NLA SoC: More work on Meta-Strips

* Added several API functions for Meta-Strips editing. One of these (flush transform) still needs a few tweaks before it does its job well enough for all cases.

* Meta strips are now drawn with a purple-ish colour. The start/end points of the strips they encompass are shown with lines along the length of the strips, with lines starting from the top indicating start-points and lines starting from the bottom indicating end-points.

* Meta strips can be made (i.e. strips can be assigned to meta-strips) by selecting some strips and pressing Shift-G. 
Meta strips can be removed by selecting some meta-strips and pressing Alt-G.

* Strips can now be 'snapped' to start from: the current frame, the nearest frame, the nearest second, or the nearest marker; using the Shift-S hotkey. 
'Islands' of adjacent selected strips occurring in the same track are moved together as a single strip so that the start-point of the first strip is on the sepcified time, but all the relative lengths of strips stay the same. Internally, temporary meta-strips are created to facilitate this.

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/editors/space_nla/nla_intern.h b/source/blender/editors/space_nla/nla_intern.h
index 422686bb424..4391a019207 100644
--- a/source/blender/editors/space_nla/nla_intern.h
+++ b/source/blender/editors/space_nla/nla_intern.h
@@ -106,6 +106,9 @@ void NLA_OT_tweakmode_exit(wmOperatorType *ot);
 void NLA_OT_add_actionclip(wmOperatorType *ot);
 void NLA_OT_add_transition(wmOperatorType *ot);
 
+void NLA_OT_add_meta(wmOperatorType *ot);
+void NLA_OT_remove_meta(wmOperatorType *ot);
+
 void NLA_OT_duplicate(wmOperatorType *ot);
 void NLA_OT_delete(wmOperatorType *ot);
 void NLA_OT_split(wmOperatorType *ot);
@@ -116,6 +119,8 @@ void NLA_OT_move_down(wmOperatorType *ot);
 void NLA_OT_apply_scale(wmOperatorType *ot);
 void NLA_OT_clear_scale(wmOperatorType *ot);
 
+void NLA_OT_snap(wmOperatorType *ot);
+
 void NLA_OT_fmodifier_add(wmOperatorType *ot);