Fix non-frame-aligned trims when using trim-to-playhead.

Reimplement Time::ceil and add a corresponding Time::floor with tests.
ceil returns slightly different results to previously with non-integer
frame rates.

Then use floor to round the playhead position when trimming.

3 files changed, 15 insertions, 9 deletions

diff --git a/src/lib/dcpomatic_time.h b/src/lib/dcpomatic_time.h
index 6834ee099..16d93ca28 100644
--- a/src/lib/dcpomatic_time.h
+++ b/src/lib/dcpomatic_time.h
@@ -119,9 +119,11 @@ public:
 	 *  @param r Sampling rate.
 	 */
 	Time<S, O> ceil (float r) const {
-		Type const n = llrintf (HZ / r);
-		Type const a = _t + n - 1;
-		return Time<S, O> (a - (a % n));
+		return Time<S, O> (llrint (HZ * frames_ceil(r) / double(r)));
+	}
+
+	Time<S, O> floor (float r) const {
+		return Time<S, O> (llrint (HZ * frames_floor(r) / double(r)));
 	}
 
 	double seconds () const {
@@ -143,7 +145,7 @@ public:
 
 	template <typename T>
 	int64_t frames_floor (T r) const {
-		return floor (_t * r / HZ);
+		return ::floor (_t * r / HZ);
 	}
 
 	template <typename T>
@@ -212,6 +214,7 @@ public:
 
 private:
 	friend struct dcptime_ceil_test;
+	friend struct dcptime_floor_test;
 
 	Type _t;
 	static const int HZ = 96000;
diff --git a/src/wx/film_viewer.h b/src/wx/film_viewer.h
index a67820a8c..aa588b926 100644
--- a/src/wx/film_viewer.h
+++ b/src/wx/film_viewer.h
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012-2016 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2017 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -41,6 +41,7 @@ public:
 
 	void set_film (boost::shared_ptr<Film>);
 
+	/** @return our `playhead' position; this may not lie exactly on a frame boundary */
 	DCPTime position () const {
 		return _position;
 	}
diff --git a/src/wx/timing_panel.cc b/src/wx/timing_panel.cc
index bd4177ffb..d7ed46f46 100644
--- a/src/wx/timing_panel.cc
+++ b/src/wx/timing_panel.cc
@@ -441,14 +441,15 @@ TimingPanel::film_changed (Film::Property p)
 void
 TimingPanel::trim_start_to_playhead_clicked ()
 {
-	DCPTime const ph = _viewer->position ();
+	shared_ptr<const Film> film = _parent->film ();
+	DCPTime const ph = _viewer->position().floor (film->video_frame_rate ());
 	optional<DCPTime> new_ph;
 
 	_viewer->set_coalesce_player_changes (true);
 
 	BOOST_FOREACH (shared_ptr<Content> i, _parent->selected ()) {
 		if (i->position() < ph && ph < i->end ()) {
-			FrameRateChange const frc = _parent->film()->active_frame_rate_change (i->position ());
+			FrameRateChange const frc = film->active_frame_rate_change (i->position ());
 			i->set_trim_start (i->trim_start() + ContentTime (ph - i->position (), frc));
 			new_ph = i->position ();
 		}
@@ -464,10 +465,11 @@ TimingPanel::trim_start_to_playhead_clicked ()
 void
 TimingPanel::trim_end_to_playhead_clicked ()
 {
-	DCPTime const ph = _viewer->position ();
+	shared_ptr<const Film> film = _parent->film ();
+	DCPTime const ph = _viewer->position().floor (film->video_frame_rate ());
 	BOOST_FOREACH (shared_ptr<Content> i, _parent->selected ()) {
 		if (i->position() < ph && ph < i->end ()) {
-			FrameRateChange const frc = _parent->film()->active_frame_rate_change (i->position ());
+			FrameRateChange const frc = film->active_frame_rate_change (i->position ());
 			i->set_trim_end (ContentTime (i->position() + i->full_length() - ph - DCPTime::from_frames (1, frc.dcp), frc) - i->trim_start());
 		}
 	}