CODEWITHSUNDEEP
pythonqtuser-interfacepyqt
user2683038
user2683038

Reputation: 677

PyQt: grab mouseMoveEvent inside a Chart

I have the following PyQt code:

import sys
from PyQt5.QtWidgets import QMainWindow, QApplication
from PyQt5.QtChart import QChart, QChartView, QLineSeries, QValueAxis
from PyQt5 import QtCore, QtGui

class MainWindow(QMainWindow):
    class ChartView(QChartView):
        def __init__(self, chart):
            super().__init__(chart)        

        def mouseMoveEvent(self, event):
            print("ChartView.mouseMoveEvent", event.pos().x(), event.pos().y())

            return QChartView.mouseMoveEvent(self, event)

    class Chart(QChart):
        def __init__(self):
            super().__init__()

        def mouseMoveEvent(self, event):
            print("Chart.mouseMoveEvent", event.pos().x(), event.pos().y())

            return QChart.mouseMoveEvent(self, event)

    def __init__(self, args):
        super().__init__()

        chartView = self.ChartView(self.Chart())
        chartView.setRenderHint(QtGui.QPainter.Antialiasing)
        chartView.setRubberBand(QChartView.HorizontalRubberBand)

        chartView.chart().createDefaultAxes()
        chartView.chart().legend().hide()
        chartView.chart().addAxis(QValueAxis(), QtCore.Qt.AlignBottom)
        chartView.chart().addAxis(QValueAxis(), QtCore.Qt.AlignLeft)

        ls = QLineSeries()
        ls.append(0, 0)
        ls.append(9, 9)
        ls.attachAxis(chartView.chart().axisX())
        ls.attachAxis(chartView.chart().axisY())
        chartView.chart().addSeries(ls)

        self.setCentralWidget(chartView)
        self.show()

if __name__ == '__main__':
    app = QApplication(sys.argv)

    mainWindow = MainWindow(sys.argv)
    sys.exit(app.exec_())

The problem is that in the code above mouseMoveEvent is only emitted for ChartView. But I would like to have the mouseMoveEvent emitted for Chart, rather than for ChartView. How could I accomplish this? If it's not possible to have the mouseMoveEvent triggered for Chart, how could I translate event.pos() to QChart coordinates inside ChartView.mouseMoveEvent?

Upvotes: 1

Views: 1292

Answers (1)

user2683038
user2683038

Reputation: 677

OK, finally I found a way. I reimplement mouseMoveEvent from ChartView and have it emit a signal mouseMoved:

class ChartView(QChartView):
    # ...

    mouseMoved = QtCore.pyqtSignal(QtCore.QPoint)

    def mouseMoveEvent(self, event):
        self.mouseMoved.emit(event.pos())

        return QChartView.mouseMoveEvent(self, event)

This signal I connect to a slot of Chart:

chartView.mouseMoved.connect(chartView.chart().mouseMoved)

In the slot I translate the coordinates to the Chart coordinate system using mapFromParent; I can even map it into the coordinate system of the series using mapToValue:

class Chart(QChart):
    # ...

    def mouseMoved(self, pos):
        print("Chart.mouseMoved parent coord domain: ", pos)
        print("Chart.mouseMoved own coord domain:", self.mapFromParent(pos))
        print("chart.mouseMoved line series coord domain:", self.mapToValue(self.mapFromParent(pos), self.series()[0]))

Upvotes: 1

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