Method eventFilter

pj_widgets/src/Scrollbar.cpp:270–429

}

bool Scrollbar::eventFilter(QObject* watched, QEvent* event) {
  if (area_ == nullptr || watched != area_->viewport()) {
    return false;
  }

  switch (event->type()) {
    case QEvent::MouseButtonPress: {
      auto* me = static_cast<QMouseEvent*>(event);
      if (me->button() != Qt::LeftButton) {
        break;
      }
      // FIX 1: when not interactive, ignore the press — do not start a drag and
      // do not consume the event so the Timeline's own filter handles it.
      if (!interactive_) {
        break;
      }
      const QPoint pos = me->position().toPoint();
      if (!pointInStrip(pos) || bar()->maximum() <= bar()->minimum()) {
        break;
      }

      const double axis_px = (orientation_ == Qt::Horizontal) ? pos.x() : pos.y();
      const bool on_handle = (axis_px >= handle_pos_) && (axis_px <= handle_pos_ + handle_len_);

      // By default only the visible handle is a drag target: a press on the empty
      // track (in the strip but off the handle) is NOT consumed, so it falls
      // through to the underlying view — otherwise the overlay would silently
      // swallow content clicks (item selection, etc.) along the whole edge strip,
      // where the native bar used to reserve a non-content gutter but now does not
      // (it is forced AlwaysOff and content reflows under the strip). A host that
      // owns its whole viewport (the Timeline) opts into click_to_scroll_, where an
      // off-handle press first centers the handle under the cursor, then drags.
      if (!on_handle) {
        if (!click_to_scroll_) {
          break;
        }
        const double track_len = (orientation_ == Qt::Horizontal) ? static_cast<double>(viewport_->width())
                                                                  : static_cast<double>(viewport_->height());
        const long total = (bar()->maximum() - bar()->minimum()) + bar()->pageStep();
        if (track_len > 0.0) {
          const double want_pos = std::clamp(axis_px - handle_len_ / 2.0, 0.0, std::max(0.0, track_len - handle_len_));
          bar()->setValue(
              bar()->minimum() + static_cast<int>(std::llround((want_pos / track_len) * static_cast<double>(total))));
        }
      }

      // Capture drag origin AFTER any click-to-center value change.
      drag_start_value_ = bar()->value();
      drag_start_axis_px_ = axis_px;
      dragging_ = true;
      setShown(true);
      return true;  // consume: prevent viewport row-selection / pan on press
    }

    case QEvent::MouseMove: {
      auto* me = static_cast<QMouseEvent*>(event);
      const QPoint pos = me->position().toPoint();