+ assert(decoder_stack_);
+ decoder_stack_->get_annotation_subset(annotations, visible_rows_[row],
+ sample_range.first, sample_range.second);
+
+ return (annotations.empty()) ?
+ QString() : annotations[0].annotations().front();
+}
+
+void DecodeTrace::hover_point_changed()
+{
+ assert(owner_);
+
+ const View *const view = owner_->view();
+ assert(view);
+
+ QPoint hp = view->hover_point();
+ QString ann = get_annotation_at_point(hp);
+
+ assert(view);
+
+ if (!row_height_ || ann.isEmpty()) {
+ QToolTip::hideText();
+ return;
+ }
+
+ const int hover_row = get_row_at_point(hp);
+
+ QFontMetrics m(QToolTip::font());
+ const QRect text_size = m.boundingRect(QRect(), 0, ann);
+
+ // This is OS-specific and unfortunately we can't query it, so
+ // use an approximation to at least try to minimize the error.
+ const int padding = 8;
+
+ // Make sure the tool tip doesn't overlap with the mouse cursor.
+ // If it did, the tool tip would constantly hide and re-appear.
+ // We also push it up by one row so that it appears above the
+ // decode trace, not below.
+ hp.setX(hp.x() - (text_size.width() / 2) - padding);
+
+ hp.setY(get_visual_y() - (row_height_ / 2) +
+ (hover_row * row_height_) -
+ row_height_ - text_size.height() - padding);
+
+ QToolTip::showText(view->viewport()->mapToGlobal(hp), ann);