/tmp/snapshot-pyside-6.2-rel/pyside-setup/examples/widgets/painting/plot

(You can also check this code in the repository)

plot.py

import math
import sys

from PySide6.QtWidgets import QWidget, QApplication
from PySide6.QtCore import QPoint, QRect, QTimer, Qt, Slot
from PySide6.QtGui import (QColor, QPainter, QPaintEvent, QPen, QPointList,
                           QTransform)


WIDTH = 680
HEIGHT = 480


class PlotWidget(QWidget):
    """Illustrates the use of opaque containers. QPointList
       wraps a C++ QList<QPoint> directly, removing the need to convert
       a Python list in each call to QPainter.drawPolyline()."""

    def __init__(self, parent=None):
        super().__init__(parent)
        self._timer = QTimer(self)
        self._timer.setInterval(20)
        self._timer.timeout.connect(self.shift)

        self._points = QPointList()
        self._points.reserve(WIDTH)
        self._x = 0
        self._delta_x = 0.05
        self._half_height = HEIGHT / 2
        self._factor = 0.8 * self._half_height

        for i in range(WIDTH):
            self._points.append(QPoint(i, self.next_point()))

        self.setFixedSize(WIDTH, HEIGHT)

        self._timer.start()

    def next_point(self):
        result = self._half_height - self._factor * math.sin(self._x)
        self._x += self._delta_x
        return result

    def shift(self):
        last_x = self._points[WIDTH - 1].x()
        self._points.pop_front()
        self._points.append(QPoint(last_x + 1, self.next_point()))
        self.update()

    def paintEvent(self, event):
        painter = QPainter()
        painter.begin(self)
        rect = QRect(QPoint(0, 0), self.size())
        painter.fillRect(rect, Qt.white)
        painter.translate(-self._points[0].x(), 0)
        painter.drawPolyline(self._points)
        painter.end()


if __name__ == "__main__":

    app = QApplication(sys.argv)

    w = PlotWidget()
    w.show()
    sys.exit(app.exec())