1 files changed, 88 insertions, 0 deletions
diff --git a/source/blender/blenkernel/intern/key.c b/source/blender/blenkernel/intern/key.c
index 2dc615c19f9..5cca948cd49 100644
--- a/source/blender/blenkernel/intern/key.c
+++ b/source/blender/blenkernel/intern/key.c
@@ -2055,3 +2055,91 @@ void BKE_key_convert_from_offset(Object *ob, KeyBlock *kb, float (*ofs)[3])
 		}
 	}
 }
+
+/* ==========================================================*/
+
+/** Move shape key from org_index to new_index. Safe, clamps index to valid range, updates reference keys,
+ * the object's active shape index, the 'frame' value in case of absolute keys, etc.
+ * Note indices are expected in real values (not 'fake' shapenr +1 ones).
+ *
+ * \param org_index if < 0, current object's active shape will be used as skey to move.
+ * \return true if something was done, else false.
+ */
+bool BKE_keyblock_move(Object *ob, int org_index, int new_index)
+{
+	Key *key = BKE_key_from_object(ob);
+	KeyBlock *kb;
+	const int act_index = ob->shapenr - 1;
+	const int totkey = key->totkey;
+	int i;
+	bool rev, in_range = false;
+
+	if (org_index < 0) {
+		org_index = act_index;
+	}
+
+	CLAMP(new_index, 0, key->totkey - 1);
+	CLAMP(org_index, 0, key->totkey - 1);
+
+	if (new_index == org_index) {
+		return false;
+	}
+
+	rev = ((new_index - org_index) < 0) ? true : false;
+
+	/* We swap 'org' element with its previous/next neighbor (depending on direction of the move) repeatedly,
+	 * until we reach final position.
+	 * This allows us to only loop on the list once! */
+	for (kb = (rev ? key->block.last : key->block.first), i = (rev ? totkey - 1 : 0);
+	     kb;
+	     kb = (rev ? kb->prev : kb->next), rev ? i-- : i++)
+	{
+		if (i == org_index) {
+			in_range = true;  /* Start list items swapping... */
+		}
+		else if (i == new_index) {
+			in_range = false;  /* End list items swapping. */
+		}
+
+		if (in_range) {
+			KeyBlock *other_kb = rev ? kb->prev : kb->next;
+
+			/* Swap with previous/next list item. */
+			BLI_swaplinks(&key->block, kb, other_kb);
+
+			/* Swap absolute positions. */
+			SWAP(float, kb->pos, other_kb->pos);
+
+			kb = other_kb;
+		}
+
+		/* Adjust relative indices, this has to be done on the whole list! */
+		if (kb->relative == org_index) {
+			kb->relative = new_index;
+		}
+		else if (kb->relative < org_index && kb->relative >= new_index) {
+			/* remove after, insert before this index */
+			kb->relative++;
+		}
+		else if (kb->relative > org_index && kb->relative <= new_index) {
+			/* remove before, insert after this index */
+			kb->relative--;
+		}
+	}
+
+	/* Need to update active shape number if it's affected, same principle as for relative indices above. */
+	if (org_index == act_index) {
+		ob->shapenr = new_index + 1;
+	}
+	else if (act_index < org_index && act_index >= new_index) {
+		ob->shapenr++;
+	}
+	else if (act_index > org_index && act_index <= new_index) {
+		ob->shapenr--;
+	}
+
+	/* First key is always refkey, matches interface and BKE_key_sort */
+	key->refkey = key->block.first;
+
+	return true;
+}