Undo: unified undo system w/ linear history

- Use a single undo history for all operations.
- UndoType's are registered and poll the context to check if they
  should be used when performing an undo push.
- Mode switching is used to ensure the state is correct before
  undo data is restored.
- Some undo types accumulate changes (image & text editing)
  others store the state multiple times (with de-duplication).
  This is supported by checking UndoStack.mode `ACCUMULATE` / `STORE`.
- Each undo step stores ID datablocks they use with utilities to help
  manage restoring correct ID's.
  Needed since global undo is now mixed with other modes undo.
- Currently performs each undo step when going up/down history
  Previously this wasn't done, making history fail in some cases.
  This can be optimized to skip some combinations of undo steps.

grease-pencil is an exception which has not been updated
since it integrates undo into the draw-session.

See D3113

1 files changed, 3 insertions, 2 deletions

diff --git a/source/blender/editors/space_image/image_ops.c b/source/blender/editors/space_image/image_ops.c
index 9740a62d4f0..c1586964b1f 100644
--- a/source/blender/editors/space_image/image_ops.c
+++ b/source/blender/editors/space_image/image_ops.c
@@ -2658,8 +2658,9 @@ static int image_invert_exec(bContext *C, wmOperator *op)
 	if (ibuf->mipmap[0])
 		ibuf->userflags |= IB_MIPMAP_INVALID;
 
-	if (support_undo)
-		ED_undo_paint_push_end(UNDO_PAINT_IMAGE);
+	if (support_undo) {
+		ED_image_undo_push_end();
+	}
 
 	/* force GPU reupload, all image is invalid */
 	GPU_free_image(ima);