timeline-tree: freeze auto-transitions whilst editing

Freeze the auto-tranistions so they do not destroy themselves during an
edit. Once complete the auto-transitions can move themselves back into
position, or remove themselves if their sources are no longer
overlapping.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-editing-services/-/merge_requests/169>

ges/ges-auto-transition.c

@@ -43,33 +43,25 @@ neighbour_changed_cb (GESClip * clip, GParamSpec * arg G_GNUC_UNUSED,
     GESAutoTransition * self)
 {
   gint64 new_duration;
-  GESTimelineElement *parent =
-      ges_timeline_element_peak_toplevel (GES_TIMELINE_ELEMENT (clip));
+  guint32 layer_prio;
+  GESLayer *layer;
+  GESTimeline *timeline;
 
-  if (GES_TIMELINE_ELEMENT_BEING_EDITED (parent))
-    return;
-
-  if (parent) {
-    GESTimelineElement *prev_topparent =
-        ges_timeline_element_peak_toplevel (GES_TIMELINE_ELEMENT
-        (self->next_source));
-    GESTimelineElement *next_topparent =
-        ges_timeline_element_peak_toplevel (GES_TIMELINE_ELEMENT
-        (self->previous_source));
-
-    if (GES_TIMELINE_ELEMENT_BEING_EDITED (prev_topparent) ||
-        GES_TIMELINE_ELEMENT_BEING_EDITED (next_topparent))
-      return;
-
-    if (parent == prev_topparent && parent == next_topparent) {
-      GST_DEBUG_OBJECT (self,
-          "Moving all inside the same group, nothing to do");
+  if (self->frozen) {
+    GST_LOG_OBJECT (self, "Not updating because frozen");
     return;
   }
+
+  if (self->positioning) {
+    /* this can happen when the transition is moved layers as the layer
+     * may resync its priorities */
+    GST_LOG_OBJECT (self, "Not updating because positioning");
+    return;
   }
 
-  if (GES_TIMELINE_ELEMENT_LAYER_PRIORITY (self->next_source) !=
-      GES_TIMELINE_ELEMENT_LAYER_PRIORITY (self->previous_source)) {
+  layer_prio = GES_TIMELINE_ELEMENT_LAYER_PRIORITY (self->next_source);
+
+  if (layer_prio != GES_TIMELINE_ELEMENT_LAYER_PRIORITY (self->previous_source)) {
     GST_DEBUG_OBJECT (self, "Destroy changed layer");
     g_signal_emit (self, auto_transition_signals[DESTROY_ME], 0);
     return;
@@ -88,13 +80,24 @@ neighbour_changed_cb (GESClip * clip, GParamSpec * arg G_GNUC_UNUSED,
     return;
   }
 
+  timeline = GES_TIMELINE_ELEMENT_TIMELINE (self->transition_clip);
+  layer = timeline ? ges_timeline_get_layer (timeline, layer_prio) : NULL;
+  if (!layer) {
+    GST_DEBUG_OBJECT (self, "Destroy no layer");
+    g_signal_emit (self, auto_transition_signals[DESTROY_ME], 0);
+    return;
+  }
+
   self->positioning = TRUE;
   GES_TIMELINE_ELEMENT_SET_BEING_EDITED (self->transition_clip);
   _set_start0 (GES_TIMELINE_ELEMENT (self->transition_clip),
       _START (self->next_source));
   _set_duration0 (GES_TIMELINE_ELEMENT (self->transition_clip), new_duration);
+  ges_clip_move_to_layer (self->transition_clip, layer);
   GES_TIMELINE_ELEMENT_UNSET_BEING_EDITED (self->transition_clip);
   self->positioning = FALSE;
+
+  gst_object_unref (layer);
 }
 
 static void
@@ -153,6 +156,7 @@ ges_auto_transition_new (GESTrackElement * transition,
 {
   GESAutoTransition *self = g_object_new (GES_TYPE_AUTO_TRANSITION, NULL);
 
+  self->frozen = FALSE;
   self->previous_source = previous_source;
   self->next_source = next_source;
   self->transition = transition;

ges/ges-auto-transition.h

@@ -58,6 +58,8 @@ struct _GESAutoTransition
 
   gchar *key;
 
+  gboolean frozen;
+
   /* Padding for API extension */
   gpointer _ges_reserved[GES_PADDING];
 };

ges/ges-internal.h

@@ -103,6 +103,8 @@ GstDebugCategory * _ges_debug (void);
 
 #define SUPRESS_UNUSED_WARNING(a) (void)a
 
+G_GNUC_INTERNAL void
+ges_timeline_freeze_auto_transitions (GESTimeline * timeline, gboolean freeze);
 
 G_GNUC_INTERNAL gboolean
 ges_timeline_edit (GESTimeline * timeline, GESTimelineElement * element,
@@ -135,10 +137,6 @@ G_GNUC_INTERNAL
 GNode *
 timeline_get_tree           (GESTimeline *timeline);
 
