trim a single other region when adjusting xfade length

git-svn-id: svn://localhost/ardour2/branches/3.0@12241 d708f5d6-7413-0410-9779-e7cbd77b26cf

4 files changed, 86 insertions, 8 deletions

diff --git a/libs/ardour/ardour/audioregion.h b/libs/ardour/ardour/audioregion.h
index fd6c3a8528..013629637d 100644
--- a/libs/ardour/ardour/audioregion.h
+++ b/libs/ardour/ardour/audioregion.h
@@ -238,6 +238,8 @@ class AudioRegion : public Region
 	bool                              _fade_in_is_xfade;
 	bool                              _fade_out_is_xfade;
 
+	boost::shared_ptr<ARDOUR::Region> get_single_other_xfade_region (bool start) const;
+
   protected:
 	/* default constructor for derived (compound) types */
 
diff --git a/libs/ardour/ardour/region.h b/libs/ardour/ardour/region.h
index 788a8d90c9..1d7894fac5 100644
--- a/libs/ardour/ardour/region.h
+++ b/libs/ardour/ardour/region.h
@@ -141,6 +141,15 @@ class Region
 	framepos_t first_frame () const { return _position; }
 	framepos_t last_frame ()  const { return _position + _length - 1; }
 
+	/** Return the earliest possible value of _position given the
+	 *  value of _start within the region's sources
+	 */
+	framepos_t earliest_possible_position () const;
+	/** Return the last possible value of _last_frame given the
+	 *  value of _startin the regions's sources
+	 */
+	framepos_t latest_possible_frame () const;
+
 	Evoral::Range<framepos_t> last_range () const {
 		return Evoral::Range<framepos_t> (_last_position, _last_position + _last_length - 1);
 	}
diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index 4ba383b37e..36d5cf0a8c 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -1148,6 +1148,20 @@ AudioRegion::set_fade_in_length (framecnt_t len)
 		if (_inverse_fade_in) {
 			_inverse_fade_in->extend_to (len);
 		}
+
+		if (_fade_in_is_xfade) {
+
+			/* trim a single other region below us to the new start
+			   of the fade.
+			*/
+
+			boost::shared_ptr<Region> other = get_single_other_xfade_region (true);
+			if (other) {
+				other->trim_end (position() + len);
+			}
+		}
+
+
 		_default_fade_in = false;
 		send_change (PropertyChange (Properties::fade_in));
 	}
@@ -1167,10 +1181,24 @@ AudioRegion::set_fade_out_length (framecnt_t len)
 	bool changed =	_fade_out->extend_to (len);
 
 	if (changed) {
+		
 		if (_inverse_fade_out) {
 			_inverse_fade_out->extend_to (len);
 		}
 		_default_fade_out = false;
+
+		if (_fade_out_is_xfade) {
+
+			/* trim a single other region below us to the new start
+			   of the fade.
+			*/
+
+			boost::shared_ptr<Region> other = get_single_other_xfade_region (false);
+			if (other) {
+				other->trim_front (last_frame() - len);
+			}
+		}
+
 		send_change (PropertyChange (Properties::fade_out));
 	}
 }
@@ -1801,8 +1829,8 @@ AudioRegion::set_fade_out_is_xfade (bool yn)
 	_fade_out_is_xfade = yn;
 }
 
-framecnt_t
-AudioRegion::verify_xfade_bounds (framecnt_t len, bool start)
+boost::shared_ptr<Region>
+AudioRegion::get_single_other_xfade_region (bool start) const
 {
 	boost::shared_ptr<Playlist> pl (playlist());
 
@@ -1810,11 +1838,10 @@ AudioRegion::verify_xfade_bounds (framecnt_t len, bool start)
 		/* not currently in a playlist - xfade length is unbounded
 		   (and irrelevant)
 		*/
-		return len;
+		return boost::shared_ptr<AudioRegion> ();
 	}
 
 	boost::shared_ptr<RegionList> rl;
-	framecnt_t maxlen;
 
 	if (start) {
 		rl = pl->regions_at (position());
@@ -1837,17 +1864,27 @@ AudioRegion::verify_xfade_bounds (framecnt_t len, bool start)
 
 	if (n != 2) {
 		/* zero or multiple regions stacked here - don't care about xfades */
-		return len;
+		return boost::shared_ptr<AudioRegion> ();
 	}
 
+	return other;
+}
+
+framecnt_t
+AudioRegion::verify_xfade_bounds (framecnt_t len, bool start)
+{
+	boost::shared_ptr<Region> other = get_single_other_xfade_region (start);
+	framecnt_t maxlen;
+
 	/* we overlap a single region. clamp the length of an xfade to
-	   the duration of the overlap.
+	   the maximum possible duration of the overlap (if the other
+	   region were trimmed appropriately).
 	*/
 
 	if (start) {
-		maxlen = other->last_frame() - position();
+		maxlen = other->latest_possible_frame() - position();
 	} else {
-		maxlen = last_frame() - other->position();
+		maxlen = last_frame() - other->earliest_possible_position();
 	}
 
 	return min (maxlen, len);
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index efaa104d35..a4a1584792 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -1654,3 +1654,33 @@ Region::set_start_internal (framecnt_t s)
 {
 	_start = s;
 }
+
+framepos_t
+Region::earliest_possible_position () const
+{
+	if (_start > _position) {
+		return 0;
+	} else {
+		return _position - _start;
+	}
+}
+
+framecnt_t
+Region::latest_possible_frame () const
+{
+	framecnt_t minlen = max_framecnt;
+
+	for (SourceList::const_iterator i = _sources.begin(); i != _sources.end(); ++i) {
+		/* non-audio regions have a length that may vary based on their
+		 * position, so we have to pass it in the call.
+		 */
+		minlen = min (minlen, (*i)->length (_position));
+	}
+
+	/* the latest possible last frame is determined by the current
+	 * position, plus the shortest source extent past _start.
+	 */
+
+	return _position + (minlen - _start) - 1;
+}
+