Wobuzz/wobuzz/ui/track_progress_slider.py

#!/usr/bin/python3

from PyQt6.QtCore import Qt
from PyQt6.QtGui import QMouseEvent
from PyQt6.QtWidgets import QSlider, QStyle, QStyleOptionSlider


class TrackProgressSlider(QSlider):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.dragged = False

        option = QStyleOptionSlider()
        style = self.style()

        self.handle_width = style.pixelMetric(QStyle.PixelMetric.PM_SliderThickness, option, self)

        self.sliderPressed.connect(self.on_press)
        self.sliderReleased.connect(self.on_release)

    def mousePressEvent(self, event: QMouseEvent):
        # we need a custom press event bc. PyQt doesn't set the slider position when clicked
        if event.button() == Qt.MouseButton.LeftButton:
            event.accept()

            x = event.pos().x()

            # old value calculation:
            # value = self.maximum() * x // self.width()
            # but we need that new calculation because the handle width is limiting the range, and we need to set
            # the slider handle's center to the click position, not to the start of the handle
            # (self.width() - self.handle_width) calculates the usable width and
            # (x - self.handle_width // 2) offsets the position by minus half of the handle width
            value = self.maximum() * (x - self.handle_width // 2) // (self.width() - self.handle_width)

            self.setValue(value)

        return super().mousePressEvent(event)

    def on_press(self):
        self.dragged = True

    def on_release(self):
        self.dragged = False