+int64_t View::get_nearest_level_change(const QPoint &p) const
+{
+ if (snap_distance_ == 0)
+ return -1;
+
+ shared_ptr<Signal> signal = signal_under_mouse_cursor_;
+
+ if (!signal)
+ return -1;
+
+ // Calculate sample number from cursor position
+ const double samples_per_pixel = signal->base()->get_samplerate() * scale();
+ const int64_t x_offset = offset().convert_to<double>() / scale();
+ const int64_t sample_num = max(((x_offset + p.x()) * samples_per_pixel), 0.0);
+
+ // Query for nearest level changes
+ vector<data::LogicSegment::EdgePair> edges =
+ signal->get_nearest_level_changes(sample_num);
+
+ if (edges.size() != 2)
+ return -1;
+
+ // We received absolute sample numbers, make them relative
+ const int64_t left_sample_delta = sample_num - edges.front().first;
+ const int64_t right_sample_delta = edges.back().first - sample_num - 1;
+
+ const int64_t left_delta = left_sample_delta / samples_per_pixel;
+ const int64_t right_delta = right_sample_delta / samples_per_pixel;
+
+ int64_t nearest = -1;
+
+ // Only use closest left or right edge if they're close to the cursor
+ if ((left_delta < right_delta) && (left_delta < snap_distance_))
+ nearest = edges.front().first;
+ if ((left_delta >= right_delta) && (right_delta < snap_distance_))
+ nearest = edges.back().first;
+
+ return nearest;
+}
+