(self, window, plots):
        self.window = window
        self.plots = plots
        self.status_bar = window.statusBar()
       
        self.x_label = QtWidgets.QLabel("x: ")
        self.y_label = QtWidgets.QLabel("y: ")
       
        self.status_bar.addPermanentWidget(self.x_label)
        self.status_bar.addPermanentWidget(self.y_label)
        self.mouse_position = {}
        for (name,pl),labels in plots.items():
            self.mouse_position[pl] = MousePosition(self, pl, labels)
           
    def set_x(self, x, prefix='x'):
        self.x_label.setText(f"{prefix}: {x:8.5g}  ")
   
    def set_y(self, y, prefix='y'):
        self.y_label.setText(f"{prefix}: {y:8.5g}  ")

Where plots is a dict with keys being (name, plotItem) and value a string that I want to show  for the x and y coordinates on the status bar. At the moment name is not used and I may delete it.

Cheers,

[Edmondo Giovannozzi]

The plotsdictionary could be something like:

plots = {('Spectrum', spectrum_plot):('t','f'),

         ('Amplitude', amplitude_plot):('t','B')}

where spectrum_plot and amplitude_plot are plotItem object.

[Bertram Gilfoyle]

Looks great, thank you.

[Bertram Gilfoyle]

This is what I ended up with, almost identical what you provided.

The TextItem pulls values from a pandas column. There's also a vertical line as an X axis highlighter. PlotIndicators is initiated in a Main function (just a dict).

I haven't found a more intelligent way to hide the items when cursor is not in the scene. Main.chart.add does plot.addItem(item) in GraphicsLayoutWidget, refresh does 'clear' first.

class MousePosition(QObject):

   def __init__(self, plot, name):

       super().__init__()

       self.plot = plot

       self.name = name

       self.proxy = pg.SignalProxy(plot.scene().sigMouseMoved, rateLimit=60, slot=self.mouseMoved)

    def mouseMoved(self, event):

       pos = event[0]

       if self.plot.sceneBoundingRect().contains(pos):

           Main.plotIndicators.labels[self.name].show()

           Main.plotIndicators.cross[self.name].show()

           Main.plotIndicators.labelCoords(self.plot.vb.mapSceneToView(pos), self.name)

       else:

           Main.plotIndicators.labels[self.name].hide()

           Main.plotIndicators.cross[self.name].hide()

...

        for name, val in self.plottedIndicators.items():

           label =                 pg.TextItem('', color="#edede6", anchor=(-0.3, 1.5),

                                               border=pg.mkPen('#fcfcfc'), fill="#443a2e")

           self.labels[name] =     Main.chart.add(val['plt'], label)

            cross =                 pg.InfiniteLine(angle=90, movable=False,

                                                   pen={"color": "#8080ff"})

           self.cross[name] =      Main.chart.add(val['plt'], cross)

            self.mp[val['plt']] =   MousePosition(val['plt'], name)

    def labelCoords(self, mp, name):

       index =     int(mp.x() + 0.5) - 1

       col =       self.plottedIndicators[name]['col']

       self.labels[name].setText(f'{self._charts[col].iloc[index].astype(str)}')

       self.labels[name].setPos(mp)

       self.cross[name].setPos(mp)

On Saturday, May 9, 2020 at 10:00:09 PM UTC+8, Edmondo Giovannozzi wrote: