+
+ // Don't change the scrollbar range if there are no traces
+ if (extents.first != extents.second)
+ verticalScrollBar()->setRange(extents.first - areaSize.height(),
+ extents.second);
+
+ if (scroll_needs_defaults)
+ set_scroll_default();
+}
+
+void View::reset_scroll()
+{
+ verticalScrollBar()->setRange(0, 0);
+}
+
+void View::set_scroll_default()
+{
+ assert(viewport_);
+
+ const QSize areaSize = viewport_->size();
+
+ // Special case: when starting up and the window isn't visible yet,
+ // areaSize is [0, 0]. In this case we want to be called again later
+ if (areaSize.height() == 0) {
+ scroll_needs_defaults = true;
+ return;
+ } else {
+ scroll_needs_defaults = false;
+ }
+
+ const pair<int, int> extents = v_extents();
+ const int trace_height = extents.second - extents.first;
+
+ // Do all traces fit in the view?
+ if (areaSize.height() >= trace_height)
+ // Center all traces vertically
+ set_v_offset(extents.first -
+ ((areaSize.height() - trace_height) / 2));
+ else
+ // Put the first trace at the top, letting the bottom ones overflow
+ set_v_offset(extents.first);