Zooming out the QChart with QRubberBand, to fit the size of the QChartView

Question

I have a QChartView with QChart. I've added QRubberBand to the QChartView to zoom the chart. Plus I overrode wheelEvent, to scroll the chart by X axis.

So, now I want to prevent 'outscrolling' and 'outzooming' over some value. By this names I mean, that I need to stop zoom out, when chart size reaches the original chart size (so, minimal size of the chart should be it's original size) and I need to stop scrolling event, when I reach the min or max chart value (for the same reason).

I've tried to use size of the QChart and QChartView to handle QRubberBand resizing as beginning, but it didn't help.

Here is my small try, but I can't find out any compatible solution for QWheelEvent and QMouseEvent (but may be there is any build in methods for these tasks, so I should not override that two events). Here is the code:

import sys
from PySide6.QtCore import Qt
from PySide6.QtWidgets import QApplication, QMainWindow, QVBoxLayout, QWidget
from PySide6 import QtCharts, QtGui

import random


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

    def wheelEvent(self, event):
        print(event.delta())
        if event.delta() > 0:
            self.scroll(-10, 0)
            print('e')
        else:
            self.scroll(10, 0)

    def create_series(self):
        for _ in range(2):
            series = QtCharts.QLineSeries()
            for i in range(100):
                series.append(i, random.randint(0, 10))
            self.addSeries(series)

    def setup(self):
        self.createDefaultAxes()
        self.legend().setVisible(True)
        self.legend().setAlignment(Qt.AlignLeft)


class ChartView(QtCharts.QChartView):
    def __init__(self, chart):
        super().__init__()
        self.setChart(chart)
        self.setRenderHint(QtGui.QPainter.Antialiasing)
        self.setRubberBand(QtCharts.QChartView.HorizontalRubberBand)

    def mousePressEvent(self, event):
        if event.button() == Qt.RightButton:
            if self.chart().size().width() > self.size().width():
                print("Fit")
                super().mousePressEvent(event)
            else:
                print(self, "Doesn't fit")
            print(self.chart().size().width())
            print(self.size().width())
        else:
            super().mousePressEvent(event)


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.layout = QVBoxLayout()

        for _ in range(2):
            chart_view = self.create_chart_view()
            self.layout.addWidget(chart_view)

        self.central_widget = QWidget()
        self.central_widget.setLayout(self.layout)
        self.setCentralWidget(self.central_widget)

    @staticmethod
    def create_chart():
        chart = Chart()
        chart.create_series()
        chart.setup()

        return chart

    def create_chart_view(self):
        chart_view = ChartView(chart=self.create_chart())
        chart_view.chart().axes(Qt.Horizontal)[0].rangeChanged.connect(
            lambda: (self.sync_chart_views(chart_view))
        )

        return chart_view

    def sync_chart_views(self, source_chart_view):
        x_range = (source_chart_view.chart().axes(Qt.Horizontal)[0].min(), source_chart_view.chart().axes(Qt.Horizontal)[0].max())
        for chart_view in self.findChildren(QtCharts.QChartView):
            if chart_view != source_chart_view:
                chart_view.chart().axes(Qt.Horizontal)[0].setRange(x_range[0], x_range[1])


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec())

Zooming out the QChart with QRubberBand, to fit the size of the QChartView

Answers (1)

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