UI: Grease Pencil Modifier Drag and Drop, Layout Changes

This patch implements the list panel system D7490 for grease pencil
modifiers. It also moves their drawing to a callback in
GpencilModifierTypeInfo in line with the extensible architecture
refactoring goal T75724.

This also adds the "set_error" function for grease pencil modifiers,
which hadn't been copied from mesh modifiers yet.

The implementation is basically exactly the same as for the modifier
patch (9b099c86123fc82).

Thanks to Matias Mendiola (mendio) for providing mockups for many
of the layout changes.

Differential Revision: https://developer.blender.org/D7978

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/editors/object/object_intern.h b/source/blender/editors/object/object_intern.h
index 1cd91f7c1f3..8feeb3b6067 100644
--- a/source/blender/editors/object/object_intern.h
+++ b/source/blender/editors/object/object_intern.h
@@ -190,6 +190,7 @@ void OBJECT_OT_gpencil_modifier_add(struct wmOperatorType *ot);
 void OBJECT_OT_gpencil_modifier_remove(struct wmOperatorType *ot);
 void OBJECT_OT_gpencil_modifier_move_up(struct wmOperatorType *ot);
 void OBJECT_OT_gpencil_modifier_move_down(struct wmOperatorType *ot);
+void OBJECT_OT_gpencil_modifier_move_to_index(struct wmOperatorType *ot);
 void OBJECT_OT_gpencil_modifier_apply(struct wmOperatorType *ot);
 void OBJECT_OT_gpencil_modifier_copy(struct wmOperatorType *ot);