Implement grouped undo option for operators

This option makes an operator to not push a task to the undo stack if the previous stored elemen is the same operator or part of the same undo group.

The main usage is for animation, so you can change frames to inspect the
poses, and revert the previous pose without having to roll back tons of
"change frame" operator, or even see the undo stack full.

This complements rB13ee9b8e
Design with help by Sergey Sharybin.

Reviewers: sergey, mont29

Reviewed By: mont29, sergey

Subscribers: pyc0d3r, hjalti, Severin, lowercase, brecht, monio, aligorith, hadrien, jbakker

Differential Revision: https://developer.blender.org/D2330

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_blender_undo.h b/source/blender/blenkernel/BKE_blender_undo.h
index 9547eeb9838..84a6d07be7d 100644
--- a/source/blender/blenkernel/BKE_blender_undo.h
+++ b/source/blender/blenkernel/BKE_blender_undo.h
@@ -42,6 +42,7 @@ extern bool          BKE_undo_is_valid(const char *name);
 extern void          BKE_undo_reset(void);
 extern void          BKE_undo_number(struct bContext *C, int nr);
 extern const char   *BKE_undo_get_name(int nr, bool *r_active);
+extern const char   *BKE_undo_get_name_last(void);
 extern bool          BKE_undo_save_file(const char *filename);
 extern struct Main  *BKE_undo_get_main(struct Scene **r_scene);