Significantly speed up marker snapping with large selections

src/audio_marker.cpp

@@ -37,7 +37,6 @@ public:
 	AudioMarkerKeyframe(Pen *style, int position) : style(style), position(position) { }
 	int GetPosition() const override { return position; }
 	FeetStyle GetFeet() const override { return Feet_None; }
-	bool CanSnap() const override { return true; }
 	wxPen GetStyle() const override { return *style; }
 	operator int() const { return position; }
 };
@@ -85,21 +84,14 @@ void AudioMarkerProviderKeyframes::GetMarkers(TimeRange const& range, AudioMarke
 }
 
 class VideoPositionMarker final : public AudioMarker {
-	Pen style;
+	Pen style{"Colour/Audio Display/Play Cursor"};
-	int position;
+	int position = -1;
 
 public:
-	VideoPositionMarker()
-	: style("Colour/Audio Display/Play Cursor")
-	, position(-1)
-	{
-	}
-
 	void SetPosition(int new_pos) { position = new_pos; }
 
 	int GetPosition() const override { return position; }
 	FeetStyle GetFeet() const override { return Feet_None; }
-	bool CanSnap() const override { return true; }
 	wxPen GetStyle() const override { return style; }
 	operator int() const { return position; }
 };

src/audio_marker.h

@@ -65,15 +65,6 @@ public:
 	/// @brief Get the marker's feet style
 	/// @return The marker's feet style
 	virtual FeetStyle GetFeet() const = 0;
-
-	/// @brief Retrieve whether this marker participates in snapping
-	/// @return True if this marker may snap to other snappable markers
-	///
-	/// If a marker being dragged returns true from this method, and another
-	/// marker which also returns true from this method is within range, the
-	/// marker being dragged will be positioned at the position of the other
-	/// marker if it is released while it is inside snapping range.
-	virtual bool CanSnap() const = 0;
 };
 
 typedef std::vector<const AudioMarker*> AudioMarkerVector;
@@ -181,7 +172,6 @@ class SecondsMarkerProvider final : public AudioMarkerProvider {
 		Marker(Pen *style) : style(style) { }
 		int GetPosition() const override { return position; }
 		FeetStyle GetFeet() const override { return Feet_None; }
-		bool CanSnap() const override { return false; }
 		wxPen GetStyle() const override;
 		operator int() const { return position; }
 	};

src/audio_timing_dialogue.cpp

@@ -77,7 +77,6 @@ public:
 	int       GetPosition() const override { return position; }
 	wxPen     GetStyle()    const override { return *style; }
 	FeetStyle GetFeet()     const override { return feet; }
-	bool      CanSnap()     const override { return true; }
 
 	/// Move the marker to a new position
 	/// @param new_position The position to move the marker to, in milliseconds
@@ -864,6 +863,11 @@ int AudioTimingControllerDialogue::SnapMarkers(int snap_range, std::vector<Audio
 {
 	if (snap_range <= 0) return 0;
 
+	std::vector<const DialogueTimingMarker *> inactive_markers;
+	inactive_markers.reserve(inactive_lines.size() * 2);
+	for (auto const& line : inactive_lines)
+		line.GetMarkers(&inactive_markers);
+
 	AudioMarkerVector potential_snaps;
 	int snap_distance = 0;
 	bool has_snapped = false;
@@ -874,11 +878,16 @@ int AudioTimingControllerDialogue::SnapMarkers(int snap_range, std::vector<Audio
 		if (pos == prev) continue;
 
 		potential_snaps.clear();
-		GetMarkers(TimeRange(pos - snap_range, pos + snap_range), potential_snaps);
+		TimeRange range(pos - snap_range, pos + snap_range);
+		keyframes_provider.GetMarkers(range, potential_snaps);
+		video_position_provider.GetMarkers(range, potential_snaps);
+		copy(
+			boost::lower_bound(inactive_markers, range.begin(), marker_ptr_cmp()),
+			boost::upper_bound(inactive_markers, range.end(), marker_ptr_cmp()),
+			back_inserter(potential_snaps));
+
 		for (auto marker : potential_snaps)
 		{
-			if (!marker->CanSnap() || boost::find(active, marker) != end(active)) continue;
-
 			auto dist = marker->GetPosition() - pos;
 			if (!has_snapped)
 				snap_distance = dist;

src/audio_timing_karaoke.cpp

@@ -52,7 +52,6 @@ public:
 	int GetPosition() const override { return position; }
 	wxPen GetStyle() const override { return *pen; }
 	FeetStyle GetFeet() const override { return style; }
-	bool CanSnap() const override { return false; }
 
 	void Move(int new_pos) { position = new_pos; }