-G_GNUC_INTERNAL
-void
-timeline_update_transition (GESTimeline *timeline);
-
 G_GNUC_INTERNAL
 void
 timeline_fill_gaps            (GESTimeline *timeline);

ges/ges-timeline-tree.c

@@ -1541,6 +1541,9 @@ timeline_tree_perform_edits (GNode * root, GHashTable * edits)
   GHashTableIter iter;
   gpointer key, value;
 
+  /* freeze the auto-transitions whilst we edit */
+  ges_timeline_freeze_auto_transitions (root->data, TRUE);
+
   g_hash_table_iter_init (&iter, edits);
   while (g_hash_table_iter_next (&iter, &key, &value)) {
     GESTimelineElement *element = key;
@@ -1548,9 +1551,10 @@ timeline_tree_perform_edits (GNode * root, GHashTable * edits)
     if (!perform_element_edit (element, edit_data))
       no_errors = FALSE;
   }
+  /* allow the transitions to update if they can */
+  ges_timeline_freeze_auto_transitions (root->data, FALSE);
 
   timeline_tree_create_transitions (root, ges_timeline_find_auto_transition);
-  timeline_update_transition (root->data);
   timeline_update_duration (root->data);
 
   return no_errors;
@@ -2032,6 +2036,10 @@ create_transition_if_needed (GESTimeline * timeline, GESTrackElement * prev,
         "]", _START (next), duration);
     ges_timeline_create_transition (timeline, prev, next, NULL, layer,
         _START (next), duration);
+  } else {
+    GST_INFO ("Already have transition %" GES_FORMAT " between %" GES_FORMAT
+        " and %" GES_FORMAT, GES_ARGS (trans), GES_ARGS (prev),
+        GES_ARGS (next));
   }
 }
 
@@ -2043,12 +2051,10 @@ create_transitions (GNode * node,
   GESTimeline *timeline;
   GESLayer *layer;
 
-  if (G_NODE_IS_ROOT (node))
+  if (!GES_IS_SOURCE (node->data))
     return FALSE;
 
   timeline = GES_TIMELINE_ELEMENT_TIMELINE (node->data);
-  if (!GES_IS_SOURCE (node->data))
-    return FALSE;
 
   if (!timeline) {
     GST_INFO ("%" GES_FORMAT " not in timeline yet", GES_ARGS (node->data));
@@ -2064,6 +2070,7 @@ create_transitions (GNode * node,
   if (!ges_layer_get_auto_transition (layer))
     return FALSE;
 
+  GST_LOG (node->data, "Checking for overlaps");
   data.root = g_node_get_root (node);
   check_all_overlaps_with_element (node, &data);
 

ges/ges-timeline.c

@@ -1110,6 +1110,24 @@ done:
   }
 }
 
+void
+ges_timeline_freeze_auto_transitions (GESTimeline * timeline, gboolean freeze)
+{
+  GList *tmp, *trans = g_list_copy (timeline->priv->auto_transitions);
+  for (tmp = trans; tmp; tmp = tmp->next) {
+    GESAutoTransition *auto_transition = tmp->data;
+    auto_transition->frozen = freeze;
+    if (freeze == FALSE) {
+      GST_LOG_OBJECT (timeline, "Un-Freezing %" GES_FORMAT,
+          GES_ARGS (auto_transition->transition_clip));
+      ges_auto_transition_update (auto_transition);
+    } else {
+      GST_LOG_OBJECT (timeline, "Freezing %" GES_FORMAT,
+          GES_ARGS (auto_transition->transition_clip));
+    }
+  }
+  g_list_free (trans);
+}
 
 static gint
 _edit_auto_transition (GESTimeline * timeline, GESTimelineElement * element,
@@ -1217,17 +1235,6 @@ timeline_add_group (GESTimeline * timeline, GESGroup * group)
   ges_timeline_element_set_timeline (GES_TIMELINE_ELEMENT (group), timeline);
 }
 
-void
-timeline_update_transition (GESTimeline * timeline)
-{
-  GList *tmp, *auto_transs;
-
-  auto_transs = g_list_copy (timeline->priv->auto_transitions);
-  for (tmp = auto_transs; tmp; tmp = tmp->next)
-    ges_auto_transition_update (tmp->data);
-  g_list_free (auto_transs);
-}
-
 /**
  * timeline_emit_group_added:
  * @timeline: The #GESTimeline
@@ -1689,8 +1696,7 @@ ges_timeline_add_clip (GESTimeline * timeline, GESClip * clip)
   if (ges_clip_is_moving_from_layer (clip)) {
     GST_DEBUG ("Clip %p moving from one layer to another, not creating "
         "TrackElement", clip);
-    timeline_tree_create_transitions (timeline->priv->tree,
-        ges_timeline_find_auto_transition);
+    /* timeline-tree handles creation of auto-transitions */
     ret = TRUE;
   } else {
     ret = add_object_to_tracks (timeline, clip, NULL);