View: Refine snapping algorithm

We now also choose the best match depending on edge density.

diff --git a/pv/data/logicsegment.cpp b/pv/data/logicsegment.cpp
index 32a7adb240fc5535a895c00f5d87abfb97d712b3..2f69e02dba3b7acc8794942caf5e26497f6bb930 100644 (file)
--- a/pv/data/logicsegment.cpp
+++ b/pv/data/logicsegment.cpp
@@ -375,6 +375,7 @@ void LogicSegment::get_surrounding_edges(vector<EdgePair> &dest,
        // use a get_subsampled_edges() implementation that searches backwards
        vector<EdgePair>* edges = new vector<EdgePair>;
 
+       // Get all edges to the left of origin_sample
        get_subsampled_edges(*edges, 0, origin_sample, min_length, sig_index, false);
 
        // If we don't specify "first only", the first and last edge are the states
@@ -390,6 +391,7 @@ void LogicSegment::get_surrounding_edges(vector<EdgePair> &dest,
        dest.push_back(edges->back());
        edges->clear();
 
+       // Get first edge to the right of origin_sample
        get_subsampled_edges(*edges, origin_sample, sample_count_, min_length, sig_index, true);
 
        // "first only" is specified, so nothing needs to be dismissed

diff --git a/pv/views/trace/view.cpp b/pv/views/trace/view.cpp
index e68c16a8dc6013634e2add3f90025a4d25e84dda..625722d4308f9e3128c4f6dd42d2d49e6e8a52b9 100644 (file)
--- a/pv/views/trace/view.cpp
+++ b/pv/views/trace/view.cpp
@@ -862,79 +862,103 @@ const QPoint& View::hover_point() const
 
 int64_t View::get_nearest_level_change(const QPoint &p)
 {
+       // Is snapping disabled?
        if (snap_distance_ == 0)
                return -1;
 
-       shared_ptr<Signal> signal = signal_under_mouse_cursor_;
+       struct entry_t {
+               entry_t(shared_ptr<Signal> s) :
+                       signal(s), delta(numeric_limits<int64_t>::max()), sample(-1), is_dense(false) {}
+               shared_ptr<Signal> signal;
+               int64_t delta;
+               int64_t sample;
+               bool is_dense;
+       };
 
-       vector<data::LogicSegment::EdgePair> nearest_edges;
-       int64_t nearest_sample = -1;
+       vector<entry_t> list;
 
-       if (signal) {
-               // Determine nearest edge from specific signal
+       // Create list of signals to consider
+       if (signal_under_mouse_cursor_)
+               list.emplace_back(signal_under_mouse_cursor_);
+       else
+               for (shared_ptr<Signal> s : signals_) {
+                       if (!s->enabled())
+                               continue;
+
+                       list.emplace_back(s);
+               }
 
+       // Get data for listed signals
+       for (entry_t &e : list) {
                // Calculate sample number from cursor position
-               const double samples_per_pixel = signal->base()->get_samplerate() * scale();
+               const double samples_per_pixel = e.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);
 
-               nearest_edges = signal->get_nearest_level_changes(sample_num);
+               vector<data::LogicSegment::EdgePair> edges =
+                       e.signal->get_nearest_level_changes(sample_num);
 
-               if (nearest_edges.size() != 2)
-                       return -1;
+               if (edges.empty())
+                       continue;
 
-               // We received absolute sample numbers, make them relative
-               const int64_t left_sample_delta = sample_num - nearest_edges.front().first;
-               const int64_t right_sample_delta = nearest_edges.back().first - sample_num - 1;
+               // Check first edge
+               const int64_t first_sample_delta = abs(sample_num - edges.front().first);
+               const int64_t first_delta = first_sample_delta / samples_per_pixel;
+               e.delta = first_delta;
+               e.sample = edges.front().first;
 
-               const int64_t left_delta = left_sample_delta / samples_per_pixel;
-               const int64_t right_delta = right_sample_delta / samples_per_pixel;
+               // Check second edge if available
+               if (edges.size() == 2) {
+                       // Note: -1 because this is usually the right edge and sample points are left-aligned
+                       const int64_t second_sample_delta = abs(sample_num - edges.back().first - 1);
+                       const int64_t second_delta = second_sample_delta / samples_per_pixel;
 
-               // Only use closest left or right edge if they're close to the cursor
-               if ((left_delta < right_delta) && (left_delta <= snap_distance_))
-                       nearest_sample = nearest_edges.front().first;
-               if ((left_delta >= right_delta) && (right_delta <= snap_distance_))
-                       nearest_sample = nearest_edges.back().first;
-       } else {
-               // Determine nearest edge from all signals
-
-               int64_t nearest_delta = numeric_limits<int64_t>::max();
-               for (shared_ptr<Signal> s : signals_) {
-                       if (!s->enabled())
-                               continue;
+                       // If both edges are too close, we mark this signal as being dense
+                       if ((first_delta + second_delta) <= snap_distance_)
+                               e.is_dense = true;
 
-                       // Calculate sample number from cursor position
-                       const double samples_per_pixel = s->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);
+                       if (second_delta < first_delta) {
+                               e.delta = second_delta;
+                               e.sample = edges.back().first;
+                       }
+               }
+       }
 
-                       vector<data::LogicSegment::EdgePair> edges =
-                               s->get_nearest_level_changes(sample_num);
+       // Look for the best match: non-dense first, then dense
+       entry_t *match = nullptr;
 
-                       if (edges.size() != 2)
-                               continue;
+       for (entry_t &e : list) {
+               if (e.delta > snap_distance_ || e.is_dense)
+                       continue;
 
-                       // 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;
+               if (match) {
+                       if (e.delta < match->delta)
+                               match = &e;
+               } else
+                       match = &e;
+       }
 
-                       const int64_t left_delta = left_sample_delta / samples_per_pixel;
-                       const int64_t right_delta = right_sample_delta / samples_per_pixel;
+       if (!match) {
+               for (entry_t &e : list) {
+                       if (!e.is_dense)
+                               continue;
 
-                       if ((left_delta < nearest_delta) || (right_delta < nearest_delta)) {
-                               nearest_delta = min(left_delta, right_delta);
+                       if (match) {
+                               if (e.delta < match->delta)
+                                       match = &e;
+                       } else
+                               match = &e;
+               }
+       }
 
-                               if (nearest_delta <= snap_distance_)
-                                       nearest_sample = (nearest_delta == left_delta) ?
-                                               edges.front().first : edges.back().first;
+       if (match) {
+               // Somewhat ugly hack to make TimeItem::drag_by() work
+               signal_under_mouse_cursor_ = match->signal;
 
-                               // Somewhat ugly hack to make TimeItem::drag_by() work
-                               signal_under_mouse_cursor_ = s;
-                       }
-               }
+               return match->sample;
        }
 
-       return nearest_sample;
+       return -1;
 }
 
 void View::restack_all_trace_tree_items()